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Idle mixture screw

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I have mine turned pretty much all the way out, this means I should rejet right? would this be a situation that would call for a leaner or richer jetting? also, which jets need to change? leak down jet? main?

:smashpc:

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BAM!!!:

https://thumpertalk.com/forum/showthread.php?t=20356&highlight=jetting+101+the+basics

This helped me out a ton, and I had never jetted before and I got mine nailed using this info.

this one kinda shows the overlap in all the circuits:

http://www.thumperfaq.com/jetting.htm

I studied the shit out of both of these before I started jetting and it made it sooo much easier. I'm still no expert but I have the understanding and I was able to nail the jetting with just a few small tweaks.

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uggh. procrastinated all winter, to the point I forgot about the starting issue. went out to start practicing for the upcoming race in april and it wont even start now. so ive heard valve clearances or pilot circuit could be to blame...

it'll start with starting fluid and the battery hooked up to a power source (jumpered to my car) with the throttle cracked just past the point of actual engagement... so im definitely thinking must be pilot circuit. ive played around with idle speed and air mixture screws but nothing allows it to start on it's own. also unplugged the headlight so that the battery won't have extra drain on it while starting.

Edited by Hatchet

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uggh. procrastinated all winter, to the point I forgot about the starting issue. went out to start practicing for the upcoming race in april and it wont even start now. so ive heard valve clearances or pilot circuit could be to blame...

it'll start with starting fluid and the battery hooked up to a power source (jumpered to my car) with the throttle cracked just past the point of actual engagement... so im definitely thinking must be pilot circuit. ive played around with idle speed and air mixture screws but nothing allows it to start on it's own. also unplugged the headlight so that the battery won't have extra drain on it while starting.

If it sat that long with gas in the carb I would pull the carb and clean it really good. The gas we get out of the pumps these days doesnt like to sit around for very long in a carb without guming things up. If it ran fine before you parked it I highly doubt its the valves. :bonk:

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I venture that the pilot jet was already startign to clog, requiring the fuel screw to be so far opened. I suggest buy a new pilot after you clean out the carb. The holes in the oilot jet are so small, it is very difficult to get them completely clean.

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thanks for the suggestions guys, I kept it running thru the winter either push starting or starting fluid and jumpstarts, always turn fuel off and drain carb when it sits..

it's an 05 and the bike's owner (I just ride it at races🤣 ) informed me it has never had a valve check. we checked em and the exhaust was .15mm on both, just a lil tight so they went down a shim size to make their clearance .22

the intakes, however... there was no clearance so we went down a shim size on all 3, still no clearance, had to go down another whole shim size - they were waaay outta spec. therefore the valves were stuck open, which makes sense why it was so damn hard to start.

it starts if you just look at the E button now :bonk:

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well damn.

took it out for its first ride in 7 years with properly adjusted valves - no midrange whatsoever. falls on it's face right after the throttle position passes the pilot circuit. I suppose the carb has been adjusted to work with the stuck open valves, so now I gotta get the carb right. it runs fine on startup and up to a certain point on the throttle then it hesitates and sputters and backfires a lil until you get it past midrange and into WFO area, then it cleans up and screams. so im assuming this is now a needle/needle jet issue.

here we go

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