Xs1 bs38 carb rebuild or ditch them for vm's?

[thrashin]

I've got my project xs1 running. After changing out the chargin system to the banshee system and pamco ign. I've got the motor running at idle. Anything more is pop pop pop out of the pipes. It will run at idle pretty ok. After I turn it off it will poor gas from the bowl overflows. Then it won't start again.

Pulled the carbs apart tonight to find a worn and bent needle in one. O rings are toasted in the seats. And the diaphram on one is torn up. I also feel a ridge on the inside of the upper needle slide. Possibly where the plastic ring that sits on the needle top has worn?

So I'm pricing parts from mikes xs and I'm over 150 pretty easy just finding what I've found tonight. Am I better off buying a new set of vm34's or any other good kits out there? Not sure I want to get a bunch of time and money in these to find they're going to be a much lesser carb. Opinions?

 

[jayel]

if you buy the VM's get them from mike morse, call and talk to him to setup carbs with proper jetting http://www.650central.com/

 

[5twins]

Personally, I would upgrade to a '76 or newer set of stock carbs. You should be able to acquire, overhaul, and set them up for around $100. That $150 in parts you quoted probably includes the slide/diaphragm assembly. You don't need or want that. Diaphragm only replacements are available for a fraction of the cost. Aftermarket carbs will run you anywhere between $300 and $600, maybe more because you'll still need to dial them in (buy tuning parts). If you're not good with carbs, you may never get them tuned right.

 

[littlebill31]

I'd stick with the newer 38's as 5twins suggests.

 

[thrashin]

yes, the 150 would include replacing the slider/ diaphragm assl. I haven't found them sold separately. They are 80 each and most other parts are 10-15 a piece. it's adding up pretty quick. I was hoping to get a pair of vm34's for under $400.

What is the difference between the later 38's and the one's I have?
I've got a few bucks saved, but I'de put it towards other parts if the vm34's are not as nice as the bs38's. what do you guys think.

 

[littlebill31]

The thing I like is the later models are linked, so one throttle and work better. Newer technology. You can get replacement diaphragms from JBM industies for 20 bucks a piece.
The 38's are very tunable and there is tons of tech help on here for them. The years of experience members have as well, on the 38's, will be worth it.

 

[5twins]

Oh, don't get me wrong, the VM34s are a good carb. It's just that they are a high performance carb. They will be harder to tune, more finicky in operation, need syncing more often, etc. Any kit you find for less than $400 will probably include inferior manifolds, air filters and throttle cable. All that will need to be upgraded eventually which will drive the price up. The kits that Jayel recommended from 650Central come with all top quality components already.

All 650 carbs from '76 on are linked and use a single throttle cable. This makes them easier to sync and they'll hold that sync longer. They're also newer and more refined than your original set. They just plain work better. Separate diaphragms are available from JBM Industries. At between $40 and $50 a PAIR, that's less than one replacement slide/diaphragm assembly.