I've struggled to get a steady tick over, and get rid of a flat spot just as I open the throttle from closed. I've reset the float level swapped jets raised the needle changed the throttle valve pilot jet needle jet. So what's left ?
The carb spacer that's what. it was about 3/4 of an inch thick and 28 mm diameter.
I bought a 30mm one about 1/4 inch thick and its a transformation.
A nice steady tick over no flat spot and it now responds to the advance retard lever as it ought to.
It used to struggle below 30 mph in top now it'll do 15 mph on full retard (insert your own joke at this point)
I'm a happy tinkerer
Who knew ?
- Harry44
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- Location: SOMERSET UK
Who knew ?
si is does non opportunus vos postulo a maior pango
- clanger9
- Posts: 1165
- Joined: Sat Jun 20, 2015 9:38 am
- Location: Chester, UK
Re: Who knew ?
Well done, that can be a tricky one to find! Was there any "step" between the spacer and the carb body (or manifold)? Anything less than perfectly smooth here will usually upset idle/off-idle running...
There's a densely-written (but very informative) article on the archives about this very issue:
http://archives.jampot.dk/technical/Car ... mplin).pdf
There's a densely-written (but very informative) article on the archives about this very issue:
http://archives.jampot.dk/technical/Car ... mplin).pdf
1989 Moto Morini Dart 350
1993 Ducati 750SS
1993 Ducati 750SS
- Harry44
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- Joined: Sat Dec 17, 2016 5:26 pm
- Location: SOMERSET UK
Re: Who knew ?
Yes there was a step a whole 1mm. Now its perfectly smooth
And the answer to who knew is Clanger
And the answer to who knew is Clanger
si is does non opportunus vos postulo a maior pango
- cfaber
- Posts: 346
- Joined: Mon Nov 20, 2017 5:37 am
- Location: USA, Colorado
- Contact:
Re: Who knew ?
Is it possible that the old spacer insulator never sealed?Harry44 wrote:Yes there was a step a whole 1mm. Now its perfectly smooth
And the answer to who knew is Clanger
Fix it until it's broken!
Otherwise how will
anything get done?
Otherwise how will
anything get done?
- Janet
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- Location: EAST YORKSHIRE UK
Re: Who knew ?
If you mean "who knew" that a spacer with the wrong thickness and/or bore would make a difference, I did.
If you mean "who knew" what yours should be, I wouldn't have had any idea.
If you mean "who knew" what yours should be, I wouldn't have had any idea.
- Harry44
- Member
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- Joined: Sat Dec 17, 2016 5:26 pm
- Location: SOMERSET UK
Re: Who knew ?
It's always possible. But I tried several times to seal it, with and without gasket sealant with and without gaskets.cfaber wrote:Is it possible that the old spacer insulator never sealed?Harry44 wrote:Yes there was a step a whole 1mm. Now its perfectly smooth
And the answer to who knew is Clanger
Can this material go porous ?
The symptoms all fit with the tech article posted by Clanger so it seems the likely cause.
si is does non opportunus vos postulo a maior pango
- cfaber
- Posts: 346
- Joined: Mon Nov 20, 2017 5:37 am
- Location: USA, Colorado
- Contact:
Re: Who knew ?
To know for sure you'd have to run it and try the propane or starter fluid trickHarry44 wrote:It's always possible. But I tried several times to seal it, with and without gasket sealant with and without gaskets.cfaber wrote:Is it possible that the old spacer insulator never sealed?Harry44 wrote:Yes there was a step a whole 1mm. Now its perfectly smooth
And the answer to who knew is Clanger
Can this material go porous ?
The symptoms all fit with the tech article posted by Clanger so it seems the likely cause.
Fix it until it's broken!
Otherwise how will
anything get done?
Otherwise how will
anything get done?