TOPIC:

Yes they are. 

yes. Head job, valve job, new pistons. 

anybody has any bad referral from IMD pistons? Look really good.

 

It sounds like money is not an issue for you.  But if you want to spend a little less you can stick with standard bore and replace the blown piston.  You can still buy standard pistons from Kawasaki, or from Partzilla for about $80 USD.


www.partzilla.com/catalog/kawasaki/motor...-j2/cylinder-pistons

I would go with the minimum overbore to ensure that the cylinders aren't tapered or something considering the lack of maintenance and abuse.

hardrockminer wrote:

It sounds like money is not an issue for you.  But if you want to spend a little less you can stick with standard bore and replace the blown piston.  You can still buy standard pistons from Kawasaki, or from Partzilla for about $80 USD.


www.partzilla.com/catalog/kawasaki/motor...-j2/cylinder-pistons

Given a truly scientific approach, each cylinder, valve, valve guide, piston, etc, will be measured, and only those parts that are out of spec to the service limit will be replaced.  

Personally, I'd measure the bores for diameter, out of round, and taper, before committing to an overbore.  I suspect it needs it, but "to measure, is to KNOW."

Same with the head; measure the valves before randomly replacing them, just because.  What's more important, is dressing the seats, and replacing the valve guides if they are sloppy.  And if dressing the seats, the valve stems need to be shortened.  

Anyway, that's my point of view.  

That's what I do.  All the specs are in the service manual.  One just needs the correct tools.

I absolutely agree and am not inclined to spend for fun on parts that are still serviceable. When it comes to valves I have only ever had to replace badly burnt or bent units as generally wear occurs in the guide rather than the valve. However given that Carlos bought the bike "as is" and the only thing he knows of it's past is that it has "had a life" when it comes to the pistons (only my personal opinion) without a definitive "root cause" of the failure I would air on the side of caution and go the rebore/replace route. You could magna-flux or X-Ray etc the existing pistons to ensure they aren't also weakened by what ever caused the #2 failure but weighing the cost of testing against "peace of mind" of new parts I know which way I would go (IMHO) Let's not forget measuring bores takes a bit of practice to complete accurately and the equipment "ain't cheap" 

I wish money was not an issue for me. The reality is I expected this resto project to be a quick face wash issue; but it has become more complicated with the broken piston (and now the  rotor too).
Once into this, I would definitely like to leave the bike as good as possible. I know nothing about the past of the bike, but I do know it was really abused and had no maintenance.
I will throw in some new pistons and skim the head. Some pistons are severely discoloured and I am afraid they may be weakened. I’ll definitely have valves looked at. If I can avoid changing them, much better.
I’ve spent the last 6 hours searching for an alternative to the original rotor, which is more than  500 dollars at Cmsnl. Found an alternative on 195. Will keep looking for the best at the lowest price.

in many things I’ll be out of depth here. That’s why I ask questions. I will ask the shop too, who’s very knowledgeable what is the best course of action. I love this bikes, and enjoy working on them.

But I don’t want to do it twice. 

I am just finishing up similar work as you are planning on the engine and bought the IMD pistons 0,5 oversize. As you said, they have very good reviews.The machine shop checked them when boring the cylinder and their general comment was that pistons like that is either good or great today.

Have you measured the cam chain and the guides wear? The reason I splitted my engine was that it had cam chain rattle noise (probably). It turned out that all the individual parts was within its service limits, but the tensioner was out of its limit (3 mm instead of 5.2 which is the minimum limit on the wedge protrusion).

Jonás, I will very probably end up splitting the cases, as there is too much wrong in this engine to take anything for granted. I will look at the chain, and measure as much as I can to be on the safer side.

Regarding the pistons, when you went +0,50, did you shim (and how much) the head to compensate for the lost compression ratio, or do the pistons have a higher “head” to compensate for that?

cartal wrote:

Regarding the pistons, when you went +0,50, did you shim (and how much) the head to compensate for the lost compression ratio, or do the pistons have a higher “head” to compensate for that?

The piston crowns account for the overbore.
Stock spec pistons will retain the correct compression ratio..
 

Cool…

Contact Thomas. He is an IMD rep.

here’s his Facebook. www.facebook.com/profile.php?id=100002915797424