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I have two CR500's one is a 91, the other is a 95. Both bikes have the 39 PWK carb on it, and the carbs were both put on at the same time. I have had the carbs on the bikes for a few years, with about 1 year of not riding due to injuries. I am having a problem on both bikes where it runs fine everywhere except idle. Both bikes will not idle, no matter what you do with the air screw. Any ideas?
My brother is convinced that we should buy new carbs since the price of an overhaul kit is close to the price of new ones. I myself think there may be crap stuck in the carb from old gas, I am thinking we should rip it apart, clean, re-gasket and see how it runs. The bikes work fine everywhere except idle and no other mods have been made to the bikes. The only problem I have with getting the new gaskets is shipping, I live in Hawaii. Can anyone tell me how it costs $41 ro ship a piece of paper? we really take it in the corn hole here in Hawaii when it comes to shipping.

How much is that 41.5mm PWK?

altitude?

Airscrew out say 1.5 - 2 turns then screw in the idle screw.

Pull the carb and bowl, pull the slow jet and spray it out. Make sure the floats move freely also. Spray evrything really well and reassemble.

Go with the above settings and let us know what's up-

First off are you adjusting the air/fuel screw or the idle screw on the PWK?
2nd, tear them apart, clean them out nice and put them back together, no re build kit... yet!!! Flush the gas tank good and fill with fresh gas and new spark plug, see what happens.

I'm in Hawaii, so I cant be more than 500 - 700 ft above sea level, I did change the gas, drained the bowl, new plug and monster coil, also have new twin air filter.

As I said- pull the slow jet and make sure it's not pluged.
I had a buddy who had the same issue- we pulled the idle jet and couldnt even push a piece of .020 safty wire through it- it was that pluged up....

I was also looking at a blown up picture of a pwk carb, and I dont see the idle screw on mine, looks like its plugged off. all I have is an air screw and a choke.

sorry... one more thing. In my opinion, the carb is flooding the engine at idle, not starving it for gas. So I'm not sure if a plugged jet or needle would cause the problems I am having.

sikryd wrote:I was also looking at a blown up picture of a pwk carb, and I dont see the idle screw on mine, looks like its plugged off. all I have is an air screw and a choke.

You probably have a PJ carb- the choke and idle circuit are the same... and they suck...

slomas wrote: You probably have a PJ carb- the choke and idle circuit are the same... and they suck...

Ok, well.... I was just going by what my brother told me he ordered for them. If they are PJ's, what do I do? thow em in the trash and buy PWK ones? What could make the motor flood at idle but be fine off idle to top end?

slomas wrote:You probably have a PJ carb- the choke and idle circuit are the same... and they suck...

Left is a new 39mm PWK and the right a original 38mm PJ, note the idle screw right above the fuel inlet on the PWK, mixture screws are lower and right of the inlet...

I had nothing but issues with old PJ, the new PWK was the best $200.00 I spent

sikryd wrote: What could make the motor flood at idle but be fine off idle to top end?

Float level too high, too big of a slow jet, bad choke valve... Same thing mine was doing!

eyesky2002 wrote:

slomas wrote:You probably have a PJ carb- the choke and idle circuit are the same... and they suck...

Left is a new 39mm PWK and the right a original 38mm PJ, note the idle screw right above the fuel inlet on the PWK, mixture screws are lower and right of the inlet...

I had nothing but issues with old PJ, the new PWK was the best $200.00 I spent

OK... mine is a pwk, looks like the one to the left in your pic. I thought the black plastic screw with the spring above the fuel inlet is the air screw. no? It seems at idle, turning that screw either direction does not seem to do a whole lot. I start at 1 1/5 turns out from bottomed, and have gone almost all the way out with no effect on the idle. Maybe I should just buy 2 new ones. Damn..... I hate spending money, probably the chinese in me.

did they idle when the carbs were new ? if not then all the cleaning wont fix your idle. letting gas sit in the carb for a year isnt recomended but this is what ive observed from people that have done it: i think castor based oils gel up over time but i seen first hand 927 turn to jello when left for long periods of... on the other hand i seen bel-ray synthetic sit for a year and be just fine other than the gas went bad

I think the needle is hanging open, probably from sitting for so long with gas in the ( I use HP2 oil ). I checked the carbs this afternoon and it has a PWK stamped just above the bowl on the right hand side, so I now know it is a PWK. I will take the bowl off sometime this week, and see if the shaft on the needle is gummy or if the seat on the needle is trashed or something. If I need to rebuild the carb, can anyone suggest a place to get a rebuild kit from?
Thanks for all your help...

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Just pull the pilot jet like Slomas said, clean it with carb cleaner, reassemble. Ya check the needle and seat. If its leaking at the over flow tube with the gas on its either bad or gummed up and not sealing.

I just did this with the 250 from sitting for two years and had to do the same thing a year before that. Wifes quad too.

This time I ran the carb out of gas and drained the tank so hopefully the next time I don't have this problem.

sikryd wrote:

slomas wrote: You probably have a PJ carb- the choke and idle circuit are the same... and they suck...

Ok, well.... I was just going by what my brother told me he ordered for them. If they are PJ's, what do I do? thow em in the trash and buy PWK ones? What could make the motor flood at idle but be fine off idle to top end?

I happen to have a rather large trash can if ya wanna throw them this way