Jump to content
Sign in to follow this  

1971 Kawasaki G4TR 100 Carburetor help

Recommended Posts

Hello everyone, I am in the process of restoring a 1971 Kawasaki G4TR 100 dirt bike/street. It has been in the family since it was brand new and I have run into a dilemma. The original carburetor was removed from it, and it has gone missing. My question is: is there any kind of universal carburetor that I can buy that will fit that model of bike? The original carburetor was a Mikuni VM19 sc, and to my knowledge, that carburetor has become obsolete. I've been extensively searching for that original model carburetor on eBay and I have come up empty. I would really appreciate if you guys could help me through this issue. Thanks.

I apologize for positing this thread twice as to I am new to this forum.

  • Like 1

Share this post


Link to post
Share on other sites

Unfortunately the carburetor for that bike and most other rotary valve singles are unique to those engines because of the design for the idle speed/throttle stop screw as the design allows access to it from the outside of the carburetor chamber through the sealing boot on the top.  Also the method of clamping or mounting to the rotary valve cover is unique to this style of carburetor as the clamp is on the carburetor itself with some early plastic as a sealing gasket, unlike most other similar carburetors that push into a rubber holder.  The carburetor is also slightly more compact in overall dimensions than a typical 19mm VM carburetor to fit within the chamber and keep the engine as narrow as possible.  I have a 1974 MC1M (90cc motocross) that uses a nearly identical (but not the exact same) carburetor as your G4TR, differences include venting and overflow outlets but it is the same size and model.  I guess long story short is not just any 19mm VM will work on your engine.  You can see my bike in the link below as well as videos on how to get the bike running, after you find a carburetor of course.

 

Kawasaki MC1 M my $25 bike 

 

**edit*  There is a carburetor on Ebay right now (the KV100 uses the same carb as well)

 

 http://www.ebay.com/itm/75-Kawasaki-KV100-KV-100-G4-TRE-TR-G4TR-carb-carburetor-/400499231868?pt=Motorcycles_Parts_Accessories&hash=item5d3f9d4c7c&vxp=mtr

Edited by thejunkman

Share this post


Link to post
Share on other sites

Hey thanks a lot for your reply. Your information is very valuable to me. So basically in other terms, I am screwed when it comes to finding a universal carburetor for the '71 G4TR 100 that wouldn't be the same exact factory size but it would still fit and work? This is the very first time I've ever restored a dirt bike(except playing around with an old rupp mini bike 25 years ago) so I've been doing a lot of head scratching lately. I've spent countless hours researching about finding a replacement carburetor. That carburetor link that you sent me would obviously be the right one, but to be honest, I can't spend that kind of money right now. So my options are limited? Thanks again for your help. I've been looking for the explanation you gave me for a while. Much obliged.     

Share this post


Link to post
Share on other sites

Well that is the thing with restoring or working on very old bikes.  You have to be ready to spend, sometimes, a lot of money on one crucial part.  In this case the carburetor, which is crucial and cannot be substituted with another carburetor easily.  Oh sure with enough modification, ingenuity anything is possible to make work but at what cost.  Basically it will be hard to find any other 19mm carb that will mount and fit behind the cover AND the throttle cable and the choke will work with the carburetor boot/cap that sits on top since it is a fairly unique design for a carburetor that has to be sealed to the outside of the engine cases.  Besides most new and used "universal" carburetors are going to run around $50-$100 even if they would work.  The other caveat to using a different carburetor than original opens up a can of worms when it comes to jetting.

 

If the bike is complete (and is free/hand-me-down) other than the carburetor, then the price is not all that unreasonable if you truly want to get it back on the road or trail.

 

If you watch this video you can see close up what your carburetor should look like as this bike I am working on in the video uses a nearly identical carburetor.

 

Getting an old bike running again

Edited by thejunkman

Share this post


Link to post
Share on other sites

Yes I agree with you. I'd probably end up spending more money fabricating another carburetor than the original one you posted. And not to mention, it'd be way less of a headache than making one fit that didn't belong on there in the first place. I'll more than likely end up ordering the carburetor that you have previously posted. Thanks a lot for your help.  

  • Like 1

Share this post


Link to post
Share on other sites

The rotary disc cover fits a bunch of bikes (part# 14019-032) I think a carb from any of those could be adapted.

 

 
 G3SS (1970)
 G3SS-A (1971)
 G3SS-B (1972)
 G4TR (Trail Boss) (1970)
 G4TR-A (1971)
 G4TR-B (1972)
 G4TR-C (1973)
 G4TR-D (1974)
 G4TR-E (1975)
 G5 (1972)
 G5-B (1974)
 G5-C (1975)
 KD100-M1 (1976)
 KD100-M2 (1977)
 KD100-M3 (1978)
 KD100-M4 (1979)
 KD80 (KD80) (1975)
 KD80-A2 (KD80) (1976)
 KE100-A10 (KE100) (1981)
 KE100-A5 (KE100) (1976)
 KE100-A6 (KE100) (1977)
 KE100-A7 (KE100) (1978)
 KE100-A8 (KE100) (1979)
 KE100-A9 (KE100) (1980)
 KH100-B7 (1976)
 KH100-B8 (1977)
 KM100-A1 (1976)
 KM100-A2 (1977)
 KM100-A3 (1978)
 KM100-A3A (1978)
 KM100-A4 (1979)
 KM100-A6 (KM100) (1980)
 KM100-A7 (KM100) (1981)
 KV100-A7 (1976)
 MC1-A (1974)
 MC1-B (1975)
 MC1M (1974)
 MC1M-A (1975)
  • Like 1

Share this post


Link to post
Share on other sites

Much obliged for everyone's help. I will post the outcome of my carburetor replacement as soon as I figure it out.Thanks again everyone. 

Share this post


Link to post
Share on other sites

Yes that one will work.  I see a lot of varnish on the floats so it will need a thorough going through if you get it.  The rubber boot/carburetor cap is torn and not usable.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×