daveg
Drag-strip hero
ProClassic
Posts: 268
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Post by daveg on Sept 23, 2014 17:39:10 GMT 1
I ordered some new O'rings from Yamaha, and the new ones were certainly more beefy that the ones I removed. In fact so beefy that it is impossible to insert the valves in the cylinders, I forced one in by screwing down the cover and pushing it in, but it looks like it damaged itself on the way... I put the others in the freezer for a couple of hours in the hope that it would reduce them a little, but no way....
Am I missing something - or did Yam send me some duffens...?
DaveG
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Post by LC_BOTT on Sept 23, 2014 20:05:19 GMT 1
Yes, be careful what you use, I got some type of degreaser on the old seals when cleaning the barrels before a rebuild, and they swelled up to about twice the normal size.
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phil38
Thrash Merchant
Posts: 426
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Post by phil38 on Sept 23, 2014 21:19:19 GMT 1
Use moly grease
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Post by 4l04ever on Sept 23, 2014 21:20:33 GMT 1
I have heard the ones now supplied by Yamaha do not fit. Try other suppliers, like Norbo, or NK Racing.
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daveg
Drag-strip hero
ProClassic
Posts: 268
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Post by daveg on Sept 24, 2014 9:18:32 GMT 1
Well I ended up damaging them forcing them in with a vice.... not good - I did try with some WD40, but not the greases you mention.
I'll have to buy some of Norbo's seals.. Thanks.
DaveG
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Post by jon on Sept 26, 2014 19:26:22 GMT 1
If all newly supplied seals from Yamaha are too big, then that is really awful.
From memory I was quoted around £2.50 each.
I need two sets.
Bearing stockists hold so many different sized o rings you would not believe. They are also a fraction of the cost. This looks like the route I'll be going down then.
As far as a lubricant, you cannot beat red rubber grease, and it won't swell and attack the rubber.
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Post by Pidz on Sept 27, 2014 6:16:06 GMT 1
I never did understand the 350 power valve O rings. All 350's share the same holders, but while my LC2 has 29198 x 4 the other models have 30640 x 2 and 30734 x 2. So one has to be careful as to which ring slips onto which holder? They should never be that tight to insert. A smear of red rubber grease and after slight resistance slip home. Anyway, power valve O rings have long since disappeared. Today we are ordering XV250 gearbox and water pump O rings. When I want a set of 4 power valve rings, I am now ordering 4 x XV750 filler cap seals @ £1.66 each.  . Makes me wonder if they can still resist good old fashioned 2 stroke carbon grinding against them? 
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Post by stusco on Sept 27, 2014 11:43:27 GMT 1
When I ordered seals from norbo they came in orange ,but I haven't fitted them yet so can't comment on fit.
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Post by jon on Sept 27, 2014 17:05:52 GMT 1
I thought the orange o-rings were made of silicone?
I also thought I'd heard in the past that some people had had trouble with them?
Silicone seems a odd choice given it's location, as it is not very resistant to petroleum oils, or as resistant heat wise as Viton.
It would be good for everyone to hear people's opinion of what worked best for them.
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daveg
Drag-strip hero
ProClassic
Posts: 268
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Post by daveg on Sept 29, 2014 10:50:14 GMT 1
I ordered some seals from NK and look at the difference the ones at the top are from Yam, and the bottom ones are from NK - the other photo is what happened when I tried to force the Yam ones in! Yamaha definitely seem to have a problem!   |
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Post by greasemeup on Sept 30, 2014 9:39:48 GMT 1
Ask for a refund..
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Post by andrew on Sept 30, 2014 21:26:21 GMT 1
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. Makes me wonder if they can still resist good old fashioned 2 stroke carbon grinding against them? 
