Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: Dirt Addict on February 13, 2013, 11:58:18 PM

Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 13, 2013, 11:58:18 PM
I have a 2005 rm250. It has an unusual amount of vibration. I pulled the ignition cover and found both fore and aft and in n out play on the flywheel. I'm guessing it's time for a rebuild. I'm a decent garage mechanic. Is a bottom end rebuild doable or is it for the experts?
I'm not even sure what I would need to replace? Crank bearings, crank? Seals?
Should I just fork over the dough for someone else to do it?
Title: Vibration and flywheel freeplay - rm250
Post by: _X_ on February 14, 2013, 12:09:37 AM
if racer x can do it any one can do it. ( even 2t institute) just get the special tools and a manual and your golden. remember no pot or beer before or during instalation. crystal meth ok.
Title: Vibration and flywheel freeplay - rm250
Post by: cnrcpla on February 14, 2013, 12:47:50 AM
You can do it, just get hold of a fly wheel puller, and preferably a case splitter, but I think you can rig one up. You will most likely need new crank bearings/seals, and maybe big end conrod bearings while you have it split open to save the hassle of doing it again down the road. Also, gaskets are a must.
Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 14, 2013, 02:00:00 AM
anyone care to post up a list of parts I should order? I will most likely get a splitter and bearing puller.....
Title: Vibration and flywheel freeplay - rm250
Post by: _X_ on February 14, 2013, 02:09:52 AM
addict, your manuel will list the parts you need. get a manuel. oh yeah may i add not rocket science.
Title: Vibration and flywheel freeplay - rm250
Post by: SachsGS on February 14, 2013, 03:01:44 AM
Pull your cylinder, remove flywheel, primary drive gear, countershaft sprocket and separate cases. The clutch and tranny can remain in one case half.
Title: Vibration and flywheel freeplay - rm250
Post by: 2T Institute on February 14, 2013, 03:36:43 AM
Quote from: Dirt Addict on February 14, 2013, 10:00:00 AM
anyone care to post up a list of parts I should order? I will most likely get a splitter and bearing puller.....

A length of aluminium and a rattle gun is also needed for the primary drive. You might as well replace all the seals and bearings at the same time. Heat the cases to get the bearings out and new ones in.
Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 14, 2013, 07:23:19 PM
I have the flywheel puller and an impact wrench (is that what you mean by ''rattle gun''). I have the manual too. So I'm gonna clear off the work bench and give this a try. No interest in pot or more than 1 beer. I'm more of a caffiene fiend.
So can I leave the whole clutch intact? What about the kick start gear?
Standby for lots of questions......
Title: Vibration and flywheel freeplay - rm250
Post by: _X_ on February 14, 2013, 07:47:30 PM
you might get away with it, sachs says its posible,but when you do split them your tranny will be exposed. just follow the steps in the manual before you actually start work. this will give an overview of the work to be done.
Title: Vibration and flywheel freeplay - rm250
Post by: evo550 on February 15, 2013, 04:58:44 AM
Have you checked the tension on the flywheel nut itself ? A loose flywheel could give you all of those symptons.
Is it an external or internal flywheel ? How much play are we talking about ?
Title: Vibration and flywheel freeplay - rm250
Post by: ford832 on February 15, 2013, 04:42:33 PM
A loose flywheel would give you more of a "rocking" motion as opposed to the movement he described.
Title: Vibration and flywheel freeplay - rm250
Post by: SachsGS on February 16, 2013, 03:15:04 PM
You can leave the kickstart/clutch intact.

With a loose flywheel the first time the engine fires it will shear the flywheel key.
Title: Vibration and flywheel freeplay - rm250
Post by: eprovenzano on February 16, 2013, 03:45:55 PM
A bottom end rebuild is not as difficult as it seems.  Yes take your time, do a lot of reading, and video review.  If you think about it, its a mechanical machine, it's just nuts and bolts.  Follow the manual and you will be fine.  I have my son's KTM 250F which I've split the cases and removed the crank  I'm waiting on the parts to arrive so we begin the rebuild.  Yes there are a few specialty tools needed like a flywheel puller.  I took the engine to a local shop and they pulled the flywheel for $5.00  I was able to split the cases without a case splitter. 

If you have any issues, or concerns let us know, we are here to help you.
Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 16, 2013, 05:22:30 PM
thanks. I will keep you guys updated.....
Title: Vibration and flywheel freeplay - rm250
Post by: TMKIWI on February 17, 2013, 04:16:03 AM
Quote from: racer x on February 14, 2013, 10:09:52 AM
your manuel will list the parts you need. get a manuel.

