Title: Recovery... problem found, but stroke another blocking problem
Post by: Anders Dinsen on November 17, 2008, 08:48:13 pm
My suspicion about air leak was correct. I have to admit, that I cut a corner when I assembled the carbs over summer:
One of the O-rings to fit in the spacers between the carbs and manifold were missing. I sealed it with silicone instead :-[ With the carbs and manifold off the car, I could see that a bit of it had been sucked in.
(http://tmp.dinsen.net/murena/siliconegasketsuckedin.jpg)
Depending on temperature, it was probably allowing quite a bit of air to pass through all around. This was on the same cylinder where the vacuum takeoff for the headlight system, which explains why I coulnd't raise the headlights last night - it was simply not producing enough vacuum.
Fortunately I ordered a set of new O-rings with my last order from Fastroadcars - and I can see now that I should have replaced them from the beginning. The new O-rings give better spring function, which is essential to prevent fuel frothing in the float chamber.
I actually noticed last night, that fuel in the right hand carb was indeed frothing. This was visible when I took the inspection lid off. The other one was fine.
Now that I had the carbs off the engine anyway, I thought I could just as well move the linkage to the underside as I had planned. It took a bit of fiddeling to get it right, but finally it worked. I thought! Because when I had the whole assembly fitted on the engine, I wanted to give it a last check by one complete push on the pedal - BUT IT COULD ONLY MOVE HALFWAY!
It turns out that the connecting rod on the linkage hits the manifold, so the throttle can't open fully :( It looks good to have the linkage on the underside, but there's not much fun if I can ever only run 2/3's of full throttle!!
I got quite pi.... off when I realised this, but I'm better now :) I "only" need to take the manifold and carbs off ONCE MORE and move the linkage... "only" two hours of work or so fiddeling with the nuts on the underside of the manifold >:(
By the way: I managed to get the carbs aligned better this time, so I think the syncronisation problem will be fixed :)
This photo shows the carbs fitted with the linkage on the underside. It does give it a somewhat 'cleaner' look, which I still think is worth "fighting" a bit for, just not now!
(http://gallery.dinsen.net/d/11593-2/DSC_2757.JPG)
One of the O-rings to fit in the spacers between the carbs and manifold were missing. I sealed it with silicone instead :-[ With the carbs and manifold off the car, I could see that a bit of it had been sucked in.
(http://tmp.dinsen.net/murena/siliconegasketsuckedin.jpg)
Depending on temperature, it was probably allowing quite a bit of air to pass through all around. This was on the same cylinder where the vacuum takeoff for the headlight system, which explains why I coulnd't raise the headlights last night - it was simply not producing enough vacuum.
Fortunately I ordered a set of new O-rings with my last order from Fastroadcars - and I can see now that I should have replaced them from the beginning. The new O-rings give better spring function, which is essential to prevent fuel frothing in the float chamber.
I actually noticed last night, that fuel in the right hand carb was indeed frothing. This was visible when I took the inspection lid off. The other one was fine.
Now that I had the carbs off the engine anyway, I thought I could just as well move the linkage to the underside as I had planned. It took a bit of fiddeling to get it right, but finally it worked. I thought! Because when I had the whole assembly fitted on the engine, I wanted to give it a last check by one complete push on the pedal - BUT IT COULD ONLY MOVE HALFWAY!
It turns out that the connecting rod on the linkage hits the manifold, so the throttle can't open fully :( It looks good to have the linkage on the underside, but there's not much fun if I can ever only run 2/3's of full throttle!!
I got quite pi.... off when I realised this, but I'm better now :) I "only" need to take the manifold and carbs off ONCE MORE and move the linkage... "only" two hours of work or so fiddeling with the nuts on the underside of the manifold >:(
By the way: I managed to get the carbs aligned better this time, so I think the syncronisation problem will be fixed :)
This photo shows the carbs fitted with the linkage on the underside. It does give it a somewhat 'cleaner' look, which I still think is worth "fighting" a bit for, just not now!
(http://gallery.dinsen.net/d/11593-2/DSC_2757.JPG)
Title: Re: Recovery... problem found, but stroke another blocking problem
Post by: Spyros on November 23, 2008, 09:23:08 am
Hi Anders,
Yes it looks cleaner with the linkage under the carbs.
But, in the other end, with the standard linkage of a Bagheera (2 dcnf), I always find it sorry that in order to actuate the linkage by hand, (when I'm tuning the carbs), I've to take the filter box off (because the access is too restrained)
Your picture with the sucked in silicone is impressive ;)
Yes it looks cleaner with the linkage under the carbs.
But, in the other end, with the standard linkage of a Bagheera (2 dcnf), I always find it sorry that in order to actuate the linkage by hand, (when I'm tuning the carbs), I've to take the filter box off (because the access is too restrained)
Your picture with the sucked in silicone is impressive ;)
Title: Re: Recovery... problem found, but stroke another blocking problem
Post by: Anders Dinsen on November 23, 2008, 07:25:26 pm
Your point is very valid, Spyros.
The photo of the gasket was not difficult to take once I had the carbs off and had sufficient lighting :)
Frederik came by today with the airbox, which fits very nicely. I'll reroute the throttle cable and vacuum pipe running behind it, and it will be painted black.
(http://gallery.dinsen.net/d/11661-2/DSC_3182.JPG)
The photo of the gasket was not difficult to take once I had the carbs off and had sufficient lighting :)
Frederik came by today with the airbox, which fits very nicely. I'll reroute the throttle cable and vacuum pipe running behind it, and it will be painted black.
(http://gallery.dinsen.net/d/11661-2/DSC_3182.JPG)
