1992 RM250 Rebuild


18 replies to this topic
  • 1992-rm250

Posted October 11, 2009 - 09:25 AM

#1

Hello All--

I just picked up a 1992 RM250 as a project bike and I have some questions that I'm hoping I can get some expert advice and opinions on. It's been a long time since I've owned and worked on motorcycles, so I will really appreciate any and all opinions.

1. Overall--Is there anything I should know specifically about the 1992 RM250 that would help me know whether this is a model that is worthy (or not) of a rebuild? I'm thinking about things like...this bike was terrible when brand new, why would you want to restore it? or, this bike is an awesome ride, give it some TLC and you'll be pleased for years to come.

2. I've got a Clymer manual on the way, is that the only manual option? or should I pick up others?

3. The pipe was a terrible fit and horribly dented. What should I consider as a replacement?

4. I've got the clutch taken apart, what should I look for in terms of deciding whether I should replace it? What are my clutch options, from most to least expensive?

5. What's the best way to loosen the nut that holds the clutch basket in place? I want to break the whole thing down and split the cases to take a good look at everything.

6. When I pulled the crankcase cover off to look at the clutch, the oil was grey and creamy looking (had the look of melted ice cream). Other than that, everything looked clean, with the exception of some grease and grime that I introduced when opening it up. What's the best way to clean this up before reassembling? Should I clean it all with solvent and then seal it up and add new oil?

7. I pulled the rotor off using a flywheel puller, but can't seem to loosen the rusty phillips screws that hold the stator to the crankcase. Any suggestions on breaking these loose? They aren't horribly rusty, but have a little rust on them.

8. The frame also has a little rust on it. Any suggestions for cleaning it up and then painting it to avoid future corrosion?

I think that's all I've got now. I realize there is a lot here. Please don't feel like you need to sit down and answer every question, I'll take and be grateful for whatever advice you have time to give, and I look forward to be being part of this community and giving back whatever knowledge I pick up along the way.

Nathan

  • zig06

Posted October 11, 2009 - 05:34 PM

#2

1. Do not worry about what this bike was or could do in 1992 when it was brand new. That was 17 years ago. You only need to know about what it's capable of today, and today a decent rider on one of these can stick with any new bike in the trails. On an MX track you would have to have it in perfect shape and be very motovated to crack the top 5, but it can be done.

2. A Clymer manual is fine, although occasionally a factory manual pops up on eBay.

3. An FMF Fatty pipe would be a great replacement, and they can still be ordered.

4. A Barnett clutch kit is a good replacement kit. Only replace the basket or hub if it's notched.

5. You need a tool to hold the hub. Motion Pro sells what looks like a huge pair of vise grips for this operation ~ buy one.

6. Grey oil is clutch fibers in the oil, and it's normal. If there's a lot of it, then it's a sign that the previous owner didn't change his oil as regularly as he should have. Clean it as best as you can and move on. If the oil looked like chocolate milk then that's a sign that the water pump seal had failed.

7. Get a hammer impact driver that was designed specifically for screws. Take the time to clean out the area where the phillips driver goes in, even lightly tap the phillips bit a couple times to imbed it into the screw head and then use the driver. It should break free with the first or second tap once the drive is on the bit.

8. Unless you plan on doing a frame off restoration a little bit of rust will not hurt a thing. PJ1 does sell a can of paint made for motorcycles that have the correct color code already mixed. Clean and degrease the area, tape everything off and use that if you feel that the rust is excessive.

In the end, take your time and if you do not have the correct tool ~ STOP! Buy the tool or bring your bike to the shop and pay them to do that one operation. In the end you will save money, time and the mechanic might even give you a pointer or two.

And post a picture of your bike, before and after pictures are always fun to look at.

Here's one of my old 1990 RM250, it should look like your '92 ~ sort of..
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  • 1992-rm250

Posted October 12, 2009 - 06:49 AM

#3

Thanks a lot Zig. Yes, your bike looks very familiar to me. Plastics and frame look the same, seat color scheme is a little different. I will post pics as I go!

The oil was just grey, no chocolate milk. The clutch basket does have notches on it, and it doesn't look like Barnett makes a basket for pre-1996. Is my next best option to go with OEM?

Is it ok to clean the entire bottom end with solvent or gasoline before putting it back together? I was planning on doing this, but I read something saying maybe it would be bad for the existing bearings that I don't replace.

