pete250 Posted September 21, 2004 Report Share Posted September 21, 2004 I've got a 1997 250 techno that will only pick up when the pilot screw is adusted to about a quarter of a turn out. Off the pilot everything ok. Checked carb and it has 30 pilot. Looking at previous postings it would seem that the pilot should be adjusted to about 11/4 turns but if I do this then it just runs flat off the bottom end . Any suggestions? Quote Link to comment Share on other sites More sharing options...
clarkp Posted September 22, 2004 Report Share Posted September 22, 2004 Give us a little history... has it been like this all along and running OK, did you just try a new pilot and now it runs different / better / worse...? The obvious would be to suggest using compressed air to clean out all the orifices (orifiae?) BUT - shoot for crisp response right off idle with the 'air screw'. When you whack the throttle open off idle you should have instant response, no bogging and, on the other extreme, you don't want it taking a prolonged time to re-attain idle. If you don't have instant repsonse, keep trying with 1/4 turn adjustments of the air screw until you get the hit you're looking for. Or to paraphrase from the Mikuni manual, (pdf pg. 14-15, document pg. 10-11): Warm up the engine and adjust the throttle stop screw such that the engine is idling about 10-20% higher than the throttle position you're trying to help (usually just off idle for a trials bike). Adjust the air screw left and right by 1/4 to 1/2 turn at a time until you get max rpms. Now re-adjust the throttle stop screw to get back to your normal target idle speed. Now, again, adjust the air screw left and right until you get max rpms. If 1-1/4 turns out and 2 turns out (for example) both give the same rpm, always choose the fewer turns out (1-1/4 is better than 2). In the end, always shoot for what give crisp response right off idle and no prolonged return to idle. If none of this works, trade it in on a fuel injected 4-stroke Montesa... and buy a laptop to tune it with. Quote Link to comment Share on other sites More sharing options...
pete250 Posted September 22, 2004 Author Report Share Posted September 22, 2004 Thanks for that. Yes had bike for about 8 months everything ok until recently when bottom end was fluffing up once warmed up. Went to adjust pilot and found that the only way I could improve the running was to turn the pilot right in. Since then the bike wont run with the pilot turned out more than a fraction of a turn. I have not done anything different to the bike ie fuel mixture the same (80:1) etc. However I have just stripped the carb and blown out the jets and noticed that the inlet stub appears to be cracked around the jubilee clip although the crack doesnt appear to go all the way through. Could this be the problem? Quote Link to comment Share on other sites More sharing options...
clarkp Posted September 23, 2004 Report Share Posted September 23, 2004 (edited) Yes, that could be part of the problem - if the inlet boot is cracked the bike will suck extra air and will be running lean. Some guys say try spraying WD-40 around the inlet boot when its idling and if it revs up, you have a leak. OBTW, as a courtesy, change your personal settings to show everyone where you're located. Edited September 23, 2004 by clarkp Quote Link to comment Share on other sites More sharing options...
terry Posted September 23, 2004 Report Share Posted September 23, 2004 Don't forget to check the plug. It will tell you whether it is running rich/lean. I always like to start any adjustments with a good plug in the bike. I also have a TL125 that was having similar problems and it was crud in the fuel petcock bowl which was slowing the fuel delivery. The bike was starving for fuel. It would idle nice but when greater demand for fuel was required it bluber because it was using fuel faster than it was being supplied. Cleaned the bowl good and solved the problem. May want to clean the tank out and change or add fuel filter if you don't have one. Just another possibility. Quote Link to comment Share on other sites More sharing options...
pete250 Posted September 23, 2004 Author Report Share Posted September 23, 2004 Thanks for suggestions. Going to check these out but wont be able to get out until weekend. Quote Link to comment Share on other sites More sharing options...
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