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Knocking

5K views 25 replies 10 participants last post by  Noobvn750 
#1 ·
Picked up a 1987 vn750 off of a trade, it needed a clutch has everything torn down on it when i picked it up(a gamble i know) got the new clutch put it and went to fire it up and it wouldn't start very easy but i got it going for like 10 second and it was knocking pretty good, seems to be coming from the middle or upper of the front cylinder, what do you guys think?
 
#3 ·
Could be Cam Chain Tensioners. Look around the forum for ACCT, MCCT conversion, and the grambo trick for some info on figuring out how these work, how to diagnose and how to possibly fix.

Could still be rod knock, but if it's high in the engine I would guess not
 
#4 ·
Al those things Knifemaker mentioned can cause a knock. Could also be piston slap. A loose cam chain usually causes a rattle. If it actually is a knock, that is not good. It is usually reciprocating parts that cause a knock.
 
#8 ·
Oh that definitely sounds like a rod knock.

One way to verify ... Remove the plug wires from the cylinder you think is knocking, then start it. If it's a rod, the knock should be reduced or stop completely with the spark removed. You'll have to hold the idle up with one cylinder running, idle speed will be cut in half.
 
#11 · (Edited)
Cam chain. The bike came with ACCT's (Automatic Cam Chain Tensioners) but they don't really work as well as they were supposedly designed to. Many here switch to manual adjustesrs (MCCT)
A slight ticking on a cold engine is fairly common and not something to be overly concerned about. A loud ticking when the bikes warm would be.
 
#10 ·
A ticking sound. A hydraulic lifter loosing a bit of oil overnight and pumping back up or upper cam chains go slightly slack when cold.

Post a video of it when cold. Senior members may be able to tell what it is.
 
#12 ·
That is definitely a rod knock. No real way to fix it without splitting the cases. I would sell it as a parts bike, or look for another engine. Ticking is usually caused by the valve lifters or a minor exhaust leak. The Vulcan has hydraulic valves, which are both good and bad. Good because they never need adjusting. Bad because they can become plugged up (especially when the oil is not changed often enough) and not pump up properly, allowing too much valve lash. You might be able to clean them by putting some kind of solvent like Seafoam in the oil.
 
#13 ·
Might not be rod bearings. Could be balancer bushings. Is it towards the front bottom left?

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#16 ·
It never fails to amaze me just how much work and money people are willing to put into these bikes. I have put nearly 200,000 miles on them, and love the way they ride. I also love the fact that they are carbureted and do not have a computer. But I do not like how mechanically complicated the engine is. There is a LOT to go wrong. They are wonderful when everything is working properly. But when they have serious internal issues that would require serious engine teardown to fix, I just don't see it. Back in 2002, a Kawasaki service manager told me "the 750 was not designed to be worked on" and he was pretty much right. Kawasaki went to extremes to make this engine as complicated as possible. That also means there are a lot more mistakes that could be made on the assembly line. My 2002 was destroyed by a broken cam chain. It was not the first. I've also had 2 other motorcycle engines destroyed by broken cam chains. But they only had one chain. The Vulcan had FOUR. If my current bike develops any serious engine problems, it goes to the scrapyard. These bikes have almost no monetary value, and they are reaching the age where they are starting to have serious problems. If you go to all the work and expense of replacing an engine, it could very well have problems as well. This was never a great bike mechanically. I love the way it looks, and I really love the way it rides and handles stock. But it is not the only good bike out there. There are a lot of older bikes far more worthy of putting work and money into than the Vulcan 750. I don't understand why so many people seem to have such an irrational love affair with this bike, even those who have never ridden one. I have bought two of them brand new, but even I am beginning to see the end in sight for them.
 
#17 ·
Jerry, With all due respect, because it’s obvious that you have a wealth of knowledge and experience with these bikes, but how can you question the “love affair” with this machine if you yourself has owned 3 of them?

