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Problems solved??

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Some may recall difficulties I've had with the '01 engine I put in my '03 frame:

Jetting

It looks like I've had a head gasket leak letting coolant into the combustion chamber making the jetting seem rich all along. The leak wasn't great enough to cause obvious steam out the exhaust, but it was sufficient to goof up my jetting. When I bought the engine, a couple of studs were loose causing the head gasket to leak, so when I had it apart to fix that, I decided to have the head machined to increase compression. The shop that milled the head didn't get the gasket surface flat, so the gasket was still leaking and has been all along.

Compression

I actually had the head milled twice, and it looks like the gasket surface was off both times. The second time, I used copper spray gasket sealer which held for quite a while, but slowly began to leak causing my cranking compression to drop over time.

Finally, I started over with a new head and had a guy at work cut it on a lathe and verified the surface with a straight edge. Now it seems to be well sealed. At the same time, my compression gauge is goofing up, so I don't have reliable compression numbers. During the ride today, my jetting changes actually seemed to make a real difference!! Moral of the story: If your bike seems to run rich and jetting changes don't seem to really affect it, check your head gasket and gasket surfaces :thumbsup: .

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well, hopfully, ole' christine will work for ya now... :ride:

that sucks about the head...but, at least you made some headway in the rundown of the problem... :thumbsup:

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I should say that I first became interested in making the engine swap after reading about it in one of your posts, so I'd say you're at least partly responsible for the outcome :ride: . I also have to say that this combo really rocks, but I can't put the differences between the '01 and '03 engines in words. The '01 seems so much more..... aggressive and free revving. Still a little bit of jetting work to do, but it's pretty close :thumbsup: .

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I should say that I first became interested in making the engine swap after reading about it in one of your posts, so I'd say you're at least partly responsible for the outcome :ride: . I also have to say that this combo really rocks, but I can't put the differences between the '01 and '03 engines in words. The '01 seems so much more..... aggressive and free revving. Still a little bit of jetting work to do, but it's pretty close :thumbsup: .

hahaha...its all my fault now is it?... :applause:

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hahaha...its all my fault now is it?... :applause:
Gotta give credit where it's due :thumbsup: . BTW, it really is a good combo. Honda should have built it for at least one year :ride: .

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Gotta give credit where it's due :thumbsup: . BTW, it really is a good combo. Honda should have built it for at least one year :applause: .

we can call it a 2001.5

:ride:

also, ryochiro takahama ran the exact same set up on his works bike 02 frame with 01 motor/kehien carb over here when he won the title.he was pushing to have that same bike put into production, but the honda bigwigs felt that the older engine was a bit long in the tooth, and went with the crm/nsr throwback instead. even the tst riders hated the newer motor. they felt a little better about the 05, but none of them could come to terms with the carb, and it still went into production...now, they dont even sell cr250's over here anymore...good thing i have 3 engines for mine, and a 03 frame on the way. i can keep mine fresh for a few decades now...... :applause::applause::applause::applause:

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I believe we're using the same setup; '01 insulator with a 38 mm PWK. If the carb isn't sealing well to the insulator, I wonder if the carb isn't fully seated. I have to really apply some force, but then the carb seems to pop right in and makes a really tight seal to the insulator. If you haven't already, you may want to raise the subframe, put some grease on the carb outlet bell and really force the issue. I'll try to post a picture later so you can compare and see if our carbs are seated the same amount.

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skip, ive got the 00' airboot on now too, it defintly fits alot better and i seem to have a little more "bark" off idle, but i ride mostly mx so i dont spend too much time at the lower rpm range

i have the carb pushed in as far as it'll go on the boot but it still seems it doesnt fit right..so its either the boot, or the piston defintly needs to be replaced

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we can call it a 2001.5

:thumbsup:

also, ryochiro takahama ran the exact same set up on his works bike 02 frame with 01 motor/kehien carb over here when he won the title.he was pushing to have that same bike put into production, but the honda bigwigs felt that the older engine was a bit long in the tooth, and went with the crm/nsr throwback instead. even the tst riders hated the newer motor. they felt a little better about the 05, but none of them could come to terms with the carb, and it still went into production...now, they dont even sell cr250's over here anymore...good thing i have 3 engines for mine, and a 03 frame on the way. i can keep mine fresh for a few decades now...... :applause::applause::applause::ride:

heres takahama's works RC250R (3rd gen chassis w/ the old motor)

http://www.putfile.com/pic.php?img=3208301

http://www.putfile.com/pic.php?img=3208306

i found the picture in an old tranworld motocross magazine i have..its one of the first issues when the mag started up about 5-6 years ago, i dont have a scanner so these pics will have to do for now. if you look closely you'll notice the 01 style shrouds and sidepanels:thumbsup:

you guys pretty much have works bikes on your hands :applause: hopefully i will be able to get my 03 cr250 shortly :applause:

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I've read that LaRocco used the '01 engine in his '02 and '03 CR's, but I haven't been able to find pictures to back it up. These guys have good taste :thumbsup: .

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