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Author: Subject: Bike carb conversion- non starter
Eviljohn

posted on 13/10/17 at 12:01 AM Reply With Quote
Bike carb conversion- non starter

Hi all. Hope you're well. As above, bike carb conversion on a mk2 polo. At the point of starting up but car just turns over. No start. Nearly starts with easy start but i don't want to use that really. Adjusted the pilot screws on the carbs. Currently 4 whole turns out, which seems a bit excessive to me but if i'm wrong, feel free to drop some xp. Needles are all set at the midway notch out of 5. Jets are currently 105's, (car is a stock 1l.) Carbs are from a kawasaki ninja, zx6, late 90's. All slides move freely. Pulled the fresh plugs after trying to start her today and after 5 different pilot screw adjustments, nothing on them. Dry, no soot. I had these carbs running when i first got them, but they had 150 jets in, the needles were set on the lowest notch and were massively overfuelling. Can anyone recommend anything to try to get her starting? Even have the idle currently set as high as it will go. Thanks for stopping by and any guidance you can give. Take it easy.
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ragindave

posted on 13/10/17 at 07:15 AM Reply With Quote
Is fuel getting to the carbs and are you using the choke
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daviep

posted on 13/10/17 at 07:52 AM Reply With Quote
There is a bit of conflicting information in your description.

You say "nearly starts with easy start", if you have a fuelling problem it should start no problem on easy start. If it won't start on easy start then the problem is not fuel related. However you also say the plugs are dry which would definitely indicate a fuel problem.

So the important question is will it run on easy start or not?

As an aside, easy start damaging engines, or engines becoming "addicted" is largely an old wives tale, the need to use easy start normally means engine has problems to begin with. As a diagnostic tool and used sparingly there is no problem with it's use.

Cheers
Dave





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redturner
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Building: Run 2 ltr Black Top in single seater race car.

posted on 13/10/17 at 11:14 AM Reply With Quote
I have R1 carbs on my Black Top, with 180 mains and air corrections at .075mm Will not start easily without choke when cold so always give full choke and not a problem. Just make sure that you have fuel in the float chambers. Checking for a spark is easy but I suspect that it is fuel related by our description.....
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Eviljohn

posted on 13/10/17 at 12:00 PM Reply With Quote
Does not start with easy start. Does come closer to starting with easy start but still doesn't start. Without easy start, engine just turns over. With easy start, engine turns and will run for maybe 1/2 second but cuts out as soon as let go of ignition key. Will try and work out how to post a video to try and show what i mean.
Choke is not attached at this point.
Fuel is getting to the carbs for sure and into the carbs. Not sure how to check what the carbs are doing with the fuel apart from checking the plugs.
Thanks for replies.

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40inches

posted on 13/10/17 at 12:11 PM Reply With Quote
quote:
Originally posted by Eviljohn
Does not start with easy start. Does come closer to starting with easy start but still doesn't start. Without easy start, engine just turns over. With easy start, engine turns and will run for maybe 1/2 second but cuts out as soon as let go of ignition key. Will try and work out how to post a video to try and show what i mean.
Choke is not attached at this point.
Fuel is getting to the carbs for sure and into the carbs. Not sure how to check what the carbs are doing with the fuel apart from checking the plugs.
Thanks for replies.

As has been said before, not a lot of chance starting on bike carbs without the choke.
You don't need to connect a cable, move it manually.
"I had these carbs running when i first got them, but they had 150 jets in, the needles were set on the lowest notch and were massively overfuelling"

[Edited on 13-10-17 by 40inches]

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Eviljohn

posted on 13/10/17 at 04:30 PM Reply With Quote
Cool. Will hook up the choke as i'm workin on my own and can't actually reach the choke mechanism and the igntion key at the same time. Thank you.
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jacko

posted on 13/10/17 at 07:51 PM Reply With Quote
What fuel pump are you using the right pump is the bike one
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Brian R

posted on 13/10/17 at 11:09 PM Reply With Quote
You say you've wound the idle up as far as it will go? In my experience any touch of the throttle whilst trying to start bike carbs it's game over. Back it off and try again with full choke.
The choke should allow a fast idle while the engine warms up. Let it run for a minute then balance pushing the choke in with a bit of throttle. You can then set your idle once it's warm.
You shouldn't need any throttle starting when warm either. Or choke.
Also are the carbs at the correct angle? They need to be installed so the float chambers are at the right level.

[Edited on 13/10/17 by Brian R]

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Eviljohn

posted on 14/10/17 at 06:31 AM Reply With Quote
Using a bike fuel pump. I know the pump works just fine.
I'll back the idle adjust out again. Should halfway be enough? I didn't have the throttle cable attached to carbs while i was trying to start it up.
Thanks again for advice.

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Eviljohn

posted on 14/10/17 at 06:35 AM Reply With Quote
Also, company i got the kit from, (carbs, filter, manifold, balance bar, fuel pump,) actually called me to make sure they got the angle of the manifold correct.
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Eviljohn

posted on 15/10/17 at 12:21 PM Reply With Quote
Success!!! Completely backed out the idle screw, full choke and fired up first time! Thank you very much! Held it on full choke for about a minute, even tried for 2 but cuts out when i let the choke off. Pretty sure it's overfuelling cuz i took the plugs out and they were black and grubby. Pretty sure that's down to the pilot screw setting so will have a crack at those this afternoon. Thanks again for the input. Most grateful.
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Brian R

posted on 15/10/17 at 07:29 PM Reply With Quote
Excellent well done.
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Eviljohn

posted on 15/10/17 at 08:20 PM Reply With Quote
Managed to get it running without having to hold the choke fully open. Adjusted the pilot screws gradually from 4 full turns out down to 2 full turns. Did have an occasional misfire on cylinder 2 before i made the adjustments but that seems to have calmed down. Idle seems smooth, no hunting at this point. There is just a slight lag between giving some throttle and the engine actually revving but hoping that will be sorted with getting it tuned. I have an afr kit that i'm looking to get installed asap, beyond that, if anyone has any tips or tricks for tuning bike carbs, i'd be very grateful. I do have a very basic guideline for which circuit controls which part of the rev range but if anyone wants to drop some xp, i'd be very grateful. Thanks again for your help so far.
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ragindave

posted on 15/10/17 at 09:41 PM Reply With Quote
Balance the carbs next before anything else
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Eviljohn

posted on 16/10/17 at 04:41 AM Reply With Quote
Carbs were balanced before shipping but probably worth checking them anyway. Thank you.
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Eviljohn

posted on 16/10/17 at 04:41 AM Reply With Quote
Carbs were balanced before shipping but probably worth checking them anyway. Thank you.
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Brian R

posted on 16/10/17 at 05:00 PM Reply With Quote
The last set I fitted I balanced the butterflies on the bench before they went on the car. I checked them once running and they were pretty much spot on but without a doubt you need to check yours now it's running.
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