Who Rebuilds Dirt Bikes?

[Jason628]

Well... since I have it I'm going to give it a shot. I'm going to go through it and make sure everything looks good. It appears that it was casted with keihin on it and then they machined it off. I'm assuming legit keihin parts will probably fit it. Idk. If I cant get it to run any better than it did with the pj I will look into the 2000 250 carb. I'm eventually going to get a yz250x. Not sure if I'm going to keep my 2015 rmz450 or sell it. I'd like to take the cr completely down and paint everything and put on new plastics and kinda restore it but, with upgrades.

 

[Bigmac]

Well... since I have it I'm going to give it a shot. I'm going to go through it and make sure everything looks good. It appears that it was casted with keihin on it and then they machined it off. I'm assuming legit keihin parts will probably fit it. Idk. If I cant get it to run any better than it did with the pj I will look into the 2000 250 carb. I'm eventually going to get a yz250x. Not sure if I'm going to keep my 2015 rmz450 or sell it. I'd like to take the cr completely down and paint everything and put on new plastics and kinda restore it but, with upgrades.

What tuning issues were you having with the PJ? Just trying to give you some early warning on the China carb, They look legit, but slides do not enter change with real pwk’s jets will fit and needles will fit. The slide isn’t numbered, and is often the wrong cut out for the application, and as I mentioned before the main jet tower is usually too small, causing a lien condition that can’t be tuned out, drilling it to OEM pwk specs helps, floats are usually adjusted wrong, and the needle seat is undersize causing a fuel starvation issue again it won’t show itself until you’re may be in fourth or fifth gear and they’ll start to cut out and sometimes burn the motor down. They have even better copies visually, they come even in Sunco boxes with genuine Keihen paperwork inside, All of the correct carb markers for quality control and a genuine made in Japan card inside the box that matches the originals perfectly, the carbs still suck they internal issues. Just be prepared to do battle with the carb and hope you don’t burn something up in the process, They will however usually start up an idle well giving you some hope…

 

[Jason628]

I maxed out the idle knob and it still would not idle. I cut a groove in the bottom of my slide to let air in and finally got it to idle and had some adjustment then. It has never really had a clean top end with recommended jets and I've tried every clip position on the needle. It loads up at idle fairly quickly even with the next size down pilot jet (58) recommended is a 60. Seems to run best with the air screw almost all the way out but, still loads up. Float height appeared to be ok, didn't really measure it or anything... The choke/throttle adjustment got bent at some point (probably when my friend crashed it) I saw the pwk for a few dollars more than what the new choke assembly costs so, figured I would give it a try.

 

[Bigmac]

I think the pilot jet is still too big 55 or even a 52 is probably better, if your air screw is all the way out you need to go down on the pilot. Most of the time the old carbs need a float adjustment and a new float needle to work properly, I hear you on the idea of a cheaper replacement carb. Honda always designed them to not idle from the factory jetting specs is it only is meant to idle for 5-10 seconds once warm and flood out and die, The idea is for racing to cool the piston down when entering a corner, most people are not racing and prefer a crisper cleaner Idle, so adjustment are needed

 

[Jason628]

I think the pilot jet is still too big 55 or even a 52 is probably better, if your air screw is all the way out you need to go down on the pilot. Most of the time the old carbs need a float adjustment and a new float needle to work properly, I hear you on the idea of a cheaper replacement carb. Honda always designed them to not idle from the factory jetting specs is it only is meant to idle for 5-10 seconds once warm and flood out and die, The idea is for racing to cool the piston down when entering a corner, most people are not racing and prefer a crisper cleaner Idle, so adjustment are needed

Before modifying the slide it wouldn't idle at all it would just die as soon as I let off the throttle. I'll order the choke assembly for it so I can play with it and see if I can get it to run right. If you rap it out a bunch the top end will start to clean up so maybe it's just an overly rich pilot that's fouling it up. Still gonna give the pwk a try and if it's too clean on the top I'll take it back off hopefully before it melts anything haha

 

[Jason628]

I've seen many different variations of this same knock-off and watched a video where someone compared the two side by side and the keihin slide did fit in the clone carb. I popped the float bowl off and all appears well minus some loose casting material that could be cleaned up. I'll pull the emulsion tube and see if it has the 6 or 8 holes (need a safety torx). Genuine pwk has 8. The hole in the seat is supposed to be 2.5mm? I put a drill bit in that measured 2.7mm and it has play so.. probably close to 2.8mm.

 

[Bigmac]

I've seen many different variations of this same knock-off and watched a video where someone compared the two side by side and the keihin slide did fit in the clone carb. I popped the float bowl off and all appears well minus some loose casting material that could be cleaned up. I'll pull the emulsion tube and see if it has the 6 or 8 holes (need a safety torx). Genuine pwk has 8. The hole in the seat is supposed to be 2.5mm? I put a drill bit in that measured 2.7mm and it has play so.. probably close to 2.8mm.

