Mixing 650 carbs, air screws with non

Heya.

I have 2 sets of 650 carbs, one's a '77, the other from another year. The set of carbs from '77 have air screws, the other does not. While screwing in pilot screws (not pilot jets) into the non-'77 carbs, the tips broke off and blocked the air passage into the carb body. I'd like to use the '77 carb bodies to replace the ones with blocked pilot screw passages, but if I do that, the 1-2 carbs will have air screws while 3-4 will not. What (if anything) can I do to make the disparate carb housings work together? Advice much appreciated.

Bump?

Just so nobody thinks they're being ignored :lol:
here's some guessing (which might be erroneous).

Likely depends on comparative flow characteristics throughout the carb range, and whether the respective carbs may be tuned to match each other's flow characteristics throughout the throttle ranges.

Even with equal bores, each carb has its own peculiar jet needle, needle jet, needle clip position, and throttle slide cutaway (and perhaps other distinctions that influence flow characteristics).

Sync at idle rpm may be possible.

But at half throttle, for example, would perhaps need an exhaust analyzer, or other method, to determine differences in quality and quantity of air-fuel mixture being delivered by each carb.

After a test ride, could immediately use an infra-red thermometer heat gun to determine temperature differences between the exhaust headers, which would help indicate differences in the air-fuel mixtures involved.

Meanwhile, perhaps someone will offer suggestions about how to remove broken pilot screw tips broken off inside a carb.

Good Fortune!

Yeah. Building a franken-carb might be more trouble than its worth.

Looks like any tips removing broken pilot screw tips from the carb is the next step. If that's possible, the search did not seem optimistic.

Infrared thermometer, eh? And here I've been using a spray bottle like a sucker all these years!

It can be done. In the hands of a pro like wiredgeorge.

www.kzrider.com/forum/advsearch?q=tip+br...te=all&childforums=1

Good Fortune!

A & A Cycle (a Yamaha Dealer/Motorcycle Junkyard)in Oklahoma City has literally hundreds of KAW Four carbs(as sets of four). "Mouse" the proprietor(ask for him), is also very knowledgable about such things. Thier phone number is: 405-634-4033.

I have a '82 650 CSR that he has been very helpful on.

Lee

That'll teach me not to read the thread all the way to the bottom.

Off to buy a dental pick. I put the carbs in the freezer, maybe the bits'll come out easier.

If not, TIME FOR EXPERIMENTAL JB WELD THERAPY *cue ominous music.

Patton wrote: It can be done. In the hands of a pro like wiredgeorge.

www.kzrider.com/forum/advsearch?q=tip+br...te=all&childforums=1

Good Fortune!

In the interest of completing threads for future generations of kz owners with carbs messed up from pilot screws broken off in the main body, this is how this adventure turned out.

The dental pick didn't help at all. Freezing the carbs didn't help either. The carbs I had with stuck pilot screws are now paperweights. Maybe you can drill them out, I don't know. Oh, and I broke 2 more pilot screws by over-tightening them. Opps.

I had to go back to my original set of carbs. The #2 carb had a giant hole chipped out where the pilot screws pokes into the carb throat. I was stuck trying to fix this set of carbs.

I got some JB Weld and very carefully put a blob in the chipped, big pilot screw passage. I then carefully screwed a pilot screw in to remake part of the (hopefully) correct passageway.

This dried over a day and I discovered the pilot screw by itself did not make a passage that was as big as the other carbs. But, I discovered that a 1/32" drill bit for a dremel tool is almost a dead match for the passageway. In the same way Luke had one chance to blow up the Death Star, I had one chance to drop the dremel tool in correctly and make a new pilot screw passage. So I did it. It worked. I very carefully made a pre-hole and then used the dremel's own weight to make a new passage.

Fast forward to ten months and many months of inactivity later, we finally found the culprit as to why the bike hasn't started in 4 years or so. An o-ring was missing from the choke plunger, plus the idle jets were totally blocked on 1 and 2. Found a carb rebuild kit i forgot I had and started digging around the bike again. F'ing Christmas around here, I tell you.

Anyway, hope to start lurking around the forums again now that she runs. But yeah. You can fix some carb problems with JB Weld and 1/32" dremel drillbits.