85 Vf500 engine noise-Valves adjusted-No throttle response-compression seems good-very little carb s

1984 vf500 with 10,000 miles. Purchased with a noisy motor and ran terrible. Adjusted the valves and found three cylinders had no clearance(maybe a .001). The valves were tight. Visually inspected cams and found no evidence of premature wear. The cams looked great. I turned over the motor by hand and the cam chains seem tight. I did a compression test with the following results:
Cylinder #1 140 dry and 170 wet
Cylinder #2 185
Cylinder #3 170
Cylinder #4 180
I only did a wet test on number #1 because of the low number.

I reassembled the 500 with the air box installed and My dad and I setup the sync gauges. The motor cycle still has the bad noise and the throttle response seems worse. My dad owned a VF500 about 7 years ago and stated this bike runs terrible still. We used a stethoscope to try to locate the noise problem and can't isolate the noise. The vacuum on the sync gauges was very low? We didn't have any vacuum and a noisy motor.

Any help would be greatly needed and appreciated.
Are new cam chains still available and what do you replace only the chains????
Should I pull the cams out and check the top of the valves for mushrooming?
How do I determine if the cam chains are bad?

The bike is a 1984. I have an error on the title.

 

I don't think the previous owner messed with the bike. He indicated the bike went to the local Honda shop for carb cleanings and Sync's But, He did have a Clymer manual. I will take it apart and check the cam timing using the Honda service manual.
Any experience with the cam chains TinkerinWstuff?

 

+ 1 with Tink. You need to back up and verify the timing. I would not sweat the cam chains so much as the tensioners themselves, inspect them for damage at the locking portion of the tensioner. It will be obvious if it is failed. It may not be a bad idea , give the ruckus, to pull the pan and inspect. If you have a serious problem such as a rod or main bearing failure those parts will be found in the pan and no need to continue the self torture.

 

First check timing as already said.
About tensioners now...
Cam chain tensioners were a big issue for my bikes. I am talking about the European version of the VF500F and also for a VF400F of a friend.
All the 3 had stucking tensioners as their design is unfortunately poor.
For the last working VF500 I had, I attempted a tensioner repair. Problem always was the locking plate made a slight groove at the rod it is supposed to slide and automatically adjust slack to minimum. In time the tensioner was stuck in a fixed position and as chain and sliders wear a slapping noise was building up.
The repair attempt was to get tensioner out and flatten the groove using a dremmel. It did work for quite some time, the engine got smooth and silent, as it was supposed to be.
Then some months later it was an steep uphill with mirror like tarmac so I couldn't resist burn some rubber, engine revved up to redline and I got that slapping in my engine again.
I guess if you follow instructions on Glymer page 72, figure 54, while rotating engine you can get tensioners in correct place, if they are out, but I don't think it will last for long.

 

Hi blitzas,

Could you throw an arrow or two on these photos showing the modification?

Thx!

VF500F Cam Chain Tensioner:

 

Actually there was no modification (yet). Just an attempt of temporary repair based on existing pieces.
The area of problem is this:



At your photo it doesn't seem like there is a groove there. In order to find out extend fully the tensioner and just let it retract slowly. If you notice a "click" at the marked area or the smooth retraction changes to harsh then you have the same issue.

I have thought of some remedies like fabricating a new rod of harder material or even replacing it with a bolt-nut combination. I will have a look at it when I will get at the engine part of restoration.

 

Toe Cutter good call on dropping the oil pan to verify the bottom end is still together. Blitzash the page number from the Cylmer book was useful and I think the Cylmer is available to download for free off this site or I downloaded it somewhere??
The steps to proceed are the following:
1.) Drop the oil pan to verify all is clean or I have a complete mess of a motor and My dream of a small V4 are out the window. Honda manual 2-4 and 2-5. Clymer page 82.
2.) Check the cams are correctly installed in the heads using pages 70-71 from the Cylmer and My Honda service manual pages 9-21 and 9-22.
3.) Check the cam chain guide for correct position. Cylmer page 72 and figure 54 Honda manual removal 9-8 9-10 and install
Page 9-18 9-20.
4.) I could pull the cams and check tolerance, Verify the valves are not mushroomed, and Inspect the rockers.

I have a used set of heads with out cams. The head is off a Magna V30 but I have valves and rockers.

I think new cam tensioner's are still available?? Would I replace only the tensioner if it appears bad or the chains also???
Would used be an option off Ebay?

 

My recommendation is to put the Clymer manual aside. Stay with the FSM - this will see you through.

 

Service Honda shows the tensioners (parts 3 & 6) as still available though it is best to check with them as sometimes the parts fiche is not up to date.

This may be getting ahead of yourself though.

With only 10k on the clock these should be in good shape.

http://www.servicehonda.com/

 

I pulled the cams out of the rear head to inspect all components. The cams look good, the rockers look good, the top of all the valves look good. The cam chain tensioner don't seem to function correctly at all. When I first pulled it out it was stuck and I had to play around with it to release. I ordered new tensioners and I hope they will be available. I still plan on pulling the front cams out and replace both tensioners.

 

Glad you were able to locate the gremlin.

Would you mind posting a photo or two of the tensioners? Specifically this area:



Thx!

 

I don't know. Something isn't sounding quite right about this. At 10k I am surprised that there are tensioner problems, if there really are. I would also be surprised if someone had reason to have this thing apart (and then mess up the timing on reassembly). I mean, look at the compression, awesome.

Back to the original post: can you describe the sound better? Can you be more specific about it and where you were best able to guess where it is coming from? Why no vacuum? Are all four cylinders firing?

 

The noise was very hard to locate. The noise seemed everywhere. I tried with a ear scope device. All four cylinders exhaust pipes were hot and I never put a timing light on the bike to verify I had correct timing. I verified all cam and sprocket timing marks to verify all was correct. It seems strange to me that a bad tensioner would mess with the timing and vacuum? My dad seems to think it could have But, I not sure. The bike side covers came apart hard and Everything appeared like it was never apart? My best guess for the noise is middle of both front and rear cylinders in the cam tensioner area?

Invisible, I will take pictures and post soon......

Bad news today. Cam tensioners are no longer available. Not sure what to do??

 

I just found both tensioners in Ohio at a Honda Dealer. Ship out today. Good News.....

 

Bad chain tensioners won't cause it to run bad. It will just be a little noisy. Like everyone else said.. the evidence points at the timing

 

Received the two new tensioner'ss today and The spring is much better. The new spring is stiff and I can hardly move the tensioner. I will install both tensioner's and Put a timing light on the bike to determine if I have correct timing. Maybe both my pulse generators or something very odd in the ignition is bad. I checked my coils and they appear good. I will inspect the wiring maybe a bare, shorted, or disconnected wire somewhere? This could take a little while. Good thing its snowy in Michigan. Thank You Everyone.

 

Good deal on sourcing these NLA parts! If I could ask, what Honda dealer did you work with?