Vintage RM

observer
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observer
Edited Date/Time 1/26/2012 10:37pm
Check it out:
http://seattle.craigslist.org/.../mcy/1968391026.html

not too bad...:-)
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captmoto
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captmoto 9/23/2010 9:10am
9/23/2010 9:10am
The biggest problem with the big bore 'zooks is the fact that there are no pistons available for overbores. The question comes up all the time on different vintage boards. Now I have heard of cyls. being bored and fitted with Maico 440 pistons. Other than that the bike is a beauty.
koolstrike 9/23/2010 5:03pm
9/23/2010 5:03pm
captmoto wrote:
The biggest problem with the big bore 'zooks is the fact that there are no pistons available for overbores. The question comes up all the time...
The biggest problem with the big bore 'zooks is the fact that there are no pistons available for overbores. The question comes up all the time on different vintage boards. Now I have heard of cyls. being bored and fitted with Maico 440 pistons. Other than that the bike is a beauty.
Wiseco does not make any pistons?

A parts fiche I just looked at shows standard bore and 0.50 over as available
project racer 9/23/2010 7:03pm
9/23/2010 7:03pm
I know of one individual who has had a batch of pistons custom made for the RM400's. The Maico guys snatched most of the RM400 piston supply up,due to the fact that the OEM Maico Mahle pistons were so expensive.

Same situation for a lot of vintage bikes. Scarce or virtually no pistons available.

Try finding 73-74 Yamaha SC500 pistons. Wiseco never made a replacement piston for them. They could have made a ton of cash,as the SC was a regular piston seizer.

74 YZ250. Good luck. Scarce and big $$ if you find a 431 or 483 piston.

79 YZ400F. One year only. Virtually non -existent piston supply.

TM 125 Suzuki pistons are also drying up.

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observer
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observer 9/23/2010 9:23pm
9/23/2010 9:23pm
FreshTopEnd wrote:
This one's a little cheaper and I think nicer, and hometown, too. I've concluded that I need to actually finish a project before I start acquiring...
This one's a little cheaper and I think nicer, and hometown, too.

I've concluded that I need to actually finish a project before I start acquiring anthing though.

http://sacramento.craigslist.org/mcy/1956788683.html
Maaann!...that IS a nice looking 400!
I think that'd be really neat to have that bike to go play around on one weekend-every now and again(easy on her you understand)Wink
Matt Fisher 9/24/2010 9:35am
9/24/2010 9:35am
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future.

I picked one up the day before I started high school, and at some point in time I'll buy another one just to play around on and for the memories. It would suck if it could only be a static display due to non-existent pistons.
Bret
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Bret 9/24/2010 9:53am
9/24/2010 9:53am
Matt Fisher wrote:
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future. I picked one up the day...
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future.

I picked one up the day before I started high school, and at some point in time I'll buy another one just to play around on and for the memories. It would suck if it could only be a static display due to non-existent pistons.
Install an aluminum sleeve and have it Nikasil coated like a modern cylinder. Then you can run the same size piston from then on. No more boring required.
captmoto
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captmoto 9/24/2010 5:11pm
9/24/2010 5:11pm
Matt Fisher wrote:
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future. I picked one up the day...
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future.

I picked one up the day before I started high school, and at some point in time I'll buy another one just to play around on and for the memories. It would suck if it could only be a static display due to non-existent pistons.
Bret wrote:
Install an aluminum sleeve and have it Nikasil coated like a modern cylinder. Then you can run the same size piston from then on. No more...
Install an aluminum sleeve and have it Nikasil coated like a modern cylinder. Then you can run the same size piston from then on. No more boring required.
Sounds good, who does that service? I passed on a 80 RM400 because of the piston issue. It seems loke you still would have to deal with the scarcity of RM400 pistons. It seems like wiseco would still have specs whip some out without too much hassle. There are 2 on Suzki pistons on Ebay right now,
Matt Fisher 9/24/2010 9:39pm
9/24/2010 9:39pm
Matt Fisher wrote:
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future. I picked one up the day...
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future.

