XJ750 Engine locked

Hi Folks,
First up, quick intro. Im Chris, live in Newcastle, NSW, Australia. I'm 26 and have just bought an 81 XJ750.

I have a, well, i shan't say slight problem, but lets say an issue. It would seem the engine is locked.

I've removed the l/h end cover and tried to turn the crank forwards and backwards but no movement at all. The wheel rotates in neutral ok.

I removed the gear selector cover and noticed the oil looks fairly new, but there seems to be a lot of swarf in the little crevices in the case along with some chunky bits.

I also popped the clutch cover off but inside it the oil is as clear as brand new oil with no sediment at all in the casing. I also broke the clutch basket and need to replace it.

In your experience with these engines should i begin removing it from the frame and prepare for a full strip down?

 

You could try pulling the valve cover to see whether there's play in the cams... to try to see whether the blocking is something in the bottom end or if it might be valve/cam-related.

Most likely, though, a full tear down, or a replacement engine, is the next real step.

Sorry to hear this.

 

Is the bike in gear? Make sure its in neutral.

 

Did you pull the plugs before turning by hand? If not can be rather difficult to turn.

 

Bike is in neutral and the engine wouldnt be any harder to turn over by hand than a 3.5L v6 with the plugs in im sure.

Its definitely locked up. the crank wont budge a mm. Gonna start pulling it out today for a stip down.

 

I would light a candle.
Kneel down.
Say a little prayer for somebody you love.
Open the Flask and take a sip of Jack Daniels and spit it on that Engine.

Don't mess with it.
Getting way into it starts-off at $300.oo ... maybe more.
Find an Engine that has some compression worthy of writing home about and just do and Engine Swap.
If the Miles and Compression on the Replacement Engine are cool; do the Exhaust Header Studs and the Intake Manifold Cap Screws before it even gets near the Frame.

Heart Transplant.
Easier on the knuckles.
Easier of the wallet.
A whole lot less swearing and fussing about.

 

Rick,
Seeing how i am unemployed, i am time rich at the moment.

So far this morning i have pulled the head and the barrels off a discovered that the big end on piston no 3 has fused itself to the crank. At the minimum im looking at a new(2nd hand) crank, full set of bearings, rings, hone the barrels, deck the head and service it. And a new timing chain as the other one met an untimely demise at the hands of my angle grinder.

 

Fused?!

Pictures?

 

Cant really show it in the photos but all the other con rods are nice and loose on the crank, no3 doesnt move at all. Even when i held the crank still and tapped it with a rubber mallet it wouldnt budge.

I will add more photos when i pull the engine and remove the sump and conrod.

 

Gee, ... that's a weird one. I hope it's now a Spun Bearing that put a hurt on the Crankshaft.
Whatever it turns-out to be, ... I hope it isn't something that causes one of those dreadful "Chain-reaction" bad situations that starts with something like finding the Oil Pump went bad and nothing got oiled.

I heard a guy go past me one-time and whatever it was that was knocking sure wasn't "Opportunity"

Fill-out the Government Paperwork to see if you can qualify for Recovery Funding to get the Bike fixed.

Restoration of a Classic Vehicle for Undercover Surveillance of Suspected Terrorists and Patrolling Highways for Illegal Alien Smuggling and Construction of a Permanent Structure to Garage and Maintain the Vehicle.

Proposed Budget: $494,750.00
5-Year Project : 95,000.00
Sub-Contractor will be required to make new hires.
EEOC
Affirmative Action
Democratic Initiatives File Number USA127D-1876F-03

 

I'm hoping that the conrod big end is the only issue as well. Luckily i can do most of the work myself. The only stuff that is out of my league is machining work. And that is only due to lack of equipment.

I'm not sure if that scheme will be applicable to me as i live in Australia.....thanks anyway.

I'll pull the rest of the engine tomorrow and see if i can get the rod off the crank and have a look see whats doing.

 

Maybe you qualify for a stimulus package from Krudd :lol: .

 

already spent that on other "expenses" incurred when me and the ex broke up in march.

 

Well, I found the problem. The big end on piston no3 had seized to the crank due to a spun bearing. The cause.....sugar in the sump......so a FULL strip down and inspection is now on the cards. Thats ok tho, as it will give me something to do and i can do it bit by bit as well.

Good times to be had.

 

Trust me,
If I was in Australia and wanted to revive a 750, I'd buy the '84 and up 900 engine and carbs and have a REAL motor !!

Or the odd chance of getting the fuel injected Police Bike.

Don't build that motor. Really.

 

I was hoping that wasn't the case.
Too bad about the Bearing.

I wouldn't get all-crazy about doing anything with an Engine that needs a Crank.
I would be looking all-over for one of those Fuel Injected Police Editions, too.

 

Anyone got any more info on those fuel injected versions? I've never heard of them...

Also, you might want to check with Yamaha if you can still get big end bearings for your XJ before you go any further....and be prepared to spend $$$$ rebuilding a motor from the crank up.

 

This is like a Race Horse with two broken legs.

You don't call the Vet and tell him to order supplies for operations on the horsie's legs, ...

You put the Horse down.
All its good days are over.
Over.
No big expenditures.
One bullet!

 

Yep - I'd be looking at parting out the useable bits and looking for a 900...

 

That really sucketh! I'm curious, how did sugar get into the sump? Act of vandalism? Terrorism? NOS energy drink instead of NOS fuel/oil treatment?