Shock/suspension questions - Wrist Twisters
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post #1 of 62 Old 03-05-2015, 11:49 PM Thread Starter
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Shock/suspension questions

Hi,

I have a 2003 919 and looking for cheap alternatives to the rock hard rear shock--will the cbr600 or cbr1000 rear shocks be an improvement? I see these on ebay for less than $150 (which is about my budget). Any real-world reports from people who have tried this?

Also, what is the deal with the front forks--they also feel hard as a rock. I weight 180, and have 0.90 kg/mm spring in my cx500, and that bike is correctly sprung. So what is the stock spring rate on my 919? Is there any improvement going to aftermarket linear (or progressive) springs? Or does it just need the shim stack adjusted? I've only had older damper rod bikes until the 919 (so I have no clue what I'm talking about)

Sorry if this treading a well-worn path, my searches have not found good info...

Thanks,

-Alan

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post #2 of 62 Old 03-06-2015, 05:59 AM
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IIRC, the adjustable suspension didn't come about until 04. I swapped the later adjustable suspension (front and rear) on to my 02.

Like you, the bike beat me to death until I changed over to the later suspension. (I weigh 165)

Take a look on eBay and ask here for the later parts. You can sell your parts (some people prefer them) to balance out any costs.

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post #3 of 62 Old 03-06-2015, 07:12 AM
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I weight about the same as you and I find the stock suspension on my 02 (same as your 03) fine with all the preload taken out of the rear. The rear spring is stiff and the front springs are soft, progressive springs so unless yours have been changed out I'd be surprised if they were hard. Maybe they need a cleaning and fresh oil?

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post #4 of 62 Old 03-06-2015, 07:34 AM
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The 600f3 shock, which is on my brother's bike, causes his tail to sit lower than mine and Clorox's when you line them up.
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post #5 of 62 Old 03-06-2015, 08:11 AM
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Here we go again....

Paging LDH....

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post #6 of 62 Old 03-06-2015, 08:29 AM
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$919 for an Ohlins is a great price but he said his budget was 150. At that price range you'll spend your days for the next few months praying, searching, and hoping for a deal to come. When it does someone will out bid you.
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post #7 of 62 Old 03-06-2015, 08:53 AM Thread Starter
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Thanks for the replies. I will check my preload.

Quote:
Originally Posted by Wolf View Post
The 600f3 shock, which is on my brother's bike, causes his tail to sit lower than mine and Clorox's when you line them up.
How is the 600f3 shock as far as ride quality? Does it have rebound and dampening adjustments?

I have won some great deals on ebay using auctionsniper.com, try it out, they charge just a few bucks, usually...

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post #8 of 62 Old 03-06-2015, 10:01 AM Thread Starter
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I went out this morning and checked the preload on my rear shock. I think I was at least 30 lbs heavier than the previous owner, so I figured he would have tried to adjust it... I was wrong. It was set to two clicks from max preload. I was able to adjust it with some big pliers to min preload and yeah, it's a definite improvement.

So I would not be surprised if the fork oil has never been changed. Will try that first...

Thanks!

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post #9 of 62 Old 03-06-2015, 11:31 AM
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Not much you can do with the shock apart from making sure your spring rate is correct. Measure your sags properly. My guess is the stock 850ish lb rear spring is to light. Harshness you are feeling is the shock speeds being to high for the valving so the shock cant flow. Im 200lb and ran a 1000lb spring but I should have been 1100lb for street.

Same will be the case for the fork.

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post #10 of 62 Old 03-07-2015, 12:46 PM Thread Starter
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So I've read here that the front fork is soft, but it seems 'hard' to me. I measured my sag at 25mm, but the entire travel (using zip-ties and bouncing the bike as hard as I could) was 75mm (3")--that sounds small to me, it is definitely an inch less than any other bike I've owned.

