My VF500 diagnosed by local VF/VFR guru

My VF500 diagnosed by local VF/VFR guru. Bad Intake Cam

This is from an e-mail from the guy working on my bike right now (Doing carb overhaul and Valve adjustments)

hwell:

 

He says in the E-mail that the low compression on Cyl#2 is from the deteriorating Intake Cam.

How that got that way..... ???

 

Decision time I guess. What are you thinking of doing?

 

Your in good company if you want to repair it......maybe a post for some cams is in order. May be a good time to get a manual and fix it yourself. Could be fun .

 

They'd have to be 86 cams, no? 86 has different cams?

The guy is offering to repair it. he says he has spare Cams and rockers.

I am debating not fixing it and just riding it till it goes.

 

A few questions I'd like some opinions on please.....any insight is welcome and greatly appreciated :smile:

1. Looks like the 86 has different Cams....what would happen if an 84-85 intake cam were to go in there instead?

2. What would have caused the Intake Cam to degrade like this?

3. if another cam is slapped in....would whatever caused the old Cam to go do the same to the replacement?

4. Impressions/thoughts regarding the compression numbers? (Motor running with the #2cylinder running at 110 and the rest at 150-160)
What is factory spec?

 

I wouldn't mess with the 84-85 cams in your '86, and I am king of the mixed years bike! I do not know what would happen, but there is a slight difference between them, as you know.

I don't know why things go haywire in one cylinder. All my problems were in the #1 cylinder. Could it by that oil was not getting up into that head as well as it should? Could it be that there was manufacturing defects in that one cam lobe or its rocker? Who knows.

I would get a new cam and do it myself. If I can do it then you can! Then I would decide once and for all if it is worth the angst to keep it as my only bike, wondering if it is a "ticking time bomb", as you have expressed elsewhere. I would likely then decide to sell it. I would probably buy a newer VFR because this forum has become a pretty cool place to hang out. I say all that because that is where I am at...

Good luck to you and keep us posted.

Edit note: TinkerinWstuff posted a better reply when I was typing....what he said. lol

 

Why did the cam go south ?? The engineers at Honda screwed up and built a flawed engine that had restricted oil flow to the upper end, causing rapid wear. That's just one reason the VFR 500s cause so much grief.

With a short riding season, something reliable needs to be a priority.

You seriously need to start looking for a newer bike,
like a clean VFR 750 '86-'97 .

Money is always an issue, and VF 500s seem cheap, but the VFR is what you really, really want !

 

what the hell is "excelleration"


I sure hope he is a good mechanic .... Acceleration incase you were wondering

 

which still doesn't answer the question squirrel. Why just the one cam?

 

Thank you very much everyone for all the advice and input so far......to touch on a few things:

Yes....I really really really want a VFR. But I cannot afford one. Someone is selling a nice 86VFR in the area but I am $1500 shy of the asking price. If everyone can chip in maybe I can afford it. :tongue:

I am tied between spending the money on this bike so I can get a bunch more years out of it, or just paying the guy for the carbs and the valve adjustment and hope the bike last until I can afford a VFR.

Regarding the 86 having different cams; I told the mechanic that the cams are different. Whether he has an 86 cam or whether he says he does is two different things. He seemed to me to be an honest guy and he really really knows these bikes.

Wont a bad Cam lobe effect the compression by not allowing the Valve to seal properly?

The bike isn't burning any oil....and the VF's aren't really known to burn piston rings (especially considering the rest of the bike seems to be fine)

A burnt valve...perhaps. You mean it's just not seating in the head properly?

If I had a garage, where I can work on a bike till the sun came back up I'd do it....but I don't and that leaves me a couple hours per day to work on the bike, with poor lighting and out in the elements.
I'll be kissing the summer goodbye.

He said the other cams were good.

....and again. Why the Front Intake cam and not the rear? The Rear cam is the one to go cause it's the one most starved for oil?

Could the one Valve on #2 been out of adjustment or adjusted incorrectly and slowly fucked up the cam?

 

Well noted post Tink.

I would tend to agree that the cam lobe issue is not related to the lower compression reading.

Also, I agree - the lifters tend to go first. Honda made a replacement 'cap' kit to help with this. I've re-posted here for reference:







Slow - I'd ask your tech to take a look at this bulletin and see what he finds up top.

It could be that at 32,000 on the clock your engine, not knowing its maintenance history, is due for a full inspection (i.e. valve springs)/re-build.

This may be more of an investment than you want to make...

 

nice diagram, you gota love the book time they give the poor wrench that has to do that job back in the day. Part your miniceptor out and buy a more current bike/thats my two cents. Cheers.

 

Thanks for the info guys.

I got this message back from him:

I really really don't want to spend this kind of money on this bike. As it stands now even if he says the compression is off, with a good running bike with a quiet engine I'll take it and save my pennies for a VFR.