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Old 12-16-2014, 09:42 PM   #1
Graybeard81242 OP
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Location: South Central Colorado
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Mikuni BS 36 carburetor question

My 1983 Suzuki Tempter has Mikuni BS 36 carburetors that are running very lean in the mid range. They are so lean that the engine misses and back fires in that range It runs better with the choke on. The float height was something over 25 mm when I took it apart. The Tempter manual says 23 mm for the BS36 but a great CV rebuild tutorial http://www.mtsac.edu/~cliff/storage/...d_Tutorial.pdf claims they should be at 21.6 mm. I set them at 22.4 mm but have not put them back on because I want to raise the jet needle.

I didn't have a tool to remove the C clip the jet needle but ordered one and should have it Monday. My plan is to replace the thick plastic spacer on top of the needle clip with something thinner, but I'm not that familiar with Mikuni CV carburetors. Any suggestions would be appreciated.

Graybeard81242 screwed with this post 12-17-2014 at 07:32 AM
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Old 12-16-2014, 09:58 PM   #2
Duck_Pilot
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Quote:
Originally Posted by Graybeard81242 View Post
My 1983 Suzuki Tempter has Mikuni BS 36 carburetors that are running very lean in the mid range. They are so lean that the engine misses and back fires in that range It runs better with the choke on. The float height was something over 25 mm when I took it apart. The Tempter manual says 23 mm for the BS36 but a great CV rebuild tutorial http://www.mtsac.edu/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdfclaims they should be at 21.6 mm. I set them at 22.4 mm but have not put them back on because I want to raise the jet needle.

I didn't have a tool to remove the C clip the jet needle but ordered one and should have it Monday. My plan is to replace the thick plastic spacer on top of the needle clip with something thinner, but I'm not that familiar with Mikuni CV carburetors. Any suggestions would be appreciated.
If it's like other Mikuni CV's of the day, each needle will have a thick spacer on top of the clip, and a thinner one by about 2/3 below. Try swapping those two first, and see how she runs. You shouldn't need to remove that clip... there's likely only one groove for position on that needle anyways, and all it does is locate position.

If that's not satisfactory, there's other tricks.... but this one will only cost you a little time. Good luck.
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Old 12-16-2014, 10:48 PM   #3
BiGR Rich
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If you head to Radioshack with your needle, they sell packs of really tiny washers for a dollar or two. Buy one pack and you'll have all the needle shims you could ever use.....

Edit: that link you posted is from Basscliff's site, correct? My phone didn't open the link, so I can't check. And I would go with the height from the service manual. I think the tolerance is +/- 1mm anyway, so you should be good there.
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Old 12-17-2014, 07:57 AM   #4
Graybeard81242 OP
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Mikuni BS36 Carburetors

Sorry about the link not working. Not sure how it happened, but it did not open for me either. I redid the link which seems to be working now. The tutorial was done by a guy named Ed Ness. This is one of the best tutorials I've ever seen.

The C clip in question is on page 63 of the tutorial. My C clip pliers were not long enough to reach it the ones I ordered should get the job done.

You are correct about the float height being + or - 1 mm which went into my decision to set it at 22.4 mm.

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Old 12-19-2014, 03:46 AM   #5
adventure950
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Have you thought of spending a little bit more and fitting a factory pro jet kit - fitted one to my cagiva elefant - uses mikunis - its transformed the running of the bike, they come with needles springs jets etc also have you checked the atomizer tubes have not started to oval out at the top - (very hard to see - but this causes all kinds of bad running problems).
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