Thinning about rebuilding the carb on my RK. Has aftermarket pipes, upgraded cams, stock air cleaner. This was my Dads bike and he doesn't think the carb was ever touched. 56k miles, runs fine except its beginning to get cranky when she's cold, sometimes hiccups while riding.

So, what kits are tried and true? Did some digging and read the carb threads with jet suggestions. Have zero plans to change carbs, just rebuild, clean up and tune this one. The last thing in the world I want is for this bike to stink of gas when others ride behind me, but I know she has more in her right now. Looking for smooth power, don't care much about MPG, rideability, reliability, maybe a few extra ponies.

All hints, tips, suggestions appreciated.

 

CV Performance Tuners Kit, replacement parts and a good cleaning unjacked my CV40.

https://cv-performance.com/

 

If it ran good with it's current set up before, then consider why it is not now. Is it old fuel? Did the bike sit for a long time and the carb/jets just need a cleaning?

Personally, I would remove, disassemble, clean the carb and jets, check for intake manifold seal leaks before removing the carb, (they can leak just from age), leaking seals are easy to check using a propane torch or carb cleaner spray. Check the diaphragm etc. But not change anything for the time being. Once you know the jetting, let us know here what jets you have.

CVP does have a nice rebuild video and instructions. They also carry the intake seals. If it ran good in it's current state before, then give it a good once over BEFORE changing any jets and try to figure out why it's not running good now.

Once you return it to it's former good running condition, then consider changing the air filter to a free flowing K&N. The cams, and pipes are done, so I would think the air filter was changed also. Usually a cam and pipes requires a re-jet and usually a cam and pipes gets a new better breathing air cleaner, but you said it ran good before so I would start from there.

Don't complicate the diagnostics by changing jetting until you figure out why it' not running good. Once it's running good, then change jetting (and air filter if still a stock element) to improve the performance. YD

 

Thanks YankeeDog. Asked my Dad what he had done to it. He recalled putting in a Sportster needle and a sized 43 jet in it, otherwise stock.. He had a K&N on it but took it off. Has Stage 1 cams and HD "off road use only" pipes according to Dad. I put a dose of Marvel Mystery oil in it at the first fill up of the season.

I figure its possibly gummed up a bit from having 52k miles on it. I'd expect the emulsion tube to need cleaned and tarnish on the jets. Appreciate the tip on possible leaks. I didn't realize that.

 

Take the carb down, clean it, check the condition of the needle and the needle jet. Write down the size of your main and slow jets, and go from there. Consider putting the K&N back in, but probably need to rejet. Pick up a 45 and a 48 jet. I don't think the 43 is the correct number, they don't make a 43 sized slow/pilot jet. It's probably a 45. YD