Author Topic: 3xv R O-ring conversion  (Read 668 times)

Bobby r

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Re: 3xv R O-ring conversion
« Reply #15 on: July 23, 2018, 12:33:55 PM »

  Confusing into what type I need, they list these types, Which one is most suited?

   
Nitrile Rubber O-Ring Seals
Nitrile O-Ring Seals
Viton Rubber O-Ring Seals
Viton O-Ring Seals
EPDM Rubber O-Ring Seals
EPDM O-Ring Seals
Hydrogenated Nitrile Butadiene Rubber O-Ring Seals
Hydrogenated Nitrile

Cruising-Blue

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Re: 3xv R O-ring conversion
« Reply #16 on: July 23, 2018, 09:21:59 PM »
Is someone able to confirm the dimensions for the groove when machining into the head or barrel (mean diameter + width & depth) and also the specification and dimensions of the "O" ring seals to suit.  Thanks, Clive
3XV4 R
3XV8 RS

tzr-v4

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Re: 3xv R O-ring conversion
« Reply #17 on: July 24, 2018, 12:01:01 AM »
you could try Oring calculator

https://oringcalculator.eriksgroup.com/#

1 Chose the temperature (150C for a test)
2 Chose oring material Viton (you have an error on NBR)
3 Oring dimensions
   - inner dimension (should be at least at 3mm from cylinder bore)
   - cross section (3mm)
4 clic on calculate results

You have the groove dimension.


Olivier.
TZR250 2MA & 2XT, RD500s et TZR-V4 building...

Scotty4321

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Re: 3xv R O-ring conversion
« Reply #18 on: July 24, 2018, 10:21:39 PM »
Clive your best bet is to buy genuine Yamaha TZR250RSP 3XV2  o rings.
Part numbers are:

94310-65721 inner
93211-07720 outer

Check for yourself. On the forum find these pages:
TZR Forum General Category Resources
Manuals, Part Diagrams, Brochures etc

Click YBKs link in the first post
Choose 3XV from the list

Chose 3xv2 parts catalog (V2 is version 2 1991 SP model)

The top end of the engine is the first page.
The o rings are items or Fig 5 and 6.

Hope this helps. I don't have spare barrels but suggested groove sizes were listed in the thread and if you measure the orings maybe the calculator can help.
Cheers Scotty

Bobby r

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Bobby r

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Re: 3xv R O-ring conversion
« Reply #20 on: July 25, 2018, 10:56:59 AM »
see link above. has anyone used these guys? I am considering contacting them. any thoughts?

maccas

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Re: 3xv R O-ring conversion
« Reply #21 on: July 25, 2018, 11:58:42 AM »
They do good work but jesus 240 quid! That's a chuffing fortune!

The outer o-ring doesn't need to have that profile, it can be just round like the inner one then swap the cylinder head nuts for the dome type with coppers washers.

Dan

vinny

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Re: 3xv R O-ring conversion
« Reply #22 on: August 11, 2018, 09:21:44 PM »
see link above. has anyone used these guys? I am considering contacting them. any thoughts?
These guys did a set of heads for me .
Skimmed re-cut the volumes plus o-ringed .They work well
But as Dan said  they are a bit on the pricey side .

jcsnook

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Re: 3xv R O-ring conversion
« Reply #23 on: August 12, 2018, 05:58:56 PM »
It's all been discussed before and most of that info can be found with a quick search

http://pure2strokespirit.net/forums/index.php?topic=164.msg1292#msg1292

Thanks to Warwick for:

Someone (Can't remember who, so apologies to them) posted these dims up a while back:

Inner goove:
o/d 69.5
i/d 64.5
depth 1.35

Outer groove:
o/d 110.5
i/d 105.5
depth 1.35

Just been up in the loft and rooted out a spare early SP barrel and measured it up. They are spot on according to my verniers.

I'd give the machinist the O rings before getting them cut myself though just to be a bit belt-and-braces  :-\.

I had mine done locally by CNC machine.  He has the block base made now with all the programming, so easy peasy do now.
If your not mixing gas, your not hauling ass!