Sad news...

[Guest]

Well I was about to finish rebuilding my carbs when I noticed the slide on carb 2 won't go in so I found out that's why the linkage wouldn't work it's been in a fire...so I thought the carb was warped...so went to the classic motorcycle shop who's gonna do my electric work and they confirmed it along with the previous broken choke tube...they said it's better to buy a new set...it's just so discouraging if it isn't one thing it's another with this build...

[Bjones89]

Sorry I got off topic...is there any upgrade carbs I can get for a good price or am I better off with the vm26s?

[Larry D]

What bike do you have ?

[Nessism]

VM26's are common and cheap. You can post here in the WTB forum for a carb body too. In the grand scheme something like you describe is just a minor obstacle that goes along with keeping a 40 year old bike on the road.

[Bjones89]

Its a 78 gs1000

[Bjones89]

Yea but this is part of a list of things...and even tho it's cheap...it adds up along with all I got to get for my build

[Gumpster]

Probably just need the #2 carb body. There is a plastic piece that keeps the slide from rotating. You may try to dress it a bit and clean the groove in the slide. Attach a picture of the bore if you get a chance.

[chuck hahn]

There isn't a plastic kidney bean shaped part with the alignment post on VM carbs. You are thinking of CV carbs. VMs have the pin molded down inside the slide tower.

[jsandidge]

Yea but this is part of a list of things...and even tho it's cheap...it adds up along with all I got to get for my build

We've all been there. It's part of the experience. Once it's completed you'll have a fun, reliable bike you can be proud of.

[chuck hahn]

Customer of mine just dropped 1300 just in parts to resurrect a 79 Honda CB750K. Needed EVERYTHING from fork seals to new intake and airbox rubber and even a rotor rewind so it would charge. But like I told him, its all needed stuff for a 39 year old bike and once its done its god for the next 20 or 30 years. The initial tally kina sucks a little but most of the parts wont need replaced and then its just routine maintenance to be one.

[Gumpster]

20180307_132755.jpg
See location of plastic that align the slide on a VM carb.

[Gumpster]

Chuck
This is the plastic bit I was referring. Enough heat could damage it.

[chuck hahn]

It looks and feels a lot like its a metal pin to me. I have used steel wool down the bores to clean them free of crud and don't recall wearing any off. I will however take one out of the bin and take a better look. As I recall Suzuki indexed the slides on CV carbs by having that little tab on the diaphrams set into the recess on the carb body. I do Know that Keihin carbs like Honda uses have a grove in the slide that rides on the protrusion off the kidney bean shaped air jet cover.

[Gumpster]

It is not metal but some sort of plastic. You can actually see light penetrate if in bright sunlight or using a good flashlight.

[Chuck78]

Yes definitely translucent plastic indexing pin type piece molded into the carb slide bore side on the gs550/750/850 kz650/900/1000/Z1 Mikuni VM carbs...
that definitely can melt and distort.
Have you tried to make any adjustments to that with a razor blade or a small carbide type cutter tip on a Dremel tool? Does it slide in smoothly until it hits that plastic pin which is probably melted?


That is much more likely than the whole carb body distorting. I have seen the carb bodies just get corroded and the slide gets totally seized in there. Several bikes actually, that had sat outside forever. Sometimes I have freed them up, a few I have not been able to. The one by that caught on fire, it was actually the melted uni air filter pod foam which had gotten sucked into the carbs and was the culprit for jamming up the slides. It melted and hit the slides, then when twisting the throttle open after the fire was out, the slides got stuck in the up position. Previous owner had KZ1000 carbs on a GS750 with poorly adjusted floats or bad float needles or bad petcock, which flooded the bike that was backfiring like crazy due to valves never being adjusted. Caught it on fire. Luckily the tank did not turn into a lethal bomb.
Then my buddy got a bike that was $1300 the week before, now "on sale for $200!" I proceeded to rebuilt it for him with about $600 in parts, not including tires. And I gave him a 4 into 1 V&H & a gas tank I had that a deer made a huge knee dent in the left side... the other tank was badly distorted. $75 parts bike for wiring harness and carb rack...