Start of engine rebuild

[Geert_Holland]

Hello guys,

Here a couple of pictures from the start of our engine rebuild.

The engine was using allot of oil, we are figuring out why.

















Lapping the valves:

[Geert_Holland]

The cylinders and pistons seemed to be fine after measuring, so the oil problem seems to come from the cylinder head.
The valves and valve seats seam in good condition, so you would thing the problem are the vale guide or seals. The seals will be replaced of course, but is there a way to test the valve guide?

greets

[daves79x]

I think you need to define what 'using a lot of oil' means first. A quart in 1000 miles is not uncommon. A quart in 500 miles is more of an issue. Are you within that range? More or less?

Anyway, even a very high-mile engine will likely show piston/cylinder clearances within range. It's the rings' ability to seal that's usually the problem. Not great success has been had just honing worn cylinders and installing new rings.

How many miles are on the engine? Hard valve seals will only allow a certain amount of oil past and that's usually seen upon start-up. No oil smoke when running. Usually an oil drinker is blowing oil past worn rings.

Valve guides can be measured, but you have to have some pretty sophisticated (expensive) equipment to do it. Most guys usually go by feel of the valve stem to guide play. If this is not a 100,000 mile engine, then the guides probably are fine.

This is where a leak-down test before tear-down would have been valuable.

Dave

[Geert_Holland]

Thanks for your response Dave!

The engine was using allot of oil, it was smoking very bad and took 1 liter oil over 150 kilometer .

I think the valve guides are ok, just by looking at them.

I dont know the exact millage of the engine, but looking at the internal parts and clutch its a verily worn engine.
Also the bike was sitting in storage for a couple of years before we start working on it, thatt also not helping for the oil use .

My idea so far is the piston rings are worn, like you are saying. So i have to install new ones, or go for new pistons maybe a little bigger as original .

Im keeping you guys updated.

Ps, sorry for my bad English

[EMS]

Thanks for your response Dave!

The engine was using allot of oil, it was smoking very bad and took 1 liter oil over 150 kilometer .

Wow! That's more than 11 quarts over 1000 miles!


And your English is fine, Geert!

[bikeymikey748]

Ps, sorry for my bad English

Most times, my English isn't so good either. No worries, we all know what you're saying . Besides, my Dutch SUCKS
Thanks for posting your progress

Also the bike was sitting in storage for a couple of years before we start working on it,

Was it stored properly, what do the cylinders look like, any corrosion?
The oil control rings ( and expander) were they free, or gummed up & unable to operate as they should?

[Geert_Holland]

The cylinders looked to be OK, just in one cylinder was very little corrosion, but nothing to be worryed about.
The motorcycle wasn't stored properly, it was just puted in the corner and left there for a couple of years.

Thanks for the respons, I will keep you guys updated;)

[metalganz]

Hello Geert, see that you live in Holland just like myself (Zwolle) so that make`s my exstra curious about your problem with loosing very much oil in your CBX factory.
Have you done a compressiontest on all the cilinders?
And do have made progress with the engine?
For myself beeing just short on this site,I am making footrestrubbers for the CBX and Nils Menten sugested to arange a groupbuy of these.For that reason I joined the site.
I am a fan of the CB1100R bike`s,so there is much comparison between the four and the six about many items problems etc.

Groeten,
Wim