TJC510s gen 4 AF conversion

[TJC510]

i got bored and not having the money to get my tranny together right now, i decided to jump a few steps and start working on my conversion.
it started at a 05 CRF250R that i bought at a used car dealer. im sacrificing my 98 cr500 for the motor and electronics.

here is it when i first bought it.


starting the disassembly



1 hour and 30 minutes later


the 98 cases and cylinder in


tank on, its gonna be a tight fit


i had to grind a weld under the clutch cover. the factory had a big bubble there and prevented the motor from rocking forward at all. i gotta clean out the Y and then i can cut some more. i should have things ready to weld by next week. im thinking about cutting the bottom of the cradle and bending it upword toward the motor to get a tighter fit and more ground clearance.

[AlisoBob]

Lookin' Good T.J., keep that momentum going!

[teemtrubble]

Nice job

[TJC510]

didn't get much done, just cleaned out the Y so i can start fitting it. that is the hardest thing yet. i need a new flapper disc for my grinder and i should have it high enough to clear the springs and pipe.
i also measured the collars for the swingarm bearing. the difference between cr500 collar and the right one on the crf is the exact distance needed to fill. tomorrow im gonna put the counter shaft back in so i can get the chain lined up and see where i gotta move everything.

[AlisoBob]

I used all Gen 3 ( 2002 CR250) stuff. Swingarm is aligned perfectly.

1 each COLLAR (49MM)
52141-KZ3-J40 001 $9.49

1 each COLLAR (54MM)
52142-KZ4-J40 001 $8.35

2 each COLLAR ( Washer) $2.10
52143-KZ4-J40



FYI Stock CRF Collars are 49mm / 59mm.

[TJC510]

just a few things to finish up

i got bored and threw it together. i got the Y where i want it, clears the rads and pipe well. i also know how im spacing the motor. ordering the parts tomorrow. when i get that part done, then im gonna finish the rest of the frame work.

[mxracr121]

I used all Gen 3 ( 2002 CR250) stuff. Swingarm is aligned perfectly.

1 each COLLAR (49MM)
52141-KZ3-J40 001 $9.49

1 each COLLAR (54MM)
52142-KZ4-J40 001 $8.35

2 each COLLAR ( Washer) $2.10
52143-KZ4-J40



FYI Stock CRF Collars are 49mm / 59mm.

Didn't you use the stuff I bought? It was for a CR125, '02-'07.

[AlisoBob]

Those items fit the Gen 3 conversion, the Gen 3 250 parts fit a Gen 4 CRF250X conversion...

Go figure?

[Zoomer]

Kick a$$, hope the conversion continues to go well!!!!!

[mxracr121]

Those items fit the Gen 3 conversion, the Gen 3 250 parts fit a Gen 4 CRF250X conversion...

Go figure?

Yeah, no kidding.

[TJC510]

the craddle and Y are welded in. every time i moved something and bumped the frame the pieces fell out so i decided to weld that up before i tackle the motor mounts. im still waiting for the collar to show up, should be here tomorrow. ill get some pics of the frame later tonight

[TJC510]

[AlisoBob]

Did not insert the solid barstock at the lower joint?

Did you install the radiators to check the clearence at the "Y"?

I think my "Y" is higher than yours.

Looks good!

[TJC510]

i did check the clearance on the pipe and the radiators, thats why i assembled the bike a few days ago.
i did not put anything inside the frame at the lower joint. i feel there is nothing wrong with properly prepped butt joint as long as the penetration is there also.
your Y does look a little higher, there was plenty of clearance for the exhaust springs where mine is. i think im also am tipping the engine forward a bit further than you.

[AlisoBob]

I think I'm also am tipping the engine forward a bit further than you.

Right on!

My rads are a little close to the "Y", I could have mounted it 1/4" lower with better results.

[TJC510]

i machined these on the lathe out of 1" solid 6061. should make a great front motor mount.


here it is installed, you can just see spacer plate on the back side of the frame.


im not quite sure if im happy with where the motor is right now. if i go any further forward, i have the cut into the bottom frame rail and replate it. alot will be acomplished, but i don't know yet if it will be worth the work. im gonna reassemble the bike before i weld the mounts in and try deciced then. right now, the clutch cover bolt is bearly sitting on the frame, feeler guage territory.

