Kawasaki VN750 Forum banner

1 - 20 of 35 Posts

·
Registered
Joined
·
499 Posts
Discussion Starter #1 (Edited)
As many of you know, I picked up my '86 last Fall and ended up pulling the engine to replace the stator with a TPE rewind. Since it was going to be offline over the winter, I ended up doing a bunch of other things like:
Damper bushings
MOSFET regulator
Brake repairs (caliper rebuild, new pads, new lines, new master cylinder)
TOC manual cam chain tensioners
Carburetor tear down and rebuild
New tires
Starter rebuild
New iridium plugs and 8mm wires with new NGK boots
Etc. etc.

The point being, what started out as a very inexpensive bike to get running quickly spiraled into about $1500-2000 of parts and quite a few late night hours in the garage. Last weekend I finally got it started up, and was able to ride it Monday and Tuesday.

On the way home last night, it developed a faint rattle that quickly developed into a full blown knock over the last mile as I got to the house. I don't know what it is yet, but maybe a spun bearing? Not sure, but I'm guessing the engine's about to come out (again).

Ugh... Sorry for the rant/vent session. Just a bit frustrated here.

Now I have to decide how to proceed on diagnosing this thing.
 

·
Registered
Joined
·
1,067 Posts
Damn man that does suck. Sorry to hear all the troubles. Hopefully you can find a decent engine again.
 

·
I'm a rider
Joined
·
964 Posts
You don't need a whole new engine over a single problem. As long as the pistons and sleeves look good the bottom end is rock solid iron and steel. Look for a bad bearing or something.
 

·
Registered
Joined
·
499 Posts
Discussion Starter #5
The good news is that I'm pretty comfortable getting the engine out at this point. It's back on the transmission jack again. I'll start watching the rebuild videos and making a list of parts to order over the next few days.
 

·
Registered
Joined
·
499 Posts
Discussion Starter #6
You don't need a whole new engine over a single problem. As long as the pistons and sleeves look good the bottom end is rock solid iron and steel. Look for a bad bearing or something.
The new engine idea was just to save time (and potentially money, depending on what all needed to be replaced) by doing a direct swap. Not unwilling to tear this thing open, just a bit intimidated by multiple cam chains, etc.
 

·
I'm a rider
Joined
·
964 Posts
I wouldn't rebuild anything at this point. Just fix it and ride it. See how solid everything is before throwing a bunch more time and money at it. Based on that tiny amount of well shaved metal you are not going to be in it for anything big.
 

·
Registered
Joined
·
499 Posts
Discussion Starter #8
I understand that, but it's not obvious where the metal is coming from. Won't I need to start by pulling each head off and work my way down until I find whatever disintegrated? Seems like I'm in for dealing with all of the timing chains, head gaskets, etc...
 

·
Registered
Joined
·
7,637 Posts
Can you swipe a magnet through that oil and see if there's steel in it?

If it's all aluminum, might be a chance the balancer dampers let go.

Could you tell if the knock was on one side or the other?
 

·
Registered
Joined
·
499 Posts
Discussion Starter #10
I thought that it was the front cylinder, left side (which would be near the dampers, obviously), but wasn't nearly confident enough to say that for sure...

I'll check the oil with a magnet tonight. Was too tired to think of that last night.
 

·
Registered
Joined
·
7,637 Posts
Might also peek into the oil fill hole with a bright light, see if there's shavings on the rotor gear.
 

·
FREEBIRDS MC CENTRAL NY
Joined
·
16,076 Posts
Front cylinder left side is where the noise from the balancers comes from
 

·
..have a vulcan good day!
Joined
·
4,508 Posts
Can you swipe a magnet through that oil and see if there's steel in it?

If it's all aluminum, might be a chance the balancer dampers let go.

Could you tell if the knock was on one side or the other?
Check out the pics in my Avatar albums to see what damage Dampers can do..........replaced left half of engine block along with a few other parts. :BLAM::BLAM:
 

·
Registered
Joined
·
499 Posts
Discussion Starter #14
Check out the pics in my Avatar albums to see what damage Dampers can do..........replaced left half of engine block along with a few other parts. :BLAM::BLAM:
Those pictures are impressive. Let's hope that I find something a little less disturbing.
 

·
FREEBIRDS MC CENTRAL NY
Joined
·
16,076 Posts
Check out the pics in my Avatar albums to see what damage Dampers can do..........replaced left half of engine block along with a few other parts. :BLAM::BLAM:
I have a motor from a 92 that someone tried fixing the case with jb weld
 

·
Registered
Joined
·
499 Posts
Discussion Starter #16
No debris under the generator cover. Balancer has no appreciable play. Nothing obvious that I can see through the holes into the bottom end of the motor.

Two things I should have mentioned previously but may not be helpful... Did a quick compression test before pulling the motor last night. About 160psi rear, 150 front - seems pretty solid to me. Also, the spark plugs look a bit weird. The two whiter plugs came from the rear, the ones with fuel deposits were up front. All of them have about 30 miles on them, they were installed after doing the stator swap.
 

Attachments

·
I'm a rider
Joined
·
964 Posts
that 1 plug in pic 3 is pretty dark.
 

·
Registered
Joined
·
570 Posts
Inexplicably forgot to look at the mesh screen until now. Anybody recognize the source of those bits?
YES! They came off of my screen i recently cleaned when i changed my oil. How'd they get in your bike?

Seriously though, they look exactly like what i removed from mine. Best guess after 30 years previous owner(s)? ==> __________
 
1 - 20 of 35 Posts
Top