1984 RM500 Restoration

Micahdogg
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9/22/2020 8:58am Edited Date/Time 10/18/2021 10:44am
I picked up a new project for when the ATK gets finished up. This wasn't really on my radar, but it was fairly local to me and I had never actually seen one. I thought if I didn't pick this up, I would probably never have the opportunity again (unless buying a finished one).

The good? It was only 130 miles away. It is fairly complete. It has some brand new Fly Racing aluminum 7/8ths bars...which will find a good home somewhere else. It has a new heavy duty tube in the rear. The gas tank was razor bladed and sanded. Its not great, but its a pretty good start and the kid did a decent job. It will save me some time for sure. It also has a brand new Wossner overbored piston and recently bored cylinder. It makes very good compression. The price was $1000. I don't know if that qualifies as good, but I don't think its bad.

The bad? It doesn't run. It doesn't appear to be producing spark. The original TM carb slide is shot. The crank has a little wiggle on the stator. The plastic is all bad. The silencer looks like Mad Max handiwork. Obviously the suspension is shot as are the tires.

















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Micahdogg
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9/22/2020 9:14am
A quick and dirty test showed correct ohm range for one of the stator poles - the other flashes numbers and then goes dead (to number 1). I'm guessing that's the problem, but not sure. After finding the crank wobble, I have now decided on a full engine disassembly whereas beforehand I was considering trying to fire it with the new top end.



I picked up a cheapo Keihin wannabe carb because this bike is already looking to swallow a couple grand. Its not one of my prouder moments, but at this point I'm not sure if I'm lighting money on fire or if I can stay positive on this thing.



A silver lining....two stage Uni Filters on each side that look to be in decent shape. I was expecting a nest of some sort.



I will have to refurbish the exhaust in order to save money. I think the silencer is original to this bike, but I'm not sure. I tore into the homemade "tetanus shot" spark arrestor to see what I had to work with.



I had the idea of spinning down an old tensioner pulley to use as a suitable endcap. I recently picked up this lathe and was excited to have it start paying for itself.



Looks like I'll be able to chop the silencer down a bit and fit this puppy in the end. It may actually look alright too.

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TooOld4WFO
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9/22/2020 9:32am
I must compliment you on your excellent before images. Great shots.

This will be a challenging restore to say the least. It is very much like the 92 CR I did starting condition wise.
No way would I buy another in the same condition as that one. Just too much work when you have others that will need so much less.
I look forward to your efforts.
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sandman768
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9/23/2020 1:40am
Cool bike! At least it still has the DLS front brake assy. Hopefully it just needs crank bearings but inspect the case bearing pockets closely, they have inserts pressed in & become loose, so new bearings won’t help. The rear shock bodies also get worn out from lack of service. These bikes are rare! Good luck & keep posting!
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LOOnatic
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9/23/2020 6:37am
Good luck I'll be following.

The Shop

philG
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9/23/2020 12:55pm
Nothing sounds better on these than the stock silencer.

Jealous

Following
9/23/2020 5:57pm
I once bought got a Chinese knock off keihin carb and it actually ran very good with it! No problems at all
captmoto
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9/23/2020 10:19pm
If the airbox covers are unmolested, those are worth some bank to concourse level restorers.
JMX82
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9/24/2020 3:39am Edited Date/Time 9/24/2020 3:40am
Change oem Keihin jets, needle and slide return spring to Chinese Keihin and you are good to go. Chinese return spring is about 10 mm too short and can cause throttle slide to get stuck


Micahdogg
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9/24/2020 6:13am
captmoto wrote:
If the airbox covers are unmolested, those are worth some bank to concourse level restorers.
They are drilled "black tape covering them." The drilling profile looks very nice too.
Micahdogg
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9/24/2020 6:15am
JMX82 wrote:
Change oem Keihin jets, needle and slide return spring to Chinese Keihin and you are good to go. Chinese return spring is about 10 mm too...
Change oem Keihin jets, needle and slide return spring to Chinese Keihin and you are good to go. Chinese return spring is about 10 mm too short and can cause throttle slide to get stuck


Thanks for that tip. I dont know how the Chinese spring can cause the slide to get stuck though. The cap needs to compress the spring before it can even be threaded.

Also, have you noticed inaccuracies between the same size jets chinese vs keihin?
JMX82
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9/24/2020 9:34pm
Micahdogg wrote:
Thanks for that tip. I dont know how the Chinese spring can cause the slide to get stuck though. The cap needs to compress the spring...
Thanks for that tip. I dont know how the Chinese spring can cause the slide to get stuck though. The cap needs to compress the spring before it can even be threaded.

