No, I've never tried it, but I don't really feel the need. Once properly jetted and set up, these CV carbs respond quite well in my opinion. Whack the throttle open and the bike goes, no hesitations or flat spots. They say the aftermarket VM carbs with the cables connected directly to the slides give quicker and better responce but honestly, I don't know how much better it could get than what I have now. I read recently the comment by another member who has VM carbs that he has to feed the throttle in gently at lower RPMs because the bike won't take a big handful, lol. That doesn't sound better than what I have with the original CV carbs, it sounds worse.
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BS34s and white plugs
- Thread starter tommytwohands
- Start date
Its been a long time
Doesn't know nothing.
My experience (not on XS650) is that on a carburettor without an accelerator pump, you're likely to create a flat spot that happens when you open the throttle quickly. I wouldn't do it.
If you do, be sure to tell us how it goes please.
The older GS of the pair I have had slide carbs - VM26s or something. It was a technique to get rapid response from them without bogging them down, but easily learned. When I got the later bike with CV carbs that technique was no longer needed, but I'd say the fractionally delayed response was just about noticeable. Easily learned, though.
So, nothing in it, and as the factory had access to much better set-up information than I did, I just went with both of them as standard.
For the past 30+ years both of them have a big single SU and while that has its downsides, the freedom from balancing and messing around with four ancient carbs is definitely worthwhile.
So, nothing in it, and as the factory had access to much better set-up information than I did, I just went with both of them as standard.
For the past 30+ years both of them have a big single SU and while that has its downsides, the freedom from balancing and messing around with four ancient carbs is definitely worthwhile.
Agreed if you have flat spot on accel you might need to up the pilot jets or adjust the needle. On US spec needles (single shim washer mod)
VM's are not worse, just not "automated" throttle control. Guess I'm so old I remember stock bikes that didn't have CV's and learning just how fast the throttle could be opened without bogging the motor. Cars were the same. Even with an accelerator pump, pre-vacuum secondaries you couldn't just mash the foot feed.
AUTOMAN
XS650 Addict
Q-Jets when tune correctly open the throttle instantly.
Before the air valve opens fully, a shot of fuel from the pull over enrichment(POE) down the secondarys eliminates WOT hesitation.
Same can be had with VM's when idle screw/idle air and cut-away is tuned. On lower overlap cam bikes only.
cliff
Before the air valve opens fully, a shot of fuel from the pull over enrichment(POE) down the secondarys eliminates WOT hesitation.
Same can be had with VM's when idle screw/idle air and cut-away is tuned. On lower overlap cam bikes only.
cliff
