Kawasaki VN750 Forum banner
1 - 20 of 33 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter · #1 ·
Was given a 1993 vn750 free. Been cleaning it up.
First found the pickup coil screws were stripped and front coil pickup was loose set both to .20. Sparks back.

went to fire it up and oh boy it’s got a clank/ping/knock noise down low.
I can’t figure out how to add the video on here.
Sounds like it’s coming from stator or crank it’s self. Any thoughts bike sat for several years 68k miles on it.
No clue on back story other than it’s pretty clean bike chromes in great shape. Etc..
 

·
Registered
Joined
·
10,801 Posts

·
Registered
Joined
·
10,801 Posts
To me it sounds like lower end? Like stator what about balance damper? I’ve been researching not 100% but it really seems like lower end
I don't know.... It sounds real tinny like the rocker arms, I hear that same sound when I use the stethoscope on mine, which doesn't have any problems, but I can hear it with the scope.

Rod knock should be lower pitched, and it sounds like you have the spark plugs out, which would just about stop knocking from a rod. You actually remove the plug wire from a running engine and stop or reduce a rod knock. That's one way to pinpoint a rod knock.

I could be wrong and it's something else that's uncommon, but at the moment I don't think it's a rod knock.

It sounds exactly like the rocker arms, yours is just louder. I would guess the lifters are collapsed with no oil in them.

Does the oil light stay on while you're cranking, or does it go off after a bit?

I'll listen again.
 

·
Registered
Joined
·
10,801 Posts
Alright, I played it on my phone and it sounds like it has a lot more rattling than I heard before. I can also tell it's got the plugs in.

Does it fire up in the video?

Had a bit of trouble playing the video, it starts out muted and ends almost as soon as I get the sound on. Then it takes me to the play store to download the tik tok app. Reload and repeat....
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #14 ·
Gotta be rod knock goes almost a
Something is definitely loose and clanking terribly. We just need to figure out what.

Maybe remove one plug from each cylinder and roll it over, see how it sounds.
just pull plugs engine seemed a lot better out front cylinder back in no clank pull and put rear in… and oh boy it was clanking like no other.. rear cylinder has been back firing a lot also while trying to get this to run.

gotta be rod bearing has good compression”haven’t tested but it’s got it”
Ugh.
Wish I could load these videos on here.
 

·
Registered
Joined
·
10,801 Posts
YouTube videos are easy here, just post the link and it's embedded.

Put your finger over the spark plug hole on the rear cylinder and see if it has compression. Better pull both plug wires in case it fires, don't want to get burned.

Thinking it could have dropped a valve.
 

·
Registered
Joined
·
1,719 Posts
That sounds BAD. I'd stop cranking that before you do irreparable damage. You should be able to see a dropped rod if you look in through the plug holes. It does sound higher pitched than a bearing, but if it's got compression ... ?
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #19 ·
That sounds BAD. I'd stop cranking that before you do irreparable damage. You should be able to see a dropped rod if you look in through the plug holes. It does sound higher pitched than a bearing, but if it's got compression ... ?
That’s why I don’t think it’s a rod drop oil looks good and piston can be seen. Compression is strong if I plug the hole it feels same as front. I gotta get my compression tester from work and I’ll test the compression. I really feel like it’s something else clanking etc
 
1 - 20 of 33 Posts
Top