Slightly stuck intake valve? Bad valve springs ( unlikely, but)
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Ninja EX500 carbs on an XS650?
- Thread starter Highside
- Start date
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- Tags
- cafe carburetors custom engine
May be the long way around but if you have the old carbs and they are good
you could mount them and eliminate the engine as the fault.
you could mount them and eliminate the engine as the fault.
Thanks. Compression testing on both cylinders is 145 to 150lb sq in. Bad valve springs, possible but I can't really check that.
For sure I'm in the realms of looking for something very unusual? It crossed my mind that the right side header internal pipe may have collapsed and be blocking exhaust flow?
Thanks. Unfortunately, the BS38 carbs are no good. I spent months and $$$ on them last year before getting the CVK34 carbs. The CVK34 carbs are to replace the BS38s.
I have some of the parts available to rebuild a good set of BS38s. But I think that's only going to happen when I'm completely out of ideas. My next idea is a collapsed inner right side header pipe?
It's a head-scratcher . . .
And the cause of right cylinder misfiring and exhaust smoke pouring from the right side carb? Drum roll.......
Blocked right side down pipe. See picture below where the outer pipe has split, the inner pipe is collapsed. Blowing as hard as I can, I can hardly blow through the pipe. Pushing a brazing rod at either end, it stops after maybe 15cm. No wonder the right side cylinder isn't running properly.
Blocked right side down pipe. See picture below where the outer pipe has split, the inner pipe is collapsed. Blowing as hard as I can, I can hardly blow through the pipe. Pushing a brazing rod at either end, it stops after maybe 15cm. No wonder the right side cylinder isn't running properly.
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Well, it had to be something totally freaking unlikely. Oh, how you must be looking forward to finally getting it right?
The joy of double wall headpipes...Are you sure that the pipe is not just blocked by some random debris? (If it was an old RD or other abused 2-stroke, i would suggest the remains of a piston and wrist pin. Don't ask why I wrote that....)
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Finger and toes crossed for you on this one.
After all that, completely out of left field.
Good to see you found the source, at least the carbs and electrics shouldn't cause any probs now.
Maybe you could cut open and take a couple of pictures? After all, this is a pretty rare problem 
Fwiw, Motad made a decent 2-1 in stainless. I've got one and it's fine.
Since the mixture screws on the CVK34 carbs are not very accessible on the bike, I ordered a pair of extended screws with a thumb grip. Idea is to make fine adjustments of the mixture screw easy by the road side if required. Seems a good idea. Unfortunately, being Chinesium one of the very fine screw tips is bent. Requested a new one to be sent. See what happens. Borrowed this picture to illustrate what I'm referring to.
Fitting a new exhaust has finally solved the running issues with my 650D back from the dead project. Just need to have the fuel tank and side panels back from painting and I think I'm all set for a few short road trials to dial in the CVK34 carbs and shake out any more gremlins lurking in there. But essentially after 18 months of struggling and meeting problems at every turn, the bike is finally back from the dead.
Now we need a little convalescence and it'll be one more XS650 returned to the road.
Now we need a little convalescence and it'll be one more XS650 returned to the road.
I bought a pair of of those extended idle jets . Snap! like you one straight one bent. I have a cunning plan to salvage it .
Vendor sent me another one FOC but I have wondered about straightening the tip that's bent.
Have to say, early days yet but I'm getting impressed by the CVK 34 carburettor conversion. Hopefully I'll get my fuel tank back from painting soon and then we'll see how it goes. Early signs are good. My first impression is one of reduced vibration. It's a 360 degree twin of course, but so far the motor does seem pretty sweet.
So, I have removed the rear cross brace from the CVK34 carburetors due to it clashing with the side panels. Now the side panels clash with the float bowl edge and screws. The is also another clash with the underside of the diaphragm if the first clash is removed. I know that others have successfully fitted the carbs and side panels. But it isn't working for me. Build tolerance issues, I guess. I'm going to have to buy another set of side panels and remove the section at the front edge of the panels. The panels are about 1cm and 3cm adrift from being fastened at the bottom. (I'm going to have to rotate the air filter hose clips, but they're not an issue).
