XJ650 UK Where to buy over size pistons?

Looking at re-boring my 1980 UK XJ650 but I can't see anywhere that sells over size pistons with most internet sites saying 'no longer available'!!! Can anybody suggest where I can buy them, preferably UK or Europe but I will consider US as well. Anybody in UK had their XJ650 re-bored and if so where did you go.

Thanks in advance for any help.

 

Have you done a valve clearance check, and then a compression test before considering a rebore?

 

Franz, yes, unfortunately compression away down. Bit of scoring and water marks (engine had sat around for a long time before I bought it) and considering a rebore to get it back to top spec.

 

You can ask Len in the United States who sells parts for the XJ series if he has any pistons on info@xj4ever but l don't think they are available now. Might be cheaper getting another good engine if you can.

 

Thanks Franz

 

Pistons and rings, on top of boring honing, circlips and gaskets? Not worth thinking about the cost of all that, if you could find some...
Maybe look for a complete engine?

 

Mmm, your the second person to suggest picking up a complete engine....... Only problem is a replacement engine might be no better than mine!!! Mine runs, just when stripped down noticed wear and would like engine back to really good, reliable, full power condition. Thanks for feedback.

 

I think it's a matter of economics. If you can afford the parts and machining, then yes, you would probably be better off rebuilding your engine and ending up with a known good engine. While you are working on it, there may be other things to replace as well.

If I was trying to do it cheap, I would look for a parts bike and test the compression before buying. But you are right, in this case the replacement engine could end up bad too.

 

Of course you're right, but generally, if not left outside to rot these engines are very good, and don't suffer undue wear (chewing gum valve seats excepted).
There's a guy up North (south of you)' DK spares, who imports and sometimes breaks these (and others). Maybe worth giving him a call? My maxim came in from Japan, 28000 Km on the clock - absolutely nothing for these engines. If you can find the bits, price up the rebuild - let us know how much it comes to? My guess not far off a £grand...

 

Thanks Dan, sound advice. I was hoping somebody would tell me where I can get pattern parts that would make the economics of the work worthwhile. If the bike was an RD LC or even an XS there’s loads of cheap pattern parts around but just can’t get the same for an XJ650

 

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Look to see if some one ( Mahle???) might be able to make a custom set......it's worth asking the question

 

Thanks David, I did see this earlier but they have contradictory sizes on their website so I initially moved on. I’ve now messaged them to see if they can clarify size issue. Thanks

 

Thanks

 

Cruzinimage, but double check your exact model no and type. There may be no difference at all.

Page one...
https://www.cruzinimage.net/?s=xj650

Page two...
https://www.cruzinimage.net/page/2/?s=xj650

CI is usually good quality stuff, with hundreds (probably thousands) of pistons happily sliding in bores all over the world.
I've only ever rarely heard anything bad, and nothing bad about their pistons. I suspect the odd bad thing was more down to owner incompetence.

 

Wow, they are cheap...

 

If bottom end is still good , in theory look for pistons and cylinder , a light hone and a new set of stock rings. Swap this on and you might be in business, of course you will need base and head gaskets , I have seen these on eBay from time to time . If you go this route , have your valves lapped in and replace valve stem seals . Cheers

 

I have an XJ750 that doesn't have the original engine. This engine had sat for some time (I presume at a breaker's) and there was rust damage, causing it to smoke. I managed to get away with a hone and a set of rings; it's fine now. Don't waste your time with a pattern gasket set, or you'll end up taking the head off again. Note: I'm in England.

 

Bought 2 sets of xj750 overbore kits and rings to suit xj900 (853cc) from these guys.
Plus some other bits over the years.
No problems at all, good service too.