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Can anyone help me?? I've got an '89 QuadRacer,It had a re-sleeved .80 over cylinder when I got it,I did away with that and went with a Brand New cylinder,piston,rings,you get the idea..all new top end.To match the Brand New bottom end,It has a Hot Rod,New Crank,New Barnett Clutch, etc.The thing it does have that I haven't messed with yet is the carb,It's got a Keihin 38mm for Race use only carb.What I need help with is this....
Can someone Please help me with getting this thing to fire up like when it was Brand New??? I kick my butt off
trying to get it started and when it does run it runs boggy,then runs at high RPM'S,if I feather the throttle it runs but runs poorly!!! Can some PLEASE HELP???

 

Please confirm...is this a lt500r? If so this may help! The stock jetting for a keihin PJ 38mm is #168 main...#62 slow...48 DGJ needle and #6.0 throttle valve........Now this may not necesserally apply to your bike but may give you a rough idea. Also the CR 500 Honda motocross bike has a keihin PJ 38 as a stock carb with the following stock jetting...#170 main and #55 slow. On my 500r, I'm running #185 main and #58 slow. It runs a bit rich at low RPM and will change the slow jet to #55 for better results

 

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I'm sorry it's a 250,I also forgot to mention that it's got a coolhead on it I don't know what size or if that even matters.?I also forgot to mention it has a Boysen reed cage and spacer as well. FMF Fatty pipe and PowerCore Silencer,too.Will jetting the carb make the boy fire up alot easier?? Dumb question maybe but I can't kick anymore til my ankle feels better,{feels broke}!!

 

Have you done a leak down test? It's the most important thing after an engine rebuild. There is no reason it can't fire right up with only 2 or 3 kicks. An air leak will make the engine not want to idle down. Go here http://www.keihin-us.com/tune.htm to help jet your carb

 

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WOW !!!!!!!!!! I THANK YOU SOOOOOOOOOOO MUCH !!!!! I never knew that there was a website like that!!
Next question...how do I do a leak test???? I've never done one before, but than again I've never put a Top End together either til this quad! But I did do it Text style "step by step"! I'm very PROUD of myself and saved myself
$700.00!!!!!! For someone else to do it for me.I can't find the leak test in the manual so could you verify this for me?? So your saying that if there is this leak and I find it, this boy will fire up like new??After of course I correct the jetting.Or should it fire up even if the jetting is incorrect????Have patients......I'm learning.THANK YOU AGAIN!!

 

http://www.off-road.com/atv/qra/top_end3.html
http://www.off-road.com/atv/ptester.htm

Here are a couple of sites that might explain what a leak test is and how to do it yourself! An air leak can be do to a bad crank seal or bad gasket or a crack in the intake somewhere (intake boot was my problem) If the test passes, doesn't automaticaly mean that it will fire right up! You still need to get your jetting right. Jetting will be much easier if you're not fighting an air leak at the same time!! Start rich with your jetting and work your way down. There are 3 aspects of jetting...wide open throttle (WOT)...1/2 throttle ...and the slow circuit. You have to work with each idividually, doing 1 change at a time, getting it right then moving on to the next. Start with the main jet (WOT)....then the needle clip position...then the slow circuit. give me a shout any time for help.

good luck