lt1bird Posted May 11, 2009 Report Posted May 11, 2009 When I try to do a plug chop it sputters if I wack the throttle open it will not recover unless I close the throttle to 1/2....then it pulls hard all the way to red-line and through the gears... If I roll the throttle to WOT then it seems to take it just fine and runs hard through the gears... I keep upping the main jets waiting for a top end rich sputter.. Looking to start at the rich point and work my way lean with the plug chops... All the tuning info says Main jet at WOT....Maybe 5K rpms is not enough rpms to use the fuel its dumping in if the main jet is too large? Quote
GrMeyer Posted May 11, 2009 Report Posted May 11, 2009 list all your mods and what your elevation is and everyone can help you out. Quote
AKheathen Posted May 11, 2009 Report Posted May 11, 2009 you're getting it up to operating temp before you try to plug chop. it should kind of run like that if it's not warmmed up Quote
lt1bird Posted May 12, 2009 Author Report Posted May 12, 2009 Yes, up to temp..... Its a 535, 165psi, big bore pipes ,modified, 38mm kehin carbs....... Ive got a bunch of work to do to it over the next few days..New throttle so i can go WOT easier... clutch lever etc.... Ill try moving the needle a clip leaner and see if it helps a bit....at least ill know im going the right direction... I guess my main question would be......WOT is the main jet.... I have power valves....Im kind thinking that the power valves when they open they will run fine with the larger main jet....When they are closed there is not enough rpm/velocity to run the larger jet. The power valves have jets on the front to control when the valves open....I might play with them as well.... just to see how it effects the power coming on.... Quote
GrMeyer Posted May 12, 2009 Report Posted May 12, 2009 this site has helped me out many of times.. http://www.dfn.com/benkaren/jetfaq.html Quote
mopar1rules Posted May 13, 2009 Report Posted May 13, 2009 sounds like your lean on mains and/or needles. by slowly opening up the throttle, you are able to give it enough fuel in a slower amount of time to run like a raped ape, but when you give it a quick stab, it wants to stall out, cause it can't get enough fuel quickly enough. i would keep upping the mains and maybe even check the float level. Quote
lt1bird Posted May 13, 2009 Author Report Posted May 13, 2009 With a smaller main it would run cleaner and rev good with no studder....It just seems to make a bit more power with the larger mains... It might like more fuel but in the midrange it suffers with the needle im using... Im gonna to go back to tune the needle for best 1/2 thottle power first...then fine tune the mains... Trinity said start at 160 and work my way down! Im at 175 now....I tried 160...seemed a bit buzzy but ill try again... Quote
2001Stroker Posted May 13, 2009 Report Posted May 13, 2009 Just curious as to what size jets you have in your powervalves. Mine have 230's. I still haven't gotten around to toying with my carb jetting yet. My carbs still have the jets and needles in them from when I bought them. My bike's rich as hell. I'm gonna play around a little with my jetting, maybe this weekend. We pretty much have the same exact motor, except for the port jobs, and I have 39PWK's. Once I mess with it, I'll let you know where I am. Quote
mopar1rules Posted May 13, 2009 Report Posted May 13, 2009 With a smaller main it would run cleaner and rev good with no studder....It just seems to make a bit more power with the larger mains... It might like more fuel but in the midrange it suffers with the needle im using... Im gonna to go back to tune the needle for best 1/2 thottle power first...then fine tune the mains... Trinity said start at 160 and work my way down! Im at 175 now....I tried 160...seemed a bit buzzy but ill try again... if it likes the bigger mains, then give it bigger mains. you just may need to get different needles, to help lean out the rich midrange then. Quote
lt1bird Posted May 13, 2009 Author Report Posted May 13, 2009 Im gonna go back to the 160s just to do a santity check.... Stroker...ill keep you posted as well....Trinity said the jets on the powervalves do nothing....Just a simpe way for them to hook the plastic tubes to them..... does not effect any power stuff..... Quote
2001Stroker Posted May 13, 2009 Report Posted May 13, 2009 Stroker....Trinity said the jets on the powervalves do nothing....does not effect any power stuff..... Yes they do. Smaller ones open the power valves slower, and bigger ones open them faster. That's how you fine tune them. If they open just off idle, you're gonna need a richer pilot and needle. If they open mid rpm, you'll need more needle. Quote
lt1bird Posted May 14, 2009 Author Report Posted May 14, 2009 Thats what I assumed....trinty said it is really just a vent for the oil and air...... not adjustable.... Do you know someone who has been playing with them? Right now, I have very little power band Hit..... It pulls pretty good from down low all the way to redline.... I never do get a good power band hit.... kinda wierd..... my 250 2 stroke with power valves has a awsome power hit..... I kept wonderin about the power valves....like...were they opening? I dont think there is an easy way to check... Quote
2001Stroker Posted May 14, 2009 Report Posted May 14, 2009 They're probably opening slowly, making the power come on smoothly, instead of the typical 2-stroke hit. I would imagine if they were not opening, it would be like not even having them at all. I'm pretty sure pabansheematt has tinkered with his some. Talk to him about how to adjust them. Quote
lt1bird Posted May 20, 2009 Author Report Posted May 20, 2009 The 160 mains feel much more crisp... Bike seems to run very good...studder all but gone....just a hint before the power valves open up... it likes the smaller mains for sure....Trinty said start at 160 as that would be very rich stilll they said I would probably end up at 150.... I am going to put some mid 150's in and see how it feels... I am also going to bump the the timing up +5 as the 110 race gas, may as well get the most out of it... I am going to make one last needle change as well to try and clean up the little rich sputter at 1/8 to 1/4 throttle...going to end up with a CEN needle... CEL working good....CEN should work better Quote
lt1bird Posted May 21, 2009 Author Report Posted May 21, 2009 Well, the +4 timing made it a bit more eager.....feels good...... the new needle did help with the studdering....Im going to g smaller on the pilot to help clean that up.....On the mains.......It pulls hard but still does not get a big power hit as it should, im thinking im still very rich... If i hold the throttle at 1/2 and let it keep reving i feel the power hit! I know the needle is very close to where it needs to be so I bet its still very rich causing the bike to not quite get on the pipe..... Im going to lean out the mains to 155 and see if it wakes up the top end more! Is this what others have seen? Running rich mains will make it still pull hard but never awsome.....and never get the power hit? Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.