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<  Performance issues  ~  Keihin CR 29mm syncronization?

cadams600
Posted: Sun Feb 25, 2007 3:39 am Reply with quote
Rookie Rookie
Joined: 20 Feb 2007 Posts: 2 Location: the mile high city
Hello all,

I've got a set of 29mm CRs on my 1977 750F2. They need badly to be sync'ed. Last time I ran the procedure, I ended up with one carbie backfiring into the filter. Further "ear" tuning yielded a better idle and response, but now there's an intermittent ticking noise like a rimshot on a tight snare-drum once the engine's warm.

Details: There are no vaccuum ports on the body of the carbs, so I've installed downstream ports with epoxy on the intake boots. I've not done a compression test in a while or a valve adjustment, so there may be the problem.

Anyhow, once I get things all tuned properly, is the mercury method a decent way of syncing things? If I've got compression issues and no way to fix them right now, is the idle-drop method a good enough solution? Good details on the procedure? The shop manual's description is, um . . oddly translated japanese and kindof stumps me.
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Voxonda
Posted: Sun Feb 25, 2007 6:17 pm Reply with quote
Member Member
Joined: 01 Nov 2006 Posts: 42 Location: The Netherlands
cadams600 wrote:
Hello all,

I've got a set of 29mm CRs on my 1977 750F2. They need badly to be sync'ed. Last time I ran the procedure, I ended up with one carbie backfiring into the filter. Further "ear" tuning yielded a better idle and response, but now there's an intermittent ticking noise like a rimshot on a tight snare-drum once the engine's warm.

Details: There are no vaccuum ports on the body of the carbs, so I've installed downstream ports with epoxy on the intake boots. I've not done a compression test in a while or a valve adjustment, so there may be the problem.

Anyhow, once I get things all tuned properly, is the mercury method a decent way of syncing things? If I've got compression issues and no way to fix them right now, is the idle-drop method a good enough solution? Good details on the procedure? The shop manual's description is, um . . oddly translated japanese and kindof stumps me.



Hey there,

I always adjust my valves before a synch job. Works for me.
Think that goes for any type of carb's.
Hope to find some of these carb's myself.

Good luck.
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cadams600
Posted: Sun Feb 25, 2007 10:19 pm Reply with quote
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Joined: 20 Feb 2007 Posts: 2 Location: the mile high city
thanks for the wishes.

I got these new from a stealership. Pricey, but at the time worth it just to avoid caging it five hours to the nearest bike wreckers and slogging through all the crap trying to find something that might work. Definitely favors the top end. My next step is to try and fab up a semi-open airbox so I can do away with my crappy uni pods.

I got a healthier idle out of her this morning just fiddling with the idle mix screws and unplugging spark plug wires to see how much fire I was getting from each cylinder. Worked nice! I'll still do the synch most likely, though.

late,
charlie
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