XJ700 Piston Rings

Good day!

I recently purchased a air cooled 85 XJ700. I searched for piston ring replacements and the best I can find is a post from 2014 which stated sadly the rings are SUPER rare. I have yet to be able to find on the forum if this was resolved or an aftermarket solution was possible.

Thanks

 

Is the engine running? Have you checked your valve clearances and done a compression test? Valve clearances are so important and a compression test will give you information on how your engine is. Better to do the checks first and then you can work on what parts you need. A small amount of acetone and ATF mix 50/50 down the bores can free up stuck piston rings if the bike has not been run for a while.

 

Long story short the bike was purchased via a heap. Guy and his son tore it down, then the son lost interest. I was told it ran when it was together. And was shown a video of it running when they first brought it home.
Motor turns freely but I was looking to just do a rebuild on it and assemble from there rather than assemble and test then take it apart again for the rebuild.

Unless it would be more prudent to go ahead and put back together for the testing?

 

http://www.xj4ever.com/catalog/e.html

rings but only stock size no oversized
http://www.xj4ever.com/catalog/e-5-pistons.html

you could resleve cylinders if needed or find a in spek set of jugs if you have to overbore

 

Sadly I got the email from xj4ever, there are no air cooled version in stock. So the search is still on. It may end up having to be bored out as the only option.

 

Oversized pistons are hard to come by too.

How far down was the engine torn? Can you measure the bores? If bore's are in spec, and not egg-snaped the rings will seal fine. Otherwise you're really looking at finding another engine, or having pistons and rings made.

 

..or find some pistons from a different bike brand. Honda for example seem for readily available and cheaper. I saw on one of Allan Millyards videos he had a 4 valve cutout piston in 2 valve bike for example. Needs must and all that - be creative!

PS Ring end gap might offer some indication of the extent of wear too. How many miles on it?

 

16K miles on the bike, Sorry I couldn't answer the measures as my tools were left at work. I should be able to remedy that today.

 

You would think with only 15 k they would be ok ,how is the cylinder wall wear look, may get away with just cleaning stuff yup.
Some of these Yamaha Dealers have kept there old stock.

 

Tsk - barely run in.. I'd take teh opportunity just to make a top end clean up - maybe new guide seals and set shims then button her back up - unless of course the father and son team knew of a problem..

 

Chacal bought most of the NOS stuff a long time ago. There is still some around, but it's hard to find now.

 

If there is no ridge wear, flinger test, and can see a crosshatch on the walls of the cylinders you know you ok...

 

Thanks for all the suggestions! I shall hopefully be around and learn enough to show off a nice bike after winter!

 

Unless the engine was really abused or water was allowed to get into the cylinders I suspect that the pistons and rings are in good shape. Putting Marvel Mystery Oil or acetone and transmission fluid (as mentioned above) in the cylinders and allowing them to soak for several days should loosed any stuck valves. Personally, I would leave them alone and get the engine running which should further loosen up any sticky rings. While you have it out get the valves in spec.

 

I was a little surprised that piston rings are no longer available and now I'm wondering what other parts are getting tough to find ?
Piston Rings
Plastic Side Covers and some of the Engine Covers etc in new condition
Fuel Tanks that are not rusted
Exhaust Systems
Plastic Chrome Covers
Metal Chrome Covers ( you can always get it rechromed $$$ )
Anything else ?

 

I'm lucky to have everything, the bike is complete just not together. Looking like the only issue I MIGHT have is the piston rings.

 

Contact Chacal at info@xj4ever and he can give you the full rundown.

 

700 paper air filters

 

I did purchase one from the local Dealer a couple of years ago, they sure are costly.
I had float stick and the air filter absorbed the fuel and I so replaced it, I'm sure a lot of us would have just let it dry out.

 

for what those filters cost for the 700 i would have saved it and dried it out

 

Yup... I did, it's in my spare parts bin.

 

Hey I’m in the same exact boat I have my motor apart I found my baby in an old chip truck in the back of someone’s house he had a nighthawk 450 and traded it for the maxim when he got it it hasn’t been running for 6 years I got it super cheap and it was in surprisingly good shape and also got a bunch of parts from this guy who had one his x gf sold it on him. as of rn I’m sandblasting all the cases and heads getting ready for powder coating and my rings are probably not good and I do not want to chance it the 700 and 750 rings are both 65mm but the 750 rings top compression rings are every so much thicker then the 700 but what I was thinking what if u shave the ring lands down to make them fit or sand the rings idk if they have a special coating or not tho maybe somebody knows. sanding the rings (if they don’t have a coating on them )would be easier then saving the ring lands this to me seems to be the only way unless the 750 pistons will work with the 700 head cylinder and crank

 

get a used set of 700 pistons bring to a machine shop have them do the work to the pistons.

750 pistons will not work wrist pin location is different


word of caution
Yamaha being Yamaha they would have used the 750 rings on the 700 if it were possible.
They must have had a good reason to change the rings the way they did.

not to rain on your idea I think it would have been done by now if it were possible to use the 750 rings with just a little mod to the pistons.
I have been on this site for a long time and the 700 rings have been un available for all of that time , biggest reason I have not purchased a 700 as much as I would like to.

 

for the tarriff years yamaha dumped the 550 and 650 to make the 600 seca II , spent millions to get the 900 approved for sale in the US and dropped it.
made the little sister of the 900 the 750 version and only sold it in canada not the US.

 

Yes I’m surprised nobody has tried it yet I’m thinking about doing this or just dropping a 750 crank with pistons if it works with my cylinder and head from what I can see that should work to but ik what ur thinking just go get a 650 or 750 complete motor but for some reason there pretty much none in Nova Scotia