Hi Guys,
1. Had lots of trouble getting '72 175 to start.
2. put bigger Pilot Jet in, and it starts right up.
3. after about half-throttle, engine resists revving higher, and will bog slightly.
4. If I twist throttle aggressively and quickly, engine bogs, labors, and eventually clears.
5. Randomly, while riding along the trail, the engine will begin revving aggressively on its own, a situation I can control only by a) upshifting, b) activating rear brake, or c) if I'm stationary, hitting the kill switch.
6. gas leaks out of bowl and collects on top of the crankcase.
7. climate temperature about 55 degrees.
Am I now running too rich? Is air sneaking in somewhere?
Did increasing Pilot Jet now necessitate that I drop the throttle needle?
???
Larry Seale
I choose to ride
Hi Larry, I had that problem with my 250 and I belive that possibly you might have acouple of things going on.I might be able to help with the reving of the engine.Have you taken the tank off lately? Can the throttle cable be hanging up? Have you replaced the cable?I bought one from Al that has a adjustment in the cable itself.I had to adjust here also.I hope this helps because I KNOW YOUR PAIN WELL!!!:)
Thomas Carmichael
1970 125 Six Day
1976 250 Hare Scrambler
Sounds like possibly a significant air leak? Seal behind the Mag or leak along the intake tract? That would jibe with the larger pilot helping the starting and increased rev for no reason, although usually the symptom is more like rev run-on after you blip the throttle on-off while in neutral.
A good test is to pull the Mag cover, get it running at low RPMs, then spray WD40 or some other solvent in behind the Mag and along intake tract, will be a noticable change in RPMs if it's sucking air.
Larry,
I agree with Big Mac that it sounds like you could possibly have an intake leak. Sound like it's lean at top end now also which isn't affected by the needle clip position. Did you install a larger main jet at the same time as the pilot ?? Thought I remember you telling me about putting a large o-ring between the carb and intake ?? I have a new crank seal for behind the magneto if you want to try replacing it. Let me know. Talk to you later.
Dave McCullough
Hi Dave,
I took the carb off in order to get the pipe off a month ago. I suspect when I put the pipe back on Thursday (in a hurry) that the o-ring in the carb throat fell out. I'll tackle that next week and put o-ring back in, then test it. If problem still persists, I'll try the seal behind the mag.
It's a brand new carb - why would it be leaking so much gas down onto the top of the crankcase?
Larry Seale
I choose to ride
Larry,
The fuel on top of the crankcase sounds like it's coming out the overflow for some reason. A couple things come to mind which might cause the fuel leaking. First would be too high a float level. Another could be a piece of dirt or something getting lodged in the float needle and not allowing it to close fully. Do you have an inline fuel filter ?? Is the fuel line in good shape and not deteriorated on the inside ?? Just had a fuel line issue with a Honda that I was working on for someone. That bike had a black rubber hose on it that looked fine on the outside but was no good internally. The bike ran great at times and other times would spew fuel out the overflow. Had that carb on and off several times before figuring out that small pieces from the inside of the fuel line were breaking loose and getting lodged in the float needle. Changed the line and put a good inline filter on that bike and solved the problem. Talk to you later.
Dave
Wildman posted this awhile back and maybe it will help in this case.
Posted - 02/16/2006 : 09:46:34 AM
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Check for the little spring do-hickey that connects the float needle and the float. Sometimes the float needle will hang up at the down position. Also check the float arm where the needle hits for a divot worn into the brass. It will make the end of the float needle jam slightly. A little creative fileing might help. Wildman
thanks for the tips, guys! I'm swamped this week, but I'll tackle this issue next week.
Larry Seale
I choose to ride
Larry, any progress?
Rod Whitman
1972 Six Day (Rider)
1972 Six Day (Project)
Hi Rod,
I've been finishing up a master's class paper, and my daughter's senior year varsity softball season started this past week, so I haven't spent any time on the Jackpiner, yet, I'm sorry to say. But I did get a couple of gasket/o-ring possibilities to try in the manifold (carb end). I'm going riding for the day (on the KTM 200 xcw) tomorrow at Stillwater Motorcycle Park - haven't been there since August (104 degrees that day) so it should be mucho smiles this time around.
My wife's out of town this coming Wed thru Sat, so I may have some evenings to focus on this Jackpiner carb. I'll keep you posted.
I did get the longer chain put on the '74 6day, and that bike is finished and as beautiful as the new Miss America (from Tulsa, thank you very much!). I put a 60 tooth sprocket on the rear (replacing a 57), so as much as I don't want to get it dirty, I'm gonna have to take it out soon and see how it runs.
Larry Seale
I choose to ride