Bab Joints ...

I pulled the carbs off my XT350 this afternoon . I found massive air leaks . Both carb holders ( Yamaha calls them carburetor joints ) were separated . By separated I mean that the rubber portion became separated from the aluminum base . The holders are an aluminum base with a rubber tube molded over that base . The aluminum eventually oxidizes negating the seal between base and molded rubber tube .

I have a 'fix' in mind . I'll try it tomorrow . Hopefully , it'll work .
Either way , I'll post the results .

Edited by pd350

Common problem. I'm interest in the fix. However, many have dealt with this before. In the end, most buy new ones. Age, environment, gasohol, and heat kill them off. If they are originals, look how long they have lasted so far.


Sudco and some others ell versions made by Mikuni. They work very well, and are considerably less expensive than the stock ones. However, the XT350 dual carb setup is somewhat oddball, so there may be no others than stock or fix-what-you-have.

Edited by Yamaguy55

Update :

The XT runs very good . biggrin.gif

The fix : As I said , both joints were separated , completely . I cleaned both pieces ( aluminum and rubber ) of both joints . Then applied a decent coat of Permatex High Tack gasket sealant to all mating surfaces and joined what needed joining . Being as I wasn't sure that a good bond was being formed , I decided to add a bit of support by running a piece of bailing wire from each joint mounting screw to and under the clamps that put the pinch on the carbs and then sharply bent forward . Once the air box tubes were placed , the carbs had very little deflection . Nice and solid . For how long ???

Of course , while I had the carbs in hand , they underwent a thorough cleaning . I replaced the stock OEM #42 pilot jet with a 22.5 Mikuni long body pilot jet . The Mikuni jet happens to have a slightly bigger oriface than the OEM Tekei jet .That slightly bigger pilot jet most definitely added low and into mid range torque .

Edited by pd350

The Tekei carb jets are very hard to get for the XT350s and XT600s, but there is the TT versions of both, and they use larger jets than the street(ish) versions. I used jets from the TT350 when I had my XT350, and they were just right. 


The biggest problem with using other jets is you can't go back. That may or may not be a problem, but it is a consideration.

Iv done the same re glue job but i used devcon because its flexible and heat resistant should outlast the bike now :)


The biggest problem with using other jets is you can't go back. That may or may not be a problem, but it is a consideration.


The main jet has a different thread , for sure .

The pilot jet threads are a perfect match with the Mikuni jets I have . The threads on each laid into each other seamlessly . The Mikuni jet screwed in just as easily as the Tekei jet .


As for the bailing wire support , I know it's not the end all system but hopefully it'll buy some time . My intention was to hold the rubber against the aluminum more than supporting the weight of the carbs . When / if I need to do something else , I'll fab something better .

Update :


It's been a bit more than 3 months since I did this 'repair' . I should have noted the mileage , but I did not . I'd say maybe 500 miles has been covered on varying terrain and definitely through an  array of weather conditions . I should note that the bike lives outdoors 24/7/364.5 .

So far , everything has held tight and no leaks have formed . The motor has ran in a consistent manner , adding to my confidence in the repair each time I ride .

Edited by pd350

I did that same glue job but with rtv black Hightemp silicone. it has been good for 9months zero leaks and no separation visible.

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