Any 79 RM250 threads?

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5/4/2014 8:15 PM

I just picked up one just to part out, but now Im thinking of saving her. I have no real attachment to this particular model but the condition this bike is in is having me reconsider. Its spraybombed and looks like hell but a lot of the parts are in very nice shape! Not a ding on the pipe, swingarm without rash, overall not bad at all! Its not like i need another project but if I see some inspiration here......

Bernie C

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5/5/2014 6:15 AM
Edited Date/Time: 5/5/2014 6:16 AM

I have one for a future project, fox shocks and 84 front end for it

I'm thinking an 84 rm125 rear wheel will fit too

If you part yours out let me know

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5/6/2014 4:04 AM

I have a super nice fully restored 79 rm 250. fox shox, rm 465 forks & rear wheel setup. I rebuilt complete engine, the tranny's in these bikes were soft from day 1, I replaced every bearing, seal & gear. the gears are hard to find, I had to buy 1 at a time off ebay, normally 50-75$ each ! I have ridden the bike some, but is much better to just look at! I like the fox shox, always dreamed of these when I was a kid, but even completely rebuilt, they are pogo sticks! if you are really going to ride the bike, get ohlins or works performance shocks. my brakes are all new, but do not work too good! The bike has to be ridden like a 125! No bottom end but when kept on the pipe, like a 125, it goes pretty good. I bought new 1980 style fenders from Vintage Suzuki, but never mounted them, the 79 square art deco style fender kind of grew on me! I'm curious what type of mods were done to the engine on these bikes back in the day. The guy's that hauled on these were truly talented, not easy bikes to ride fast. I will post some photo's soon! I have a complete front end for this bike, with rebuilt forks, new oem frnt brake cable, slotted shoes & good clean wheel if anyone interested.

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5/6/2014 5:44 AM

Photos please. I had one for a brief period in late 79, early 80.

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Harrison Backmon, Esq.

5/6/2014 6:26 AM





I took these a few years ago, still in same condition, b4 everyone roast me, I know the tank graphics are for a 1980, they came on bike when I bought it, & they are not bubbling! I drain tank & carb when not being used! notice the Honda Cr style chain guide, this was also put on by previous owner, but works good and are readily available on ebay for next to nothing. I have not even 2.0 hrs on meter since complete rebuild...rebuilt crank, transmission, all bearings & seals, first overbore, wiseco, boyesen reeds.. fox air's rebuilt by Thor, the fox shox expert. Sometimes I just stare at it in my garage! I love this era of bikes..
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5/6/2014 8:21 AM

Thanks for that info, your bike looks awesome!
You gave me some things to think about.
I do have a few parts left from the first one I parted out.

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5/6/2014 10:47 AM



My 79 with 80 plastic. It has 82 forks and wheels. Answer silencer, everything rebuilt, I had a new one in 79. My brothers 79 YZ 250 would smoke it in a drag race but on the track they were equal. I went with Works shocks so I wouldn't have to adjust them. I had Fox Airshox back in the day and the Works are as good.
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5/6/2014 1:46 PM

Nice bike edgo897! I'm partial to these old Suzuki's. When I was a kid I would go down to the local suzy dealer & sit on these and dream of 1 day owning one! I'm sure your works performance shocks work better than the fox air's do, I've had both. this bike came with them or I would have bought works or ohlins. I see you have the Cr style chain guide also, nice. You can also get modern foot pegs for these from DC. I hate to see the old bikes parted out, but I guess someone is buying the parts to keep one alive?

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5/6/2014 1:47 PM

I agree with the interesting era of the 79's, I remember the RM 125' well and the "box" rear fenders, I even remember the sound.
While the KX and CR of this year are popular for restore, I really dont come across many RM's, why is that? Back in the day there were enough on the local tracks and had attention in the magazines, the factory team had some big names too.
I will have to clean my rm up and really see what Ive got then go from there. I realize there is more value in parts then as a whole. It should be cheap to fix up as a display bike....not so much as a runner! A DC plastics kit is just over 200, and a seatcover around $50..? The hard parts will be the hurdle.

thanks

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5/6/2014 4:27 PM

BigAl wrote:

I have one for a future project, fox shocks and 84 front end for it

I'm thinking an 84 rm125 rear wheel will fit too

If you part yours out let me know

Rear wheels are narrower.

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The older I get, the faster I was.

