misab plates

[Bob_Rich]

hi again 

 

in other earlier post  I got useful info re- fuel rating of hose --that was very helpful. I have now got the twin 40DCOE back in the car (S3 lotus 7 sprint spec crossflow)  and I was wondering how tight should the 8 bolts that hold the carbs be?  I assume a check with a feeler gauge should give a clue  see pictures attached below 

 

thanks in advance for any help

 

bob richardson

[Bob_Rich]

having trouble trying to upload the pictures so trying to add them here

bob richardson

[Miker7]

I don't think you can use a feeler gauge. They want to be tight enough to hold on the carbs, but not so tight the carbs can't move if rocked. The idea is they insulate the carb from the engine to reduce vibration and frothing of the fuel. If you can rock the carbs 10mm up or down, they're too lose. If you can rock them a few mm they're probably about right. An alternative view is the metal cups on the bolts should be squished so they're between 1 to 2mm apart.

[anthonym]

I just refitted mine and the eight nuts were all different tightnesses so the gaps were all different, consequently getting the mixtures right was impossible I now know. 
 

Feeler gauges no not really. I used a vernier caliper, the internal measuring legs, set to around 2mm from manifold face to carb face, using one corner that was already about that, then adjusted all others to match, which with that first gap fixed tight was easy (ish!) to do. The inner lower nuts can be difficult when all components are in place (Dellorto).

I will be checking them again per mike7 above.

 

Edited Thursday at 16:45 by anthonym

[Roger King]

Bob, your photo of the "cotton reel" bobbins looks about right. I'm afraid this isn't an exact science because the steel cups are not made to a precise and consistent dimension. Miker7's description is about right re. the amount you can move the carbs up and down at the air filter end so long as this is done without exerting significant force (yes I know that's really vague). Tiny air leaks are an absolute no-no at idle, but will have no significant effect at full throttle.

What you can do is to spray WD40 or similar over the Misabs when the engine is idling. If it makes a noticeable change to the idle speed or smoothness that suggests a leak (which the spray has temporarily sealed).

[Bob_Rich]

thanks for all the replies-- all useful info.

they do seen about right based on Miker 7 comments and supported  by most others posts

will try the WD40 trick when I get to setting up the idle

thanks for all the useful advise

cheers Bob

[Gridgway]

The rolling road people checked mine by rocking them by hand at idle and at a faster speed, say 3k rpm.  If it changed the rpm then it was too loose.