1986 VFR750F engine locked up

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. :frown:

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

 

86 700-750

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.:thumbsup:

 

Thanks, I'll start the looking for both.

 

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

 

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.

 

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?

 

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...

 

Gen 2 engines

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?

 

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.....

 

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.

 

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

 

Well,

got the engine back in VFR#1 I bought in August finally in a few weeks ago and have been riding it, new fork seal and the NOS rebuilt Fox Twin Clicker with the heavier spring from Jamie. This thing runs strong and the suspension is a million times better!! The only problem I can report is that it kind of makes a PUH sound out of front left cylinder area every couple of strokes upon warmup- but dissapears when the engine gets warm- other than that the engine is pretty tight- I'll look for maybe a loose exhaust clamp to see what I can find- valve adjust did happen before I installed the carbs on engine install.


I sidelined VFR#2 to put a new NOS rebuilt Ohlins rear shock, new brakes, new fork seals and sonic springs, new carb rubbers, new float valve and gasket for #1- this thing will be running like new when I get it buttoned back up.

I will get pics up if you guys really want to see them but since I am waiting from my fairing set from Chuck (Ordered back in March!!!) it is pretty ugly, I want to save you guys the ugly sight until I get some decent fairings on this sucker. I am glad to finally get some of the things the PO's had done to it worked out and get this beast back to a running condition.

 

Congrats!

Did you ever figure out what was wrong with the other motor?

 

No, no time yet between getting VFR#1 buttoned up again after improvements/replacements and getting my siding secured and painted on the house before cold sets in. I'll save that as a winter project along with resurrecting my Harmon kardon Citation II amplifier with new parts.