CR Special Carbs / '83 650 / occasional single carb fuel leak ?

I doubt that the seats need to be replaced. If the needles have a ridge around them, then I would replace them. I don't know what they get for real Keihin needles now a days. Sudco sells ONLY REAL FACTORY KEIHIN PARTS. I believe K&L has a needle that is a direct replacement, but their quality is not near as good as the factory Keihin parts. K&L stuff is hit or miss. Some folks here can tell you better than I can..........

thank you Nessism, really helpful intel as well !

question for you Dr G ....can I do this needle & o-ring swap with the entire rack of carbs still mounted to the engine ? (ie: caps off and bowls removed "only") or do I / will I have to remove the entire rack of carbs for this job to be done on my bench ? I would HIGHLY not prefer to remove the entire rack of carbs unless absolutely necessary ....let me know, thanks -

If you want to set the float height correctly, you have to pull the carbs. You have to get the carb bodies to be angled at a certain degree to set the float height. Everytime I replaced the seat o-rings my float height changed!!! I cheat now when I go to put the CR's back on the motor. I heat up the rubber intake boots with a hair dryer. Then the carbs slip right in!!!!

 

 

morning ....hey, if I could get a full copy of that float adjustment page(s) with all the text readable, and all drawings / diagrams and instructions, I'd highly appreciate Dr G !

There is only one tiny paragraph and two drawings on how to set the float height in my vintage '80's CR manual.

I never set up any of my CR's using the fuel level measurement in the bowls. I always got the same plug readings across all four cylinders with just setting the float height. So I never bothered doing them that way. You angle the carbs over till you get the weight off the spring inside the float needle. You want the little plunger on the float needle to be fully extended when you measure your float height.

Here you go!!!!
 

hey Dr Gamma, finally got around to swapping out the o-rings you recommended for the seats and installed new needles as well ......question, see these 3 pics .....noticed (first time since 1985 !) that one of these solid ports is drilled out, has threads in the hole but has no fastener (a bleed screw of sorts I would imagine) .....can you supply intel on what this 4th port is / does and why there are threads in it .....where you attach synching tool maybe ? ....bottom line: does this port need to remain open or have something screwed into it ? ....THANK YOU !!!!

There is a little bracket that holds the fuel tee in place from sliding back and forth. It is held in place by a screw that threads into that place on #2 carb. I just went and checked the carbs on my bike and I removed that bracket years ago and have not have any problems since removing it!!!!! I say don't worry about it being missing!!!!

awesome, thanks for checking your bikes .....hey, my 650 has been running good for decades with nothing threaded in there, so be it ....have a great Summer !

question on my air fuel mixture screws: how best to adjust that air fuel mixture with those flathead screw adjusters ? ....my 650 runs great but I do find my plugs not chalky brown enough for my preference, so their darkness tells me she is running a little rich on all 4, can the air fuel mixture screws help lean the carbs out resulting in a more lean fuel burn ? ....

Uncle Freddy wrote:

Houston: WE HAVE A PROBLEM .....bike started and runs great, warmed up fast and firing on all 4 .....but with petcock wide open, fuel literally squirting out of the vent holes for #2 carb ?!....I have the air cleaners off and the dual stream of fuel is shooting literally on to swingarm .......assuming the float is stuck for #2 ? or ? ........all troubleshooting help appreciated .....nothing coming from the other 3 carbs ......I have never seen this .....cut the petcock off, bike running great no fuel squirt from #2, open the petcock to feed whole rack of carbs, fuel squirt out of vent holes (or whatever these holes are) from #2 carb ......

 

Drain that bowl into a clear glass container and look for small pieces of trash!!! It don't take much to keep the needle from seating. Maybe the float is stuck in the down position.
Yea the CR's will piss fuel all over the place when the needle sticks!!! Check the float height again. Just look across all four floats they should all line up. When you set the float height
you have to have all the weight off the floats. Thats why Keihin wants you to lean them over like 30 degrees when you check the floats. Does your gas tank have any rust flakes or
dirt??  To save the hassle of taking the carbs off if they keep pissing bench test them first... 

 

well, I drained the bowl for #2, dropped the bowl, zero dirt nor trash, bobbed the float, freely moving ....I had just put them back together after entire rack on bench for o-rings & needles and their interiors were immaculately clean ....put the bowl and drain plug back up, started the bike, opened petcock, squirting fuel leak from # 2 gone now .....bike running great .....see my next post about getting the 4 of them to run leaner a bit ....off to shoot around some back roads with her & go fill the tank after her winter Zs ......THANK YOU Dr Gamma !!! (to note: gas tank clean & clear, zero debris nor rust (I did the Kreem inner coat 15 or so years ago, looks great in there) and the petcock filter strains for super fine debris)