Anyone know of a how to?

[Thet]

Anyone know of a how to reassemble (with pictures preferably) a completely disassembled 81 carb set? I bought a project off a guy I used to work with and just realized the carbs he gave me in the box are 100% disassembled.

Any help would be much appreciated!

 

[azman857]

I think its bikers.net are manuals you can look at and print out what you need for free.

 

[5twins]

I don't know of any step-by-step write-ups w/ pics for any of the 650 carbs. Basically, you just have to know carbs and study up on the 650 ones in particular. They have some unique features I've never run across before in any other carb. As mentioned, an exploded parts diagram is probably the best place to start. I like the ones from the Yamaha USA website here .....

http://www.yamaha-motor.com/sport/m...L2hvbWUuYXNweA==/Parts Catalog/starthere.aspx

Be aware that there is one glaring error in their BS34 diagram - the floats are pictured upside down, lol.

This is how they should look when installed correctly .....

There are a couple other BS34 specific details you'll need to get correct. The mix screws should have a small o-ring and metal washer on them. The o-ring seals the screw in the hole and the washer keeps the spring above from destroying the o-ring .....

There should also be a rubber plug over the top of the pilot jet. This makes the jet draw it's fuel supply from the side only. Leave the plug out and the jet will pull in too much fuel and run rich. You can see the rubber plug in the float pic above. It's just to the left of the main jet.

 

[5twins]

There is a rubber coated metal "T" between the 2 carbs that feeds fuel to both of them. It's a loose fit into the carbs and seals by being pinched between them. If your carbs have been separated, you'll need to gently clamp them together so the "T" is tight and won't rotate before fully tightening the screws into the top and bottom mounting brackets .....

Here's some fully assembled pics showing details of the linkage and throttle lever/adjuster screw. Various choke parts are missing in these .....

And one more from the air filter side .....

 

[Thet]

I consider myself to be a mechanically inclined person, but... damn. haha
I'm thinking I might just buy a pair of Keihin carbs off of MikesXs

 

[littlebill31]

They are really not that difficult to put back together. I was a little reserved, but have gotten it down. It's tuning them that is a pain. But even if you buy brand new one's you still have to tune and sync them. Just takes some time. Probably more info and knowledge on the Mikuni then the Keihin on here and such.

 

[RFLIVES]

I have a set that came off my running 80 special I'd let go cheap if you need them

 

[Thet]

Ok, where in the HELL does this mix screw go??? :/

 

[littlebill31]

It's on the front towards the intake.

 

[littlebill31]

They are covered with a little cap. You may need to remove it if the screw head is not exposed. You can use a self tapping sheet metal screw. Gently, and carefully, screw it in and use the screw as a kind of handle to pop it out.

 

[Thet]

Ok, so I FINALLY got one of them together (L side as sitting on the bike) BUT...
I have some parts left over and I have no CLUE where they go...

Any help?

 

[RFLIVES]

45 bucks should fit in a med flat rate box so shipping should be 10.50 sorry couldent add pic's in a pm

 

[gggGary]

woosh.... Two throttle shaft seals. two and one half float valves. One float valve body
one throttle shaft spacer, two screws 1 lock washer and a washer. I am guessing the washer and lock washer are from the throttle arm on the throttle shaft. I hope you had more than 1 complete set to start with. It's kind of scary if the throttle shafts were out of the bodies.

 

[5twins]

Yep, you're gonna need some of those parts, lol. The 2 float needles with the wire clips are originals, the smaller one could be from some other carb. The float needle seat looks threaded. If it is, it's from an earlier carb. Yours are a push-in type sealed by an o-ring and retained by a small clip and screw. Those screws may be for that.