2 Strokes Down Under

A question to you RZ gurus who know stuff!

Are the actual valves the same?

Are the seal kits the same?

My bike is a 250 with 350 barrels. I didn't put it together so I don't know what PV is installed (assuming they can be different?). Leaking oil out the left side PV cover so I thought I'd pull the PV out and install a new seal kit. Never done it before but I'm thinking I can wing it. Any tips or traps?

Cheers,

Rob.

No.

Yes.

No real tips... you need to remove the barrels tho to pull and clean the PVs. They also wear in the (plain) bearings, and those wear in the cyls if left too long, makes for expensive repairs.

Thanks Jon. Although I hate the answer. Having to remove the barrels seems like a hassle that could've been designed differently. Sigh. Oh well. More mechanical adventure than I was hoping for, but maybe I'll learn something. Hopefully I won't learn that I bit off too much!

Will it be worth it to upgrade to 350 valves if I find that there are 250 valves in there? And, how do I tell if they are 250 or 350 valves? For some reason the Yambits site seems to have different seal kits for the 250 and 350 valves...

If this bike wasn't so much damn fun to ride I would get rid of it!

250 and 350 PV's are different sizes, not interchangeable, you'll need to work with what you've got.

To be totally clear Rob, you wont have 250 PVs in 350 cyls, they dont fit...

Yambits seals... do your research before you buy those.

Ah, good info gentlemen. Thanks.

I will see if I can get Yamaha seals locally before going the Yambits route.

Try the boats.net site which Jon has recommended elsewhere for seals and such. Ebay has repro bushes and some have produced repro PV's.
I'm comparing various 250 and a set of 350 valves at the moment

The bushes are a different size too, which means that although the castle seals seem to be the same, the O-ring around the outside of the bush is a different size between 250 and 350

I can get this kit from Yambits:

http://yambits.co.uk/rz350n-powervalve- ... 13482.html

Or pay about 40 bucks more to get them from Yamaha Australia.

Are the Yambits parts ok?

honestly... read up on yambits seals and make your own decision...

what price from partzilla?

and... some people have found the outer seals yamaha supply now are a bit 'fat', just worth noting that you might need to look elsewhere for those if theyve not fixed the issue.

Man, this is turning out to be a headache. Thanks for your comment Jon, but it's a bit cryptic for a slow thinker like me. Are you saying the Yambits seals are not that good? I googled but didn't really come up with much.

Also, the Yamaha parts are not right? Outer seals (castle seals?) are a "bit fat". So, not useable?

So, where do people get useable bits for this job? I thought it would be straightforward...

Dunno about fat seals, but any non-genuine rubbery bits can be a bit dodgy, I'd take a punt on footpeg rubbers and exterior things but I'd be much less inclined to get engine related items such as seals and manifolds.

"Man, this is turning out to be a headache."
Hee hee, welcome to our World Lowflying!

I have some spare o-rings I can sell you and post. Where are you? Pm me.


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The castle seals are fine from yam, but a few years back they started supplying fatter o rings for the holders, they may have fixed the supply tho with the correct size part now... maybe not. I would go with Gavins kind offer of his o rings, thats a good offer, Id blag some too if he has a bunch of good ones that are heat and fuel resistant

Yambits... Ok... try this: NEVER BUY THEIR SEALS. ok? Plenty of people have had their crank seals fail, its not worth it, we all (those who have been around this a while, tho i bet some wag will say they dont) just buy OEM seals now, we call it 'cheap insurance'. Other suppliers like Wicked supply good seals, I used to sell sets of them a few years back for those with good memories, but for the uninitiated just get OEM. And... BRG, their footpeg rubbers fall apart too... beware, its been reported on norbos forum. Rubber parts are not created equal... Failing PV seals is annoying but not catastrophic like crank seals of course.

You can buy OEM seals here, or you can buy from America... I choose to save money and waste time waiting, but your mileage may vary... pay the money, take the choice as Quo once said, or something

Remember that you will need head and base gaskets to do this job too, we only ever use OEM of those too... and your Aussie dealer wont compete with head gasket prices in the USA I bet...

Finally... Buying from abroad takes a bit of work and waiting. You need to work out what bits of the USA bikes differ to yours, but its not impossible to do so and the rewards are monetary as well as learning more about your bike. Ron Ayres, Partzilla/Boats.net and others sell parts and have been reliable for many of us. If Yamaha Aus wants to rip us off then vote with your feet, a head gasket is half the price in the USA and can be had for even less in canada, the more research you do the cheaper you will find the prices Ive found... to save on post buy a few bits at a time and always pick up spare head/base gaskets, you will need em i bet, its a 2 stroke afterall...