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Well this is an old, but helpful thread. Thanks for digging it up PeWe!
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I'm just selfish
I need advice from other CB750 guys with tuned engines with VM29 carbs and their jetting experiences.
Your thread is a good start since it contain facts about one case. (Now with more setups since other VM29 guys have joined the thread!
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I read Kawasaki threads and understood that the VM29 jettings differ due to the different VM29 setups from the very beginning.
CB750, Kawasaki and Suzuki have different std setups in the Sudco catalog, not only mains and pilot.
My current setup worked 1984. Not too rich, I jetted richer when the bike ran a little bit lean.
Popping sound during decelerations (pilot) and bike accelerated when release the throttle at full speed, (lean main). pilots 25, mains 127.5 was rather OK then.
After the problem with cracked boots I used original carbs. Needles one step up (clip one step lower) and mains 147.5! Worked very well, maybe a little bit rich, but not what I experienced when driving, visible when lifting the head many years after.
2013: Hotter cam , CX-7 (close to Megacycle 125-75) , stiffer carb boots and NGK iridium plugs + PAMCO Ultimate ignition.
I think I can jet the carbs OK by using jets closer to the initial recommendation.
I hope that more people can write their VM29 setups here as this thread asked for from the beginning.
If all 4 carbs behave equally it is smaller risk for cracks or other problems, right?
I can imagine that all 4 can become dirty, oxide that block the internal passages. But too rich, float levels OK must be the jettings inside.
If the carbs are bought used, the PO might have drilled somewhere? Marks on jets say something else than the reality.
- Air jets can be blocked? It must be easy when they are placed very open.
Thread with air jet talk
http://www.jdsleds.com/community/viewtopic.php?t=5206&p=37206Here another good carb tuning links.
http://www.3cyl.com/mraxl/manuals/carbtune/carbtune.htmhttp://www.dansmc.com/carbs2.htmI have to spray my carbs with carb cleaner. They were very clean but I saw some white powder when opening them to check the setup. Oxide that can still be there and need to be flushed away.