canuckxxxx's Single carb manifold build

Classic Goldwings

Help Support Classic Goldwings:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Things aren't going so well. Put the whole thing together and have a major air leak. Won't idle but revs up then almost dies then revs up again. Sprayed starting ether and engine reved up. Did any of you guys have trouble with air leaks.

So I'm looking at all the junctions;

for the plenum to plate junction I was using the existing gasket which I thought was good but maybe not so I made a new gasket. Still air leak.

So turned my attention to the bottom of adapter (square flange) to the plate on top of plenum. To mount the adapter I drilled and tapped 5/16" holes in the 3/8" aluminum plate and had bolts screwed into them. But then I thought that maybe there is air leaking past the threads on the 2 lengthwise bolts so I've cut the heads off some bolts and JB welded them to the plate so I will have studs that won't leak air. But it is hard to see how those bolts could leak much air since I had locktite on the threads.

Now I am looking at the carb to adapter junction. Please take a look at the bottom of the carb: the gasket area around the bolt holes is not very wide...maybe 1/8". When I put the adapter flange onto the bottom of the carb and drop the bolts in then carefully take the bolts out without moving the adapter I find that the inside corners of the slotted holes comes very close to the edge of the carb gasket surface. In fact with the bolts in loose you can move the adapter back and forth on the carb so you would have a passage for air. I wasn't looking at this when I put it together the first time so maybe that is my problem.

Anyways I have managed to ruin both of the gaskets that came with the adapter so will have to make some new ones.

Any comments or suggestions would be greatly appreciated.
Brian
 
If you have thick gasket material make it to fit the carb not the adapter. If no material use a cereal box to make your gaskets. Almost all of these builds had air leaks to fix from the start. Check every union. Plate to plenum. Plate to adapter. Adapter to carb. Runners at both ends. All of the air leaks need stopped before you can hope to jet it right or attempt to dial it in.
 
ok ...on the carb ..the lined out carb path for gasket is ok it actually put the pressure on gasket at the the place weber wanted sealed and is not compromised with other flat surface ......on my build i have the carb on and off many times and it reseals fine ...the deal here is the gaskets i seems t me that gaskets are made to fail .... they are all made to be used one time and then there useless .... my gaskets are thick .....they are not torque to death ... seems to me that leather is the best gasket .....just need to slow down and really figure this out it is easy to seal air out .....on my set up they is ne goo used and thing come off an on easy ... i find that saveral times off and on it actually seals easy .... could be something else leaking too brian if you need more help pm me and we can talk on phone or something to figure things out :builder:
 
Thanks Slabghost and Joe. It's a new day and I have new gaskets so will see what happens. The carb to adapter gasket is cut to fit the bottom of the carb as Slab suggested. That is the junction that I suspect is leaking: I will make sure adapter is centred on carb.

Will report soon.

Brian
 
There are a few grades of gasket material.
One that I know of at Pep Boys says it's for carb base and is thicker than the other.
The thinner gasket material has no place here. Chances are good it will not seal.
 
Success! Put it all back together being very careful to centre the adapter to the carb. No goop on gaskets...glad you mentioned that, Joe, because I was planning on gooping it up real good ( or bad). :Doh2:

No air leaks, sprayed starting spray on all joins and no reaction. Bike idles real smooth, maybe smoother than before even. Having a coffee then going for a test ride. Will report soon, maybe post a video if I can figure out how to do it.

Thanks for all the help
Brian
 
oK, took about 50 mile ride mostly highway. Bike ran very well. About the same performance as before but definitely smoother. Idles much better now. Had the idle set at 1100 rpm before now it is very smooth and even at 1000 rpm, might try a bit lower yet. Slow idle is nice for finding neutral and putting into gear without clunk.

Filled up with gas and reset trip meter so will do a MPG calc next time I fill up.

Shot video with my cell phone and appeared to upload to YouTube but cannot find it so still working on that.

Brian
 
Both bikes sound great it's just one of them appears to be missing 2 cylinders...
 
[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=126473#p126473:36ebs6bd said:
Ansimp » Wed Jul 23, 2014 3:50 pm[/url]":36ebs6bd]
Both bikes sound great it's just one of them appears to be missing 2 cylinders...

TWO!! :smilie_happy: Umm the Royal Enfield is a single. :whistling:
 
[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=126476#p126476:3poamdnd said:
slabghost » Wed Jul 23, 2014 1:54 pm[/url]":3poamdnd]
[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=126473#p126473:3poamdnd said:
Ansimp » Wed Jul 23, 2014 3:50 pm[/url]":3poamdnd]
Both bikes sound great it's just one of them appears to be missing 2 cylinders...

TWO!! :smilie_happy: Umm the Royal Enfield is a single. :whistling:
You're Slabghost. It is a model J2. Single cylinder but head had 2 exhaust ports so it looks like a twin.
 
Top