Finished disassembling top-end

[Dritto]

Hi guys. As I stated in the title, I've finished disassembling the top-end of the engine, and now I have some questions for you and I will include pictures.

1. Are the steel gaskets reusable?

2. Does the cylinder look like it's in good condition?

1718109950

I measured the bore with a telescoping gage and a digital caliper. The numbers I got, were these:

Top
Y1 = 85.01
X1 = 85.01-02

Mid
Y2 = 85.04-05
X2 = Between stock and 85.05

Low
Y3 = 85.04
X3 = 85.04

To these numbers seem inaccurate? I was doing multiple measurings. This is close to the limit isn't it? The engine has very low hours on it.


3. Can I deglaze the cylinder wall with industrial general purpose Scotch Brite?


4. What are these marks on the inside?
1718109945171810994617181099471718109948

[400man]

the cylinder looks good from what I can see. if there is no visible scratches or gouges that you can feel with your fingernail, buy you a stock size aftermarket piston and run it.

As for re-using the gaskets, ive done it before and had mixed results. if your in a pinch and have to re-use the head gasket, get some copper gasket spray and it will help it some from leaking. but most likely it will leak at some point.

id take the cylinder to a shop and have em do a light hone job to clean it up.

[Dritto]

I've got honing stones, so might just do it myself.

[ride red 14]

Also go ahead and put a timing chain in it while your down this far. They are notorious for stretching on these quads. Use a crf 450 chain. Exact same length but much heavier.

[Dritto]

I did a kerosene test on the valves, and it seems that one intake and one outtake valve is leaking, it leaks around a drop per 30-60 secs. Should I just leave it or? It's just that the engine has very low hours on it, maybe around 120 hours.

And what are those marks on the inside of engine case?

[backwoods572]

I did a kerosene test on the valves, and it seems that one intake and one outtake valve is leaking, it leaks around a drop per 30-60 secs. Should I just leave it or? It's just that the engine has very low hours on it, maybe around 120 hours.

And what are those marks on the inside of engine case?

if your valves are leaking , now is the time to fix it before it gets worse after you put it back together...... Just lap the valves and you will be good, as its not a bad leak..... also I believe the word your looking for is exhaust valve... not "out take" valve :tired:

[Dritto]

Hahah, yes :)