First Carb Rebuild - 2 Mikuni BS34s

ebay is the only place I have seen them but they are always junk. I got mine about 5 years ago from a savage yard that is now out of business. :shrug:
 
I took a quick look at a chart and it looks like aluminum expands more than brass. Heat that thing in a pot of boiling water then try to push it out...watch your hands.
 
Been there as well. If you push anything in there hard (witch you would have to do) it will change the hole of the seat making it no good. This is why they changed the design of them in 1980.
 
I work for a fab company and we do powdercoating, s I'm gonna throw it in the oven for a while and heat it up to 400 and see what I can do. Good call on the boiling idea, in theory it sounds like a plausible solution, but my only concern would be water in the carb. Probably not anything to worry about, but the other advantage to the oven is it will get the carb twice as hot as boiling it.

I will post any results,positive or otherwise..
 
I work for a fab company and we do powdercoating, s I'm gonna throw it in the oven for a while and heat it up to 400 and see what I can do. Good call on the boiling idea, in theory it sounds like a plausible solution, but my only concern would be water in the carb. Probably not anything to worry about, but the other advantage to the oven is it will get the carb twice as hot as boiling it.

I will post any results,positive or otherwise..

I boiled my carbs in vinegar water for 2 hours to clean them- no problem.

My suggestion is based on theory, so who knows if it will work. I'm interested to hear if it works out.
 
Here is one other thought/question- seems like everything I have read thus far leads me to believe that even if I CAN get the screw ends out of the holes, there may be damage to the holes that they were stuck in (ie they were screwed so far down that it punched the holes out too big for new screws to do any good.).

But, correct my reasoning if it is wrong, wouldn't the fact that the tips are stuck imply that there is still a small enough hole diameter to "seat" the screw, it will just seat slightly lower than before the tip was broken?

To put it another way, the screw tip broke off and is plugging the hole- doesn't this mean that the hole is till small enough to seat a new screw? The "seated" position that I would need to find and then back off a few turns would just be slightly lower but will still provide a seal at the "seated" position?

Does any of this make sense?
 
Yeah, you'd just adjust the seat depth of the pilot. But I think the problem is that the hole is tapered and not straight (if I'm not mistaken) and you'd have to drill a hole similar..
 
Anyone know if you can use XS650 carbs on a 400? There are a bunch of them on ebay but none for the 400
 
So I just got a couple of carb bodies of eBay for under $60 and free shipping. They should be here by monday or tuesday. They were Mikuni BS34s, looked good, and had nothing blocking the pilot screw holes.
 
Damn, looks like I'm on my own with this project. I knew finding someone with the exact same problem on the exact same day was too good to be true. Enjoy riding your bike while I'm still getting these damn tips out. I'm just not sold that it is impossible yet.
 
Here is one other thought/question- seems like everything I have read thus far leads me to believe that even if I CAN get the screw ends out of the holes, there may be damage to the holes that they were stuck in (ie they were screwed so far down that it punched the holes out too big for new screws to do any good.).

But, correct my reasoning if it is wrong, wouldn't the fact that the tips are stuck imply that there is still a small enough hole diameter to "seat" the screw, it will just seat slightly lower than before the tip was broken?

To put it another way, the screw tip broke off and is plugging the hole- doesn't this mean that the hole is till small enough to seat a new screw? The "seated" position that I would need to find and then back off a few turns would just be slightly lower but will still provide a seal at the "seated" position?

Does any of this make sense?

Call me crazy, but I personally think you could get it to work fine. You'd just have to ignore the factory setting...and everyone else's setting and find your own tune.
 
you can push the tips through with a ground down nail. i've done it twice and no problems with tuning, still 3 turns from bottoming out.
 
Frisk, by no means am I giving up haha. I'm gonna drill the Ω∂ƒ© out of it! That's what's next for me. The new carb bodies I will use if my drill work sucks.

plus..we could always send them to drewpy and houghmade ;)
 
i used a tack hammer to get mine out. make sure the nail has a really fine tip on the end and tap it through. Of couse its a little larger, but I'm sure youve red that we all double the mix by 3 turns from bottom, so I think that there is no problem.
As I have said, I have done it on all my carbs and my bike can do the ton and cruise at 80mph all day!
Nuff said?
 
Call me crazy, but I personally think you could get it to work fine. You'd just have to ignore the factory setting...and everyone else's setting and find your own tune.

I think so too. I'm sure If I'm really careful, not too much can go wrong (knock on wood..or in this case Brass!).
 
Frisk, by no means am I giving up haha. I'm gonna drill the Ω∂ƒ© out of it! That's what's next for me. The new carb bodies I will use if my drill work sucks.

plus..we could always send them to drewpy and houghmade ;)

Best of luck, I'm gonna give it the ol' college try this weekend. I'm gonna bake it first and fashion a nail, and if that don't work, gonna get out the big guns!
 
Frisk! I got one of mine out! I took the tiniest size of drill bit I could get (which might even be a little smaller than the width of the original hole) and aimed it in through the top of the pilot hole carefully. Then I just started to screw it down lightly to seat it in there. The brass is so soft it seated fairly easily. I went back and forth between working the drill bit down into it with my fingers and using a vice grips. It popped through and left a nice even hole that looks great.

I've attached some pics, I hope they help bro.
 

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