tonyc
XS650 Guru
Bill my next build I am going to run a single carb but I will use a plenum. I think there will be ample fuel to cool either cyinder.
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Replacement carburetors for XS650?
- Thread starter jim540
- Start date
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- Tags
- carburetors
Let us know how it works out.
jim540
Wrench turner :)
tonyc
XS650 Guru
Bill it will be down the road I have to finish my BSA engine first. I could experiment with my 78 xs.
Here is a picture that Joe Wiseguy sent me. Looks like something new he is working on.
Hey, if nothing else it gets the carbs out where they're easier to work on.
Good point Bill. I guess you could tune the intake tracts to length. Trial and error, probably only take 2 or 3 hundred goes to get it bang on.
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I'm sure there's some sort of algebraic formula that one could use to figure it out but it's beyond my pea sized brain.
I found that with an oil cooler the head and cylinder temps drop about 40-50 degrees and evens the left right to less than 5 degrees.
When running one carb the cooler will balance the cylinder temps.
Leo
When running one carb the cooler will balance the cylinder temps.
Leo
jim540
Wrench turner :)
I have been looking at carburetors and I was curious if there would be and difference in tuning a flat slide compared to a round slide?
No, the steps are the same, unless you're dealing with a dedicated 4-stroke pumper; then the steps are still the same, only with less fiddling.
jim540
Wrench turner :)
The TM series looks like they use the same jets and needles as the VM's.
Mostly, yeah, except for PJ's and NJ's--different series entirely. Member timg at XS650 Garage reported success with TM34 jetting that's very close to what you'd use in the VM34; the thread is "stickied" at the top of the Carb board for easy reference.
jim540
Wrench turner :)
Thank you. I will check it out.
jim540
Wrench turner :)
So in my checking out the Mikuni TM36 flat slide carburetor I have found that they are offered with and without accelerator pump. My question is, is it worth the money or necessary to go with the accelerator pump?
The TM36/68 is a dedicated 4-stroke carburetor--essentially the Radial Smoothbore (RS) type configured for single cylinder use rather than in banks of 4 like the RS34, RS36, and RS38. I use them on my ported and cammed 700 cc. engine, and they're wonderful carburetors, but carb bodies must be drilled and tapped for bracketry , throttle shafts must be linked, and a push-pull throttle system must be installed. If I had it to do over, I'd use the 34 mm. kit for the XS 650 from Topham Mikuni in Germany, at www.mikuni-topham.de (Mikuni America evidently decided we didn't need the 34's). The TM33/8012 also shows promise; as the venturi is unobstructed by a throttle plate, 33 mm. is plenty big, and unlike the larger 4-stroke pumpers, the 33's mount the throttle shaft in front of the slide tower, enabling the use of extended mounts. If you can find a used bank of RS34's, you can split two carbs out of it; but be sure to mod the throttle shaft to hang the bellcrank outboard on the left to avoid clearance issues with the backbone of the frame.
There are several threads with tuning baselines here and at XS650 Garage; a little looking will turn them up.
There are several threads with tuning baselines here and at XS650 Garage; a little looking will turn them up.
1974jh5
Curmudgeon.
I'm going to wind up replacing the carbs on my bike because I still can't get rid of that damn flat spot and I'm tired of screwing with them. Anybody have experience with the Mike's PWK setup vs. the 650 Central VM34?
1974jh5, I see your signature says 80 XS650 street tracker. I assume this is the bike with issues. Your flat spot may be caused by the air filter itself.
What air filter are you using? If it is a tapered K&N style, even the large ovals. The CV carbs don't run as well with them as a straight bodied filter. A Uni-Filter will help there.
Maybe not as pretty as the others but work.
Leo
What air filter are you using? If it is a tapered K&N style, even the large ovals. The CV carbs don't run as well with them as a straight bodied filter. A Uni-Filter will help there.
Maybe not as pretty as the others but work.
Leo
1974jh5
Curmudgeon.
Yeah, that's the one. I've been running the XS pods on BS34's. These are not the garden variety BS34's, these have cast tops and easily accessible idle mixture screws. I think they are originally from a 500 twin.
Anyway, the bike ran GREAT with them, pod filters and all, for about 300 miles. Then, all on its own, it developed a huge flat spot just off idle. It's so bad that it's not rideable. If you pull out the choke (enrichment knob) the flat spot goes away. I started what turned out to be a LONG thread here about the darn things. http://www.xs650.com/forum/showthread.php?t=13245
I have cleaned the freakin' carbs about 4 times, right now they are sitting in a gallon can of Berryman digestive carb cleaner and will be there another day or two. If this doesn't fix it, I'm going to have to go to something different.
Anyway, the bike ran GREAT with them, pod filters and all, for about 300 miles. Then, all on its own, it developed a huge flat spot just off idle. It's so bad that it's not rideable. If you pull out the choke (enrichment knob) the flat spot goes away. I started what turned out to be a LONG thread here about the darn things. http://www.xs650.com/forum/showthread.php?t=13245
I have cleaned the freakin' carbs about 4 times, right now they are sitting in a gallon can of Berryman digestive carb cleaner and will be there another day or two. If this doesn't fix it, I'm going to have to go to something different.
If you do a bit of searching here and at the Garage, there are many threads on both carb sets.
The Mike's PKW Set up, One guy, I think it was spent $600 bucks to get them right, on top of buying them. Others have just bolted them on and road away happy.
The 650central VM34's are a tried and true set up and have the tech support of Micheal Morse. Very good fellow, Raced these bikes since forever.
Mike's Tech support?
Leo
The Mike's PKW Set up, One guy, I think it was spent $600 bucks to get them right, on top of buying them. Others have just bolted them on and road away happy.
The 650central VM34's are a tried and true set up and have the tech support of Micheal Morse. Very good fellow, Raced these bikes since forever.
Mike's Tech support?
Leo
1974jh5
Curmudgeon.
Mmm, yeah. Having tech support is good. I think there's my answer.
