Carb intake manifold worries......tips for "re-use/ limping"

my bike is an 82 650, i have completely torn down the carbs once so far for cleaning, they werent that bad but it did help out. there is still an issue that i cant cure that is boggling my mind, and the symptoms all lead to an air leak from what i understand.

the problem i am having is that when trying to warm it up, the idle will rise and lower about 200-500 rpm's every once in a while, and takes about 10 minutes to warm up. i will have to raise the idle for a while then lower it back down. once i get riding it just about goes away. so far the previous owner of this bike has used some silicone on the intake manifolds (from engine to carb). i still saw some cracking so i put some more on it.

A while back i read something and cannot find it again, someone said that you can use a bicycle inner tube and somehow wrap it around it or something like that. does anyone remember seeing this, OR:


Short of buying new ones (new baby here) is there anything i can do that will help this out? Also: does this sound like i do have an airleak somewhere?

thanks in advance!

 

The inner tube is a bad idea in my opinion unless its desperate you will have to use vulcanized rubber solution to stick it. You’re probably best of buying new ones; usually an indication of an air leek is a squeaking coming from the engine. All so there’s all ways instant gasket.
Or it could be carbs need balancing and setting up.

By the way have you not got any form of air filtration? Because this might contribute to the problem to much air and not enough fuel.

 

I am just going through this problem now. One cylinder wasn't heating up as fast as the others, and although I couldn't detect a miss, it would backfire once the revs got up. I felt around carefully on the intake manifolds and discovered air moving from the #4 intake. I removed the carb bank, removed the manifold only to find only half a gasket. (I've only owned this bike for a month so some PO was to blame !) My dealer said 'in a pinch' I could use some silicon, but it's going to rain for the rest of the week here, so I ordered a new gasket and the manifold itself was 'really' cracked and showing it's age, so I ordered one of those two. Price for the gasket was around $6, the manifold was $53 for an 82 750 Seca

 

Carefully inspect the inlet rubbers - it is likely that they may be cracked on the outside but fine on the inside.

I have used the bicycle inner tube - from a mountain bike - on my rubbers before. The p.o. had smeared black RTV sealant all over them so I feared the worst.

When I cleaned it off they didnt look too bad, in fact, there was minimal cracks but the clamps had chafed quite deeply, so I cut some sections of inner tube and slid the hoop over the rubber and held in place with some high temp RTV black sealant.

I looked almost like a factory job! (There is a pic in my gallery)

 

Re: Carb intake manifold worries......tips for "re-use/ limp

I went one better than the sylicone idea on mine. After seeing the cracked intake boots, I covered them with GOOP and painted them black with high temp paint. I haven't had a problem with them since and that was 4 years ago.

 

I had one Manifold that was split.
I held the Split open from the inside and "Troweled-on" an application of Plasti-Dip."

http://www.plastidip.com/home_solutions/Plasti_Dip

Following the Plasti-Dip, ... which bleeds through and got smeared on the inside, ... I coated the Outside with some:

Liquid Electrical Tape

http://www.plastidip.com/industrial_sol ... Insulation

Simultaneously, coating the inside of a small Latex Rubber Patch.
(A small patch cut-out from a band of Exercise Rubber Strip.)

I applied the Patch and used the Cap of a Bic Pen to position and smooth the Patch over the Split. >> You need to work fast. The stuff sets real fast.)

Covered the Outside of the Patch with a coating of Liquid Electrical Tape.
Let it dry.
Sanded it smooth with Plumbers Sanding Strip.

"Painted it" with BLACK Nail Polish.

Works like a charm.

 

**** UPDATE****

well guys, i just bought a bicycle inner tube, cut it into 4 small sections, slipped it over then pulled it back a little bit so that i could spread a little silicone under it - then i pulled it back over (kind of like unrolling your sleeves).

After that i spread clear silicone over the entire outside and smoothed it out.

Once i installed everything back together again ( i did do a simple cleaning to the carb again too) i fueled her back up and it started easier, while also holding the idle better. i think i am on the way to getting this thing "truly" road worthy again! (traded it for atv parts)

thanks for the info guys! i know this wont last and it is just a band-aid, but with only 3.99 invested, i think it will last me through the riding season until next winter when i tear it down for a little bit of modification....