Also, have you noticed inaccuracies between the same size jets chinese vs keihin?
I haven't done any comparison between Chinese and oem Keihin Jets. I have always used Keihin jets because they are easy get from the local dealer and the price difference is not that big.
PRM31
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9/29/2020 3:52am
Very cool! Could be a fun project. Quite possibly the best rear suspension ever.
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Micahdogg
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10/10/2020 5:13pm
First batch of parts. Picked up some plastic and also a seat foam and cover. This is the safety seat foam, which goes up on the tank a bit.

I figured it would be best to mock up the seat, plastic, airbox, etc... because I'm confident that my seat rails are bent. This should help me figure out how bad, then I can repair and get the frame powdercoated.




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Micahdogg
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10/12/2020 5:34pm
I ran a 1/2 bar in each frame rail, used a torch and straightened the subframe. I got it pretty well lined up and installed the seatpan, foam and fender to have a look.

Yeah I would say it is still pretty tweaked. I know the ergonomic are whack, but this seems a bit ridiculous. I will have to zip a pie cut out of the bottom of each of those rails and heave them down.




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Micahdogg
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10/17/2020 7:11pm
Back with the grinder and welder. I ended up cutting the tops of each subframe rail and moving them down almost 2 inches! My welding and grinding was adequate. I think its strong enough for my needs...plus reinforced with the 1/2 rods in each tube so Im not saying it won't crack or break again, but I dont think my 210lb self will do it.

The body fits much better. We went from a 1 to an 8 outta 10. The bike is starting to feel ok to sit on. I can fudge a little more fitment with the seat foam, seat pan and mounting bracket to get it to a 9.



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sandman768
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10/18/2020 5:39am Edited Date/Time 10/18/2020 5:42am
Nice work... remember it’s a Suzuki, those frame rails needed to be re welded when it rolled off the assembly line👍Don’t forget to test fit the silencer mounting... I just went through this with a 92 Yz250, every time I had the seat & rear fender mounts correct, the silencer mount was off, took me several hrs to get it all correct. Removable subframe are worth their weight in gold!
burn1986
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10/22/2020 6:03pm Edited Date/Time 10/22/2020 6:06pm
It’s amazing how much better that seat makes it look. I had the 465 - super plush and easy power. Ima smaller guy 5’7” and I loved that bike. Easy to ride
Micahdogg
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10/23/2020 5:58am
Agreed on the newer style seat foam!

Speaking of, I attempted to mount the seat foam and cover last night but forgot about a couple seat repairs. The seat bracket mounts to a couple flimsy (and trashed) tabs that reside inside the seat pan. I took some scrap metal and welded a couple nuts here and there, then trimmed out my own new mounts.

Next, there are two nuts that sit at the tail of the pan...one was missing. I reused one of the old oem seat tabs from inside the seat and with help if a file and heat gun was able to press it into the seatpan. These mounts are a bit superficial as the fender has two stronger mounts on each side.

Also the seat cover seems to have a bit of excess material near the front so I glued a 3/4 inch chunk of foam to the pan to give me a little lift. Hoepfully I can produce a wrinkle free cover.


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Micahdogg
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10/24/2020 6:51pm
I was able to get the seat foam and cover mounted finally. This was by far one of the most challenging covers I have ever done. It must be due to the fact that there is a tank protector now, yet there is no pan under that section to pull it tight. I adjusted it several times and barely got the wrinkles out up front, while not losing the "RM" placement in back....though the logos got stretched a bit. Glad this is done.


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Micahdogg
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1/10/2021 4:16pm
Ive been ordering parts and have nearly everything I need. Before stripping it down, I wanted a footpeg solution.

In an effort to save money i found some old footpegs laying around the garage that had extensions on them. I zipped the extensions off and welded em to the stock RM pegs. Now there is an actual platform...and it was free.

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sandman768
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1/10/2021 5:53pm
Nice job on the pegs.... the foot pegs, pins & springs are always a challenge on the older RM”s. I have many hrs into trying to reconfigure the pegs on these bikes, I always to to get larger diameter pins & drill out the stock holes, then that leads to finding springs that will work. The early Suzuki foot pegs were torturous
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Micahdogg
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1/26/2021 6:02pm
Here are a couple vid updates. Also I started taking a fork leg apart. It has some funky oxidation that is hard to remove.





