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WR450 cylinder boring and Nikasil plated

By Kennoy,
in WR400F/426F/450F

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Kennoy

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I have a 08 WR450. Started hearing a little piston slap so I tore it down and sure enough needs piston and cylinder replacement/boring with bigger piston.

 

I'm NOT looking for all out power. Need reliability. I do 85% of my riding down in Baja. 

 

Looking for a GOOD shop with a GOOD reputation to send my cylinder and the NEW bigger piston to so it can be bored and nikasil plated.

 

Any suggestions?

 

Thanks

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Kennoy

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The chances of it running and still needing an over-bore are pretty slim.

 

Treating and re--plating are usually all you need 

 

Just mic it to the service manual specs to see where you are

Really? How many engines have you taken apart? Been working on my own stuff for 35 yrs. I've taken apart many. 2 stroke, 4 stroke. singles, twins, triples ;4 cylinder and even the old CBX 6 cylinder. I've seen some pretty messed up pistons and the bike still ran.On my current bike, there is some vertical scoring (not major) from the piston and grooves around the top from the rings. Normally I just buy new but this time I want to bore and replate

 

Thanks.

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FORMA MOTO

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Really? How many engines have you taken apart? Been working on my own stuff for 35 yrs. I've taken apart many. 2 stroke, 4 stroke. singles, twins, triples ;4 cylinder and even the old CBX 6 cylinder. I've seen some pretty messed up pistons and the bike still ran.On my current bike, there is some vertical scoring (not major) from the piston and grooves around the top from the rings. Normally I just buy new but this time I want to bore and replate

 

Thanks.

 

Wow, so defensive.

 

It's obviously not as bad as needing a re-bore, or you would be burning blue smoke all day long from the blow-by, have poor throttle response, and it would be way down on power.

...unless you chose not to divulge that.

 

You are implying that it is not 2 hundreds worth of scoring, so that would indicate that there is no need for an over-bore.

 

Pistons usually come in 1 or 2 hundreths over-size, to accomdate wear, and still stay in class dispacement size.

 

Weisco offers sizes from 94.95 - 97.0 mm in 1 hundreth increments. Stock is 95.00.

 

Now, if you mean a 'big-bore' piston, as in 2mm or larger, that's a different set of circumstances:

 

You just WANT a rebore and a bigger piston.

 

Why do you assume that because I have an opinion to your public post, that I have never worked on a motor?

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William1

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Really? How many engines have you taken apart? Been working on my own stuff for 35 yrs. I've taken apart many. 2 stroke, 4 stroke. singles, twins, triples ;4 cylinder and even the old CBX 6 cylinder. I've seen some pretty messed up pistons and the bike still ran.On my current bike, there is some vertical scoring (not major) from the piston and grooves around the top from the rings. Normally I just buy new but this time I want to bore and replate

 

Thanks.

Grooves and damage has to be very severe to prevent a repair/replate. If the damage is really bad, often they simply will consider the core garabage and not touch it un;less it is rare or has had special work done to it.

 

I think you'll find Krannie has done more engines this year than you have done in your lifetime. Truth be told, if you had all the experience you profess to have, you would not be the one asking questions.

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Kennoy

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Grooves and damage has to be very severe to prevent a repair/replate. If the damage is really bad, often they simply will consider the core garabage and not touch it un;less it is rare or has had special work done to it.

 

I think you'll find Krannie has done more engines this year than you have done in your lifetime. Truth be told, if you had all the experience you profess to have, you would not be the one asking questions.

Sorry, :doh:  I mis read Krannie's post when he said "It's obviously not as bad as needing a re-bore, or you would be burning blue smoke all day long from the blow-by, have poor throttle response, and it would be way down on power" 

 

Not sure what I read but I was wrong,

 

Sorry Kah Ran Nee

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GuyGraham

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Even if the barrel is badly scored, it will have the OE plating stripped off, then the scores will be welded up and it will be bored to a pre-plating size, then plated back to std OE size

 

You are thinking in terms of the old style cast iron liners, where they were rebored to the next oversize, typically +0.25mm or +0.5mm when worn or damaged

This is not the case with modern plated cylinders

This is why Yamaha only supply one size of piston - there are no 'oversize' piston

As said above, some aftermarket piston manufacturers supply bigger pistons but this is for obtaining the correct clearance rather than for overboring to next size up to reclaim a worn/damaged cylinder

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SteveThe Snakes

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I'd only go with US Chrome, I'd say the second choice is Millenium but they are lesser quality and about the same price. Terrible customer service I found though. Also Millenium stole the process from US Chrome but never got their plating to be as good/ consistent.

 

Interesting as I've heard it Millennium did stellar work. They are honed to finished size.

 

Why even bother? A brand new cylinder is $240 at Partzilla...

By the time you ship your cylinder both ways and pay the replating company

you will have about that much into a used cylinder. Seems like it just makes

more sense to get a new one and be done with it.

 

That's certainly a good way to go as well. 

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Texas2Smoker

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Interesting as I've heard it Millennium did stellar work. They are honed to finished size.

That's certainly a good way to go as well.

They do ok work, US Chrome does the best work though as I see it. I have actually heard of problems with Millenium as well.

I talked to the GM of US Chrome at length about a lot of things. He is a very nice guy and deserves our business as far as I'm concerned. When I called Millenium I got a surly woman on the phone who was not happy to have to explain some things to me, so I said see ya.

I would advise against going eBay route as a cylinder plated by US Chrome OR Millenium is of MUCH higher quality than any factory plating, and will last longer as well.

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William1

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I have heard both M/T and USC do great work and stand behind the work. I usually use M/T and have a rapore with them, not that that means anything, just that they have never disappointed me and often have barrels/pistons on the shelve ready to ship. I call, the order goes out within 24 business hours. I get a core charge that is refunded when the oild barrel is sent back. They take all barrrels back as a base core, unless they are shattered. Not sure if USC also does this.

I know a few have had problems and both companies were reasonable and quick to try to make the customer happy. The few times they did not, I am pretty positive it was actually a customers royal screw up.

 

Sadly, Yamaha OEM coating is not as tough as M/T or USC. Not sure why.

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SteveThe Snakes

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I have heard both M/T and USC do great work and stand behind the work. I usually use M/T and have a rapore with them, not that that means anything, just that they have never disappointed me and often have barrels/pistons on the shelve ready to ship. I call, the order goes out within 24 business hours. I get a core charge that is refunded when the oild barrel is sent back. They take all barrrels back as a base core, unless they are shattered. Not sure if USC also does this.

I know a few have had problems and both companies were reasonable and quick to try to make the customer happy. The few times they did not, I am pretty positive it was actually a customers royal screw up.

Sadly, Yamaha OEM coating is not as tough as M/T or USC. Not sure why.

William,

Did you ever measure their piston to cylinder clearence to see if you get tight clearences.

Just wondering as most bore and hone shops do some sloppy loose work.

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William1

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William,

Did you ever measure their piston to cylinder clearence to see if you get tight clearences.

Just wondering as most bore and hone shops do some sloppy loose work.

Yup, as well as check ring gap.

 

Over the years, getting a 'perfect fit' is not a 100% sure thing. But as long as it is close to being 'in range', I do not sweat it. I find it tight more often than loose. I resolve that when using a NikaSil barrel by emery cloth on the piston in a rotating jig. Not like olden tymes when I could whip out the hone and hit the barrel witn a few swipes. If it is loose, I send it back. I think I've sent only a few back over the years.

 

Local guys doing bore jobs and honing on iron barrels, the biggest issue is the bore taper. I have not ever had a taper issue with a nikasil barrel.

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