o-ringed heads

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trix
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o-ringed heads

#1 Post by trix » Fri Feb 09, 2018 9:00 pm

My head gaskets are leaking and probably because they were non-yamaha.
Does anyone know if CMS's gaskets are genuine yamaha?; Seem to be too cheap??

https://www.cmsnl.com/yamaha-rd500lc-19 ... n41IKhl_cc

What about o-ringing the heads. Has anyone any experience with these guys;

http://bdkraceeng.co.uk/tc/products.php?241

silverstrom
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Re: o-ringed heads

#2 Post by silverstrom » Fri Feb 09, 2018 11:09 pm

O-rings sound like an ideal solution, especially for a race bike, but proper head gaskets with flat heads will last 20 years if done correctly.

How much are Yamaha head gaskets in the UK?

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adr1an
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Re: o-ringed heads

#3 Post by adr1an » Sat Feb 10, 2018 6:50 am

If not Yamaha, try Vesrah. Used them number of times and they were fine on 500's and 350's. Had issues with other cheaper brands.

trix
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Re: o-ringed heads

#4 Post by trix » Sat Feb 10, 2018 8:35 am

Hi Adr1an
Have you sold your bike?

I think I must have used "NE" brand as I have another set of these in the garage and i think I bought 2 sets. I lapped the heads on a sheet of plate glass with grinding paste, and I had them pretty much flat. I've since read bad things about NE brand on here. The water pump gasket was leaking a bit too but I tightened it up a bit more and it seems to be ok now.

John; the head gaskets are £48.68 each from Yamaha in the UK and they have them in stock in Europe (Holland). A complete set of Vesrah gaskets is about £70. So I've just ordered a pair from Yamaha, should have them on Thursday. Cant help thinking I would be better to pay an extra £200 and get them o-ringed?? I'd imagine if they're o-ringed it should be 100% chance of success; can probably cope with a bit more warpage than gaskets?? Although if I can get them sealed with gaskets I'm unlikely to be taking them apart again, maybe ever!

I've been doing them up to 22Nm. Would a few extra Nm help??



If these yamaha ones leak I'll be cross!


https://www.fowlersparts.co.uk/parts/view/47X-11181-00

jeff10
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Re: o-ringed heads

#5 Post by jeff10 » Sat Feb 10, 2018 9:52 am

Have both heads skimmed the
minimal amount to remove any
distortion .
Make sure each one is done
in one machining operation .

Do not exceed the recommended
torque setting .

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adr1an
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Re: o-ringed heads

#6 Post by adr1an » Sat Feb 10, 2018 4:18 pm

Hi Trix, yes, just sold it.
I think I used the NE brand gaskets on the 350lc at a time and they were hit and miss on both the heads and engine. I have always since used Yamaha head gaskets on the 350. Could not get a Vesrah set.

On the 500, the Yamaha head gaskets were harder to get and expensive. I sourced Vesrah complete sets which are a reputable supplier, at a much more reasonable price (about GBP 70 for a full set out of Germany I remember) and have used them on a few engines / rebuilds and they are good. Here's the same set from another supplier.http://www.ebay.com.au/itm/TMP-Pochette ... SwA4dWIMQ7" onclick="window.open(this.href);return false;

My engine builder who's been around a circuit or two over 40+ years is happy with them (heads and other gaskets) and I have had no issues. He generally uses a coat of copper gasket spray (Permatex) on the gaskets on fitting.

Of course the faces need to be clean and flat. Hope this helps.

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Speed Freak
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Re: o-ringed heads

#7 Post by Speed Freak » Sat Feb 10, 2018 5:39 pm

Original gaskets use a high temperature NBR (rubber) coating which helps for micro sealing.
This rubber coating is what you can find on the sealing surfaces when disassembling the heads.

Maybe this coating is a bit complex to get it onto the metal layer or it`s expensive... Most of the aftermarket gaskets only have paint on them which doesn`t really work.
Material is also a big thing in this case. Wrong material will loose a lot of the spring force in the bead when heated up.
The bead is getting hardened by cold deformation in the manufacturing process, heating it up means to glow it soft again.
Therefor you need the right material for head gaskets.

I think the aftermarket gaskets are often just cheap painted metal with the more or less correct shape.
Yamaha price is crazy but you get the quality which you expect.

I have contacts to do propper metal bead gaskets, but I think the price for tools and parts will be too high.
For 100+ parts it might make sense to think about it - but as long as they are available take them from Yamaha.
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

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Re: o-ringed heads

#8 Post by silverstrom » Sat Feb 10, 2018 6:24 pm

Speed Freak wrote:I think the aftermarket gaskets are often just cheap painted metal with the more or less correct shape.
That is it exactly. They apply paint rather than sealant and most people don't know the difference. Genuine Yamaha means you only need to do the job once (assuming your heads are flat).

trix
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Re: o-ringed heads

#9 Post by trix » Sat Feb 17, 2018 11:08 am

got my yamaha head gaskets.
have lapped the heads on plate glass with 600 grit paper

when you guys mention re-torquing the head nuts, at what stage do you do this; just let the engine warm up to about 80 deg C and then stop it and retighten?

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