Who Rebuilds Dirt Bikes?

[Kiwioilboiler]

@rogue60 anything to add for Mr @Mastermind ? You've recently finished a KX250 yeah? Mine was too long ago to be relevant i feel.

 

[afleetcommand]

Did for years, out boards too (old inline 4 and 6 cylinder mercuries ). Injury took the "racing" sport away (age too ). Still have a few projects left. A 2001 VOR 503 given to me by that company when I worked for them, the very first X-Country version. A long story. Moto suspension & motor tune with a wide ratio gear box. They were "cassette's" anyway so could change from 3 speed, to 5 close ratio to 5 speed wide ratio in 1/2 hour without pulling the motor. Have the 5 speed close ratio as well....

A 1979 KTM 420 MC80 like the one I turned "expert" on. It's in running condition. New shocks built by a famous suspension shop. Haven't even started that bike in a few years I built and rebuilt those from 1978 to 1981 when Kawasaki's ruined it for me....( quickly went to Honda's for the mid to late 1980's )

A 1989 Suzuki rm250. Love the way they handled...a bit pipey for some but fit my skill set at the time. Never got used to the 4 strokes after decades of 125/250 racing. Fan the clutch and steer with throttle as those old things needed....not enough torque to matter so it was all about keeping cornering speed up and the thing "on the pipe" bet very few now even know what that was about!

BUT two strokes are two strokes. Those old ones get air leaks just like old saws, often for the same reasons. Case seals, and the real PITA is the ones with rubber manifolds that get old and brittle. And the later ones with power valves and water cooling are a bit more complex...a manual really helps. Never built a KX250, but several Honda 125/250's as they transitioned through the 80's into the 90's My kid had a couple of CR125's when he was racing, the other kid a kx500 that never needed anything but...gas. Lots of it.

 

[rogue60]

@rogue60 anything to add for Mr @Mastermind ? You've recently finished a KX250 yeah? Mine was too long ago to be relevant i feel.

Not much to add just that paying someone to do the work cost will get out of hand fast.
They are easy to work on no harder than a chainsaw if you ask me.
Only thing I get a shop to do is rebuild the cranks or send a barrel out for replate.
Just get a wossner conrod kit they are good and get the old crank rebuild heaps cheaper than a new crank a lot of the new aftermarket cranks are just rubbish.
As has been said the Tusk crankcase tools are good and plenty of cheap flywheel pullers out there to choose from.
About the only other thing the clutch basket nut needs to be undone with a rattle gun.
1st thing to look at is the power valves if they are ok or not they are mostly no longer available and out of stock for most 2T dirt bike's now days and costly to find in good nick.
Oh and suspension is basic stuff to rebuild if needed shock can be done in under 30min with basic tools and rattle gun forks of course take longer.

Nothing Mastermind and the young bloke couldn't handle but as he say's its finding the time if ya busy.

 

[rogue60]

As for bearings most can be crossed referenced at a bearing shop and bought at a 3rd of the cost for the exact same bearing made by the same company Kawasaki sourced them from most bikes are like this.

 

[Kiwioilboiler]

As for bearings most can be crossed referenced at a bearing shop and bought at a 3rd of the cost for the exact same bearing made by the same company Kawasaki sourced them from most bikes are like this.

Not my experience. "Yes we made it, no we can't sell it to you. It's a Kawasaki part" I'm glad it sounds to have changed.

 

[rogue60]

Not my experience. "Yes we made it, no we can't sell it to you. It's a Kawasaki part" I'm glad it sounds to have changed.

What year bike?
Some bikes do have one off odd bearings here and there that you can only get OEM if they still have any left in stock.

 

[Kiwioilboiler]

What year bike?
Some bikes do have one off odd bearings here and there that you can only get OEM if they still have any left in stock.

Was 97 KX250. Crackhead took it saltwater swimming so I had to go through gearbox as well as Electrosil cylinder etc.
Double wheel bearings I think were proprietary too.

 

[rogue60]

Was 97 KX250. Crackhead took it saltwater swimming so I had to go through gearbox as well as Electrosil cylinder etc.
Double wheel bearings I think were proprietary too.

Ok things must have changed.
did all the bearings in my 02 rm250 engine as well used SKF.
For OEM parts I use www.megazip.net you get the option to order from Japan it cuts out the crazy high postage for parts from the US down here.

To cross reference part numbers to see what years use the same part I use this its easy just click on the part and it will bring up all other years and models that use that same part handy if trying to track down a no longer available hard to find part www.partzilla.com

 

[S Sidwell]

Grandson has a KX65, screaming little demon. I've piped it up and install a different silencer. Then I had to install a bushing in the carb and washer in the exhaust. We were afraid he'd really get hurt. Kind of tame right now til he gets better. Son inlaw has a KDX220 which works well as a woods bike. Too bad you can't do much to help the power except a pipe and silencer.

Sent from my SM-G550T using Tapatalk

 

[Bigmac]

On the main bearings, I have seen the aftermarket replacement bearings, not be as dementialy accurate as oem, I have had koyo bearing with the same number as oem fall off a brand new oem crank and the oem bearings were a slight interference fit. I feel the oem gets a higher quality bearing, they are more expensive but I think they are different, have just seen the loose fit too many times. I went to a bike shop years ago, and tried 4 different koyo bearings and they all fit the crank differential...ordered oem bearings and they were tight like they should be.