5/7/2014 5:52 AM

BigAl wrote:

I have one for a future project, fox shocks and 84 front end for it

I'm thinking an 84 rm125 rear wheel will fit too

If you part yours out let me know

If you try to run a stock 79 front fender with the 84 front end, you MUST notch the fender (circled) because the different position of the 84 brake cable stay (lower fork). If not, when the forks compress the fender will kink the cable at the lower fork cable mount. Regardless of what fender you use, stand over bike and sight down the cable to be sure it's an unobstructed straight shot. This oversight almost got me killed my first time out with the 84 front end. Good luck!

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5/7/2014 9:25 AM

The rear hub will fatigue on the 79 and the result will be that the wheel bearings won't fit tight. Also check the threads on the drive shaft as they can wear out and make it impossible to tighten the drive shaft nut. The frames also can crack on the bottom area where the chain guide it welded on, below the swingarm.

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5/7/2014 10:25 AM

Great bikes, easy to work on, lots if parts around
Way better than a 78-79-80 Honda's stock junk
Great looking bikes!

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5/7/2014 3:47 PM

Edgo and Sandhill, do you know what CR the chain guide came from? I have a slow going 79 RM250 project but the chain tensioner is a pain.
Does the 80 rear fender bolt straight on to the 79 frame?

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The older I get, the faster I was.

5/7/2014 4:16 PM

BigAl wrote:

I have one for a future project, fox shocks and 84 front end for it

I'm thinking an 84 rm125 rear wheel will fit too

If you part yours out let me know

captmoto wrote:

Rear wheels are narrower.

Yep, I was gonna run a 125/250f size tire

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5/7/2014 4:17 PM

BigAl wrote:

I have one for a future project, fox shocks and 84 front end for it

I'm thinking an 84 rm125 rear wheel will fit too

If you part yours out let me know

tb901 wrote:

If you try to run a stock 79 front fender with the 84 front end, you MUST notch the fender (circled) because the different position of the 84 brake cable stay (lower fork). If not, when the forks compress the fender will kink the cable at the lower fork cable mount. Regardless of what fender you use, stand over bike and sight down the cable to be sure it's an unobstructed straight shot. This oversight almost got me killed my first time out with the 84 front end. Good luck!

I'm gonna swap steering stems between the 79 and 84 with a tony d fender

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5/8/2014 8:49 AM

BigAl wrote:

I have one for a future project, fox shocks and 84 front end for it

I'm thinking an 84 rm125 rear wheel will fit too

If you part yours out let me know

Swap the stem, but first a little mill work on the lower clamp. I think I had to make the counter bore a little deeper because the 84 clamp is thicker, or mill off a boss so the 79 bearing and seal would fit. Maybe did both, I can't remember. It'll be pretty obvious.

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5/8/2014 12:41 PM

I think all the CR chain guides are the same going back to the 1990's. it doesn't bolt on. I made an adaptor bracket. To get 1981 forks to fit I just had the stem pressed up 3/8's of an inch. The stem still has plenty of overlap. It won't come apart as it took a 50 ton press to move it. Then I had to file the top of the stem so the clamp would slide down against the bearings.

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7/6/2014 2:26 PM

I finally pulled the beast out and washed it up. its seems to be a decent base to start with, if I decide to make it a runner. From a short checkover, the rims are straight, no slop in the s/a pivot or steering head, no bottom frame rail dents, cases look good except for the upper case protector mounting boss. Silencer is toast. Pipe, swingarm, forks all look great. However I am expecting more issues as I go through it (35 yrs old!)
First problem is no spark. Is there a common part on this bike that fails, in the electrical system? it could be something simple, I have not check it over yet.





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7/7/2014 4:29 AM

bike looks like it has alot of original parts, original shocks usually did not last long! seems like parts for these bikes are readily availible. the prvious owner of my 79 had same issue with no spark, he told me, rather than chase the issue, he replaced complete system with digital unit from pvl. not cheap approx. 500$, but never had spark problem again! you may be able to find cheaper on ebay? I have some nice parts for 79-80, 1980 fenders from Vintage suzuki, never used , high gloss, unlike Dc fenders. Also sourced oemparts from Paul Miller vintage Suzuki in Ct. good guys, you can call them with part #,and they will search & let you know what they have. Bring that Rm back to life! Actually much easier finding engine parts for the 79 than the 88 i"m doing!