Also under hard braking I don't feel the bike dive that much, so maybe I work through whatever travel I have quickly. I have not completely unloaded the front end to see the true travel, maybe an inch of travel is being taken up by just the weight of the bike? Or maybe the fork oil level is too high?

But also, I get the sense it does not absorb small bumps well and is not moving quickly enough to respond to small bumps. So will this be addressed by taking it in to be tuned? The fork oil may be in extremely bad shape, but I live near Catalyst Reactions, which has a great reputation for race tuning bikes, so thinking of just pulling the tubes and letting them take care of it. I also need fork seals... thoughts?

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post #11 of 62 Old 03-07-2015, 01:00 PM
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Quote:
Originally Posted by Manzanita View Post
So I've read here that the front fork is soft, but it seems 'hard' to me. I measured my sag at 25mm, but the entire travel (using zip-ties and bouncing the bike as hard as I could) was 75mm (3")--that sounds small to me, it is definitely an inch less than any other bike I've owned.

Also under hard braking I don't feel the bike dive that much, so maybe I work through whatever travel I have quickly. I have not completely unloaded the front end to see the true travel, maybe an inch of travel is being taken up by just the weight of the bike? Or maybe the fork oil level is too high?

But also, I get the sense it does not absorb small bumps well and is not moving quickly enough to respond to small bumps. So will this be addressed by taking it in to be tuned? The fork oil may be in extremely bad shape, but I live near Catalyst Reactions, which has a great reputation for race tuning bikes, so thinking of just pulling the tubes and letting them take care of it. I also need fork seals... thoughts?
Yea, its a fault of restrictive piston and low spring rate. It will hammer you.

I had Dave from Catalyst Reactions go over my bike last week. Great people. They will sort it for you.

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post #12 of 62 Old 05-09-2015, 11:12 AM Thread Starter
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Okay, an update. New 0.9 springs in front, rebuilt by Catalyst Reaction. He did not change the valving, and thought it felt okay. Did some windy roads after work and although the front is an improvement, the bike just does not feel right. Hard to put my finger on it. But both my cx500 and my new Zero just feel easier to ride, and I feel I can ride faster, easier on those bikes.

I just increased my sag (cut the spacer), lowered the front tubes on the triple tree by 20mm, and got rid of the handlebar risers this morning... just experimenting...

A somewhat separate question: would a power commander help with smoother throttle roll on, or is this just my crappy technique? I suppose if I hit at the right entry speed I could get on the throttle sooner, but yeah, cracking open the throttle to just get maintenance throttle through a turn feels like I'm upsetting the suspension. The 919 is the most powerful bike I've ridden so maybe that's part of the deal?

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post #13 of 62 Old 05-09-2015, 01:05 PM
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You're half way there with the front done. Save your $$ and invest in an aftermarket shock, I have the Ohlins and it transformed the 919. As for the PC, the throttle control you'll gain is well worth it IMO.

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post #14 of 62 Old 05-09-2015, 03:06 PM
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PC helps smooth out the on/off transition but it's still there. I think it's exaggerated because you go from off with engine braking to on/maintenance (depending on rpm). I've just learned to keep on the throttle.

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post #15 of 62 Old 05-09-2015, 03:59 PM Thread Starter
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Thanks for the replies. One more thing to buy... if I don't just give up and sell the bike. I need to ride it some more and maybe do a trackday before throwing more money into it...

Yeah, I spent a few hours reading old threads here on rear shock options. The el-cheapo option of my choice seems to be buying an ebay f3 shock ($60) and having it rebuilt by Catalyst Reaction ($175 labor + parts).

I actually made a $400 offer on a Ohlin F4i shock on ebay, and the seller came back with a counter-offer of $500 (there was a thread here saying that this shock will fit, but is a tad longer). Although this would have to be setup/rebuilt also (right?), so that is another $175.

