Top end refreshment

[bomber]

I started with broken tappet now it looks like a top end rebuild...
I'm about to remove cylinder block to replace gasket on the bottom of it, I would like to check if I need to replace piston rings and if pistons needs replacing.

How can I check if bottom end is in good nick?

Also, I have changed oil before this operation and did about 100miles, oil looks very dirty, there were clear signs of black deposit when I took rocker cover, and just have a look at the pictures of valves and pistons.
Interestingly when bike was running it didn't smoke, and form the pictures as suggested here before it must have done few miles, I would have thought that rings would be leaking oil and so it would smoke a lot.

Any suggestions much appreciated.

Off to shops to get micrometer!

[florence]

I think the only sure way to checke the big ends is to strip them and use plastigage.

[bomber]

Thanks guys,
I decided that I'm not going to attempt digging any lover than top end, I'm already way past my depths.
Very interesting point about the crescent mark, I had a look at the other picture and it doesn't look like the valve was hitting it, but will need closer look at it.

[bomber]

Can someone please tell me what are these for? Also it looks like they should be screws, not nuts on top of studs with copper washers.
Any idea?

[matthewmosse]

Think these bolts hold the rocker shafts in place. I was very surprised on my 500 and 550's that at the worst wear rate on any of my bikes I've only ever had to re ring them, appart from where dammage was really obvious, as in smashed pistons.

[Trigger]

If there were no noise from the bottom end, leave well alone. What i would suggest is take the sump of to clean it out and check the mesh filter is in good order. While you have the top end of you may as well check the piston ring's and as i can see the head is in need of an overhaul. Oddjob must have bloody good eyesight or a better zoom than me to see contact marks on the valves. I would not like to make that judgement without seeing the head up close and personal. Any bent valves would need replacing and can be tested. 

[bomber]

At the moment only one nut has copper washer which is half broken, would you say that I should replace it with steel washers?

Yeah those bolts were only fitted to the modified rocker covers. It was meant to stop the rocker shafts spinning as they were elongating the hole they sat in.

[bomber]

Thanks for suggestions and comments so far.
Here comes another question.

I cant find any local soda blasting place, so far I found a company which uses plastic mixed with glass, can anyone reccomend using it?
They reckon it works same as soda and they will mask off whatever needs to be masked.
I would like to have cylinder block and head cleaned off, should I ask for the carbon deposit form inside the head to be cleaned too, or just the outside.

Thanks

[Trigger]

Yep, see what you mean now oddjob. I was still half a sleep when i had a look. Too clean for a carbon area.

[bomber]

I took exhaust valves today and they look straight, struggling with taking valve stem oil seals, how would you take them off?

I've cleaned outside of cylinder block, but there was still a lot of sand and some of it got inside, I think I will not worry about this now and just change oil twice shortly after rebuild, what do you think? is this going to screw bottom end?

There is a bit of rust on the studs, do you think they need replacing?

I still don't have micrometer and used vernier to measure quickly pistons only one of them seems way out it seems to be 58.5mm while max serviceable limit is 58.35 but not sure how precise this measurement is, I also tried to measure ring end gap and it was waaaay over what manual indicate.

I'm wondering how to measure precisely inside of cylinders, I'm guessing that vernier is not precise enough.

Admittedly I'm way out of my depths...
And lastly on all images and in both manuals I got there is a single mark for the "timing mark" I have two super close to each other, would you say that the way I took picture, is correct position to set timing and valves of course it need to be 1and4(for valves setting) not 2and3 as in my picture.

 

[Trigger]

You can take the valve stem seals out with long nose pliers . Sand in the head? you should of got it soda blasted. Now you must get every grain out. A couple of grains stuck in a oil way will destroy a bottom end. 

[bomber]

There was a sand in the cylinder block, stuck to the studs, when I was lifting it it got loose and went in...
The whole block was painted silver at some point, whoever did it couldn't be bother to clean sand and other carp beforehand.

You can take the valve stem seals out with long nose pliers . Sand in the head? you should of got it soda blasted. Now you must get every grain out. A couple of grains stuck in a oil way will destroy a bottom end.

[Trigger]

You should always clean a engine before working on it. Unless you intend to do a full strip and rebuild.

[bomber]

Sadly, I have no space to take engine of the bike, I guess I'm learning the hard way...

You should always clean a engine before working on it. Unless you intend to do a full strip and rebuild.

[Trigger]

Yes Bomber, but at least your learning.