The inlet hole in my genuine PWK, is slightly larger my than 3.175 bit so I think it’s supposed to be 3.2 mm, the emulsion tube will fit a #33 2.87 mm but not a #32 2.94mm so it’s probably 2.9mm

my pwk slide will fit in the China carb but super loose, and the China slide will not fit in the pwk, So yes technically it fits, but it’s not correct, I would have a ton of air bypassing the slide.


I had someone bring me in an 01 CR 250, that would idle and run OK down low but not rev out at all, it was a touch fat down low but not horrible, so stared to check the basics, first thing I went to was the air screw to see where it was at, it was fully seated, turned it a turn a half out and it ran perfectly fine everywhere no longer super fat up top, it’s surprising how much the pilot/air screw can effect the entire jetting spectrum, I know the literature and everything says different, but my experience says different.

 

[Jason628]

Well... the pilot circuit works throughout the throttle range. So that makes sense.

 

[Bigmac]

Also check the gap on the plug, older cr’’s like a tighter gap .018ish some won’t run in the top under load at .025-.028, an with weak ignitions an iridium plug br8eix is a good choice

 

[Jason628]

Cool I'll give that a try when I get the boyesen set up. I like the boyesen setup because if the rubber boot ever deteriorates they are $8. think it currently has a br8es in it. I got a kit of keihin knock off jets. I heard they may vary in size compared to genuine so I'll probably order a set of size gauges just to double check. Wouldn't be bad to have as I do some carb work every now and again and I cant always read the number or the number isnt stamped on the jet of what I'm working on.

 

[Jason628]

Got the old cr running. Have yet to taken her for a ride. Just picked this one up for $750

 

[birdmeter]

o dirt bikes . i remember when i could ridem.

 

[Jason628]

o dirt bikes . i remember when i could ridem.

Yeah... not quite sure I can ride em for much longer with the medical issues I've been having. Spent way too much time at the doctors and they haven't a clue what is wrong with me. I can ride for a little while and then I start to hurt and then it's not fun anymore. Alcohol seems to help lol

 

[Bigmac]

Got the old cr running. Have yet to taken her for a ride. Just picked this one up for $750

Keep us updated on how she’s running! Nice RM! Is it a 99?

 

[Bigmac]

Yeah... not quite sure I can ride em for much longer with the medical issues I've been having. Spent way too much time at the doctors and they haven't a clue what is wrong with me. I can ride for a little while and then I start to hurt and then it's not fun anymore. Alcohol seems to help lol

That’s why I stick with quads in the dunes! LOL just got a fresh 363 put back together for the 86! Got it in fired it off today, going to take it out tomorrow!

 

[Jason628]

That’s why I stick with quads in the dunes! LOL just got a fresh 363 put back together for the 86! Got it in fired it off today, going to take it out tomorrow!View attachment 303055

It's a 96. Actually been looking for a atc 250r. I love those things. Found one in a field at a guys house but, he wouldn't give me a price and it needed a ton of work... the new bike looks to be in good shape and runs well. Needs a little work but, it was $750

 

[Bigmac]

It's a 96. Actually been looking for a atc 250r. I love those things. Found one in a field at a guys house but, he wouldn't give me a price and it needed a ton of work... the new bike looks to be in good shape and runs well. Needs a little work but, it was $750

Atc250r’s are hot right now! Have seen trashy bikes go for 2500! Here 2t’s are nuts, a cr500 sold for 10k, it was super nice, 92-96 cr’s are getting pricey. Have an 03 cr street legal 250 that I should probably sell right now! Lol
The gen of rm was really good

 

[Jason628]

Atc250r’s are hot right now! Have seen trashy bikes go for 2500! Here 2t’s are nuts, a cr500 sold for 10k, it was super nice, 92-96 cr’s are getting pricey. Have an 03 cr street legal 250 that I should probably sell right now! Lol
The gen of rm was really good

If only we had known this stuff was going to increase in value.... I did a little digging on the rm before I bought it and couldn't find any really negative reviews on that year other than people comparing it to a CR or YZ. I did look to make sure I could still get parts for the thing as well... if I really like this bike I will probably keep it and maybe sell my rmz450 idk. Been looking at the yz250x

 

[Jason628]

Toodled around on the rm250 a little today. Not sure what previous owner did to the grips on this thing but, they have turned to sticky mush that refuses to come off my hands with dawn dish soap. Bike seems to run really good and has a ton of power. Neck bearings are trashed... will have to get fixed before next ride. Almost died when powerband lit and kicked the ass sideways and it wouldn't steer. OK maybe a little dramatic but, I did cut a little hole out of the seat when I clenched.

 

[Jason628]

https://youtube.com/shorts/gf1Zeq2pKyk?feature=share

Well... she seems to run a lot better with the pwk and boyesen setup. It will idle now and not load up like it used to. It will load up if you let it idle for a while but, a few blips of the throttle clears it right up. I took it down the county road and pinned her out in 6th for a bit and no hesitation at all. She rips right through the gears with no spitting, sputtering or bogging now. Pulled the plug and it's tan. Best this thing has ever ran...