lt1bird
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Posts posted by lt1bird
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thanks guys....I love it too.... built it a few years ago...now finally have time to tune...
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This is the 485cc cheetah powered bike.....280LB wet..... aprilia rs250 based...
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I think I would rather down shift a few gears to get some power before I would put the power valves back in... im sure once ive tuned it a bit more it will get better..... the aprilia rs250... 62Hp to the wheel on my stock bike... high strung....power valves...you could lug it all day.... that's the difference between a drag setup(banshee cheetah cyl's) and a road race/street setup.... it is what it is.... ill keep you guys posted.,...thanks a bunch for the advice
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I think you nailed the power valve issue...that is exactly what it was doing... you could hear the valves slapping around...one broke at one point.. im just not a fan of them.....
180 main jet...yes, I feel its to large as well. I had a 162 in there...ran great...a bit lean... went to 180.. trying to get it to 4 stroke...and it still pulled hard but the egt was a cooler but not in the 580 range yet.
im like...I was looking at the jetting last night....I really wonder if my DGH needle is just too rich at 3/4 throttle... I might try leaner taper needles...drop the main jets to 150 and use the power jets...see if that helps....
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The bike is running very clean. Down low.....even right tru 1/2 throttle and higher...maybe just a tiny bit rich at 1/8throttle..... Very happy everyplace else... The power vales use to pulsate a lot at 1/8 throttle just putting along....ran very crapy...pulled them off and so much nicer....quite and smoother...Ive actually Gita backup plan...I've got 2 fuel solenoids....going to put one each in the power jet lines....open the solenoids at 6k rpms via my ignitech...should work good...
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42 rear
268 gears
rz350 transmission
17 front
yes, way over geared but I really wanted to drive at 80 on the highway at low rpms etc....
I think I will just tune it more and live with it.... ill just down shift if I want to get into the power band quick... im pretty sure its just loading up while it waits to get on the pipe.... like you said...just not realistic to ask it to do that with the setup I have.... I could maybe lean the crap out of it in the midrange and make it work but its just not cool to do that either...
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im sorry for the crapy last posts...did it on an ipad and it just stinks...
motor specs
485cc
stock ported trinity power valve cyl with port matched block off plates
wiseco 10018m07300 pistons
ring gap .012
custom domes 73.5-24-12 degree .054 squish positive to a .058
155 psi compression
.059 base gasket
268 gears
slingshot lockup
vforce reeds
k&n pod filters
ignitech cdi ignition running stock curve +4degrees
110 race gas to be safe
PWK 38mm carbs DGH needle 2nd clip, 178 mains, 48 pilots, stock slides, power jets
it is geared very tall as its a streetbike! In the lower gears is will pull through fine with little issues...just loading it down in a high gear...and going WOT, without down shifting... it will load up off the pipe.... maybe I just need to adjust my driving style.....or put power valves back on.... I did not like the power valves as they pulsated real bad a cruise...maybe stiffer springs would have helped...I hated the oil dripping from them...etc...had one break... but the bike did have a ton of midrange power... almost 4 strokish power band which was a bit boring LOL.
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It's a 155 psi motor...stock trinity porting..none.... Basic squish.positve unlik trinity domes lol...newer build....leak down was fine... It runs and drives just fine.....all in al you can drive around town etc...just fine... If you start in lower gears and go wot it will pull Caen right past the Souter, no issues...I really am luging it low..4th gear at 40 mph...3k rpms.....then go wot...I'm in that gear fora while before I hit 5-6k then it 4 strokes....then gets on th pipe and pulls hard. I wonder if I had the power valves in there if it would still do it...it lost a bunch of mid range power without the power valves...
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Yes....Ido lug I then go wot.".pulls for a bit fine...then seems to start loading up..then 4 stroking...then on the pipe and running clean....I wonder if the k&n filters are a litte restrictive ausing it to suck too much fuel.... I'm tuning by feel... Egt for reference...I run egts on all my 2 strokes. I've built a bunch of these motors...mostly for drag racing...
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they are open all the way... turbo throttle twist... I always check them....
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yes, stock cyl...no porting...I just clean up the mold lines a bit...
the neddles are DGH I think im at now... second clip position... I don't think the needle will have any influence at WOT as its not really in the bore much.....
yes, gearing is very tall.... takes a bit to get to 6k rpms if in higher gears.... I can down shift a few gears and get through but I don't want to have to do that....
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Guys, im in need of some help. Ive got a 485 street bike...cheetah with block off plates, stock porting 39mm pwk carbs.... my jetting at WOT seems to be way off and I cannot seem to fix it.