Thanks again,

  • Vankaye

Posted October 12, 2009 - 07:05 AM

#4

+1000 on Tools!

Essentials are:
Case splitter
Hub/flywheel holder
Fly wheel remover
snap ring pliers
impact screwdriver
Crank installer
Feeler gauges
Caliper (digital is good)
Torque wrenches (8ft-lbs - 60ft lbs probably two wrenches)

Tear it down and keep watching riding videos, it'll motivate you to learn
whatever is needed to finish!!!!

  • zig06

Posted October 12, 2009 - 08:24 AM

#5

Here you go, not only does Barnett make a kit for your bike but you can buy one through the ThumperTalk store

Kit # 2012-530
http://shop.thumpert...t.asp?p=767&s=2

As far as cleaning out the engine, unless you disassemble the motor you will never get it all out. Personally I never liked using gas to clean with, that whole exploding into flames thing never excited me. Plus it's not exactly cheap. Just get a can of carb and parts cleaner, spray off and wipe down what you can. Maybe consider using a cheap trans oil for the first ride and when your done after that ride, with the motor still warm (or hot) drain the oil and then put in the good stuff.

That's about as good as you are going to get with out pulling the motor down but that should do the job.

  • 1992-rm250

Posted October 12, 2009 - 10:31 AM

#6

Thanks guys, heading out to Sears to get the Craftsman Impact Driver now. On the clutch, I saw the Barnett clutch plate/spring kits, but what I didn't see was a clutch basket available for the 1992. For this I was wondering if I had any options other than OEM?

  • zig06

Posted October 12, 2009 - 05:32 PM

#7

It kind of looks like you will be stuck with buying an OEM basket, on the plus side the original OEM basket lasted almost 17 years.

With a new clutch kit (plates and springs) a new basket, and new oil every 5 or more hours of riding and you should be able to get another 17 years out of your new clutch.

  • 1992-rm250

Posted October 12, 2009 - 06:43 PM

#8

Hey, looking at it that way, not bad at all!

Here's some pics of the top end. My gut is that I should just have it honed and get new piston kit. Anything else noteworthy on the top end, like say power valve (can you adjust it) or reeds (any reason to buy new)?

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  • 1992-rm250

Posted October 12, 2009 - 08:00 PM

#9

I also added a couple pics of the clutch basket and hub, if you care to opine on them. Again, many thanks, this is so helpful. The impact driver helped me get the stator and power valve out. Ordering the clutch hub holder to move forward here.

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Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • zig06

Posted October 13, 2009 - 08:17 AM

#10

Your clutch basket does look very worn but I have seen worse, check eBay and even try calling Moose, Barnett or MSR directly and see if they have one back in the warehouse ~ it's worth a shot. In a pinch you could still run it.

Your cylinder is plated so you may not be able to hone it. Bring it to a shop and see what they can do. I didn't see any flaking in the bore so if they can't or won't do anything besides wanting to replate, then try using WD_40 and a green scotch brite pad. That should get another season out of that cylinder. Granted the best way would be to have Millennuim replate it.

For a piston, I would just order one from Wiesco. And because your cylinder is plated then it's mostly likely still on the stock bore. Have that measured before you order.

While you are waiting for parts, use that green pad and WD-40 on the head. It's looks good so don't get too crazy.

  • 1992-rm250

Posted October 19, 2009 - 08:06 PM

#11

OK, I finished pulling it all apart tonight and I'd appreciate some more of your advice. Everything looked pretty good to these rookie eyes, doesn't seem to be any major damage.

Here are the case halves. The crankshaft bearings and crankshaft in general look sort of rusty, is that normal? What should I bother replacing since I have this all opened up? All of the bearings and seals, or just the seals? I don't want to put a ton of money into this thing, since it'll still be a '92 when I'm done, but at the same time, I want to take advantage while I have it open. So let me know what's a must and what's an "if you want."

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In this picture, you can see that in the process of splitting the cases, I sort of scuffed up the threads on the crankshaft on the magneto side. I haven't tried the nut yet, but any thoughts as to cleaning up first? Maybe some light filing? or just try the nut?

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Here is the transmission assembly. The gears all looked really good to me. Anything in particular I should look for?

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Lastly, this is the only thing (aside from my damage to the crankshaft) that looked messy to me. The top and bottom of the shift drum both had a sort of rough/gashy parts. You can see in the pics. Also, on the left case side of the shift drum, you can see that it sort of marred up the case a bit. It looks just like superficial scuffing to me. Have you seen this before? Any clue as to the cause? Should I replace the shift drum or just file it smooth?

