Replacement Yamaha XJ900F Cylinder Liners 68.5mm

Hi All

I'm sure this has probably come up a million times before, but does anyone know if its possible to get hold of, or get made, new cylinder liners for the 1990/91 XJ900F (68.5mm)?

I have several sets of barrels which are all a bit worn. Oversize pistons (or even standard size for that matter) seem impossible to get hold of.

I got a quote here in the UK for a set and they wanted £135 EACH LINER, PLUS VAT!!!! Then there's the cost of having them fitted and then bored/honed to tolerance.

I'd go to India, China or even Timbuktu if I had to to get some made at a reasonable cost!

Cheers,
Shaun

 

I had a conversation with @non_quotidiun years ago about boring 31a jugs to 58l std.

He had 58ls which were a bit tired and I have 31as.

So... I bought some 58L standard pistons, from Germany of course, and some std 58L OEM rings on eBay and had a friend, who just happens to be a motorcycle mechanic, bore out a set of 31a jugs to suit the 58L std pistons and rings.

Works. Walls are a bit thinner but I figured I'd turn the bike off if I got stuck at a set of lights for too long.

Kinda what you want but from a less standard perspective.

 

There you are, find a set of jugs, pistons and rings (good or pref new rings), stick in the post and I'll bore and hone to size.
Send me a pm, not sure about cost, I'll have to think about time etc
I'm in West Wales.
Huw

 

You know, I wonder when I carc it and someone ends up with my bikes, how much they will curse the damn PO. Haha sucks to be them.

 

Are the 58Ls a larger cylinder, or are they really just a bored out 31A from the factory? You might not be any different from a stock 58L. Unless they changed the cylinder itself, all they could do is give it a thinner sleeve.

 

Well I can tell you that the chamfer at the bottom was not completely gone. Less mind you.

 

Hi Huw

Believe it or not I do actually have a set of brand new 31a barrels which I bought by mistake and I can't seem to sell them on! So that might be an option. I also have a few sets of second hand 58L pistons. Not sure how round they still are though. Additionally I have a set of new IMD 58L/4BB STD piston rings. I'll send you my details. I haven't compared the 31a barrels to my old 58L ones. I thought maybe they'd be a different height, but it seems not. I guess thinner walls would be no worse than going up a rebore or two on standard 58L cylinders?

 

Funny you mention that as I have a set of new 31a barrels. I think if 58L liners went out to their maximum permitted rebore (3rd size?, 4th size?) then they'd end up being just as thin? Sounds like a plan!

 

I'm in Rye East Sussex.

 

Huw

I don't think I have enough account preferences to send you my details. I think restrictions my prevent me sending them from this thread?

 

I take it new standard 58L pistons are unobtainable? I have several used sets. I have tried to measure them and none are perfectly round. Usual wear front to back if I remember rightly. Just thinking that if Huw can do his magic then would that only be negated by worn pistons? Although the rings would be brand new of course.

 

from my observations putting a big bore kit together for my Seca Turbo
the 31a block is 77.39 mm in height
the 58L block is 77.52 mm in height
you will be raising the CR

below is the kit I put together boring 31a block to fit 58L pistons like @cds1984 did.
With the shorter stroke of the 650 it works out to 772 cc but I also had to machine the block shorter for the Turbo 8.2:1 CR.
Hoping to start on this soon.

 

An increase in compression ratio? So its a performance upgrade then! Albeit, no doubt very small - I wonder how much. Would this affect valve clearances?

 

I have just spoken to a piston supplier here in the UK. Very helpful.

They can make brand new standard bore 58L cylinder liners for around £70 per liner incl VAT. To make it viable at that cost they would need to make a minimum of 10 engine sets. Well, I shall want two. They can also fit the liners, bore and hone - I think the person I spoke to said that bit would be at no extra cost, but I'd have to check.

Additionally they can make the pistons in STD and plus .5mm. They would need to make a minimum of 25 engine sets. They gave a figure of £200-250 per complete piston engine set which would include the rings.

If anyone is interested please let me know.

For anyone outside the UK, especially in the US just consider shipping and import duties.

Regards
Shaun

 

Looking forward to this.
Anyway, 6 thou less clearance - not worthy of discussion really, probably go some way towards making up for the lost cr from valve seat recession. If you really want to you could take a cut off the crown of the pistons, but I wouldn't.

 

Have you checked LA SLEEVE?

 

Thanks. Ive sent them an enquiry.

 

by my calcs, 31a block on a 58L results in a CR of approximately 9.8:1 so as @Minimutly said, should not be a problem

 

I see xs 400 is 69mm