I started at 152 mains, it ran lean 650c... I went up to 180 mains and its close at 610C but still a tad lean but runs hard, im getting very close. Here is the problem... the main is so large that when I go WOT and im not on the pipe it 4 strokes a lot....I can slowly work through it...or down shift and get the rpms over 6k and on the pipe and its happy. how the hell can I get rid of the 4 stroking when at WOT but not on the pipe? Well I added some power jets, and it does run much nicer with them at WOT...tons of fuel added and 580C egt is prefect...but the power jets start adding fuel at like 1/2 throttle so the problem actually got worst... I cant seem to get a happy balance. I tried moving the power jets out of the carbs more to raise the activation point of the power jets but that did not seem to change much. Im sure I could cut them more, move them out more but it might not work any more if I go to far.
Thanks!
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non air strikers.... in an aprilia rs250 chassis...bike with this motor in it weighs 280LBS...
I am wondering if the carbs are too large as well,,,, but my 440 cub(non ported) street bike had the same carbs and it ran fine....but that bike was a lot heavier.... hmmmmm
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I build my own motors....they are unported just cleaned up....... since its in a streetbike, I want to keep the low end performance...
Ill swap the carbs from my drag bike to this bike to make sure its not an issue with the new PWK carbs....
reeds are Vforce carbon...they still are new...no issues... some folks say they don't work well at lower rpm?
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tim from titan made them...they were exactly what I wanted... positive quish unlike the negitative squish angle on the trinity domes.
The DEQ needle.... the Q is the diameter, and its the leanest I can find.... that's why I went to a leaner slide...the leaner slide most definatly leaned out the idle as well... so the slide leaned from idle to 1/4 throttle... and it still seems to misfire like its rich... even the EGT seems to drop when it starts to miss at 1/8 throttle... drops to 290-300C from high 300's This is the second motor ive had do this...I had a 535 do the same thing... but I never spent much time to fix it.....whole different motor, pipes etc... with power valves... im just wondering if im being to picky? maybe a built in issue with the stock cylinders? I would imagine not many quads would be staying at 1/8 throttle lol I might take a day and go trhough the setup and check for leaks, comprssion, leakdown etc... check timing... just to make sure....
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The porting is stock.... the PV block off plates I cut to fit so they matched the port perfect...full open. Even with the power vavles installed it was going the same thing....maybe a bit worste..
I have tried pretty much all the pilots from 50 up...
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The needle in it is the leanest dia I can find... That's why I went to the 7 slide to lean it out more
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its a 485 with trinity PV cyl's... blocked off.... stock porting....155psi compression... setup for pump gas...ignitec ignition...24 total timing... 38mm keihin carbs.. pipes are midrange pipes... v force reeds,
158 mains
65 pilots
#6 slides
DEQ needles
Ive tried leaner slide, richer slides....different needle dia etc to try and clean up 1/8 throttle... im starting to wonder if there is a leak in the exhaust.. so its sucking air in at lower throttle settings... think that could do it?
whole new setup so its never been dialed in... well, 1/4 throttle up was and I rode it like that for a little bit...now im making a big effort to make it smooth... and its just not good.... don't get me wrong...you can ride it like this but it should not be doing that at 1/8 throttle, you should be able to put along at 1/8 throttle steady cruise without is misfiring/sputtering...
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yes, new motor....new reeds....
What about a small exhaust leak at the pipe where it attaches to the motor...there are orings in there...I don't think I used any silicone like my other bikes...
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carbs are clean, no power valves as they are blocked off.
Ignition...its all new, timed etc but ill put a timing light on and see if its misfiring via the spark plug wires... you don't think jetting would do this? air leak...guess I could check the reed block gaskets etc...
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Guys, this misfire is driving me crazy... 485 trinity setup... runs great at 1/4 throttle up... for the life of me I cannot fix the what im calling a misfire... at 1/8 throttle it seems to sputter a lot....I lean it out and you can feel it get a big boggy as you would think, but the sputter is still there....seems to be there if im rich or lean...does not matter..again, everyplace else seems just fine...If it were ignition I would think it would do it under more of a load as well... any help would be awesome, im lost at this point and ive built a bunch of these LOL
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spraying nitrous
using nitrous to clean up that rich idle is not a good idea... LOLOn a serious note, hope your not spraying that low in the rpm range, your asking for trouble...Nitrous backfire etc...bent rods....even a tiny shot hit by acident at idle could back fire.
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Pretty intersting....I have a 535 and Im wondering if the big bore pipe is really the best choice....regular race gas.... so far its looking like small bore!
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I have not seen a turbo setup yet that ran two pipes..... Just wondering about the reasoning...Maybe just a pain to to connect two pipes to the turbo? Ill read back more on this post, I am confusing two folks
485 jetting issue at WOT
in Jetting & Exhaust Forum
Posted
Well, im done... I kept cutting the power jets down so they added a bit less fuel down low... she is real close to prefect... I might drop the clip one more clip but it is running real nice!
thanks again!