Dirt Bike suspension

In the middle of doing a full rebuild on my suspension, I have a 2003 CR250, replacing all seals, most bushings, and found I have Race Tech gold valves so I figured might as well revalve while I have them apart. I miss my old suspension so going with a FMX/Supercross, A class, standard age/height/gas tank for 165lbs. So wondering if anyone else does their own suspension work or tuning? It seems tough but actually pretty easy once you have taken them apart and see how they work


In pieces



Shock valve stack, rebound on the top and compression on the bottom

 

I used to do my WP's until I took them over to see what GDR in Wilkesboro, NC could do with them. Huge difference. Now I just play with the clickers.

 

Generally I would agree and have always had someone else do it too. But I had the same bike a few years ago and just copying the suspension it had before, I havent ridden on it yet, so I may be wrong but I think it will be pretty easy

 

Nice work Cr250jumper.

I have done suspension work on my own dirt bikes many times over the years. Changing springs and seals, replacing bushings etc. The factory manuals from Honda & Yamaha usually are pretty good, plus a ton of info on you tube & web now a days.

FYI, the rear shock is charged with nitrogen usually. I had to go to an airport years ago to get my shock re-charged. I think some car dealerships have nitrogen now.

Good luck.

 

Thanks. Yeah I have a nitrogen setup for the shocks on my truck so I can charge it myself. With 6 shocks and 2 bump stops on my truck filled with nitrogen it was worth the investment lol

 

I have the nitro and all the tools, tried a few times with different bikes, multiple times and I finally came to the conclusion that I suck at valving....
I have TBT racing as a sponsor now so I aint fuckin with it no more, lol.

There is so much more to it than I thought...I think it has a lot to do with experience which I apparently dont have enough of. Good luck!! hope you do better than I did.

 

Im trying to diagnose a squeak in my rear suspension. 03 YZ250. Of course I cant hear it when the bike is running but to me if its squeaking, it needs lubrication.

 

Doing it isn't hard.

Doing it right is an art.

Doing it without making a giant mess is freaking impossible!

 

Been doing moto suspension since the mid 1970's. Yes, back when Fox first started and Dual AIRSHOX were common. Since then I've done some racecars, roadrace bikes, drag bikes, street bikes and opened a bussiness in the mid 90's rebuilding and modifying MTB rear suspension and forks.

Still work on the stuff more as a hobby for myself and friends. Recently friends are trying to pull me from Suspension Retirement.

Quoted from the previous post...

Doing it isn't hard.

Doing it right is an art.

Doing it without making a giant mess is freaking impossible!

The first two are 100% correct, the third about the mess, with experience it is less messy.

PK

 

Have you washed the bike recently? Sometimes the wiper seal on rear shocks can squeak when they 'stick' to the shaft. Smear a little hi-temp, light grease on the shaft, then cycle the shock a few times. If that doesn't do it- pull the shock off and check the bearing on the top, where it mounts to the frame/subframe.

 

Im halfway(?) through a teardown of my 03 YZ250.
Most of it is in good shape but the swingarm bearings were totally shot. Rusted and broken needle bearings, a real shitshow.

To remove the bearings I am using a large c clamp with two sockets on each end to push them through. The outside bearing moved in until it is touching the inside bearing but now it wont move. I can apply heat and penetrant. If that doesnt work, is it safe to try and hammer them out? I dont want to destroy my swingarm.

 

Check for any circlips or bearing seats. They may only press in/out in one direction.

 

I'd love to do my own suspension but I dont have that much knowledge on them to work on them on my own. Just got my rebuilt and revalved last year along with the steering stabilizer and what a huge difference!!

 

Got one side out. Using the socket and a BFH. The other side though is missing all of the needles on the outside bearing and the housing lip is missing 1/3. It may be required to cut and dissect that one out instead of trying to move it. I fear it might collapse.

 

So here are the bearings and components after removal. They had to be taken out with a dremel. Absolutley pitiful condition. The linkage bearings on the other hand look good to go.

 

Yeah, you want to grease your bearings after every wash

 

But that's after every ride. Maybe I can incorporate a zerk.

 

Swingarm bearing installation went well.
Moving on to the rear shock now.
The only issues i have with the rear shock is that the bump stop (or rubber jounce) is completely rotten and falling off. Ill have to disassemble the entire shock to get at this wont I? I have the spring off, that's it.
Also, I would bet the fluid in the shock is original.

 

yes the shock has to be disassembled

 

CR250> Is this diagram accurate? It looks like the lowere part of the shock is threaded on.
Maybe I can replace the jounce w/o having to get into the shock body!
http://www.yamahapartshouse.com/oemparts/a/yam/50044d56f8700209bc79126a/rear-suspension