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post #16 of 62 Old 05-12-2015, 11:58 AM
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I have an 07 so not much help with your suspension. I haven't used a PC but just working on controlling the throttle can make a big difference, also taking out any play in the throttle really helps because you at least get a consistent response for your input; and reduce wrist fatigue IMHO. give that a shot, and when you get back on it in a turn, think "ggennnnttlllee". it's really satisfying when you get it all right.
**
just want to add. i've been bouncing around like a bouncy ball on my niner for quite a while. Finally started fiddling with the front end and it's making a big difference. the rear shock has been a pain to adjust but messing with the damping has helped some.
there are probably better riding bikes out there, but i like this one pretty much.
good luck

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post #17 of 62 Old 05-12-2015, 03:01 PM
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Quote:
Originally Posted by Manzanita View Post
Okay, an update. New 0.9 springs in front, rebuilt by Catalyst Reaction. He did not change the valving, and thought it felt okay. Did some windy roads after work and although the front is an improvement, the bike just does not feel right. Hard to put my finger on it. But both my cx500 and my new Zero just feel easier to ride, and I feel I can ride faster, easier on those bikes.

I just increased my sag (cut the spacer), lowered the front tubes on the triple tree by 20mm, and got rid of the handlebar risers this morning... just experimenting...

A somewhat separate question: would a power commander help with smoother throttle roll on, or is this just my crappy technique? I suppose if I hit at the right entry speed I could get on the throttle sooner, but yeah, cracking open the throttle to just get maintenance throttle through a turn feels like I'm upsetting the suspension. The 919 is the most powerful bike I've ridden so maybe that's part of the deal?
A 20 mm tube raising in the clamps is a mega one step drop of the front.
The 919 is a nominal 26 degree steering head angle bike, drops that sacrifice trail to get it towards a 23 degree bike is not an ideal approach.
0.90s in a 919 should have a starting point installed preload of 15 mm, 10 mm being a minimal amount.
If you cut a whack off and still have some installed preload, they began with too much installed preload.
What oil grade went in ? Nominal stock viscosity ?
I'd stay at nominal stock viscosity on stock valving.

There's many good threads on this site covering suspension in general, plus front ends and shocks.

Good luck with it all.

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post #18 of 62 Old 05-12-2015, 06:04 PM Thread Starter
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Oh, yes, this was with 5 weight oil (Maxima). That was my call, given that racetech recommends this with gold valves and the comments here that the valving is restrictive.

Right now with all my changes it's definitely better--although the small bump absorption is still not ideal, increasing the sag seems to have put the travel in a region where the shock is moving and responding to smaller bumps. Before I increased the sag, it still seemed like the fork was not moving.

The thought was that the new stiffer springs will have reduced my sag, as so the rake similar to what it was before, I could lower the fork tubes some. I knew 20mm was a big leap, I'm going up to maybe 12mm, although I was not feeling any instability. But yes, with both the increased sag and lowering the fork tubes, the net effect is the rake is reduced from the previous OEM setup. I have done this experiment on other bikes and have had it lead to some instability under certain conditions (accelerating over bumps).

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post #19 of 62 Old 05-13-2015, 04:12 PM
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Quote:
Originally Posted by Manzanita View Post
Oh, yes, this was with 5 weight oil (Maxima). That was my call, given that racetech recommends this with gold valves and the comments here that the valving is restrictive.

Right now with all my changes it's definitely better--although the small bump absorption is still not ideal, increasing the sag seems to have put the travel in a region where the shock is moving and responding to smaller bumps. Before I increased the sag, it still seemed like the fork was not moving.

The thought was that the new stiffer springs will have reduced my sag, as so the rake similar to what it was before, I could lower the fork tubes some. I knew 20mm was a big leap, I'm going up to maybe 12mm, although I was not feeling any instability. But yes, with both the increased sag and lowering the fork tubes, the net effect is the rake is reduced from the previous OEM setup. I have done this experiment on other bikes and have had it lead to some instability under certain conditions (accelerating over bumps).
I did an experiment with Racetech US-1 2.5/5 in stock 05 forks fittted with 0.90s and 15 mm internal preload.
They were pogo sticks.
Drained them and put in 10W Maxima and was fine.
5 sounds light to me.