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Many thanks in advance!

Nathan

  • zig06

Posted October 22, 2009 - 01:17 PM

#12

I do not understand the rust on the crankshaft, do yourself a favor and really inspect the crank/rod bearing. It's possible that this bike spent some time sitting around without a pipe and some moisture got in there. If there's funds available then have the crank rebuilt, any bike this old should have that done. I would also replace both of the main bearings and both of the main seals.

If you have an industrial bearing supplier in your area consider pulling both of your main bearings, bring them to that supplier, and see if they can order them. I normally save 50 to 60% over any dealer when I do that.

All of the bearings in the transmission should be fine, inspect them to be sure, but I would expect all of them to be worth reusing. Your shift drum does have one really ulgy burr, see if you can clean that off before it falls off. But it is case harden steel, so only worry about the pieces that look like they want to fall off.

The case half that has the "booger" in the metal by the shift drum bearing isn't a concern. Just make sure that it isn't cracked in that area. It's not a really stressed area so don't sweat it.

So beyond a good clean up, deburring the shift drum, new main seals and bearings and maybe a crank rebuild, I think you are ready for reassembly!

  • 1992-rm250

Posted October 23, 2009 - 08:10 PM

#13

Thanks! I think your guess about the rust is right on. The pipe on the bike was horribly banged up to the point that it really had no seal against the cylinder, so probably lots of moisture.

In my research so far, I've actually found out the bike is a 1990, and the engine came out of an 1989 (had to call actually Suzuki to find that out). So, I'm getting my OEM parts list ready for an order.

Any gasket recommendations? I'm seeing some complete gasket sets on eBay for around $35. Anything to watch out for here? Also, any thoughts on an OEM piston kit from Suzuki vs. Wiseco?

  • majeka

Posted October 25, 2009 - 06:20 AM

#14

ive just finished rebuilding a 1992 rm, was a good project . Shot blasted the frame and repainted it a more modern grey, fitted new bearings throughout and new fork seals. Previous owner had fitted new chain and sprockets new pipe and can and new CDI but he couldnt get it to run. I got it for a snip and hardly cost me anything to complete it.
Took it out for the first time yesterday and i have to say its awsome. You just cant keep the front wheel down. Get it sorted and enjoy it.

  • Metty

Posted October 25, 2009 - 06:56 PM

#15

rebuilding a crank is pretty easy if you have some tools and time. i did mine with a set of V-blocks, 2 dial indicators, a lead hammer and a press. scribe a line across the crank halves before you take it apart and get it as close as you can as you press it back together. spin it in the v-blocks with the dial indicators on each half and whack it with the lead hammer till you have less than .001" runout. my crank had .0015 from the factory and it has less than that now because my dial indicators wouldnt read any runout at all. oh also make sure you measure the width of the crank before you take it apart so that you know when to stop pressing it together.

metty

  • 1992-rm250

Posted November 17, 2009 - 09:18 PM

#16

Thanks for the input all. The project is ongoing....I've been in sort of a holding pattern as I get parts.

Got the crankcases all soapy clean tonight, put in new bearings and seals, also cleaned up the cylinder and exhaust ports per Zig's comments with a green pad and some wd-40. Going to just give the tranny a once over tomorrow with some degreaser to clean it up and then hopefully get the cases put back together.

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  • zig06

Posted November 18, 2009 - 05:12 PM

#17

So far I'm impressed! Keeping it clean and taking your time and in the end you will have a very nice bike.

:excuseme:

  • Tailender

Posted November 18, 2009 - 05:38 PM

#18

I would rebuild the crank. Why take a chance while you have it this far apart? Then you know the bike will go a long time with no problems.

  • Pyramid Kid

Posted November 18, 2009 - 06:56 PM

#19

I too have a 92 RM 250. And mine doesnt look anything like you guys.

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To the best of my knowledge everything on the bike is stock accept for the FMF pipe and silencer and some race tech parts in the front forks.

By the way I have the original service manual for mine and it says NOT to hone the nikisal cylinder. So you might be able to just clean it or you could go with a resleave and then you not limited to 249 CC's. But my bike makes plenty of power as it sits.

Edited by Pyramid Kid, November 19, 2009 - 11:41 PM.





 
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