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Post by warriorrider1146 on May 16, 2013 17:33:40 GMT -6
I have a 1987 warrior 350... Fresh rebuild with hot rods stroker +4mm crank, hot cams stage two, Vito's trimming key, vertex piston, minkuni vm-38mm carb brand new and I just installed a UFO... Has 160 main jet 25 pilot and a 3.3 needle seat. With the needle on the middle clip there is no airbox just a k&n air filter... I've tried every combination of jetting I can think of and nothing ever changes... It falls on its face when it starts getting higher in rpms... Today I switched to a 16/38 gearing and it wast bad until it started to warm up then back to fallin on its face wide open throttle... I'm thinkig electrical but have no idea what is causing it the CDI? Or the stator? or the coil?... This has me and a good friend of mine whose a atv mechanic both stumped anybody have any idea what my problem is??!!!
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Post by wv98yfm350 on May 16, 2013 19:29:14 GMT -6
What do ya have in the way of exhaust? All that air coming in has to flow out the exhaust that easily too...there is a Tutorial section with a thread on here to ohm the stator and eliminate it from the equation. What did the plug look like? Good blue spark? Just a few starting points for ya maybe. Try a smaller main like a 155 or so as well. May be over carbing on top end, thats a good size carb
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Post by warriorrider1146 on May 16, 2013 20:03:46 GMT -6
I have a DG head pipe with a HMF competition exhaust so it's pretty free flowing yea I've got good spark.... I haven't tried any lower than 160 so far cause it's brown from a wide open run but I can try it... What's over carbing? Sucking to much air?
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Post by Alex on May 16, 2013 20:22:34 GMT -6
Are you running a cam at all?
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Post by warriorrider1146 on May 16, 2013 20:29:50 GMT -6
Hot cams stage two with stock valves and springs
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Post by MudBug on May 16, 2013 20:37:05 GMT -6
like i told you earlier it quite possible you are floating valves my man. especially with the added comp of the stroker and a hot cam 2 w/ factory springs. Change out the springs and put i think you will be fine. By the way good to have ya.
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Post by MudBug on May 16, 2013 20:51:49 GMT -6
I have a 1987 warrior 350... Fresh rebuild with hot rods stroker +4mm crank, hot cams stage two, Vito's trimming key, vertex piston, minkuni vm-38mm carb brand new and I just installed a UFO... Has 160 main jet 25 pilot and a 3.3 needle seat. With the needle on the middle clip there is no airbox just a k&n air filter... I've tried every combination of jetting I can think of and nothing ever changes... It falls on its face when it starts getting higher in rpms... Today I switched to a 16/38 gearing and it wast bad until it started to warm up then back to fallin on its face wide open throttle... I'm thinkig electrical but have no idea what is causing it the CDI? Or the stator? or the coil?... This has me and a good friend of mine whose a atv mechanic both stumped anybody have any idea what my problem is??!!! Okay man i didnt see you had a ufo in your carb either. you have to be running way rich on you carb at idle........ I'm also running a UFO in my carb and i'm at a 10 pilot in mine. second if it was electrical rpms i dont think would play a factor in your bike cutting out on top end. I understand you dont see any change when you change out your jetting and i dont see how that is at all possible? Take the 3.3 needle seat out and go back to the 1.5 that was in it turn your air screw all the way in and turn it out a full 2.5 turns and then see how your bike idles...... i Bet it dosent very well. then you can pick up smaller pilots till you figure it out and it idles great. Then you move to your needle which i dont think you will have to worry about to much. Then once you have your idle and mid range figured out move to the main jet and figure that out. Stroker or not a 350 is a 350 and your not breathing to much better then my bike if at all( is your head port and polished?) so you should not be that far off of what i'm running with jetting which is a 10 pilot, 3 notch needle and 230 main and i'm still real rich on idle. Start there and we will get you right.
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Post by gen1pat on May 16, 2013 20:55:16 GMT -6
What is you compression ratio? I agree with Levi. Valve float is what my mind is tellin me. If your plug looks good, runs well otherwise, has no abnormal noise, I'd look into stiffer valve springs. They say that the stage2 is good with stock springs, but, I'd never run it like that.
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Post by DuneRacerWeston on May 16, 2013 22:59:11 GMT -6
Hmm. I concur. I wouldn't run that cam with those springs.
As for tune. What part of the plug are you looking at?
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Post by JeffsYFM350 on Jun 7, 2013 7:07:19 GMT -6
What is you compression ratio? I agree with Levi. Valve float is what my mind is tellin me. If your plug looks good, runs well otherwise, has no abnormal noise, I'd look into stiffer valve springs. They say that the stage2 is good with stock springs, but, I'd never run it like that. Prob 9:1 with a vertex piston..
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Post by Lycan on Jun 7, 2013 10:36:21 GMT -6
The S2HC has a good bit of duration and overlap. 9.1:1 is low for it IMO. The Stroker still help it done but not cure a low compression. I'd like to hear a video of out running through the gears. Internet diagnostics are hard. It's not like having it in front of me or riding it for myself ya know.
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Post by gen1pat on Jun 7, 2013 17:59:03 GMT -6
Ditto^^^ To many variables to do over the net.
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