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Re: Too large main jet

Posted: Sun Apr 24, 2011 10:28 pm
by djh66
Is a fast flow tap essential on a 185 ali kit? As I have a standard tap i'd like to try.

Re: Too large main jet

Posted: Sun Apr 24, 2011 10:46 pm
by coaster
djh66 wrote:Is a fast flow tap essential on a 185 ali kit? As I have a standard tap i'd like to try.
It'll probably be ok but best to check the flow rate. Reading back over some of the suggestions you've had, you haven't said if you have checked your float hight as per Storkfoots post. If you haven't ruled that one out I think you should before changing the fuel tap especially as you said the fast flow was flowing ok a few posts ago :?

Re: Too large main jet

Posted: Sun Apr 24, 2011 10:57 pm
by djh66
coaster wrote:
djh66 wrote:Is a fast flow tap essential on a 185 ali kit? As I have a standard tap i'd like to try.
It'll probably be ok but best to check the flow rate. Reading back over some of the suggestions you've had, you haven't said if you have checked your float hight as per Storkfoots post. If you haven't ruled that one out I think you should before changing the fuel tap especially as you said the fast flow was flowing ok a few posts ago :?
Hi Coaster,
I hav'nt checked the float height, but my float bowl is the clear type, so I can see the bowl is full. How do I check the float height?
It does concern me about the air in the fuel pipe!
Dave

Re: Too large main jet

Posted: Sun Apr 24, 2011 11:26 pm
by coaster
I didn't realise about you had a clear bowl but here's a link to how it shouls be set up.
http://scootrs.com/tech.cfm?tip=float

Re: Too large main jet

Posted: Mon Apr 25, 2011 8:41 am
by nelson pk
I may have read this wrong but you said you always have a big air gap in the pipe from fast flow tap to carb? If you have.... this is the key to your problem. It has the effect of reducing the pipe diameter. If the big air gap does not go away after a short journey this is a problem.
Take pipe off carb as if checking flow rate and turn tap on. If no air bubbles run through pipe it is very unlikely it is your tap. If a seal in your carb has failed or your not sealing the ends of the pipe correctly the air will trap in the pipe and cause a vapour lock and this will not allow fuel to flow correctly when its all together.

Re: Too large main jet

Posted: Mon Apr 25, 2011 8:48 am
by nelson pk
Also a good test is to take the carb off the bike with the fuel pipe on. Put a container under the carb and undo your float bowl nut while your tap is on until the air in the pipe has disappeared (effectively bleeding the system) and do the float bowl nut back up. Re connect the carb to the bike without diconnecting the fuel pipe and keeping the fuel tap in the on position.
Run the bike and go for a quick ride. If air appears in your fuel line again then you have an air leak getting into the pipe and this will get worse as you ride the bike further and further causing the problems you mention.
Good luck.

Re: Too large main jet

Posted: Mon Apr 25, 2011 9:10 am
by djh66
nelson pk wrote:Also a good test is to take the carb off the bike with the fuel pipe on. Put a container under the carb and undo your float bowl nut while your tap is on until the air in the pipe has disappeared (effectively bleeding the system) and do the float bowl nut back up. Re connect the carb to the bike without diconnecting the fuel pipe and keeping the fuel tap in the on position.
Run the bike and go for a quick ride. If air appears in your fuel line again then you have an air leak getting into the pipe and this will get worse as you ride the bike further and further causing the problems you mention.
Good luck.
My OKO / Kehein carb has four screws holiding the float bowl to the carb, however, I will try this today, I'll check all seals, but unlike the Dellorto, it has no seal were the petrol inlet goes into the carb.
Cheers
Dave

Re: Too large main jet

Posted: Mon Apr 25, 2011 8:33 pm
by djh66
Thanks for all the replys, I finally have it sorted :D
You were all going down the right road! Two things I have done today:
Adjusted the floats in the bowl to the correct 19/20mm, they were at about 25mm so not enough fuel in the bowl, this seems to be how the air was going back up the fuel line!

Removed rear exit CamLam fast flow tap, and replaced with standard fast flow tap.
Fuel line now completely full, even after test out on the road. Now not cutting out at all.

Re: Too large main jet

Posted: Mon Apr 25, 2011 8:38 pm
by coaster
djh66 wrote:Thanks for all the replys, I finally have it sorted :
Now not cutting out at all.

Fantastic, well done for keeping going and not throwing in the towel :bouncing:

Re: Too large main jet

Posted: Mon Apr 25, 2011 8:51 pm
by djh66
coaster wrote:
djh66 wrote:Thanks for all the replys, I finally have it sorted :
Now not cutting out at all.

Fantastic, well done for keeping going and not throwing in the towel :bouncing:
I just hope it gets me to Skeggy, not worried about getting home ;)
Thanks for your help Coaster.