Kawasaki VN750 Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter #1
Hey everyone,

My bike has a bit of a knock/rattle to it. It seems to get worse the higher thr RPM's go. I am using 10w40 oil, I noticed just after I changed from what was first in the bike, to the 10w40 that my clutch makes a groan when I first start up and take off, after that its no more. I am wondering if the knocking is anything I should be worried about or maybe if it is a lubrication problem, any clues to where I should start checking would be great, thanks
 

·
Forum Faciliator
Joined
·
369 Posts
This one is a hard one. I see you have a 2002. So without hearing the noise I can't tell you if it is normal or not. The vulcan vtwin engines are a bit noisy, and you can hear the lifters.. You may also need to adjust the cam tensioners..sometimes they stick.

The clutch growl/coffee grinder noise is normal. You can eliminate that by replacing the clutch places and clutch springs with better ones. That is about $100 in parts and less than two hours of your time to do that.

Best bet is to find a vn750 rider in your area and listen to their bike to see if it sounds any noiser or less than yours.

Good luck
 

·
Registered
Joined
·
15 Posts
Discussion Starter #3
Hey thanks for the reply,

Ive been searching for this noise and I think I know where its comming from but I have no idea what the part is or what it does. Its under the seat in front of the battery. It looks like it connects with hoses on each side of the engine and then one comming straight in from the front. I cant tell for sure if it is that but it really seems to be what is making the noise. I also notice my carb is shaking a bit too but I dont think it is the sorce of the noise. You can hear it predominately on the left side of the bike but when I popped the seat off I was pretty sure it was comming from there. It really starts makin some noise at higher RPM's. I have tried to grab this part and just hold it to see if it was rattling but no change. I think it might be comming from inside. Any clues would be greatly appreciated. By the way I have ordered a clymers manual from e-bay and am waiting patiently for it but I cant seem to keep myself off my bike long enough for it to get here, thanks again

Al
 

·
Forum Faciliator
Joined
·
369 Posts
First thing I would try is to adjust the cam tensioners.(acct)
Information about the ACCT and the procedure is in the manual but can also be found here, at the yahoo vn750 group.

Files > Engine, Air Intake and Exhaust > About Those Cam Chains
 

·
Registered
Joined
·
10 Posts
I know exactly what it is, It is the air valve and it does produce a knocking sort of sound. With the seat off, you can hear it very well. It is located between the rear of the gas tank and front of the seat. I tried seveal things to reduce the, what is not really knocking but rather the valve opening and closing. I performed the marbling fix to the bike and this seems to reduce the knocking alot along with reducing the popping during decleration.
 

·
Premium Member
Joined
·
1,766 Posts
I know exactly what it is, It is the air valve and it does produce a knocking sort of sound. With the seat off, you can hear it very well. It is located between the rear of the gas tank and front of the seat. I tried seveal things to reduce the, what is not really knocking but rather the valve opening and closing. I performed the marbling fix to the bike and this seems to reduce the knocking alot along with reducing the popping during decleration.
If you have it marbled, you can remove the air valve completely. You just have to plug the small vacuum line leading to the right carb and plug the air hose leading into the surge box.

Part of the beauty of "coastering" (marbling, etc.) is to remove all that garbage.

I have mine coastered with blocking plates on the heads where the reed valves were and the ears shaved (chrome air boxed removed) and like how much more open everything is.

Jon
 

·
Premium Member
Joined
·
3,505 Posts
This may be a dumb question, but will your bike pass emissions inspection after marbling or coastering? I think in MD it's gotta get past the air inspectors (which is more easily done with marbling), but given the ridiculously warm temps here this winter ("which are not necessarily related to global warming"....), I'm inclined to just reduce some of the decel popping and leave it at that. Are there any other options to reduce pollution, but improve performance?
 

·
and the Adventure Cycle
Joined
·
6,141 Posts
I'm guessing with a marble or coaster job, emissions may be a bit higher at the tail pipe.

Not sure how MD is, but here in PA, emissions regulations are governed by the individual countys.
The county I live in doesn't have emission inspections, but they do require a visual inspection, and if it (the emissions equipment) was on it when it was manufactured, it's got to be on it at the time of the safety inspection. But whether it works properly or not doesn't really matter. (so what's the point of that law then ??)
That really screwed me when I got a motor in a car changed and had all the pollution stuff left off. A year later is when they changed things to how they are now. :doh:
Ended up selling it to a guy to put in a demo derby.
 

·
Uber Member
Joined
·
1,280 Posts
ya'll are aware this posting is almost 2 yrs old right?
 

·
Premium Member
Joined
·
1,766 Posts

·
Premium Member
Joined
·
4,054 Posts
Well, since Cindy asked a question on this ol thread, I think she deserves an answer, even if it's a bad one.:D Actually, even though I didn't have any real mpg rise when trying acetone, adding a smidgen, like a 1/4 oz to a full tank of gas is supposed to help your fuel burn much more thoroughly and decrease emissions, so if I knew it was time for inspection, and, I knew they were doing emissions testing... I'd add that 1/4 oz of acetone just for kicks... Can't hurt.
 

·
Registered
Joined
·
1 Posts
hello im colonel and ive just bought a 85 vulcan 750 , and i have motor noise loud noise ?????? i dont know what it is
can some one tell me ?
 

·
Premium Member
Joined
·
3,505 Posts
We might need to narrow it down a little bit: first, what kind of noise is it? Loud, cracking? Soft, thudding? Rattle? Second, approximately where in the engine does it seem to be coming from? Engine itself? If so, towards the handlebars or closer to where you sit? If not, does it seem to be coming from the frame (like, from behind you somewhere)? Finally, under what riding conditions does it occur? Cold-start at idle? Above 55 mph? 3rd gear only?

Welcome to the Forum - I'm sure with a little more info, we can help you pin down the problem.
 

·
Old Truck Junkie
Joined
·
4,133 Posts
hello im colonel and ive just bought a 85 vulcan 750 , and i have motor noise loud noise ?????? i dont know what it is
can some one tell me ?
Sorry that we are walking on your thread Alkb.
In most cases this noise is very likely the atomatic cam chain tensioners (ACCT). There is much information here on that particular problem. Other may be able to guide you better than I.
Welcome aboard and I hope you can fix your bike, enjoy the forum.
 
1 - 14 of 14 Posts
Top