89 TW200 yamaha trailway. Barn fresh with 700 miles on it.
So far: new petcock, cleaned gas tank, new air filter, new spark plug. Fresh oil.
Carb: cleaned, roughly 5 times, new needle valve & seat, float level verified, cleaned emulsion tube & new o-ring, cleared jets, air fuel mix screw out 2.5 from seat. Honestly, I would eat off this carb. It's that clean.
I'm stuck. Starts/runs on full choke. Warms up, runs clean, less and less choke... Push the choke in completely.... dies. Hold throttle open a touch, no choke, runs fine. WILL NOT IDLE on it's own. The obvious answer is to crank the idle screw up but that ends up being quite a bit. Plus, I like to have things done right.
My thought is pilot jet or the passage it follows. Correct me if i'm wrong. The choke, main jet (for throttle), and pilot jet (for idle), all draw gas separately from the carb bowl. Right? Can pilot jets wear out? I'm sure it's clean. I just checked.
I need a few of you gurus to help. I need a full list of things to check, start to finish. It's getting spark cause it runs on choke. No misfires or smoke or backfire. But I'm at a standstill. I don't even know what the next step is.
spray carb cleaner or wd40 around the carb while its running and if it revs up there is a air leak... which might explain the running with the choke on....
The symptom you describe is caused by a clogged pilot jet.
You need to remove your pilot jet (slow jet) from the carb body to clean it. This is a very small jet and is very hard to clean. Sometimes they look clean, but aren't. Sometimes it's just easier to replace it with a new one. It's #11 in the picture.
I once bought a 6 month old DRZ350E from my old neighbor Ken Rogers of Dynatek ignition fame for $1200.00 because it was hard to start and he couldn't get it to idle except when it was being full choked. I knew it had been sitting for about 4 of those months, so I told him what the problem was and what to do. Well, I guess he didnt believe me and he just kept goin' down the road he was goin'. The next day I asked him if he got it running and in a very upset manner he said that the first person with $1200.00 could have it!
I pulled the money out of petty cash and bought the bike. 45 minutes later I was doing wheelies in front of our shops. He was stunned! He asked what I had done. I said; raised the float height 3mm and replaced the pilot jet (I had one in my jet box) with a new one just like I told you yesterday. He was so pissed off he went and bought a new XR400 just to make himself feel better.
Except for at idle, does the engine run well? I'm with Barton - check for leaks at the manifold or the boot from the airbox to the carb
Just hope its not the crankshaft seals
If your bike runs well in the rest of the range, I'd pretend I had a chopper and rev it at lights..............yeah, I know, you want it right.
No the TW is still not running. Progress has been slow on it for the past week or two. I've been pretty busy with random things. Tomorrow or Tuesday I will check for air leaks.
Hasbeenracer: The pilot jet was my first thought also. I have cleaned it, 3 times, and it shines now. But for a $20 part you're probably right to just replace it. I'm gunna order one tomorrow. The last progress was another cleaning paying special attention to the path from the pilot jet.
Crankshaft seals I'm assuming only apply to 2 stroke?
EDIT: I forgot to add. I have a corroded air/fuel mixture screw o-ring. I was stripping the carb down and the o-ring crumbled in my hand. That also may be giving me trouble.
EDIT: I forgot to add. I have a corroded air/fuel mixture screw o-ring. I was stripping the carb down and the o-ring crumbled in my hand. That also may be giving me trouble.
I was going to ask you about that. That would for sure cause an air leak that would cause the problem you're having. It's drawing vacume past the fuel screw before it can draw gas through the pilot jet.
Did you soak the carb or just do an external cleaning?
Sounds like one of the passages needs some attention, and if the pilot (slow) jet is not perfect, it's not go to run right when you gas it. I almost always go up a size on the slow jet, and raise the needle a small washer or two - but that is getting off track.
What does the plug look like?
And I've seen more than a few machines that will not idle when warm if the valves are too tight - with those few mile, I doubt that is the problem, sounds carb related to me.
Good luck
Oh - and you did drain the tank and put in all new fuel?
Also, you might verify fuel flow from the petcock.
UJM, I did not soak the carb, i used carb cleaner and an air compressor. What should I soak it in? And i'm assuming i'd have to break everything down and just soak the carb body right?
As far as the rest here's what I have so far:
Runs on choke, or throttle, won't idle. New gas, plug, float valve and seat, air/fuel ratio screw & o-ring, new pilot jet, no air leaks that i could tell with WD40. Ratio screw out 2, 2.5,3 turns.
The plug looks darker and darker every time i pull it. I do think it's still a carb issue and there are quite a few very small passages that could have anything stuck in them.
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