GSF250 crankshaft rotation - which way?

[cbfb]

Am trying to check the tappet clearance on my GSF250 Bandit. I'm going off the GSX250F service manual because there isn't one for the GSF, but it's the same engine. You probably know that already.

Anyway, the manual says to turn the crankshaft in the normal running direction. Problem is it doesn't say what the normal running direction is. This is where to turn from, just need to know if I go clockwise or counterclockwise:



Sorry if this is obvious - but you can give a one-word answer so all good

[Hitcher]

Blip the starter and see which way things turn.

[cbfb]

Blip the starter and see which way things turn.

I've removed the radiator and cylinder head cover, guessing it won't do any damage to turn it over on the starter?

Also is it OK to give it a few turns on the starter like this to do a compression test?

Thanks heaps

[ducatilover]

It will turn clockwise from where that pic is looking at. I'll put a beer on it. It's safe to give it a quick crank.

[Ocean1]

I've removed the radiator and cylinder head cover, guessing it won't do any damage to turn it over on the starter?

H just meant to nudge the starter a tad to see which way the crank turned but if you're worried about it take the plug out and give it a single squirt of oil.

Also is it OK to give it a few turns on the starter like this to do a compression test?

Thanks heaps

Yup, in which case don't do the oil thing first. However if the pressure ain't what it should be I always put a squirt of oil in and test it again. Gives you some idea where the problem is...

[cbfb]

Great, thanks heaps for that. Will get the tappets sorted first and worry about the compression test another day.

[onearmedbandit]

Most bikes have a 'forward' rotating crankshaft I would have thought, the inertia of the crank helping to keep the weight on the front wheel when accelerating.

[cbfb]

Most bikes have a 'forward' rotating crankshaft I would have thought, the inertia of the crank helping to keep the weight on the front wheel when accelerating.

My instinct was that it would be forward rotating, but I've learned it can be expensive to go with my instinct so thought I'd better check! Cheers

[ducatilover]

Most bikes have a 'forward' rotating crankshaft I would have thought, the inertia of the crank helping to keep the weight on the front wheel when accelerating.

With the exception of the YZF-M1 master Rossi rode and a BSA bantam being kick started whilst drunk....

[Robtharalson]

Inline fours are one of the easiest to connect the crankshaft to the transmission: a gear cut into one crank web turns a larger gear on the clutch basket, followed by a two shaft transmission turning a small sprocket which pulls the drive chain across the rear sprocket, turning the rear wheel and moving the motorcycle forward. There are two direction reversals -- once in the primary geartrain, and once in the transmission. The end result? The crank turns in the same direction as the rear wheel. Why? Two reasons. It's easy and inexpensive to manufacture and the parasitic is low, meaning more power to the rear wheel.

There are exceptions, but not for that era Japanese inline four cylinder motorcycle that I know of.

Logically, and long experience with hundreds of engines bears this out, that is the correct answer. But my long experience also tells me that logic is a perfect way to go wrong with confidence, so I always test any assumption with actual observation -- in this case observing two conditions to confirm my hypothesis. If while turning the crank you hear the starter motor turning that means the starter clutch is engaging, which cannot be normal operation. Turn it the other way. The other is to watch the intake and exhaust valve cam followers for one cylinder while turning the crank two full turns: if you see the exhaust valve open immediately followed by the intake valve you are going in the right direction (that's overlap BTW), but if you see the intake open immediately followed by the exhaust go the other way. Simple.

Rob

[kiwi cowboy]

It will turn clockwise from where that pic is looking at. I'll put a beer on it. It's safe to give it a quick crank.

Gee mate you know alot about ondas for a onda hater

[onearmedbandit]

Gee mate you know alot about ondas for a onda hater

And it seems you don't, it's a suzuki.

[cbfb]

Inline fours are one of the easiest to connect the crankshaft to the transmission: a gear cut into one crank web turns a larger gear on the clutch basket, followed by a two shaft transmission turning a small sprocket which pulls the drive chain across the rear sprocket, turning the rear wheel and moving the motorcycle forward. There are two direction reversals -- once in the primary geartrain, and once in the transmission. The end result? The crank turns in the same direction as the rear wheel. Why? Two reasons. It's easy and inexpensive to manufacture and the parasitic is low, meaning more power to the rear wheel.

There are exceptions, but not for that era Japanese inline four cylinder motorcycle that I know of.

Logically, and long experience with hundreds of engines bears this out, that is the correct answer. But my long experience also tells me that logic is a perfect way to go wrong with confidence, so I always test any assumption with actual observation -- in this case observing two conditions to confirm my hypothesis. If while turning the crank you hear the starter motor turning that means the starter clutch is engaging, which cannot be normal operation. Turn it the other way. The other is to watch the intake and exhaust valve cam followers for one cylinder while turning the crank two full turns: if you see the exhaust valve open immediately followed by the intake valve you are going in the right direction (that's overlap BTW), but if you see the intake open immediately followed by the exhaust go the other way. Simple.

Rob

Thanks for your detailed reply Rob, I took your advice re listening to the starter motor and can now confirm that indeed the crankshaft should be turned clockwise.

So now I've successfully measured the clearances and they're a wee bit small... but that's another thread...

[ducatilover]

Gee mate you know alot about ondas for a onda hater

It's a zook mate
But yes, I actually love Hondas

[kiwi cowboy]

And it seems you don't, it's a suzuki.

I seem to be getting good at this ah well i like this little fella