Engine overhaul or not...

[sterzam]

Ok guys, this is what happened...
During the last 800 kms, my AT used about 1.5 lt of oil!
Most of the mileage was done either on dirt roads, with a lot of clutch use and about 300 kms on highway, on a very hot day doing 140-160 KM/H...
What happened was that suddenly the oil bulb came on, some white smoke came out of the exhaust and a metal noise was heard, but only for a second or 2.
Then I did about 10 kms more, added 1.5 litre of oil and off I went.
Do you think I need an engine overhaul (rings, camchains, pistons) or should I get a new engine and fit it?

[sterzam]

Anyone?

[anton88]

Probably piston ring or rings gone - a compression test would help confirm i think.

I think its easier to get a good 2nd hand engine and fit that rather than re-build.

[sterzam]

My concern is finding a reliable second hand engine.
In case I decide to replace the piston rings, should I do any work with the cylinders such as reboring?

[Steve C]

I have read before that folk here seem to like the idea of getting on ebay and maybe get an engine that's coming out of a bike that's being broken, and I can see the attraction. On the other hand, having a rebuild gives you a known quantity - your engine, rebuilt at the mileage you know about. Engine and frame also remain as original, which I think helps resale value. I totally get that there's a sensible/rational argument for just getting and existing engine - usually a relatively lower cost option thatn full rebuild. And then you would have a second/spare engine though... now that would be handy if you're giving the bike a real work life, which sounds like the case

[africajim]

Hi mate, your description would point to drastic failure of either the piston rings or a holed piston. Neither is good news really.

Agree, simple answer would be an engine from a breakers, but also would have to agree a rebuild would be a known quantity. If your engine is reasonably low miles and the rest of it's ok I would consider stripping it and finding out the damage. Pistons and rings would be a reasonable fix, I don't know if the barrels are boreable or not, but if it's broken rings chances are they will be scratched. The metalic sound would have been either the crank and/or camshaft due to oil starvation. This could turn your rebuild into an expensive operation.

If it's going to be a costly rebuild I reckon I'd go for the 2nd hand breakers engine and swap them out.

Hope this helps mate.

[pinoy-al]

I have been riding(and racing) for over fifty years and I can tell you that I would NEVER buy a "used" engine instead of a rebuild!!!!!! DON"T DO IT!!! You know that there are several parts on your bike that are good such as the trans and clutch so why take a chance that these are good on the engine that you want to buy?
Sounds to me that all you need is a top end job. Take it apart(or have someone do it), measure everything, and you'll find that all you may need are rings, valve seals, gasket set, and your done. Worse case would be new pistons and maybe a bore job.
Don't be afraid to do it. You'll be happy because you will know exactly what you have and won't have to worry about changing the paperwork with another engine number!!!!

[sterzam]

Thanks guys for all the advice...
I am leaning towards rebuilding it and I ll try and sourve the parts slowly through ebay maybe and get a really good mecahnic to do the job for me...

[atgreg]

Untill you pull it apart and look and measure things you wont know what you need

[sterzam]

Well, I think that I definetely need a full set of gaskets, camshaft chains and cylinder rings...
I may need pistons but this will have to wait, until I open it up...