I picked one up the day before I started high school, and at some point in time I'll buy another one just to play around on and for the memories. It would suck if it could only be a static display due to non-existent pistons.
Bret wrote:
Install an aluminum sleeve and have it Nikasil coated like a modern cylinder. Then you can run the same size piston from then on. No more...
Install an aluminum sleeve and have it Nikasil coated like a modern cylinder. Then you can run the same size piston from then on. No more boring required.
I'd read that on air cooled motors that can have issues due to the larger than normal expansion levels when compared to a liquid cooled engine.

I guess if you set it up right, you could pre-select which piston was going to fit in there forever.
project racer 9/25/2010 9:26am
9/25/2010 9:26am Edited Date/Time 9/25/2010 9:33am
When you go to a plated cylinder,instead of the original iron bore, doesn't the ring material have to change in order to be compatable with the plated bore?

Chrome bores back in the day used iron rings.

Iron bores used chrome type rings.

Use of a chrome ring in a chrome bore resulted in black death of the cylinder / piston / rings.

Just seems like another goose chase to try and find the proper rings in the proper material when converting to plated / chrome bore.

Is someone offering these components that are compatable with a plated / chrome bore conversions? How are these old iron bore cylinders that are being plated surviving with OEM / Wiseco standard type iron bore (chrome) rings on a chrome / plated bore?
Matt Fisher 9/25/2010 9:44am
9/25/2010 9:44am
If someone like Wiesco makes the pistons for the RM400, then it might not be out of the question for them to make iron rings as an option.

If not, then the trick would be to find a piston from a newer bike who's measurements were close to the RM's and make that work.
project racer 9/25/2010 10:03am
9/25/2010 10:03am
Matt Fisher wrote:
If someone like Wiesco makes the pistons for the RM400, then it might not be out of the question for them to make iron rings as...
If someone like Wiesco makes the pistons for the RM400, then it might not be out of the question for them to make iron rings as an option.

If not, then the trick would be to find a piston from a newer bike who's measurements were close to the RM's and make that work.
Expensive it if goes bad.

$200 plus plating.
$100 plus obsolete piston.

$ 40 makeshift ring snagging on a port, priceless.
Bret
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Bret 9/26/2010 4:35pm
9/26/2010 4:35pm
Matt Fisher wrote:
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future. I picked one up the day...
I sure hope there's a solution to the RM400 piston dilemma, as I will have another one in the future.

I picked one up the day before I started high school, and at some point in time I'll buy another one just to play around on and for the memories. It would suck if it could only be a static display due to non-existent pistons.
Bret wrote:
Install an aluminum sleeve and have it Nikasil coated like a modern cylinder. Then you can run the same size piston from then on. No more...
Install an aluminum sleeve and have it Nikasil coated like a modern cylinder. Then you can run the same size piston from then on. No more boring required.
captmoto wrote:
Sounds good, who does that service? I passed on a 80 RM400 because of the piston issue. It seems loke you still would have to deal...
Sounds good, who does that service? I passed on a 80 RM400 because of the piston issue. It seems loke you still would have to deal with the scarcity of RM400 pistons. It seems like wiseco would still have specs whip some out without too much hassle. There are 2 on Suzki pistons on Ebay right now,
I don't know of anybody that does it. I was thinking out loud more than anything else.
RM400Pinger
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RM400Pinger 9/26/2010 6:03pm
9/26/2010 6:03pm
Hey everyone, I just found this site while researching the '86 CR250s since I am looking at buying one. I wouldn't pass up on an old RM400 just because of piston issues...they are out there. When i was restoring my RM400, I found two .50mm pistons on ebay. There is another one on there right now and I believe you can get some pistons and rings from alpha-sports.com. Anyway, here a couple pics of my RM.

Before:


After:












observer
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observer 9/29/2010 9:32pm
9/29/2010 9:32pm
Maaann...that is boss. Niice!

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