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post #20 of 62 Old 05-13-2015, 05:48 PM Thread Starter
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That's strange. When you say 'they were pogo sticks' you mean there wasn't enough dampening, I assume. I still feel like the fork isn't responding to small bumps enough, so maybe it is a different in the model year or my particular fork... I do have a 0.90 spring in my cx500 and it weighs about the same and has 7.5W oil, and absorbs small bumps better. And as another reference, I rode my Zero in today, and man, do I appreciate the suspension on that bike now; it's dialed up to be really stable, but still absorbs the bumps.

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post #21 of 62 Old 05-14-2015, 07:55 AM
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Quote:
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That's strange. When you say 'they were pogo sticks' you mean there wasn't enough dampening, I assume. I still feel like the fork isn't responding to small bumps enough, so maybe it is a different in the model year or my particular fork... I do have a 0.90 spring in my cx500 and it weighs about the same and has 7.5W oil, and absorbs small bumps better. And as another reference, I rode my Zero in today, and man, do I appreciate the suspension on that bike now; it's dialed up to be really stable, but still absorbs the bumps.
Correct, pogo = lack of damping.
Lighter oil reduces damping force.
Stiffer springs increases required rebound damping force and reduces required compression damping force.
919 forks are super stiction design, so are not very compliant on initial bump.
Fork seals are an element, they are too good, make sure they are greased between the lips.
Check to make sure the front end build up is nice and square, to minimize binding.
Assumed is that all involved parts are straight.

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post #22 of 62 Old 05-14-2015, 09:46 AM
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What would you recommend for grease on the seals? I'm currently rebuilding mine.

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post #23 of 62 Old 05-14-2015, 12:16 PM
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What would you recommend for grease on the seals? I'm currently rebuilding mine.
Racetech Super Slick Seal Grease or similar.

Also.
Mirror finish tube polishing is not ideal on stock sealed 919s.
The seals are so good, the tubes run on the dry side.
Some grease between the lips, and a wee bit of cross hatch, barely detectable is the way to go.

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post #24 of 62 Old 05-14-2015, 01:25 PM Thread Starter
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I will try greasing the seals/tubes.

I did try adjusting the alignment of the fork tubes after installing them and got a tiny bit of improvement (the FSM does say to bounce the front end before tightening the pinch bolts on the axle).

Thanks!

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post #25 of 62 Old 05-14-2015, 09:00 PM
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Quote:
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Racetech Super Slick Seal Grease or similar.

Also.
Mirror finish tube polishing is not ideal on stock sealed 919s.
The seals are so good, the tubes run on the dry side.
Some grease between the lips, and a wee bit of cross hatch, barely detectable is the way to go.
Good to know. I don't have access to racetech super slick seal grease. what would be similar that is readily off the shelf locally?

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post #26 of 62 Old 05-15-2015, 07:58 AM Thread Starter
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Bouncing the front end with the top seal up on the tubes so they are not affecting movement, the forks can definitely move easier. Now it feels awesome, can't wait to try it out. I was out of ideas, so thanks for the input!

However, the synthetic grease I tried seems to be too thick, will buy the racetech on amazon.

@Pvster, it seems like this could be applied after the fork is assembled if it is the top seal that is causing most of the stiction. You could unweight the front end and get it down there.

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post #27 of 62 Old 05-15-2015, 11:55 AM
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Quote:
Originally Posted by mcromo44 View Post
Correct, pogo = lack of damping.
Lighter oil reduces damping force.
Stiffer springs increases required rebound damping force and reduces required compression damping force.
919 forks are super stiction design, so are not very compliant on initial bump.
Fork seals are an element, they are too good, make sure they are greased between the lips.
Check to make sure the front end build up is nice and square, to minimize binding.
Assumed is that all involved parts are straight.
Which is why 5w is a good thing. If you are going to stick with the stock comp piston you will get help by running 5w then beefing up the rebound stack and modding the rebound adjuster rod. A 1mm hole in the outlet side of the comp piston or stuntion will help the comp a lot to.

