Posts
96
Joined
4/3/2019
Location
Clatskanie, OR
US
Fantasy
953rd
Edited Date/Time
3/2/2022 6:22am
Alright guys... Here is my first ever build... Little bit of a back story.
I know these bikes don't have the most sought after engines... but ever since I was a kid I have been in love with the final generation CR250. There has always been something prestigious about them to me. I've spent the last 5 years letting bikes on Craigs list slip past me and spent my money on modern bikes off the show room floor.. last Feb I got ACL surgery, and sold my beloved 2017 KTM250 sx... which got me thinking about building a bike. I have never had the time to tear something down and not ride it for months, so back to CL I went... After a bit of searching I stumbled on this thing...
She was not a looker.. corrosion on the frame, beat plastics, roached tires, dirty... but she also had all the right things... the stock chain and sprocket, bars, grips, seat cover, front tire... no rub on the clutch cover, shock reservoir all the signs on a VERY low hour bike. I sat on it, it felt decently tight for a 16 year old barn bike, I turned the gas on and gave it a solid wack and like a kitten the thing purred to life with no hesitation. Tight and rattle free listening to the crisp bung of the old smoker had me hooked. I dropped the cash, $2400 bucks later I was loading her up.
Of course once I got home I unloaded it with a shit eating grin and my dad was standing there just shaking his head... I had to take her for a lap around the yard, despite my doctors orders off course... I was smiling like a fool. After Making sure it had all its gears, getting it hot enough to let the coolant cycle and just letting the fork and shock get moving again I hosed her off and parked it in the garage for the tear down.
This is how far I have got into the tear down. A couple more hours in the garage and I should be able to start cleaning! I originally had all these plans to build the thing with sick wheels, get the engine cases coated etc... but as I tear it apart everything is still tight.. no slop in any of the wheel or linkage bearing. The headstay bearings feel rough but I'm very surprised. I'll inspect them when I get it apart but perhaps Ill just be cleaning greasing and riding the sucker sooner than I thought! Time will tell.... Stay Tuned guys!!
Give my instagram a Follow ( @kdubsteezey ) as I will be doing day by day updates there, and then weekly I plan to hop on here and share what's going on!
I know these bikes don't have the most sought after engines... but ever since I was a kid I have been in love with the final generation CR250. There has always been something prestigious about them to me. I've spent the last 5 years letting bikes on Craigs list slip past me and spent my money on modern bikes off the show room floor.. last Feb I got ACL surgery, and sold my beloved 2017 KTM250 sx... which got me thinking about building a bike. I have never had the time to tear something down and not ride it for months, so back to CL I went... After a bit of searching I stumbled on this thing...
She was not a looker.. corrosion on the frame, beat plastics, roached tires, dirty... but she also had all the right things... the stock chain and sprocket, bars, grips, seat cover, front tire... no rub on the clutch cover, shock reservoir all the signs on a VERY low hour bike. I sat on it, it felt decently tight for a 16 year old barn bike, I turned the gas on and gave it a solid wack and like a kitten the thing purred to life with no hesitation. Tight and rattle free listening to the crisp bung of the old smoker had me hooked. I dropped the cash, $2400 bucks later I was loading her up.
Of course once I got home I unloaded it with a shit eating grin and my dad was standing there just shaking his head... I had to take her for a lap around the yard, despite my doctors orders off course... I was smiling like a fool. After Making sure it had all its gears, getting it hot enough to let the coolant cycle and just letting the fork and shock get moving again I hosed her off and parked it in the garage for the tear down.
This is how far I have got into the tear down. A couple more hours in the garage and I should be able to start cleaning! I originally had all these plans to build the thing with sick wheels, get the engine cases coated etc... but as I tear it apart everything is still tight.. no slop in any of the wheel or linkage bearing. The headstay bearings feel rough but I'm very surprised. I'll inspect them when I get it apart but perhaps Ill just be cleaning greasing and riding the sucker sooner than I thought! Time will tell.... Stay Tuned guys!!
Give my instagram a Follow ( @kdubsteezey ) as I will be doing day by day updates there, and then weekly I plan to hop on here and share what's going on!
Don't listen to the nay sayers.. Have been fortunate to have owned or ridden many 250 2t's & can say this engine is no slouch with some minor tweaks..
Enjoy the build !
So I got the tear down all the way done the other day.
Then I started cleaning, scrubbing and polishing! I just finished up the frame, swing arm, and linkage. I have a lot more to do but I'm excited with the progress and how it has came out so far. While cleaning and inspecting I notice this thing truly has almost no time on it. The swing arm, chain guide, and frame spars have virtually no rock rash you get from riding ruts, or just riding in general. All the chain slider rubber is OEM still and I was able to clean and grease all the OEM bearings and they feel great!
I have a lot of cleaning, oiling, and greasing to do so I'm headed back to the shop now.... Stay Tuned!
I decided to take the "made in Japan" off the stator case, I think it looks much cleaner now.
The Shop
And then made a sweet bracket to mount the CDI box and relays under neath where the upper shock mount is. I need to source some longer engine mount bolts where the bracket mounts up. Its still rough and Im going to do some tweaking, but besides the carb having to sit just touch crooked compared to stock it seems like its going to work good. Plus it cleans up the bike not having boxes sticking out of the shrouds ready to get messed up in a crash, or having wires running all the way up behind the front plate.
