RD Motor Pull-Torques needed

[2_DONE_THE_TON]

left cylinder first 2 pics...looks quite good no scoring on the walls and on the piston.

the right cylinder looks quite bad though...

 

[2_DONE_THE_TON]

the right cylinder has 2 bad scars on its wall...one goes down right to the low end of the body of the cylinder....
right piston shows the same scratches and scars...

 

[2_DONE_THE_TON]

last pics of the right piston

looks like i need to replace the right piston and cylinder...or how would you guys solve this problem?
just checked out ebay...50 euro for a cylinder 50 euro for a new piston...so honing will be expactedly more expensive than doing a new one...

help!

thanks!

 

[xb33bsa]

that is a shame :'( be sure and check the radial clearance on the big ends of the rods
i dont know what the service limit is proly .002-.003" or so

 

[2_DONE_THE_TON]

AW: RD Motor Pull-Torques needed

dont think i can reuse that piston and cylinder...what you guys say?

 

[xb33bsa]

time for new oversize pistons and fresh bore $$ :'(

 

[Rich Ard]

There are a fair amount of options for pistons, though, eh?

 

[2_DONE_THE_TON]

AW: RD Motor Pull-Torques needed

bore+oversize is way to expensive...im checking on ebay now for a cylinder and piston...dunno what the PO did to that poor little rd...

 

[1sttimer]

I don't know your budget but I got a fresh bore, hone and new oversize pistons/rings for a total of $175. I didn't think that was bad at all...and I had no connections to the shop.

 

[2_DONE_THE_TON]

I don't know your budget but I got a fresh bore, hone and new oversize pistons/rings for a total of $175. I didn't think that was bad at all...and I had no connections to the shop.

wow nice.jsut checked...bore is 100 euro at my shop...where did you order pistons sets (rings,...)?did you order it from a yamaha dealer?

 

[1sttimer]

wow nice.jsut checked...bore is 100 euro at my shop...where did you order pistons sets (rings,...)?did you order it from a yamaha dealer?

Sorry, no I'm speaking of a different bike..a honda. I was just generally saying that the bore/hone doesn't have to hurt the pocket too badly - maybe shop around? I can't help you with the piston/ring situation...

 

[Rich Ard]

Send bradj a PM, I know that he uses banshee pistons when he goes oversize. I agree that you ought to check around for prices on machining, but I expect we're dealing with slightly different markets.

 

[2_DONE_THE_TON]

just searched a little...yambits sells RD 250 E pistons..are they the same make as the 1 A 2 pistons?

do you guys stick to yamaha parts or do you use other manufacturers?

 

[teazer]

Try Wemoto in the UK for Pro-X pistons and probably Mitaka. 1A0 is RD250 C, 1A2 is RD250D, 2R8 is RD250E and 3M3 is RFD250F. I don't think the piston changed between models but you can check part numbers to be sure.

 

[2_DONE_THE_TON]

Try Wemoto in the UK for Pro-X pistons and probably Mitaka. 1A0 is RD250 C, 1A2 is RD250D, 2R8 is RD250E and 3M3 is RFD250F. I don't think the piston changed between models but you can check part numbers to be sure.

thanks teazer!

just checked it out...

Make Model Year Of Manufacture
Yamaha RD 250 A/B 74-75
Yamaha RD 250 DX C 76-77
Yamaha RD 250 DX D 77-78
Yamaha RD 250 DX E 78-79
Yamaha RD 250 DX F 79-80
Yamaha RD 250 LC 80-86

i am a little confused right here...my model is 1 A 2..1978..so RD 250 D and what are the other figures?
the wemoto pistons dont show any brand on the website...no pro x..nothing :-(

 

[bradj]

I got nothing for that guy we didnt get that bike and i have no idea what fits or swaps follow teazers lead. maybe you could find a use cylinder and piston

 

[teazer]

DX means it's like an RD400 - C on
LC is Liquid cooled different bike but pistons probably fit

So A/B is like an RD350, DX is like the 400.

Try https://www.pjme.co.uk/acatalog/Yamaha_RD250_Engine_Parts_Top_End_.html for Mitaka and google search Pro-X or ProX + RD250 and see what you find

 

[2_DONE_THE_TON]

Try https://www.pjme.co.uk/acatalog/Yamaha_RD250_Engine_Parts_Top_End_.html for Mitaka and google search Pro-X or ProX + RD250 and see what you find

i think ill take the mitaka parts...are they quality parts?any experiences on them teazer?

just by interest:

im replacing crank seals too...there are METAL crank seals available...should i take the rubber ones or the metal ones?
LINK:
http://www.pjme.co.uk/cgi-bin/sh000002.pl?WD=rd250e&SHOP=%20&PN=Yamaha_RD250_Engine_Parts_Bottum_End_.html#a1789

 

[teazer]

The rubber seals go on the outer ends of the crank and have to be replaced. The Lab. seal is aluminum and fits between the two crank halves and rarely if ever wears out.

I haven't used Mitaka but I read good reviews of them on line. I'd use them if I couldn't get OEM Yamaha pistons. Pro-X are great for street motors. Wiseco are good but I melted too many of them. Wossner are too nice to put in an engine. I just want to keep them on my desk and look at them.

 

[xb33bsa]

once again be sure and check the big-ends of the rods for radial clearance,rust, and or too much side clearance
it is a little bit of tricky procedure , but really only requires dial indicator and a steady hand
if the crank big ends are on their way out there is no sense in pouring money into a rebuild without refreshing them as well