Author Topic: Top end Rebuild  (Read 466 times)

ukblade

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Top end Rebuild
« on: September 05, 2018, 04:10:27 PM »
I've been thinking whilst I've got most of the bike apart and having not got any history on it, I'll give it a refresh.
where is the best place to start with pistons/gaskets.
Only thinking of doing Pistons/Rings.
Is it all still available OEM?
Is it critical to use genuine gaskets etc?
Mines a 3XV8 RS if that makes any difference.
I know on a previous question I asked about PV seals, I was given details for Webbs.
Are these the guys to use for this.
Cheers again for any advice.

« Last Edit: September 05, 2018, 04:19:37 PM by ukblade »

yanw

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Re: Top end Rebuild
« Reply #1 on: September 05, 2018, 04:53:52 PM »
OEM (domed) pistons are available but they can be prone to the ring pins falling out, the rings spinning and catching on ports.

Wossner make forged pistons but they are only available in "group buy" batches via a single forum member who Wossner will talk to only (Jim?). Other pattern ones on eBay are only fit for use as ashtrays.

Pattern gaskets are available and Dan on this site (https://www.gasketguru.co.uk/) makes good ones. Most advice is to only use OEM head gaskets or get them cut for o-rings.

Andy at Webbs is "the man" in my opinion. I get all my parts from him by post.

The manual has the specs for measuring the tolerances on the crank but I think the service interval is about 20K miles. If you need a new crank or rebuild it's £500-£750 either way.

Steveog

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Re: Top end Rebuild
« Reply #2 on: September 06, 2018, 12:19:11 AM »
yan - I'll be in the same situation as "blade" at the end of our Track Day season (three, maybe four TD's possible before its not a good gamble).

To my point: Can you offer another alternative source for pistons, assuming "Jim" can't be found?

Thanks in advance.
Brief, fleeting Glory. Which of itself cannot last, but while it does is the greatest game of all.

yanw

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Re: Top end Rebuild
« Reply #3 on: September 06, 2018, 07:48:27 AM »
To my knowledge it's OEM domed pistons, OEM flat top pistons (sp) plus head work, TZ single ring pistons plus head work or the Wossner (domed) group buy pistons.

The group buy only got started as there were no alternatives and the old-time-members had been through every other conceivable option.

Someone (ybk?) bought some eBay China ones (£20 each?) to see the quality and they were total gash.

OEM will last but some members have reported pin loss/ring spinning towards the end of life of them. When they go the chip off big chunks of the ports and you have to go down the welding/replate route. Search for "ring spinning" on the forum.
« Last Edit: September 06, 2018, 04:41:02 PM by yanw »

Steveog

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Re: Top end Rebuild
« Reply #4 on: September 06, 2018, 02:34:13 PM »
Thanks, yan. That helps a lot.
Brief, fleeting Glory. Which of itself cannot last, but while it does is the greatest game of all.

yanw

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ukblade

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Re: Top end Rebuild
« Reply #6 on: September 15, 2018, 03:13:59 PM »
Pulled the barrels off, pistons look really clean with no sign of pick up, but have put my order in for the possible new group buy of Wossner kits.
What's your opinions on the barrels?
The photos make them look much worse than they look with the naked eye.
Do you think just a hone or should I replate?
Also Top Barrel did not have a head gasket, yet the front barrel did, is this correct?
Thanks again.
« Last Edit: September 15, 2018, 03:15:43 PM by ukblade »

SeaR1ck

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Re: Top end Rebuild
« Reply #7 on: September 15, 2018, 05:32:18 PM »
I would have them replated the plating is worn lots of vertical scratches. Honing plated cylinders is a bad thing unless properly done with a diamond hone.

A green scotch brite pad is the best way to clean them up by hand. Using a ball hone on them will actually damage the plating further and you risk removing plating in the process. Just because people have gotten away with doing that in the past doesn't mean it's the correct way to do it. I've seen guys ruin the plating using ball hones on plated cylinders.

They should both have head gaskets on  them.

ybk

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Re: Top end Rebuild
« Reply #8 on: September 15, 2018, 09:33:32 PM »
Yeah the plating looks borderline. Looks like slight pitting as well? As Rick said a proper hone may help the cross hatching but plating is probably the way to go. Can you feel the scratches with your nail?

ukblade

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Re: Top end Rebuild
« Reply #9 on: September 16, 2018, 12:25:23 AM »
Ok, so where to send for plating in the UK please?

yanw

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Re: Top end Rebuild
« Reply #10 on: September 16, 2018, 10:06:15 AM »
http://www.poetonaptec.co.uk

But there is a bike shop up Warwickshire way that can send them there for less but I forget their name.

scrimsmustang

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Re: Top end Rebuild
« Reply #11 on: September 16, 2018, 02:52:51 PM »
I used my Imexjp account for all my gaskets and bearings and outer crank seals all oem genuine parts. Even with shipping and duty nobody in the uk could touch them on price.

Steveog

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Re: Top end Rebuild
« Reply #12 on: September 16, 2018, 03:19:15 PM »
SeaR1ck -

Who do you recommend for plating in the US? I may need repair and might seek SP-Esque porting for (R) barrels. Is that a one-stop deal?

Am I better off looking for SP barrels if a cylinder is damaged?

I guess shipping to England isnít a big expense when considering costs of cylinder work. Just curious if there is a US source.

Thanks
Brief, fleeting Glory. Which of itself cannot last, but while it does is the greatest game of all.

SeaR1ck

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Re: Top end Rebuild
« Reply #13 on: September 16, 2018, 04:06:18 PM »
I have been using power seal lately they are very good. Did my pair of nsr cylinders a pair of 2xt and kr1 and my yz 250.

They charge $180 a cylinder which is much better than millennium who has increased prices recently to $250 per cylinder and the same with u.s chrome.

These shops can do porting services but i have not used them for that.

TZRtim

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Re: Top end Rebuild
« Reply #14 on: September 16, 2018, 07:11:56 PM »
On this plating business , is it better to have plating or have iron liners for re-boring ? Not sure which is more desirable ?
May the wind blow light and your groups shoot tight - UKV...  Biker and shooter for life ...