Some people just like the challenge or want a project. If this bike was your primary/only means of transportation then maybe it’s worth a second thought before diving in. But if it’s a hobby then what does it matter? If I add what I paid for the bike and the necessary costs I paid to fix it I’m still under $3G. That of course isn’t counting any accessories or things I chose to update, but I’d probably do that to any bike so all in all it’s not that crazy IMO. Especially after walking the showroom and seeing bikes well over $20G. Is the engine on this bike complicated? From what I read yes it is, but there may be some pride in someone saying “if I can fix this bike I can fix any bike”. You just never know what someone is thinking.
 
#18 ·
It's kind of a bummer to see you crap on these bikes so much, Jerry.

The massive wall-of-text posts are starting to get a little tiring, as well. You've got a wealth of knowledge on these bikes, and I respect that, but sometimes it seems like you just start typing without much regard for the actual question at hand and wind up way way off on a tangent
 
#20 · (Edited)
^This.

By the way, I had no problems with my bike other than POOGS, which was a rare event. Hot start issues disappeared after installing an AGM battery. Never relocated my R/R either.
Keep in mind how old this model is now. Find me another 30 year old motorcycle that doesn’t have an issue now and then.

Also this is a forum for those that do like these motorcycles. It is getting tiring reading your long winded opinions, over and over again, about the bike Jerry.
Any one with a good memory can read something and regurgitate it and make it sound like they said it and make people think it happened to them... But to do it properly, you can't have any discretions that people who have done it may see through and realize that it is just regurgitation... And I'm getting tired of calling him out...

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#19 ·
^This.

By the way, I had no problems with my bike other than POOGS, which was a rare event. Hot start issues disappeared after installing an AGM battery. Never relocated my R/R either.
Keep in mind how old this model is now. Find me another 30 year old motorcycle that doesn’t have an issue now and then.

Also this is a forum for those that do like these motorcycles. It is getting tiring reading your long winded opinions, over and over again, about the bike Jerry.
 
#21 ·
I absolutely love these bikes. I wish they still made them (with carburetors of course) I'd buy a new one. But they are not designed to rebuild or even extensively repair. Even a Kawasaki service manager admitted that. I spent 38 years as a fleet services mechanic. I started working on things as soon as I was old enough to hold a wrench. I worked on my first motorcycle (with a mechanics help) at age 8. I TOTALLY believe in repairing and rebuilding older motor vehicles and keeping them on the road forever. But that is almost impossible with older Japanese vehicles, due to their disposable design and a lack of parts. Sadly, the Vulcan 750 is one of the worst in that regard. It's extremely complicated design means it needs a lot of parts, and makes working on it frustrating and labor intensive.

I am not crapping on these bikes. I'm on my third one. I bought my first one 27 years ago. I was young back then. And I appreciate the fact that there are those willing to do what it takes to keep them going. The more old motorcycles still on the road the better as far as I am concerned. But there is no denying their issues. The only problems I ever had was with the cam chain tensioners and one stator replacement. That's it, in nearly 200,000 miles. I did have the POOGS issue, removing the EVAP system permanently solved that problem. But it was not Kawasaki's fault that that piece of crap was even on there.
 
#23 ·
Nobody is trying to ignore their issues, anybody who has wrenched on these bikes knows they can be difficult to work on, but you don't need to remind us EVERY POST YOU MAKE.

If you know how to help somebody with an issue they're having, post that info. Just please for all of our sake please stop posting these long posts about how difficult these bikes can be to work on. WE ALL EFFING KNOW THAT ALREADY. WE STILL WANT TO FIX OUR BIKES AND RIDE THEM BECAUSE THEY'RE VERY FUN-TO-RIDE CRUISERS.
 
#24 ·
My main complaint so far is the unavailability of parts. However for a few hundred bucks and my project time on the weekends i might be able to have a running motorcycle again for the summer. This thing isn't something I'll pass down to my son, but it is a cheap bike that'll be fun to ride and hopefully get me back and fourth from my 7-330 job until maybe i can convince the ol lady to let me spend a little more lol
 
#25 ·
Have you checked on ebay? Almost everything for my bike came through there, the rest I found on this site.

Although, a lot of the stuff I was able to find seems to be really scarce now, such as aftermarket add-ons. I must've got in right at the peak.
 
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