Suzuki T20 Carb Main Jet

[ettore]

Greetings All,

I am rebuilding my 1966 Suzuki T20 carbs. I bought two rebuild kits and they come with a #90 main jet. My carbs have #85 main jets. My parts book lists a #95 as what appears to be the standard size and #'s 85, 90, 100, 110 as optional main jet sizes. Am I significantly affecting performance using a main jet #90 versus my current #85's or the standard #95. I am a little confused, any help would be greatly appreciated. Thanking all in advance for any help.

Charles

[ettore]

Sorry I forgot to mention the carbs are Mikuni VM24SH models, my bad.

Charles

[jabcb]

Suzuki issued service bulletins providing carb specs for the various model years. Parts manuals are not necessarily correct.
See Service Bulletin Specification-11: http://www.ozebook.com/compendium/techb ... 010-14.pdf

There probably is a number stamped on the carbs. Probably on the flange or near the starter mechanism. It's the second part of the carb part #. You can use that to see if you have the carbs that are stock for your model year.

[ettore]

Jacob,

Thanks for the reply and link to the T20 carburetor information. The only thing stamped on any of my 4 Mikuni VM24SH carbs is an "E" on the flange that mounts to the engine. My jet needles are stamped 4DH5, not 4DH5-3 as the carb info states. I am guessing the -3 is an indication of which slot the needle cir-clip is suppose to go into as there are 5 slots and 3 is the correct setting for positioning the needle jet. My rebuild kits are from Keyster Carburetor Parts for motorcycle models Suzuki T20 the rebuild kit number is KS-0007. The replacement needle in my kit is stamped Y-2 not 4DH5 and the main jet is #90 not #95 as indicated in the carb info. Am I correct to assume #90 is a leaner jet than the original #95 and could this Y-2 needle be sized for this specific jet, even though the parts manual shows only one needle for the carburetor and 4 main jet optional sizes, the #90 being one of them. Any insights would be welcomed, Thanks again for the information link.

Charles

[jabcb]

I haven't worked with any Suzuki carbs as old as yours. Didn't know if Suzuki stamped the carbs back then or not.

You are correct that the "-3" refers to the clip position & is the one in the middle.

You are better off using genuine Mikuni parts if you can get them. Pilot & main jets should not be a problem. But needles & needle jets for a lot of old Suzuki two strokes have long been no longer available.

#95 main jet is stock, but individual bikes may run better with an optional main jet.

jetsrus.com has lots of info that will help you figure out which ones to get.

For best results, Ivan Performance has a carb kit for your T20. Its pricey but he has done the work to get results better than stock.
http://www.ivansperformanceproducts.com/T20.htm

[alanr]

For what its worth, l tried keyster in my old t350.ran like rubbish so l cleaned old parts and put them back in.back to normal running. I found the best place for the keyster was in the rubbish bin.

[ettore]

Thanks for the link to Ivans site. I am feeling the same way about Keyster Kits at this point also. Not only is the needle wrong but the float bowl gasket is to small and the holes do not even line up. Think I will go back to #95 main jets and the original needles (4DH5-3) Cannot say how much I appreciate the information and thoughts regarding carburetors.

Charles