1986 VFR750F engine locked up

[Dukiedook]

Hello,

Just picked up the above bike last Friday from a guy that said the engine stopped running as he was driving to the DMV to get his permanent moto license. His mechanic said the cam chain could be broke (I know that is not the case, these are gear driven cams) so I knew the engine was potentially a 170 lb paperweight when I bought the bike.

In his garage before I bought it the solenoid would click and the starter would click but no moving of the crankshaft (could be a dead battery) is what I thought there. Get it home and I bought a new battery, charge it a little before I put it in and the same thing happens with the new battery when I try to start it. Click at solenoid and starter but no crankshaft movement to speak of.

So I drain the oil, pull the right cover to get a lookey loo at the parts and try to move the crankshaft by hand, I couldn't get it to budge a bit, damn.

Sooooo, does anyone know what year of donor engines can be readily swapped out on an '86 750 and where I might want to look to get one?

Any help is greatly appreciated.

Ryan

[TOE CUTTER]

You will need to find an 86 engine to have a trouble free swap. The 86 700 and 750 had a secondary speed sensor on the cam and without it your tachometer will only read half speed. An engine should not be too hard to find with a little looking, you may have to settle on a 700 but you wil not notice the difference.

[Dukiedook]

Thanks, I'll start the looking for both.

[Tighe]

Ive got a spare 700 and 750 motors. PM me if you are interested.

[CARMINE]

hi,
I think that Toecutter is right. Once I had the same problem with my VFR 750 ('87) at about 45,000 km. The problem was the "free wheel gear" on the crankshaft. When this gear is broken, the engine doesn't "feel" the RPM and does not start. In other terms, no trigging signal for the front pk = no sparks.
Hope this can help and pardon for my english.
Lamps,
Carmine.

[Dukiedook]

So, is this repairable or is the engine toast? I should be able to hand crank the crankshaft, or would this problem prevent the engine from hand cranking it?

[tinkerinWstuff]

Sounds toast to me. No matter what, you likely need to pull the engine. So get to it, yank the motor, pull the valve cover and oil pan so you can see how healthy everything is.

[Dukiedook]

Oh yeah, I pretty much knew the engine would be pulled at the very least to fix whatever is broken. At least I have my other 750 to ride until then...

[TOE CUTTER]

Would like to know what failed with this engine, the 2nd gen's were a very tough machine and engine failures were pretty rare.When you find out let me know. Can you shift gears?

[squirrelman]

Hey, pour about 1 oz kerosine mixed with oil down the cylinders and let it soak for a couple days, then try moving the crank both directions using a socket ( 17mm) and breaker bar on end of crank applied through the access hole on clutch cover. ( Bike in neutral, of course.)

This sometimes loosens up a stuck engine if the rings have rusted to cylinders.

Check the level of coolant under the radiator filler cap. If it's way down or you see a milky-looking mess, a headgasket may have blown.

Hope u got it cheap.....

[Dukiedook]

I'll be sure to post on here what happened, I'll start ripping into it further this weekend hopefully. Can shift through the gears, I don't think the rings have rusted to the cylinders, this was pretty recent (month or two ago) when the PO had the engine quit on him. Got it fairly cheap, felt bad for the guy because he dumped several hundred dollars in it for clutch, new back tire, air filter, and some other things.

[captb]

Guess I would start with the clutch if someone had just worked on that area.