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7/7/2014 1:06 PM

Step 1: Either have a priest perform an exorcism or at least say a prayer over the beast

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7/7/2014 1:39 PM
Edited Date/Time: 7/7/2014 1:39 PM



Those bikes could be made to scream. Here's one (#666 behind #14 Mary Tripes) getting a 4th maybe 5th place start against the cream of the crop at the '79 AMA 250 National at Saddleback. The start hill before they swung left down Banzai was a true test of horsepower.
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7/7/2014 2:35 PM

Thanks sandman, Ill keep those fenders in mind. What about DC plastics? Only $209 for a whole kit, but are they shite?
The front fender is in decent shape but will take a lot of love to bring it back, Id rather put that time into the tank, which might have bed liner on it! Oven cleaner wont touch it! Its on thick and hard.
As for the electrics, Ill just ohm each component and check with suzook for specs. I pulled the stator cover off and it looks brand new inside.
For the silencer I might just make a new front piece for it and make it a removable type, the cannister itself is also decent (no dents/scrapes)

Ya Bigal, it looks like hell but remove the cosmetics and a LOT of the parts are in real nice shape.

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7/7/2014 3:14 PM

I agree everything you need is there. The pipe looks dent free. OEM spokes are available online, most everything internally is still available front suzuki.

I think I have 2-3 original bore cylinders if you get in a bind.

I used DC plastics on my 76 RM250 racer, I liked them and thought they were a great deal. Not museum quality but great if you're gonna ride it.

I'd try some gel type paint stripper for the tank. No sissy enviro citrus stuff

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7/7/2014 3:19 PM
Edited Date/Time: 7/7/2014 8:42 PM

Thanks Al, here is canada the enviro regulations have made all types of chems a lot weaker then they used to be. But I have a few ideas Im gonna try.

Edit; The bike has bridgestone M19 and M18's on it, are those original??!!

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7/8/2014 6:23 PM

So what kind of cylinder porting has anyone done to give these a little more zip? I have a spare cylinder to work on and I just bought a cone pipe.

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7/8/2014 6:30 PM

edgo897 wrote:

So what kind of cylinder porting has anyone done to give these a little more zip? I have a spare cylinder to work on and I just bought a cone pipe.

Perhaps the good folks at FMF still have some notes from back-in-the-day. They built some fast Zooks in that era.

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7/8/2014 8:39 PM

I owned / raced a RM250N (79) after selling my highly modded 78 Model. Granted I didn't know then what I do today about 2 strokes . But I could never get the beast to generate that haulin arse kinda horse power my 78 had. I did all the basic trick stuff. Porting , thinner head gasket, big carb, even tried the Lectron of the day .
Lookin back.. the 2 areas I didn't touch was the bore size and we left the stock ignition on it.
After reading the rules it was legal to go 80 thousanths over. making it a 265 . I would also try advancing the timing a little to put some snap into it. The power was just "soft feeling". Suzuki did upgrade the tranny gears and the 1980 model RM250T stuff is the replacement gears of choice. The original 79 tranny part numbers were changed to the 80 part number. But for porting advice, lower the floor of the intake 3 mm's and do not open up the boost transfers at the bottom of the cylinder. If I knew how to degree cylinders, cut squish bands, etc in the 70's we would have had works engine's. As it was we only kept notes on how far we moved existing ports .
The 79's didn't feel faster but they had a distinct advantage in the handling department , after I rode one on the track I knew then, I was severly handicapped riding my 78 RM250 warhorse.

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Just Old.

7/9/2014 2:51 PM

when i rebuilt mine the cylinder was on original bore, never been ported either. I thought about finding someone to do it, but was nervous about someone hacking up syuch a good cylinder. I put it back together stock, first overbore with new boyesen reeds. i only have 2.0hrs on it since complete top & bottom rebuild, not much low end, decent mid range with some overev. has to be ridden like a 125, shift too early it falls flat on its face! I"m curious to know what the factory guys did to them in the 79 season, if anyone knows? One thing that I noticed, there is some gas blow by coming from intake boot on front of carb where it attatches to carb. bikes runs good, intake boot is new, jetting does not appear to be too rich , carb clamp is tight...?

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7/10/2014 7:08 PM

My kickstarter knuckle is In horrid condition, the splines look like they are made of putty. Is the 1980 piece an improvement?
I know that the trans gears were.

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