 

[Kiwioilboiler]

Grandson has a KX65, screaming little demon. I've piped it up and install a different silencer. Then I had to install a bushing in the carb and washer in the exhaust. We were afraid he'd really get hurt. Kind of tame right now til he gets better. Son inlaw has a KDX220 which works well as a woods bike. Too bad you can't do much to help the power except a pipe and silencer.

Sent from my SM-G550T using Tapatalk

https://www.steahlyoffroad.com/kawasaki-kx-65-00-16-suzuki-rm-65-03-05-flywheel-weight-605

Big fan of these. Really tames the hit and allows the bike to hold a gear much longer, which reduces the downshift-powerband-loop out risk.

 

[ktmtigger]

Definitely a weighted flywheel, we ran a different carb and reed setup plus a gnarly pipe from fmf. Wakes the kdx right up

Sent from my E6910 using Tapatalk

 

[Mastermind]

Update. Rebuilt the bike with new crank, bearings, seals, 1.1mm oversize piston. Rebuilt the swing arm too. Runs great.

 

[Lightning Performance]

Grandson has a KX65, screaming little demon. I've piped it up and install a different silencer. Then I had to install a bushing in the carb and washer in the exhaust. We were afraid he'd really get hurt. Kind of tame right now til he gets better. Son inlaw has a KDX220 which works well as a woods bike. Too bad you can't do much to help the power except a pipe and silencer.

Sent from my SM-G550T using Tapatalk

Have you unleashed the beast?

 

[Jason628]

I did my 1989 cr125 years ago. Hung a new rod and found a sleeved cylinder for it. My friend hit a deer with it at like 80mph and bent the frame and forks. He broke his arm and was lucky that was all he broke. Slowly working on getting the old 125 back together. Luckily I had bought a parts bike and so I had a spare frame and forks but, the forks need seals and I keep getting sent the wrong ones.... I bought a 2015 rmz450 new and have barely ridden it since I've gotten it. I need to do the first valve adjustment on it. I finally got a toy and my friends get rid of all of theirs.... go figure. Started buying stuff to make it street legal.

 

[Egg Shooter]

My grandson's buddy got a 02 KX250 that is locked up. The jug seems ok......needs a piston. The rod bearing is done.....and the mains are stuck. Do any of y'all rebuild these things? I'd love to send this thing to someone for a rebuild for him.

I have a few times in the past.

 

[Jason628]

Been doing some work to the cr. Got new fork seals and bushings installed. Fired it up and it ran like crap and couldn't get it to idle. Choke/idle adjustment was stuck so I pulled it out and appears to be bent. I hate the OEM carb that came on it so I figured I would upgrade. I ordered a 36mm keihin pwk clone on ebay for $40.problem is the manifold size is quite larger than the original and my intake manifold is starting to crack. So last night I ordered the boyesen rad valve setup that has a straight coupler that makes the manifold to the carb. Supposed to be a good performance upgrade as well.

 

[Bigmac]

Been doing some work to the cr. Got new fork seals and bushings installed. Fired it up and it ran like crap and couldn't get it to idle. Choke/idle adjustment was stuck so I pulled it out and appears to be bent. I hate the OEM carb that came on it so I figured I would upgrade. I ordered a 36mm keihin pwk clone on ebay for $40.problem is the manifold size is quite larger than the original and my intake manifold is starting to crack. So last night I ordered the boyesen rad valve setup that has a straight coupler that makes the manifold to the carb. Supposed to be a good performance upgrade as well.

What year is the cr? That is a China clone carb. You may have to make several mods to get to run decent, often times the emulation tube/main jet tower is underside, and the float seat is small and will starve for fuel on long runs. Sometimes they come with numbered jets and sometimes they are blank. You can drill them out with index bits, and some will run, and some have issues and never run right, have been though a few! I recommend getting a 99 or 00 cr250 38 mm air striker, and upp sells a manifold that fits the cr it’s made for the later 00-01 but will fit older models too, I haven’t personally tried that manifold yet but plan too

 

[Jason628]

It is an 89 model. I bought it as a basket case years ago and got it running and then my friend hit a deer at like 80mph and so I swapped frames and am slowly getting her back together. I bought a jet kit for the pwk so, I have a variety of jets for it. I couldn't find much info on the manifolds other than the I think 1992 had a different part number. I was hoping to find one with the same mount but, a bigger carb side.

 

[Bigmac]

It is an 89 model. I bought it as a basket case years ago and got it running and then my friend hit a deer at like 80mph and so I swapped frames and am slowly getting her back together. I bought a jet kit for the pwk so, I have a variety of jets for it. I couldn't find much info on the manifolds other than the I think 1992 had a different part number. I was hoping to find one with the same mount but, a bigger carb side.

The upp manifold should work, the 92-01 manifold and reeds are a bolt on, but the manifold angle changes and pedal count switches between 4 pedal and 6 pedal reeds. The 00 carb is a fantastic carb, jetted for a 250, 38mm and a good buy oem, $209 on Rocky Mountain atv. I would ditch the China carb