SH104
03-31-2016, 07:03 PM
Hi guys this is my first post. I'm a long time stalker and love this site. The help I'm looking for is in paragraph 2 if you want to skip. I have an 85 250R that I've been working on for the past year and have it looking good. After fighting with jetting for a while I bought a needle jet from jets r us and have the 34 PE running great. I noticed mine was out of round with a magnifying glass. It was the best $9 I spent as the difference was night and day. I also ordered a dgh needle. It will idle until it's out I gas I imagine, no bogs or stutters in the low, mid, or top end. I'm really happy with it and know I should leave it alone but....
It seems I'm not content unless I'm out in the garage trying to fix it. I bought a used pwk 39 cheap that I wanted to make sure was good (see how much better it runs on the top end) and then sell it to help fund a 38 AS carb. I cleaned and put compressed air through all the orifices, replaced the jet block oring after noticing a leak there, lightly polished the float valve seat, set the float height, no air passes through the inlet once the float levels out with the carb body, new bowl gasket and started with a 48 pilot, 172 main, and dgh on the 4th clip down. It started right up but runs so rich on the pilot that it spits premix out the silencer a lot. The air screw doesn't affect much. Anything under 1 turn out will die. I went all the way down to a 38 pilot up to a 55 and it acts the same way running in the garage. The part that really confuses me is that when I blip the throttle lightly to keep it running the engine runs on and on. Not like a typical lean idle hang, it's more like rev, bam, bam, bam.....sometimes 10'times in a row. It does this with every pilot jet I've tried. It has 180psi compression and a leakdown test holds 6psi with zero loss over a half hour that I left it there. It sounds and acts super rich and then rev hangs like its lean. I'm thinking either the choke is bad or the needle jet (guessing here). Any suggestions would be greatly appreciated.
Edit....I forgot to mention that whatever pilot is in it starts without the choke on and if I pull it the engine dies right away. Another question please. I notice that BDT lists a lot of pwk chokes and towers on ebay. Are these commonly replaced items? Is there a way of testing if a choke needs to be replaced? I think it's easier to take the tank and shrouds off as one with the six bolts than it is to try to put the airbox boot on the back of that carb with the tank in place. No fun at all taking that carb off and stretching it back on what seems like 20 times since last weekend. The ol fingertips are raw :-)
It seems I'm not content unless I'm out in the garage trying to fix it. I bought a used pwk 39 cheap that I wanted to make sure was good (see how much better it runs on the top end) and then sell it to help fund a 38 AS carb. I cleaned and put compressed air through all the orifices, replaced the jet block oring after noticing a leak there, lightly polished the float valve seat, set the float height, no air passes through the inlet once the float levels out with the carb body, new bowl gasket and started with a 48 pilot, 172 main, and dgh on the 4th clip down. It started right up but runs so rich on the pilot that it spits premix out the silencer a lot. The air screw doesn't affect much. Anything under 1 turn out will die. I went all the way down to a 38 pilot up to a 55 and it acts the same way running in the garage. The part that really confuses me is that when I blip the throttle lightly to keep it running the engine runs on and on. Not like a typical lean idle hang, it's more like rev, bam, bam, bam.....sometimes 10'times in a row. It does this with every pilot jet I've tried. It has 180psi compression and a leakdown test holds 6psi with zero loss over a half hour that I left it there. It sounds and acts super rich and then rev hangs like its lean. I'm thinking either the choke is bad or the needle jet (guessing here). Any suggestions would be greatly appreciated.
Edit....I forgot to mention that whatever pilot is in it starts without the choke on and if I pull it the engine dies right away. Another question please. I notice that BDT lists a lot of pwk chokes and towers on ebay. Are these commonly replaced items? Is there a way of testing if a choke needs to be replaced? I think it's easier to take the tank and shrouds off as one with the six bolts than it is to try to put the airbox boot on the back of that carb with the tank in place. No fun at all taking that carb off and stretching it back on what seems like 20 times since last weekend. The ol fingertips are raw :-)