Arrow Engine gaskets

roy.craddock
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Arrow Engine gaskets

Postby roy.craddock » Mon Nov 19, 2018 7:27 pm

Hi just bought a spare engine and noticed that the bottom gaskets on the cylinders Have hermatite on is there any benefits in doing this or is it just bad practice?.Also does the club sell arrow gasket kits by any chance? Thanks Roy

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Roger James
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Re: Arrow Engine gaskets

Postby Roger James » Thu Nov 22, 2018 11:10 am

Hi Roy,
Its not normally necessary to use Hermatite or similar sealants with the cylinder base gaskets, that said there are always exceptions such as on my Sports Arrow engine that's led a bit of a hard life with numerous strip down and rebuilds as it was used as a Production Racer and is now used for Parade Riding on track, the first time I rebuilt this engine and took it out on track I ended up with worn pistons around the gudgeon pin holes needing replacement pistons fitting, this happened twice more and replacement new pistons, finally after a seizure at Snetterton I realised the problem wasnt timing, mixture or lack of bore clearance so set out to investigate a possible air leak around the heads or base of barrels, found that the top face of the crankcase needed skimming but the engineer couldn't go far enough down due to the narrow bridge across the inlets so I ended up applying sealant called 'Threebond' both sides of the gasket, this cured the air leak problem.
I don't think club spares sell full gasket sets although John might be able to supply some individual gaskets. I purchase my Cylinder base gaskets off ebay.
Jess

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Re: Arrow Engine gaskets

Postby Ivor Collins » Thu Nov 22, 2018 1:49 pm

Hi Jess

I was interested to hear of your experience and have a question. Is there a disadvantage to simply applying a modern silicon gasket sealant on this joint face and not bother with a paper gasket?

Regards
Ivor

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Re: Arrow Engine gaskets

Postby TonyBaxter » Thu Nov 22, 2018 8:19 pm

As an aside, all the major Jap dealers sell their versions of 'Threebond', ie: Yamabond, Kawabond, you get the idea! As far as I can tell they are all the same product. Beware getting it cheap off the 'net, it's usually short dated. I get mine from the local Yamaha dealer, it's not even expensive.

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simon.holyfield
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Re: Arrow Engine gaskets

Postby simon.holyfield » Sat Nov 24, 2018 10:24 am

You can get threebond in various varieties and it comes in grey and black. It's excellent stuff and the grey one is quite discreet.

There's a high temperature version for us SQ4 types too.
cheers

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