Seals need to be greased regularly, I do mine every 2 months.

No they are not a stiction design, they are not maintained correctly. This same fork is common to many bikes models and brands. My Bandit 1200 has exactly the same fork internally.

On an interesting side note. On a Bandit 1200, if you cut the tightly wound part on the stock spring you end up with a spring with the same wire size and coil distance as a Racetech .95. Free .95s anybody?

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post #28 of 62 Old 05-15-2015, 12:26 PM
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Which is why 5w is a good thing. If you are going to stick with the stock comp piston you will get help by running 5w then beefing up the rebound stack and modding the rebound adjuster rod. A 1mm hole in the outlet side of the comp piston or stuntion will help the comp a lot to.

Seals need to be greased regularly, I do mine every 2 months.

No they are not a stiction design, they are not maintained correctly. This same fork is common to many bikes models and brands. My Bandit 1200 has exactly the same fork internally.

On an interesting side note. On a Bandit 1200, if you cut the tightly wound part on the stock spring you end up with a spring with the same wire size and coil distance as a Racetech .95. Free .95s anybody?
For a stock cartridge, increased spring rate mean going light on oil is the wrong move as damping force is reduced while more is needed, as motorcycles are dominantly rebound controlled.

Do whatever you want to a 919 and you'll still never replicate the +/- range of a good modern era fork when doing sag checks, especially on compression.

Carefully done in every way, they get better, modified internally they get even better, but no matter what you do, they can' be great.
Good enough, yes.

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post #29 of 62 Old 05-15-2015, 08:59 PM
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Quote:
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For a stock cartridge, increased spring rate mean going light on oil is the wrong move as damping force is reduced while more is needed, as motorcycles are dominantly rebound controlled.

Do whatever you want to a 919 and you'll still never replicate the +/- range of a good modern era fork when doing sag checks, especially on compression.

Carefully done in every way, they get better, modified internally they get even better, but no matter what you do, they can' be great.
Good enough, yes.
Which is why you change the rebound stack. Pointless putting a USD etc fork on a steel framed bike.

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post #30 of 62 Old 05-15-2015, 09:49 PM
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Which is why you change the rebound stack. Pointless putting a USD etc fork on a steel framed bike.
don't follow the connection on those two statements. What not to like about USD setup? Stiffer, more stable, less stiction and the most of all.... LOOK AWESOME

my 2c regarding steel frames:
Based on some designs by MotoGP developers, steel frame is more forgiving to not so perfect suspension setup .... it has an ability to "to absorb some of the energy not damped by the bike’s suspension and release it in a relatively gradual manner compared to an aluminum-framed bike"

That plus some home brew USD setup....perfect for do it all bike IMHO.

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post #31 of 62 Old 05-15-2015, 11:25 PM
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don't follow the connection on those two statements. What not to like about USD setup? Stiffer, more stable, less stiction and the most of all.... LOOK AWESOME

my 2c regarding steel frames:
Based on some designs by MotoGP developers, steel frame is more forgiving to not so perfect suspension setup .... it has an ability to "to absorb some of the energy not damped by the bike’s suspension and release it in a relatively gradual manner compared to an aluminum-framed bike"

That plus some home brew USD setup....perfect for do it all bike IMHO.
Ok, my 2c on steel frames. Steel frames can be made to flex however you want. EG a Cro-moly frame on a Superduke will be made to flex to suit the suspension package. A 919 which is as far as I know mild steel and designed around its original suspension package is not designed for a USD fork. Take a look at the front engine mounts on a 919.

I would have the same problem if I fitted a USD fork to my Hawk which has an alloy frame.

Im restarting the build of my partners CBR600 F2. Again no point fitting USDs on that as its a steel frame.

