Torn Carb Slider Diaphragm Issues?

[digitalsam]

I tore apart the carbs totally yesterday and soaked them, poked them with guitar strings, sprayed them with cleaner, blew them out etc and am now confident that they are clean and "all" the tiny holes and passages are clean.

First Issue: the third carb diaphragm is torn. Can I ride with the tear, or do I need to wait for the news one to arrive? What is the potential damage or will it even run?

Second Issue: the brass jet screw next to the main jet on the third carb was stripped, I poked at it with the wires and think that it is clean, but what can I do to get it out?

[Montreux_Blue]

I believe a few people have used "gasket maker" RTV on torn diaphragms to make them work again. I don't believe it will run well at all without any vacuum to raise the slide and would basically be running on 3 cylinders above idle.

[oseaghdha]

I have read where folks have patched the diaphragms with RTV. Hell, I guess you could put a tire patch on it.

My idle jet was stuck as yours is and I had to drill it out and clean out the threads. I don't recall what size drill I used, it was just about the minor thread diameter.

It's going to need to be removed or it will sit in there and mock you.

[digitalsam]

It's going to need to be removed or it will sit in there and mock you.

Drat! Drat! Drat!

[bikerphil]

I've done as follows to remove stuck jets with success and no drilling....

First, soak it down good with some PB blaster penetrating oil. Next, get out your small Allen wrenches. Between the metric and SAE sets, you should be able to find one slightly larger than the hole in the center of the jet. Carefully tap the Allen wrench of the correct size into the jet until it has a good bite. Loosen and remove the jet. The jet will be no good anymore, but most of the time it will thread right out without causing any damage to the carb body. If this method fails, get a left hand drill bit and go at it easy. HTH

[digitalsam]

Carefully tap the Allen wrench of the correct size into the jet until it has a good bite. Loosen and remove the jet.

Now that is good thinking! Dang! Will try that tomorrow at lunch. Good thinking!

[CatatonicBug]

A long, thin screw-extractor from Lowes works great on them too. The tip slips into the center hole and grabs on tight. Of course, this too kills the jet, and you'll need a new one.

[latexeses]

There is this solution. Pretty close to a sure thing.

http://cgi.ebay.com/ebaymotors/NEW4p...item4149af8e7e

[digitalsam]

So, could a torn diaphragm and dirty carbs be the cause of a bike idleing well in neutral but during in gear?

[digitalsam]

... but during in gear?

sorry, I'm typing on my iPod. What I meant to say was but not when it is in gear.

[TopCatGr58]

Yes!

These carbs are vacuum controlled, and adjust via the vacuum slide according to the engine vacuum that's created during LOAD/RIDING conditions. When the bike's sitting there in neutral there's no real load on the engine, the vacuum slides barely move when you slowly turn the throttle. But when you're riding it, they will move quite a bit to allow the proper amount of air/fuel in according to the riding load.

With a damaged leaking diaphragm, the slide will NOT be able to move up and down to provide proper metering of the fuel/air mix=poor performance!! Fix the diaphragm or get a new one.
T.C.

[digitalsam]

I am going to attempt to repair the diaphram, but the jet is a goner. I will remove it this evening if time allows. For the new jet, how do I tell if the current one is stock? Are there different sizes? In the schematics, I think that is part number 53? Is that right?

[DGXSER]

Sam,

Most of the pilot jets or mains I have seen have the sizes marke don them. For the pilot jets it is on the side underneath the threaded area, for the mains it is usually on top.

Stock pilot jets for the 80 model were 42.5 and I think the stock mains were 120s.

[bikerphil]

I think that is part number 53? Is that right?

Yes, the pilot jet is #53 in the schematic.

[Montreux_Blue]

Sam,

Most of the pilot jets or mains I have seen have the sizes marke don them. For the pilot jets it is on the side underneath the threaded area, for the mains it is usually on top.

Stock pilot jets for the 80 model were 42.5 and I think the stock mains were 120s.

110 stock mains outside cylinders 1 and 4, 120 stock mains inside cylinders 2 and 3 on 80 SG "Special", so I have been told.