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SUPER FRUSTRATED!!

P901 Single carb intake, FLAASH Cams, Super Charger, NOS.......
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SUPER FRUSTRATED!!

PostAuthor: Thrash47 » Mon Sep 11, 2017 12:54 am

I've asked about this before and I'm here asking again. My bike is an 87 xv700 that i have Adam Smith intake and Mikuni TM40 carb. The jetting i have it setup with right now is a 152.5 main, 17.5 pilot, e clip on needle is at the bottom (and yes ive tried it everywhere else too) 3 turns out on PMS, and accel pump set to come on as soon as i roll on the throttle. I still am getting a spit thru the carb after i crack the throttle in the garage, idle is set at 1100. I am getting conflicting opinions of what rich and lean is and tonight i talked to an auto mechanic of 30+ years that when he heard my bike running from across the alley, he said it was running lean by the popping. Everyone else on here says that is a rich condition??? tonight i took off the air filter and fire shot out the carb!! Scared me to death!! I went back thru the valves today and RE-RE- adjusted them just to make sure, and they are within the manual specs. I have sprayed around everything and i find no change in idle. My float is set at 19mm just as the manual says. Could this be a coil issue?? I mean i have spark on both cylinders. Should i change the pilot to a 20? Any help would be appreciated!

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Bike year & model: 1987 XV700 Virago
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Re: SUPER FRUSTRATED!!

PostAuthor: choppin » Mon Sep 11, 2017 5:44 pm

I have never worked on a carb like your talking about, but my experience is you are lean if popping through the carb. I would try a larger pilot. You have the needle raised as high as it will go I think so go bigger on the pilot. Trial and error. Only do one thing at a time.
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Bike year & model: 1982 920J VIRAGO
2004 harley 883
1987 150 Elite Honda (sold)
1983 920K virago
1986 XV700ss (sold)
1982 GL Honda Goldwing (sold)
1982 920 virago (parts bike)
1987 XV1100 (sold)
1984 XV700 (building trike)
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Re: SUPER FRUSTRATED!!

PostAuthor: mark75 » Tue Sep 12, 2017 3:40 pm

yep, old school rule-of-thumb .... backfire thru carb = lean ---- backfire thru exhaust = rich

I am curious why you would consider it to be a coil issue?

it does not take much of a leak to throw things out of kilter. is it popping at higher rpm or at/around idle? does a dab of choke change it?

are you sure you got the manifold & carb connections sealed?
The views, opinions, and experiences expressed in this post are mine and may not necessarily represent views and opinions of other VTF members, so feel free to agree, disagree, or ignore them.
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Re: SUPER FRUSTRATED!!

PostAuthor: Thrash47 » Tue Sep 12, 2017 10:14 pm

I've checked for leaks three times and i get no change in idle speed whatsoever, so I'm good on being tight. I have a 20 pilot jet in it right now, and from what i am being told, that should be plenty big for running stock exhaust, but i'm not so sure. Main jet is 152.5, clip is at the bottom of the needle. I have adjusted to accelerator pump, but can't seem to get it just right, and this may be in part my problem. as for the coils, they are working, it just seems to be weaker than anything i have worked on in the past, 4 wheelers, cars, etc....I don't know, just trying to cover all the bases, and thought one could be causing a misfire.... also, when i got the bike, the valves needed adjusted badly, they were very tight and i know that can cause a burn valve it goes too long like that, or the valves could just be not seating and need some seafoam to clean them up. compression test showed about 142 lbs on both cylinders, but I was unable to do a leak down test to see if there was anything leaking out.

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Bike year & model: 1987 XV700 Virago
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