Tank Slap - Motorcycle Forum

Hi guys, any advice or help would be greatly appreciated. I don't think this is going to be an easy or cheap fix!

I have a 1987 Yamaha TT350. Been out on it for most of the afternoon today and was running perfectly. On my slow plod home the engine all of a sudden lost all power. I pulled over and tyres to kick the bike over, the kick start to my horror was rock solid. After leaving it for a few minutes it began to free up, however, the engine now has no compression and will not start.

It is possible that I got a bit of water into the cylinder, which I know can cause a seizure but I'm doubtful that this is the case.

I was thinking that it would more be the thinning of the oil as the engine heated up has caused a partial seizure.

Any thoughts or information? I have done some reading and believe my first port of call would be to check valve clearances, piston and rings.

Thanks in advance.

What oil you running and when was the last time you changed it?

Silkolene semi synthetic. Changed it last Friday, along with oil filter and air filter.

Have you drained any of the oil out to have a look at it? It should (fingers crossed) still look fresh. That'll eliminate a couple of bigger problems.

I can drain it, I haven't yet done so. I'm unsure what you mean by fresh, from my experience new oil that's been run around an engine is almost instantly a dirty colour? What exactly am I looking for?

You're looking for discolouration in the oil or any metal.

There are a load of off roaders on http://www.throttlemonkey.co.uk/forums/" onclick="window.open(this.href);return false; they might have someone on there with experience of your bike.

Just drained the oil, it is no different to the colour that I would normally expect. There is however metal flakes in it. They are very small, look a bit like glitter.

From past (sad) experience that usually means either the big end has gone.

I might not be so with this bike. They do get some flakes in the oil. Its not a sure sign of failure provided they get regular maintenance.

Have you seen flakes in your oil before?

Before it cut out did you have any backfiring or smoking?

I changed the oil on Friday, there were no flakes in it then, not that I noticed anyway. The only reason I noticed this time was due to the fact they were caught on the base of the sump plug.

There was no bang, backfire before it cut out and I didn't notice any smoking. However I have no mirrors so wouldn't have noticed it.

It was odd, immediately when I stopped I checked the fuel as it felt that it had run out. It was half full so I tried to kick it over and kick was solid.

From what you've said I think you were right in your first post. Piston and rings are next to investigate.

In the case it doesn't seem all doom and gloom, maybe a top end rebuild should suffice.

I will attempt to get the engine removed and cylinder off tomorrow and report back with my findings. Thanks for your help.

Good luck.

Might be worth asking around any engineer friends you have and see if you could borrow an Endoscope and have a look in the spark plug hole. Dead handy bits of kit even if you end up buying one, a cheap but reasonable one is a similar price to a head gasket set.