1991 Kx 500 carb problem!

[Johnnybricks]

I seem to have found an unfixable problem according to all the kawi dealers.

My bike has been loading up big time has crap power and blowing a ton of smoke, after the usual checks, plugs, jets, gas, head gasket ect I replaced the bottom end seals and bearings while it was apart...... no go.  With a fresh top end and bottom end problem still there!    we found that there was a leak around the jet housing/caseing there are two saftey screws holding the housing witch all the jets sit in( make any sense?)
We have tried to re seal it with gasket maker but didnt work.
every dealer says its a manufacture DO NOT REMOVE part and dont sell the gaskets

anyone have an idea or had this problem before?

[Friar-Tuck]

 Hey John,
 Welcome to the forum.  I didn't see that you checked to see if the reeds sit tightly against the block at rest.
   What can happen if the reeds are worn/cracked chipped is that the fuel air mixture will get blown back across the carb and pick up more fuel creating havoc trying to jet the bike and making starting difficult.

  If you have already done this, it may just be time to get a new carb. 
         Most of these bikes have been around a while and the carb body can just get too sloppy.    I had an '85 CR5 I swapped out carbs on from an '99. 
    I was experiencing the same kind of frustration trying to jet it.   Put the old PJ back on and the bike ran pretty darn good.    I used the same cap, slide, needle, pilot and main.  It had to be the body.
   For what it's worth.
  Tuck\o/

[Johnnybricks]

Thanks for the info, I have checked and inspected the reeds they are all in great shape. I feel the same way its the last option at this point not much else to check or fix! I'm on the look out right now for a good carb.

Thanks again.

[cbxracer30]

I just picked up 2004 kx125 and it has a mikuni 38 tmxx carb on it. The carb can be bored to 41.5mm and is a very narrow front to back so the carb would be closer to the motor for better bottom end. I'm sure the jetting would need to change along with a possible needle change, but I really like the looks of this carb and there was one on ebay for $80 buy it now.CBX

[Friar-Tuck]

Hey John,
 CBX has been around and his recommendation is good as gold..  I If I had the sheckles I'd like to give that TMX a whirl.
  I can verify my 38mm Air Stryker certainly wakes up the throttle response. 
The 39.5 PWK's are usually around   $200.00 - $250.00 range..  Decisions.. descisions..
    I'm sure you'll get it worked out..
  Tuck\o/

[Rd]

Johnny
Where are you located? If another member is close enough maybe someone would be kind enough to lend you a good carb to verify your diagnosis. I know that would make me feel alot better about dropping the $ on a new carb.

[Friar-Tuck]

 Great Idea RD,
John is Ontario Canada
  Tuck\o/

[crawford]

I think I have heard of that carb body problem you described,the carb has two safety type screws holding the casting together,the gasket between is not available,it's not meant to be serviced,sometimes you can get lucky and put a light coating of yamabond and reassemble,then pray it seals it up.

[Johnnybricks]

Thanks for all the info. I have tried to seal it up twice with defferent compounds to no avail.  I live in Toronto if anyone is willing to lend me a carb to check I would be vary greatfull 
I am really busy these days and havent found the time to even think about it for a couple of weeks but I'm getting an itch for a lil ice riding once I dedicate some time to the 5hundie.

[cbxracer30]

Down here in the states we have Seal-All, it works with gas & oil not sure if you have tried it or not it looks like contact cement.CBX