Hello,
There's a post somewhere but I can't for the life of me find it, that refers to damage caused to an engine if it runs while the bike is on it's side after a fall. I'm guessing there must be something bad about an engine that's continued to run on it's side for a while because I figure oil flow would be disrupted. But can someone alert me to the dangers of buying a bike that's been dropped and potentially run for a while while it was down. What goes wrong? What can develop in the future as a result of it? And what should I look out for when looking to buy something if it appears to bear signs of some sort of 'spill' or slide, even if it was low speed?
Thanks
Nathan.

The oil breather on the Triumph Triples goes into the airbox, and if the bike is dropped on its left side whilst running, it will suck oil into the engine, creating a Hydrolock situation. A lot of people have circumvented this by running the breather hose into a small plastic bottle with holes punched into it, and stuffed up next to the battery box. I've only dropped mine on the right side, so haven't done that mod yet.

This does not apply to all the triples...only up to the first couple of years of the 955i. Since a revision in 2002 (if I recall the date correctly) they are much less likely to inhale oil during a left-hand-side spill.

If you're not familiar with the "hydrolock" term, Urb, it means that liquid (oil, in this case) gets into the combustion chamber. Since liquids don't compress like the normal fuel/air mixture does, there are incredible pressure pulses in the affected cylinder on the compression stroke. That can damage the connecting rod, causing it to break while going down the road anywhere from a couple hundred to a couple thousand miles later. This, in turn, can cause your engine to break apart and blow hot oil all over your leg and rear tire, which is something you especially don't want when the engine itself slams to a halt and locks up the rear wheel.

There were very dramatic pictures of an engine to which this happened in the Tiger forum a few years back.

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John

That is exactly the kind of info I needed! There is a bike near me that has been over on its left side, which promted the question. So basically, what you're telling me is that it would need it's head taking off before being run (it's certainly not been ridden since falling over as the left clip-on is bent) to make sure that there is no oil in the left chamber - or any chamber for that matter. That fact that the problem can present itself hundreds to a few thousands of miles later is worrying. I think I'll give that bike a bit of a wide berth actaully. Or perhaps haggle very hard, with good reason, and obtain it for spares or for cautiously putting right again.

You don't need to pull the head to avoid the damage. What you need to do before starting the bike after the spill is pull the plugs and turn the bike over several times with the starter. Check to see if any oil comes out, if none does then your good to go. If you get oil run the starter for a few seconds to clean the oil and and button it back up and off you go. It is a pain but not all that hard.

Personally I would use this as a hard bargaining point to drop the price on the bike.

Originally Posted by Garyhjd

Check to see if any oil comes out, if none does then your good to go. If you get oil run the starter for a few seconds to clean the oil and and button it back up and off you go.

It depends. These statements are true only under certain conditions.

If no oil comes out that's good news only if the accident happened recently enough for the oil to still be sitting in there. (For example, when somebody knocked my '01 Tiger over in the mud last year while it was parked at an auction, I was able to trailer it home and check for oil that same afternoon before I tried firing it up again.) If the spill was weeks or months ago, or if the engine has been cranked over since it happened, this sort of test may tell you nothing useful now.

Also: Clearing out the combustion chamber of accumulated oil is only a sufficient solution if the engine was not running at the time of the tipover and has not been cranked since. In the case of the one U.P. is looking at, it was running. If oil got sucked into the chamber then, while the other cylinders were still pounding away, any possible damage has already been inflicted.

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John

Nathan, You didn't mention which Triumph model so here's a general overview. Any wet sump engine that's still running and tipped 90D runs the risk of not being able to pump oil from the crankcase...very bad. Any engine can only be expected to run only a couple of seconds before damage in that condition.

The 955 Triumph triple is more troublesome because the crankcase breather is on the LHS of the engine, rather than centrally located as usual. In left side tip overs, even if not running oil can enter the airbox if tipped far enough.

Is the seller willing to start the engine? If not I'd walk away.

Brad

Hi guys,
Thanks for the new posts on this engine running while tipped 90degrees business. The bike I'm after is the 94-96 Super III. There is one near me that has a bent left clip-on following a spill, but seemingly very little other damage (yeah, yeah, bike traders will say anything in an advert to get attention.) I won't realistically know how much other damage there is until I see the bike - planned for this weekend, tomorrow in fact - so I was trying to get a good handle on what may well be wrong with the bike in the engine dept before I end up poor trying to fix what possibly ought to be a breaker. My Dad's telling me to walk away (he's too many years of past experience under his belt, and about 20 bikes in various states of repair and decay in the garage!) but you know how it is when you want something and there aren't many around. I just missed out on a very nice sadly, couldn't get to see it in time. Always the case.
Cheers for now.
Nathan.