Who is this manuel guy.?
Is he any good and can I get 1 as well. ;D
Title: Vibration and flywheel freeplay - rm250
Post by: _X_ on February 17, 2013, 02:04:57 PM
you got a problem with my spelling kiwi? HA! you can see my training video in the open forum, i'm a bad dude.
Title: Vibration and flywheel freeplay - rm250
Post by: TMKIWI on February 18, 2013, 05:03:31 AM
Don't have a problem with your spelling.
Just thought you said you had your own mexican and wanted to know where to get one. :D
Title: Vibration and flywheel freeplay - rm250
Post by: evo550 on February 18, 2013, 07:51:13 AM
I thought it was the spanish waiter from Faulty Towers...
Title: Vibration and flywheel freeplay - rm250
Post by: _X_ on February 18, 2013, 10:54:58 AM
no, every time i aquire a mexican they always seem to runaway to the nearby stables where thee seek amnisty. the last one was named manuel...i'm going to miss that little guy. so if you are quick enough to elude the stable owners may aquire one there. hope this helps. evo, we used to get faulty towers here in the states, good show.
Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 18, 2013, 09:18:46 PM
what is the best way to remove the main bearings? Heat the cases up on the outside?
Title: Vibration and flywheel freeplay - rm250
Post by: cnrcpla on February 18, 2013, 09:31:58 PM
I heard somewhere but never tried this, you put the cases in the oven facing down and heat them up and the bearings will fall right out. I don't know what temperature or if this even works, but search around on google, I'm sure you'll find something, or another member with more experience with this will know a better trick.
Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 19, 2013, 01:15:47 AM
Does anyone have pointers on installing oil seals for the crank bearings?
Before or after installing the bearings?
From the inside of the cases or the outside?
Title: Vibration and flywheel freeplay - rm250
Post by: _X_ on February 19, 2013, 01:44:24 AM
bearings then seals, install seals from outside. i use a bearing/seal driver. if you turn old seals over you could use them to drive the new seals in.
Title: Vibration and flywheel freeplay - rm250
Post by: 2T Institute on February 19, 2013, 05:24:41 AM
Heat the cases up with a heat gun or stick in the oven and heat to 160deg C Freeze bearings and they will drop straight in. Fill the V in the seal with grease before installing.
Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 20, 2013, 03:47:29 AM
I got the bearings in. The left side was easy. It practically dropped in. The right, not so much. I got it 1/2 way in and it locked up. I put it in the oven at 350* f for an hour  :o . After that I was able to tap it in using the old bearing as a driver. It took quite a few taps. The seals were the same.... left side easy, right was difficult. I'm not 100% happy with the right side install. It looks ok but it left my a little uncertain.
I did the install with the trans still in. some gears slipped off. I re-installed using the manual, and again, I hope it's right. I rearranged them about 100 times till it matched the diagram as close as possible.....
I'm waiting for the crank to get here to finish the job.
Title: Vibration and flywheel freeplay - rm250
Post by: evo550 on February 20, 2013, 08:10:41 AM
If the left bearing was quite easy to fit, I would check to see if the movement wasn't caused by a worn bearing surface on the case.
Bolt up cases with old crank (no trans if you like) and see if any play there.
Title: Vibration and flywheel freeplay - rm250
Post by: 2T Institute on February 20, 2013, 09:20:17 AM
To check the gearbox put the case halves back together,put the gear lever on the selector shaft, spin the clutch shaft backwards and use the lever to change gears
Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 21, 2013, 01:07:46 AM
holy cow Batman! cases are back together and the tranny shifts!
I still need to piece everything else back on, but the scary part is done. Everything seems nice and solid.
I will bolt it back together over the weekend. I found a broken engine mount while pulling the motor. I will strip the frame, get it welded and maybe powder coated while I'm at it.
Thanks to everyone who helped.
Title: Vibration and flywheel freeplay - rm250
Post by: Dirt Addict on February 25, 2013, 03:32:20 AM
I took my frame to a welder buddy to get the broken motor mount fixed. We were looking at the bare frame and welds. Has anyone noticed how rough the welds are? They look almost frankenstein. I was thinking that the frame may have been previously repaired but my buddy pointed out other welds all over the bike that were rough. And the amount of slag painted over was surprising too. Is this common with suzuki?
Title: Vibration and flywheel freeplay - rm250
Post by: 2T Institute on February 25, 2013, 05:36:49 AM
Most steel/CrMo were robotic MIG welded whereas later aluminium frames are hand welded which you will be lucky to even spot the slightest defect