Carbs sending fuel into filter not cylinder

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Re: Carbs sending fuel into filter not cylinder

21 Mar 2020 13:04 - 21 Mar 2020 13:06
#821324
Mikaw wrote:
calum wrote: To confirm that it's an issue with the floats you could just set the petcock to prime. If it doesn't overflow then the float height should be fine.

Not a true statement. Don’t trust the measurement method. It’s just to get you close. The only true float level is achieved by the wet method as Baldy110 states. Been there done it. Truly a PITA. COMPLETELY WORTH IT

Yeah, I probably didn't word that very well. I was assuming that the float level had been set as the OP said he had done it. I just meant that if the floats were sticking causing the fuel to overflow then this would also happen when the petcock is set to prime (or just on for a non-vacuum job). I didn't mean that the float levels are fine if you don't have fuel in you air box ;)
Last edit: 21 Mar 2020 13:06 by calum. Reason: Added quote
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Re: Carbs sending fuel into filter not cylinder

22 Mar 2020 17:26
#821456
Thanks for all the info. Gonna go with a carb issue. All are firing. Plug wires are correct as the boot lenghts are different (got it backwards one time last year). No leaking from the bowls and they are full. So gonna pull amd blow air through them. As i did this last night and now its only cylinder 3 that is shooting fuel out of it. Thanks again for everything. Really like this forum.

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Re: Carbs sending fuel into filter not cylinder

24 Mar 2020 12:49
#821611
Im having a hard time wrapping my head around the idea. The float bowl is full and not over flowing while sitting with the pet cock on. Once the bike starts I can feel air and sprays of fuel on my hand. If I let it run then it will start to drip fuel from the carb itself no the leaking from over flow or gasket area. How does this connect to float height?

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Re: Carbs sending fuel into filter not cylinder

24 Mar 2020 13:01
#821614
I just went back and read your first post. Did you check the valve lash and cam timing after you did the rebuild?
1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.

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Re: Carbs sending fuel into filter not cylinder

24 Mar 2020 13:22
#821619
If its only that single carb leaking I would remove the bowl and check out the float needle. Maybe its damaged, sticking or it's upside down.
1979 KZ1000B3 LTD Glacier Green

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Re: Carbs sending fuel into filter not cylinder

24 Mar 2020 13:38 - 24 Mar 2020 13:39
#821624
I tend to side with Mikaw on this. I can't see how a carb issue would cause airflow back out of the carbs. Can only really see that happening if the intake valve is opening too early. Can't come up with a reason that this would only happen on one cylinder, though.
Really interested to see what is causing this (not very helpful, I know...).
Last edit: 24 Mar 2020 13:39 by calum. Reason: spelling :)
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Re: Carbs sending fuel into filter not cylinder

24 Mar 2020 13:46
#821626
calum wrote: Can't come up with a reason that this would only happen on one cylinder, though

Good point. Just trying to cover the basics, and look at things that were disrupted. Carbs could be the issue if they were stored wrong during the rebuild. Just my way of diagnosis I look at things that are different.
1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.
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Re: Carbs sending fuel into filter not cylinder

24 Mar 2020 13:49
#821628
I just wanted to come back and edit my post :)
If the valve clearance is way off (e.g. no clearance) on the #3 intake valve, then the valve will never close. I was just thinking about the timing before, not the valve clearance.
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Re: Carbs sending fuel into filter not cylinder

24 Mar 2020 14:06
#821633
calum wrote: I just wanted to come back and edit my post :)
If the valve clearance is way off (e.g. no clearance) on the #3 intake valve, then the valve will never close. I was just thinking about the timing before, not the valve clearance.

What he said!!!
1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.

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Re: Carbs sending fuel into filter not cylinder

25 Mar 2020 08:19
#821706
OK I am going crazy. Pulled the carbs (again) cleaned and blew air through them. Rolled motor to TDC. Marks are correct 28th pin count is correct. Rolled the motor over (clockwise never counter) used my camera and can see the valves fully open at the correct lobe positioning through the spark plug. When running I hear no odd noises but the puffs coming from cylinder 3 then the dripping. Might set this thing off to the side and let it collect some dust for a bit.

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Re: Carbs sending fuel into filter not cylinder

25 Mar 2020 08:21
#821707
I will go through and double check everything. Thanks.

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Re: Carbs sending fuel into filter not cylinder

25 Mar 2020 16:25
#821747
Things I would check:
- Is cylinder 3 firing?
- Is it running as hot as the others?
- Valve clearance on intake #3
- Compression on 3 (maybe the intake valve isn't seating/sealing properly)

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