[AlisoBob]

It dosent look like it, but I cut a depression into the top of the rail to allow the bolt to "sink" into it slightly, and still leave 0.015" clearance.The original wall thickness is 0.125", its probably more like 0.060" now.

If I had it to do over, I would cut it deeper, and weld in a piece of half-round to make both deeper, and more structural.

[TJC510]

i picked up may parts from the dealer, which included the collar to space the motor over, fits perfectly. i decided to cut the frame near the clutch cover bolt. was alot easier filling it in nicely than a originally though. ill get some pics with the motor out once its welded up. tomorrow im turning the coil mounts on the lathe. im gonna it about where teamtrubble put his on his gen 3. seems like a good spot. cdi is gonna be in the stock 250f holder in the stock position. its about the only place i can get both to fit and still keep a clean look. also have the pipe fitted for the forward rubber mount. i used the PC pipe because it has the lowest mounting tab of the all the pipes. if i used the stock pipe to place in for welding, i would not be able to put the fmf or pc on without drilling a hole. im trying to get the pipe on without modifing the mounts. seems almost impossible for the rear mount though. i hope to have all this welded up this weekend so i can start putting the bottom end back together.

anyway here are some pics.

[TJC510]

i finely got my camera fixed so no more camera phone pics.
it sucks waiting for parts, but i been trying to get some stuff done. almost everything to finish it up will be here this friday. just have to wait for the crank to get done, and ill be finishing this up.

here is the engine mounts welded up. i filled the side of the front mounts to get the bolt to sit flush with the side of the frame. fits like a glove. you can also see the front pipe mount welded.



coil mounted


i re did the rear pipe mount like what service honda does, it fits almost perfect without putting too much stress on the pipe. only problem is i now have to modify all my other pipes the same way the subframe mount is the stock crf exhaust mount. just need to make a bushng to use a 6mm bolt.


i modified the gas tank, and moved the petcock. it is now at the lowest point of the tank. i screwed up and moved it too far, and split it at and edge. some epoxy and ill find out if the petcock leaks. i used a salamander heater to heat the tank up. next time i will use a heat gun so i can focus the heat more on a particular spot. this is only temperary, the tank has 2 stipped shroud holes, and i want a bigger tank. this will get it done so i can fire it up and start playing with the suspension. it will be changed before the first race.

[Zoomer]

Looks like your moving along well. If your going to be around Bridgeton for an of the Hillclimbs this year, I'd like to check this thing out.....

[TJC510]

its coming slower than id like though. the rest of my parts will be in friday. hopefully ill be able to ride it by next friday.
they got a schedule up anywhere? ill be there june 1st for the harescramble.

[TJC510]

i hate waiting for parts. i originally ordered an 01 airboot, backordered till the 10th. so i ordered a 00 boot, which will be in wednesday. i also ordered a FMF turbine core 2 which is coming from cali, i hope it is in by friday. i picked up my crank tonight, so the motor should be together tomorrow after noon. but i still won't be able to do anything to it till it get the silencer and air boot.
once i get the silencer i can make the tabs to mount it and finish welding everything up.

[AlisoBob]

[TJC510]

between the cold and waiting for parts its taken longer than i wanted it to. the motor is finely complete, and sitting in the frame.

here is the unmolested silencer. i need to make a spacer for the rear mount. it uses the rear fender bolt as the mount just as the steel frame, fits ferfect.



with the plastic on, looks more 2 stroke-ish than the big offset of the 4 stroke.

the head stay and air box i hope to get done today, im going to the Indy Dealer Show this weekend and hope to have it done before i leave.

[TJC510]

i didn't get crap done, my friend called me and told me that i need to come with him to pick up his new bike. but he also needed to use my truck since his tranny went out a few days ago. anyway we came home with this.

not bad for $2200.

but the 00 air boot doesn't fit it like i want it to. there is about a 15mm gap between the air box and the air boot groove. i found a measurment on the mikuni carb used on the 01 and its 15mm shorter than the 00. so the air boot should be 15mm longer. i called today and its still backordered, so i guess ill wait for it. god i hate waiting for parts. in the mean time ill finish the head stay and all the welding.


btw, i have a brand new 2000 cr250 air boot now for sale.