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1/28/2021 4:33pm Edited Date/Time 1/28/2021 4:33pm
Why did these old rm500s sound so damned good? Every one I’ve ever heard that was in good shape has always been the tightest 2 stroke sound ever. Was it the pipe and silencer? Certain kind of porting? They always sound freaking awesome.
Micahdogg
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1/31/2021 8:08pm
I got the forks rebuilt and cleaned up the front wheel. Had to make a special tool to hold the cartridge. Pro Tip #3. Don't weld by a garbage can full of rags soaked in brake cleaner. You'll get a forest fire in your garage. No footage of that Smile







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Micahdogg
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2/21/2021 4:19pm
I finally tore it down to the frame. For the most part, the bolts and fasteners came out well. That was until I pulled the last part from the frame...the upper shock mount/full floater link. The bolt is about 9 inches long and it was froze to the outer sleeve.

I have never had a bolt freeze this solidly. I hoisted the frame sideways into my 20 ton press and it wasnt moving. I was afraid to damage the frame rails I kept cranking. So my last resort was to chop it out. I hated doing that, but with the bolt and sleeve free I was able to work out on it with the press and eventually separate them. It took a couple hours and it popped along with a lot of pressure and heat. So I need another bolt now which Im sure is going to be fun to find!



Frame is bare, shock spring came out, so both of these will go to powdercoat. Im going to do a blue that matches the seat and fork boots for both. I know its not "correct" but I think it will look better.


3
Micahdogg
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2/24/2021 11:51am
Got the shock torn down. Everything cleaned up well. I got a shock sealhead and bumber combo on Ebay from Bike Buzzard. The sealhead looks a bit longer than the original. It appears that I will be losing 1/4 inch of travel.



Also, when grinding the nut to remove the peening, apparently I didn't go far enough. When the nut broke free it tore a thread loose from the shaft. I ground away the damaged area, but I'm afraid to cleanup any further. I know the Showas have a jet that can fall out, but I dont know if the peening was holding anything inside this KYB shock. I think everything will be ok because I still have like 5 full threads on the shaft. In this pic you can see exactly how much broke free compared to the profile of the nut.

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450exc115
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2/26/2021 10:33am
That's a bummer on the shock seal head. That looks like a All Balls/Tusk/MSR generic seal head. I tend to look at RaceTech site as they have a downloadable spreadsheet with all the dimensions of various fork/shock components. The 84 RM500 seal head they call out is SKSH 4616. Their table says 46mm OD, 16mm shaft and 26mm tall.. If it was me I'd get a RT one. Looking a 1/4 of travel in the suzuki full floater set up is like losing 1" at the rear wheel. Bummer about the threads but just file off the extra loose thread and run it. IMO there is a good chance a modern 46mm shock piston would slide right on that and give you the opportunity to run modern valving, similar to run a racetech gold valve. I've done it on a few of my late 70s early 80s YZ shocks

I usually have to get my 70/80s yamaha seal heads from RT since Yamaha doesn't use a integrate rebound bumper. Sometime I can get away with a generic one if the stack height is within a mm or 2.

Also don't waste your money on some of these aftermarket bumpers. You can get shock bumpers from Honda from 10-12 dollars. For the 14mm shafts I like to use ones from CR80/85s and for the 16mm shafts the 00s CRs..
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Micahdogg
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2/26/2021 2:54pm Edited Date/Time 2/26/2021 4:35pm
Good to know on the bumpers.

Yeah I think you are right about the sealhead. I think I will buy some race tech seals and a bushing and rebuild the stocker. Parts look like $35. I honestly didnt think parts would be so readily available but I should have checked first before buying this sealhead

Edit = Just ordered a Racetech seal, dust cover and bushing to rebuild the stock sealhead. Total was closer to $50 shipped. The BikeBuzzard sealhead/bumper combo was $70 shipped and the bumper looks to be a good piece. I remember now that Racetech listed the bumper at $35 and I was afraid of wasting a bunch of time trying to find a suitable (cheaper) bumper so that's why I got the combo off Ebay.

Now I'm going to end up with $140 freaking dollars spent on this shock rebuild....that bums me out. It shoulda been half that price.
Micahdogg
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3/1/2021 7:10pm
This isnt the $25 bolt that I needed for the full floater link. It was advertised as the right part number according to the 1984 RM500 schematic. But who knows what parts I have on my bike or what the sea1ller had. Either way...this bolt was 1mm too thin. And I just spent another $40 on what I think was the right bolt now. Think about that kids when you go sawzalling out a seized bolt.



Also my powdercoating guy called today and was like, "You got some rot on the lower frame rails." Yep. I sure do. I blasted some weld at it and brought it back two hours later. Sorry, no after pics.

BTW, this is my go-to welding station.

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