Author Topic: identify these pistons and rods  (Read 2831 times)

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Offline unkle fester

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identify these pistons and rods
« on: January 01, 2007, 12:45:08 PM »
the cylinders measure 2.75 inches....about 70mm.....rods have S 3 A stamped on them....these are in my motor that has some RC mods done to it.....I'm thinking it is the 900cc kit....but not sure......what have I got here????...thanks.....

Offline heffay

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Re: identify these pistons and rods
« Reply #1 on: January 01, 2007, 01:47:08 PM »
used pistons






 ;)






and rods







 ;)
Today: '73 cb350f, '96 Ducati 900 Supersport
Past Rides: '72 tc125, '94 cbr600f2, '76 rd400, '89 ex500, '93 KTM-125exc, '92 zx7r, '93 Banshee, '83 ATC250R, 77/75 cb400f

Offline scondon

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Re: identify these pistons and rods
« Reply #2 on: January 01, 2007, 01:55:33 PM »
I think the 900 pistons are 67mm. Yours are 970 maybe?  Rods look like stock but may be hardened. Just guessing.
Give me..a frame to build a bike on, and my imagination will build upon that frame

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Re: identify these pistons and rods
« Reply #3 on: January 01, 2007, 02:52:53 PM »
and what is wrong with used pistons? if no hole in them I'd use them again in
a rebored cylinder to fit. Looks like you might have the 1000 Mike!

Offline heffay

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Re: identify these pistons and rods
« Reply #4 on: January 01, 2007, 03:09:23 PM »
and what is wrong with used pistons? if no hole in them I'd use them again in
a rebored cylinder to fit. Looks like you might have the 1000 Mike!

'twas a joke... i had no real answer but i did have two cents!   ;D
Today: '73 cb350f, '96 Ducati 900 Supersport
Past Rides: '72 tc125, '94 cbr600f2, '76 rd400, '89 ex500, '93 KTM-125exc, '92 zx7r, '93 Banshee, '83 ATC250R, 77/75 cb400f

Offline 750goes

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Re: identify these pistons and rods
« Reply #5 on: January 01, 2007, 04:00:51 PM »
Mike

Cannot help with the identification but they have not seen a lot of use -there is no burn past the first compression ring from looking at the pictures, how come you have pulled the head off??

Offline unkle fester

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Re: identify these pistons and rods
« Reply #6 on: January 01, 2007, 04:20:59 PM »
this is my RC motor that supposedly had the 1000cc "Cobra" kit in it......but couldn't verify that......so I pulled the head so I could see for myself what it possibly was.............

Offline 736cc

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Re: identify these pistons and rods
« Reply #7 on: January 01, 2007, 04:57:22 PM »
look at underside of pistons; usually maker leaves a logo or initials

Offline MRieck

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Re: identify these pistons and rods
« Reply #8 on: January 01, 2007, 05:15:28 PM »
Wel...it does have the crappy 1 piece oil ring THOUGH the pistons are clean as previously mentioned. Put some verniers on the skirts and let us know. The rods have definitely been reworked as Sean mentioned.
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Offline Sam Green Racing

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Re: identify these pistons and rods
« Reply #9 on: January 01, 2007, 05:21:36 PM »
If the pistons are 70mm and the stroke is stock you have a 969.935cc motor.

Sam.
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Offline MRieck

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Re: identify these pistons and rods
« Reply #10 on: January 01, 2007, 05:23:24 PM »
 + heavy duty studs, heavy duty cam chain and the upper case has been bored.
« Last Edit: January 01, 2007, 05:25:39 PM by MRieck »
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Offline nippon

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Re: identify these pistons and rods
« Reply #11 on: January 01, 2007, 06:56:21 PM »
Hello,
probably MTC pistons,....check out Axel's site:

http://www.satanicmechanic.de/board/viewtopic.php?t=92

nippon

Offline MRieck

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Re: identify these pistons and rods
« Reply #12 on: January 01, 2007, 06:58:47 PM »
If the pistons are 70mm and the stroke is stock you have a 969.935cc motor.

Sam.
Could we just round that out to 970cc you stickler. ;) ;D
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Offline Sam Green Racing

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Re: identify these pistons and rods
« Reply #13 on: January 01, 2007, 07:00:50 PM »
OK then, just for you  ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

Sam ;)
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Offline unkle fester

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Re: identify these pistons and rods
« Reply #14 on: January 01, 2007, 07:19:05 PM »
just read the big bore article on satanicmechanic.org   and on mine, the  holes in the air gaps between cylinders 1+2 and 3+4 are welded shut....I figured it was because of clearance issues between cylinder walls......and those pistons are just like mine..........who wants to buy it?????

Offline Terry in Australia

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Re: identify these pistons and rods
« Reply #15 on: January 01, 2007, 08:09:05 PM »
just read the big bore article on satanicmechanic.org   and on mine, the  holes in the air gaps between cylinders 1+2 and 3+4 are welded shut....I figured it was because of clearance issues between cylinder walls......and those pistons are just like mine..........who wants to buy it?????

Yeah mate, they're MTC 970CC pistons and rings, like previously mentioned it could be an RC "Cobra" engine, what are the cylinders like? How much for the whole top end? I want to build another engine, and if the price is right, I'll take everything! Cheers, Terry. ;D
« Last Edit: January 02, 2007, 08:18:48 PM by Terry in Australia »
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: identify these pistons and rods
« Reply #16 on: January 02, 2007, 08:00:02 PM »
Have you removed a rod yet? They look stock from your picture however RC had 3 levels of rods. The first 2 used stock rods. Level 1 (High Performance) used stock rods which were shot peened. Level 2 used stock rods which were shot peened and had larger bolts. I believe these were his Super Rods. I have 4 of these (don't laugh Mike! I'll let him explain) that have the larger bolts. They have RC stamped on the sides of the big ends and have bronze bushings for the piston wrist pins. 
« Last Edit: January 02, 2007, 08:02:22 PM by RxmanGriff »
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Offline MRieck

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Re: identify these pistons and rods
« Reply #17 on: January 03, 2007, 06:42:43 AM »
Have you removed a rod yet? They look stock from your picture however RC had 3 levels of rods. The first 2 used stock rods. Level 1 (High Performance) used stock rods which were shot peened. Level 2 used stock rods which were shot peened and had larger bolts. I believe these were his Super Rods. I have 4 of these (don't laugh Mike! I'll let him explain) that have the larger bolts. They have RC stamped on the sides of the big ends and have bronze bushings for the piston wrist pins. 
It might be funny Jerry if you hadn't spent good money on them. >:( Difference in big end ID's of approximately .009. The smallest one would have seized on the journel just tighteneing it up. 1 rod twisted (a lot). Weights all over the place and one bored bolt hole was of in regard to cap/rod alignment(which it was new from RC). Like I said before...check all this old stuff very carefully. Quality control wasn't that great to begin with and only gets worse with age
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Offline bryanj

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Re: identify these pistons and rods
« Reply #18 on: January 05, 2007, 08:42:07 AM »
OUCH that sounds worse than the ones from a GM i deliberately bent for a students checking exercise
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Offline Big Jay

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Re: identify these pistons and rods
« Reply #19 on: January 05, 2007, 10:51:01 PM »
Thosed are our studs. RC used to get them from us. 

The pistons should have a name forged up under the dome. If it says "RC Eng" then they are Arias.

The 70 mm rings with the one piece oil were from the old CB450 twin. You can get the ones from the old CB500 twin and have the three pice ring.

Jay