I'll get better pics at some point.
Then I got the fork all cleaned up. I was thinking of getting the lugs Cerakoted black... but the raw turned out good... maybe down the road when it comes apart for a re-valve. Along with DLC coatings and ano on the tubes/ shock body. Anyway... here's some pics.
As far as I know, 2004 and earlier CR250s used regular nuts on the cylinder head, at least going back into the 90's.
The '05 - '07 motors had acorn nuts on the front two cylinder head bolts and the rest regular nuts.
The story I got was that the first owner somehow blew the top end up. (I think I have figured out why) It sat until around 2014 when a guy bought it for dirt cheap blown up, fixed it and sold it to the guy who I bought it from. The guy I bought it from was some dude that seemed like he bought bikes for the fun of it. He had like 6 just around his house and this thing was in the barn. He said he didn't have time to ride it so it sat.
Of course who knows how accurate this is. All I know is that it started up first kick, and it was 99% original still, so I was stoked.
My theory on the top end is that the first owner had no idea what he was doing. There was a 380 main Jett in the bike, stock is 420. This was probably to try to stop fouling plugs, which it won't, obviously. My guess is someone rode it on the road. They took it out and just held it wide open and didn't let off... in the lean state things got hot and the top end went. Which seems like the only possible way for a premature failure like that to happened.
I took the head off inspected it and the piston top and cylinder walls. The crosshatch in the cylinder looked good minus one little spot by the exhaust port that was scuffed up, I have definitely seen worse. The piston was a little black on top, not bad. I should have looked to see if it were an "A" or "B" piston. Then I would have had a better idea if it were replaced.
Thought you guys might find that interesting or have some ideas haha...
The plan for this thing is to keep the internals in the motor in stock trim for the winter, with the addition of bolt ons. To start I'm doing a Boysen Rad valve & Exhaust manifold, HGS Pipe and Bud Carbon silencer. I'm going to start with stock jetting in the TMX carb and just work from there. I've always been very sensitive to small changes so I was just going to work through each thing step by step. I found the "elusive" S-7 nozzle for the carb that some have had good luck with fixing the jetting on these bikes. I'll do the 04 reed intake boot (straighter) and the 05-07 airboot (increased volume) at some point. Also I'm going to try out the 05-07 head gasket before getting motor work done. It is thinner which boost compression. Figured its worth trying!
When its time for a rebuild I'll send the cylinder/head off to get reworked. Possibly even get the chases epoxied to lower crank case volume. By then I'll have a better idea of the engine characteristics, so I can get a package that's closest to what I am searching for.
When I do the carb upgrade I would like to do the newer Kein that has a Power Jet. Get the proper wire harness and CDI box through Blackdiamond? who built the holy grail of CR's as you all know haha... That way I can get the more efficient power valve mapping he developed as well (assuming all this is something that is attainable)
I'm sort of a ride it stock, change one thing I think needs changed at a time guy.I think it lets you develop a better feel for the bike and the best possible package out of the bike in the end.
Of course I'm going to throw all sorts of bitchin' trick goodies on there as I go too!!
Pit Row
As I have torn it apart and cleaned everything up I have probably spent an equal amount of time searching every thread I can find on these bikes to get a feel for what people have done and works. Just trying top build the most kick ass CR a mortal dude can!
Also I think I just figured out a source for a Doma pipe... so I might be trying one of those once I am cleared to ride again too!
Purchased a new 01 CR250 in the spring of that yr. & did some mods to it & in comparison to an 03 with mods the 01 engine is not up to par with it. You see a lot of people bash this engine, but in reality it has more power (at least 5-7 hp) than the traditional cyl. reed induction engine when done right.
Unlike my 17 KTM, that thing was a monster when it came to mid rpm hit. Basically I found myself using the Power valve adjuster different exhaust and jetting to try to smooth it out... but could never get it to not sign off early right after that mid hit either... That bike was a handful to ride haha! But I never worried about getting pulled exiting corners! As long as I didn't forget to shift! haha.
2 stroke in stock trim, flywheel weight goes a long way with these engines as it helps keep the traction control at bey by keeping the engine from revving two quickly, plus dyno charts iv seen add 1.5lb of torque at peak, and 2hp, next thing I took care of was the stock reed block, an 02 reed block will help the engine flow better, specially up top, and add some good useable top end power, or a boyesen rad valve, the v3 block I found Narrowed the powerband, and took away top end, and made the midrange more potent than it already is, it was tiring, but the cheapest power was a small peice of carb hose that I heated with a lighter, and pushed onto the pv actuator stop pin, it stopped the pv from closing fully, and added a lot of pickup right off idle, and smoothed out the bottom to mid transition very well
I have yet to ride a 250 2t that has the topend the 02-03 CR2 have. The 93-96 models had good topend power & are probably the closest, but not close after cyl. / head mods are done to the 02-03.
I already ordered up a Boysen Rad valve, and I am going to order up their Exhaust manifold as its supposed to help as well with bottom end pick up without compromising the top end.
Thats really interesting with the PV that's the first ive heard of that mod. I'll have to go out and look at that the next time Im out working on the bike. If its as simple as making a little bumpstop to limit the pv distance when closing I'll give that shot too.
Thanks for all the info I really appreciate it!!
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