1987 CR500 motor

[Ndog]

Hey guys, a guy I work with wants to let his 87 CR500 go for like 500 bucks. I have a 85 atc250r and a 2000 cr250r. Is 87 one of the monster engine years? Ive heard its 63hp and has the lightest
crank out of any year. I know they have the ugly pipes and gastanks that year but for 500 buck in good running condition I have to get it right?

Even the motor is worth 500. Can you say atc 500? or cr500 aluminum frame. Or just to get crazy on. Compared to my heavily modded atc and 2000 cr250 shaved and modded, will this old of a bike still be impressive? My atc and cr will gas wheelies in 5 gears (and the CR has a 14t front sprocket...runs race gas).
I would only like it if it was scary fast and dangerous.

let me know


NDog

[super90]

a cr500 with the right gearing can be very fast and dangerous! I would go for it. You should like it. alot. I know i would!

[350xBomb]

I just picked up an 87 cr250 for 750 so 500 bucks for a cr500 sounds like a hell of a deal if its in running order.

[X2guy]

If you like the vintage motocrosses get it. Hell it's only $500. I rode a 87 250 and it was great. I could ride the track like it was my 02 and was way better than my buddys 97. 97 was a terrible year. The bike would not handle.

[Ndog]

Well, I finally picked it up (havent made an offer for it yet). Its pretty trashed. Pulled off the water pump cover and its corroded to the point where its eaten through the housing. So unless losts of CLR, wirebrushing and jb weld can get it to work im looking at 300 bucks for a new side cover.
Took a compression test and got 120...pretty tired, should me up like 170-180 right? So there is 300-400 bucks on a bore, piston and clean up.
The plastic is trashed so theres 150 bucks. The spokes on the rear wheel are trashed. I tried to tighten them but they are shot. So basically a new rear wheel (it has a brand new tire on it though).
It has a chitty mikuni 38 on it that was all rusted up. Cleaned it, it would probably function but we all know it needs a pwk, so another 200 bucks.
Rear subframe is bent, I could straighten it and weld to reinforce but damn. Basically the whole thing is trashed. I have never seen a bike so beat up. Inside the right case did look good though. The clutch, gears and all that looked healthy. I have no idea what shape the crank and transmission are in. The cylinder is smooth and clean with no scratches and the piston looks good too! I know the bike has sat for years and am wondering if maybe the rings just need some heat to kind of reseat ya know. Anyway, Im going to post some pics. As of right now this guy wants 250 bucks. I dont even know if I can handle that.
The bottom line is, im looking at over a 1000$ just to get this thing running decent. Thats withougt touching the bottom end or any cosmetic stuff like contols and frame paint or whatever. The 87 motor is what I want. It will either go in an ATC or ill build a SM for the street. I took some pics to show what im dealing with. Tell me your thoughts on this one guys. Thanks

Ndog

[Rm250RF900R]

Ouch..But 500 bucks is not bad for a whole bike. But I feel its still to much for for that bike.

[Ndog]

He only wants 250 now but I am still thinking it would be rough getting even the motor (mainly b/c the cooling corrosion) going. Then there is the ugly frame that needs blasted and painted.

Should I just wait for a better prospect to come along. Even for 250 bucks this thing might just be totaled. Half the stuff couldnt even be parted out because of the condition its in. Im still debating.

Ndog

[Louis Mielke]

What bore is the cylinder on? Dude buy that thing and part it out. I'll give you the $250 for the engine as is if you can wait a month.

[KASEY]

you beat me to it louis,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

[Ndog]

Ok so, ill work with it. What do you guys think of the water pump housing corrosion though? If I could get it to hold without going into the case or whatever I could fire this thing up and see whats up.

What should I do about that corrosion and ate up channeling so I can start this beast?

Also, I dont know what bore it is on but I have a small caliper that only reads to the nearest mm. Across the middle I got 90mm on the dot I think. But without a more accurate gauge thats as good as I can do. If I pull the cylinder off, do you guys know what the max play on the crank is side to side. I could use my feeler gauges to get a picture of what shape the crank is in.

Also, is the 87 motor the nastiest? I know it put out 63 hp stock during the tests in 87. It is also supposed to have the lightest crank making it really snappy right? I know 85-89 were all beasts but each were unique with their delivery. 87 would be the most likely to throw you off the bike. Thats what I want! I want to be scared. Ive never been scared of a motor.



Thanks

Ndog

[Louis Mielke]

everything i've read said 86 was the last really nasty year before they slowly started to tame it down.

There really isn't any fixing those water ports o nthe clutch cover. Tried it, didn't turn out all that well. Buy a new one, only $166 from service honda.

My jugs at 91mm and thats, 2mm over, as big as they go. I don';t recall if there's a size in between 90 and 91mm, you may be at the end of your jug.

Lemme know if you plan on parting it. I wanna build another bottom end wiht a wide ratio trans.

[Ndog]

I dunno dude, ive read all the reviews at larry's :
http://sidecase2.tripod.com/larrycr500.htm. I think its the 87. 88 and 89 they turned them into tractors (which is good for mx). 85 and 86 were still 61-62ish and didnt spool as fast as the 87. It doesnt matter thought b/c a port and polish job can change everything. The lowers do matter though, and they changed them quite a bit during the 80's (lots of different part numbers for cranks) but you could get a high perf aftermarket crank too. I guess its just about your foundation. The better the start the better the potential.
I took the cylinder off and was looking at the porting and it is pretty radical. The exhaust port duration and timing is insane and honda blended the sleeve into the cylinder really well (no steps and notches). Anyway heres where im at:

Cylinder off measures 90mm top mid and bottom. So I have two bores left (90.5 and 91). It looks awesome: shiny, smooth no scratches at all. The piston looks great. Except for the normal black top, it is completely clean and no cracks or sieze marks. Crank amazingly was not bad. There is rust and some minor pitting but runout and everything was within specs. No excessive play anywhere and the bearing was not corroded and tight. There are some marks on the crank that look like a series of lines crossing on the left side of the crank that was kind of strange. Keep in mind that I havent cleaned any of these parts in the pics. A shop towel and wd40 would take most of the rust off. The water housing soaked in CLR and looks better. I think I could use some jb weld and some silicone and get it to work for now. I cant get the impeller off to replace the seals though. Its like fused to the shaft. I even tried an impact wrench. The case is off the 86 it looks like because it is one piece. Add that with the water pump stuff and its like 300 bucks from service honda. I have to find a way to get the impeller off.

Basically, aside from the cooling system, I think the rings are just worn. I put them in the cylinder and the gap was huge. When they are on the piston, to get them to touch the posts you have to compress them flush. My guess is that when last ridden, the cooling system was trashed and excessive heat fried the rings.

Does anyone have specs for ring gap on the 87 500?
What do you think those lines are on the crank?

NDog (Yeah and just what I need, my freshly restored 250r just stripped its oil plug threads out today. 2500$ and 3 months of work just to be stopped by a mutherfcin stripped hole. Helicoil this week i guess)

[Ndog]

Here are the breakdown pics....sorry

[Billy Golightly]

The waterpump cover on my 500 is the same way. I was going to change the impellar seal on it a while back and after I seen what it looked like I decided to just leave it alone and put it back together. The later model cases can work from what I read I believe, the difference is they had a clutch basket made for one more additional disc, so the clutch area is wider. I think everything else matches up. You might also try www.cr500riders.com in addition to Larry's 500 page.

[Bryan Raffa]

check the exaust port bridge there known to crack. Ive seen a few that it happend too.