Carb rebuild kit recommendations

[sarathchandars]

I’m a new owner of a 1979 GS850G. It requires work, obviously. I’ve been searching for reliable factory spec (preferably) carb rebuild kits but I’m finding it super hard to find one. I found a keyster ks-0525 but not sure if it works for my bike. Any recommendations for available kits from more experienced folks here?

thanks!

[Big Block]

I try to use the original jets and other hard parts if I can. I just clean the old parts and use new gaskets from wherever I can find them. Have you pulled them apart yet to see if they have original jets that are in good shape?

[Nessism]

Unless the brass jets are damaged, there is no reason to replace them. Clean well, and reuse. If the bike is high mileage, the float valve may be worn, in which case those should be replaced. Generally speaking, the original OEM brass jets and so forth, are better than aftermarket parts. The only thing you need for sure, is new O-rings and maybe float bowl gaskets. My signature has a link to where you can get O-rings.

[zed1015]

As others have advised.
Never replace any original brass internals unless they are physically damaged and then only use genuine Mikuni / Keihin items or Keyster if genuine is unavailable.
The only parts that may benefit from replacement are service items such as float valves, gaskets and 'O' rings.
The rest should just need a clean and ensure any drillings etc are not clogged etc.

[sarathchandars]

Thanks for the reaponses! The original jets seem to be in decent shape - the heads are sort of knackered I guess due to the use improper size screwdrivers.

Nessism I’ll get some O-Rings ordered from you!

[sarathchandars]

So there are few problems on deeper dive.
1. All 4 fuel screws are missing the springs
2. The tip of one of the fuel screws is damaged (about 1mm of the tip has broken off).
3. Float bowl o-rings are all shot and float bowl screws heads have been treated very inappropriately.
4. 2x float needle seats don't have gaskets.
5. Float needle seems to be in good condition under a magnifying glass.
6. Since I've opened it up, I thought of replacing the 2 gaskets - top and float bowl.
7. Jet needle tips seems ok under a magnifying glass
8. Choke plunger was sticky but forcing the movement a number of times seems to have released it (don't feel like disassembling the set completely)
9. Floats are fine
10. Main jets once cleaned look ok
11. Bleeder pilot jet orifices seem ok (any suggestions on how to test it, if even required?)
12. Any recommendations for a good soak? I used PJ-1 carb cleaner

Looking for recommendations on how to proceed.

[sarathchandars]

Also, while cleaning, I found a white powdery material in the float bowl. What is it?

[Nessism]

Also, while cleaning, I found a white powdery material in the float bowl. What is it?

Corrosion. If it's in the float bowls, it's also in the internal carb passages. You best do a full teardown and rebuild.

https://gsarchive.bwringer.com/bikecliff/images/vm_carb_rebuild.pdf

https://gsarchive.bwringer.com/cbsaunders/gs/pilot_screw_removal.pdf

[sarathchandars]

Very helpful, Nessism. Given the parts that are not proper (based on the points I shared), do you recommend replacing the parts as well?

[Big T]

I think Z1 Enterprises will have all of your carb parts at a reasonable cost

From what you've described, a full year down and dip is required to get your carbs ready to go.

Just follow the tutorial Nessism posted for your VM carbs

[sarathchandars]

Z1 enterprises doesn't have a full kit. some parts are missing too... I traced down one vendor who has parts from Keyster but there are two kits that look practically the same, and I don't have the knowledge to figure out if there are differences.

http://siriusconinc.com/products/detail/620

http://siriusconinc.com/products/detail/615

The KS-0525 is said to the one for '79 GS850G, but both the pilot and main jet sizes are the same between the parts. Need help!!!