On an side note we are fitting a pneumatic seat that will inflate once the bike gets up to 5kph.....

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post #32 of 62 Old 05-16-2015, 07:19 AM
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Ok, my 2c on steel frames. Steel frames can be made to flex however you want. EG a Cro-moly frame on a Superduke will be made to flex to suit the suspension package. A 919 which is as far as I know mild steel and designed around its original suspension package is not designed for a USD fork. Take a look at the front engine mounts on a 919.

I would have the same problem if I fitted a USD fork to my Hawk which has an alloy frame.

Im restarting the build of my partners CBR600 F2. Again no point fitting USDs on that as its a steel frame.

On an side note we are fitting a pneumatic seat that will inflate once the bike gets up to 5kph.....
There is no engineering principle to preclude the successful and advantageous application of USD forks on steel framed bikes.

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post #33 of 62 Old 05-16-2015, 08:18 AM
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There is no engineering principle to preclude the successful and advantageous application of USD forks on steel framed bikes.
Exactly. This motogp marvel is the proof.

Attachment 105857

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post #34 of 62 Old 05-16-2015, 09:04 AM
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Quote:
Originally Posted by NZspokes View Post

Ok, my 2c on steel frames. Steel frames can be made to flex however you want. EG a Cro-moly frame on a Superduke will be made to flex to suit the suspension package. A 919 which is as far as I know mild steel and designed around its original suspension package is not designed for a USD fork. Take a look at the front engine mounts on a 919.

I would have the same problem if I fitted a USD fork to my Hawk which has an alloy frame.

Im restarting the build of my partners CBR600 F2. Again no point fitting USDs on that as its a steel frame.

On an side note we are fitting a pneumatic seat that will inflate once the bike gets up to 5kph.....
I don't think 919 was designed around its suspension package as you said. I think 919 suspension was designed on one simple principle "what do we have on the shelf to install while keeping the cost to the min"

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post #35 of 62 Old 05-16-2015, 11:23 AM
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I don't think 919 was designed around its suspension package as you said. I think 919 suspension was designed on one simple principle "what do we have on the shelf to install while keeping the cost to the min"
Well nailed.

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post #36 of 62 Old 05-16-2015, 11:50 AM
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There is no engineering principle to preclude the successful and advantageous application of USD forks on steel framed bikes.
If you read what I wrote you would see I didnt say that you couldnt run USD forks on a steel frame. They just need to be designed for it.

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post #37 of 62 Old 05-16-2015, 11:53 AM
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I don't think 919 was designed around its suspension package as you said. I think 919 suspension was designed on one simple principle "what do we have on the shelf to install while keeping the cost to the min"
So if you think that then by extension, why would they have put any thoughts into the design of the frame?

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post #38 of 62 Old 05-16-2015, 12:44 PM
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The 919 has the best suspension of any street bike I have ever owned

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post #39 of 62 Old 05-16-2015, 01:00 PM
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Originally Posted by NZspokes View Post
So if you think that then by extension, why would they have put any thoughts into the design of the frame?
they didn't put any thought into 919 frame design.

Poisoned by domestic success of CB250 and later world success of 599, they followed suit only to put 919 engine into it.
CBR250 into CB250, CBR600 into 599, CBR900 into CB900.
It was a brilliant marketing idea while keeping production and development cost down (Thank you Ducati).
"Suspension? No problem .. what is left in that Showa parts bin?"

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post #40 of 62 Old 05-16-2015, 01:44 PM
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BTW, honda is not the only one. For example Ducati and Aprilia are doing the same, using whatever suspension showas had sitting on the shelf. Same with production Ohlins for that matter. SBK Ohlins valve kits for Ducati Ohlins forks work just as good in Aprilia or RC51 Ohlins. FG series Ohlins forks are designed the same for RC51, Aprilia, Ducati etc etc (obviously different length, caliper clamps and a few minor differences) I don't think they were concentrating on the frame design while designing the suspension.

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