Cam lobe flattening '85 VF500

[jazclrint]

Well the 600RR (and others?) have double valve springs now to handle the high RPMs. Are there aftermarket springs that might work. Or maybe stock Honda spring that will fit?

Rich

[magnavmx5]

Originally Posted by jazclrint

Well the 600RR (and others?) have double valve springs now to handle the high RPMs. Are there aftermarket springs that might work. Or maybe stock Honda spring that will fit?

Rich

thats the million dollar question but after the cost of that given dealer prices most of us would have more in our motors than our entire bike. These 500's are trully awesome but as jamie said everything has its limits even the vf500. While im not as pessemistic about the top end issues we have they are real and can be adressed to fix 90% of all issues, and the other 10% will most definatly have to do with user error and maintenance variance. So just get your bike on the raod and enjoy it.
If it blows up no big loss yeah it was and is a great bike but at the end of the day you can get as good or better bikes with better parts to carry you through your riding carrier.

[DKC'sVFR]

In the instance that I have seen a Vf500 loose a valve I would blame the single groove stem keepers as a weak point in the valve train design. But who knows what the owner/mechanic did to cause the retaineer/keepers to come apart and drop the valve? There are probably heavy springs out there somewhere that could be subsituted for the stock springs, but then you get into the problem of loosing the seat to pounding because of the strength of the spring and increased wear on the cam and followers because of the force placed on the wiped portion of the cam follower and cam by the stiffer spring. But then there's the old adage that goes: "If you want to go fast it's easy, just keep your wallet open with cash on hand." People who have to have speed don't care what it costs, they just spend whatever it takes to get what they are after. If the springs cause the seat to drop so what. they knocked off a few tenths of a second on the last few runs they got out of the head. Buy a replacement and get on with getting there faster. The only thing that will move faster than your project will be the speed at which you spend your money.

[tinkerinWstuff]

Originally Posted by DKC'sVFR

Spec is for a good cam lobe to have overall no less than 1.387 in. intake max measured size, or no less than 1.383 in. exhaust max measures size. You say you have .005 in. wear. Do you mean your max overall measured size is 1.382 in. intake or 1.378 in. exhaust? Or, are you subtracting from the maximum allowed "new" cam overall measured value?

Honda quotes that minimum lobe overall is .002 below minimum allowable Spec height? So are you below the "minimum allowable overall height"?

My book shows the wear limit on the cam lobe as 1.385 and I measured, with crappy tools, at 1.380. Just throwing that out there as a reference because the visual damage looks a lot worse than what I expected dimensionsally. I'll have to see if I can get a couple photos of the cam and rocker for those who have never seen what this looks like.

The lobe that had the damage was the one that would have had the hardest time getting oil while idling. The oil would be pumped up to the head, then enters the H pipe on the top of the head, has to travel down, across the H and then back up against gravity to get to the lobe.

I'm leaning toward skipping the lube kit as DKC's suggested. The motor is all back together and may go back in the bike tonight. I still have to tear my carbs down again to deal with two needle/seats not sealing and surging issues.

Meanwhile, I have my eye on a '82 Honda CB900 touring bike with full front fairing, stereo, and hard bags. It'll be easier to get my wife on the back of that ride.

[DKC'sVFR]

Honda minimum spec for an acceptable cam overall height is 1.387 inch. Honda wear limit is .002 inch. Honda considers the cam lobe to be trash when it wears to less than 1.385 inch. You are .005 inch below the line where the cam lobe became trash and .007 inch below what Honda accepts as "in spec". But Honda starts with a new cam lobe with a height as big as 1.393 inch. So if your Vf started with a full grind it has lost .013 inch of material overall. My Clymer's manual gives the same information as your's does.

As for the pictures, they would be appreciated and admired. Why don't you send along some pictures of the replacements as well.

Per the surging problem: there is another thread that dealt with "surging" on an 86 Vf 500f started by 'Matt1986vf500f' in the weeks before you started your thread (TITLE 'Having some weird bike issues'). It turned into an epic that has not seen the bike resurrected as of this date. His carbs were missing some of the adjustment springs that are used to position and adjust the linkage of V4 carbs. There are three set of 2 throttle plate adjustment springs on any V4 carb set. They have to be there or the throttle plates will rock freely while driving. You might want to read that thread if you find you have lost some of the same adjuster springs. They are hard to realize on some of the online fisch. You need to get a dark clear fisch to see that those little squiggles are small springs that fit between the throttle plate linkages.

Per the CB 900: "Old ladies" like cruisers. Hope you convince her that she does. The fairing might help keep her from getting blown off the bike. Have a great ride.

[JamieDaugherty]

Originally Posted by jazclrint

Well the 600RR (and others?) have double valve springs now to handle the high RPMs. Are there aftermarket springs that might work. Or maybe stock Honda spring that will fit?

Rich

The VF500F's already have dual valve springs on each valve. There isn't anything that I know of that would fit. Valve springs are a very touchy item, they need to be designed around more factors than most people realize.

[tinkerinWstuff]

so anyway, back to my topic of flattening cam lobes....

The beastie runs again, the motor sounds sooooo much better. No more valve train noise. I also found plugged orifices in three of the carbs. The jet that you can't remove which orifices up by the diaphram was plugged. I'm hoping that was the biggest cause of my surging problem. We'll see, it's 37degrees out and I'm bundling up to take a test spin.

[DKC'sVFR]

Why don't you get some for me next time you are out. One thing is for sure, you get things done fast. So you are out freezing your butt off now? Good work and I do mean work. Just standing up in that kind of weather is work, especially at 5000 ft. I hope that bike is as fast as you are. I bet you don't 49 mpg anymore, after you open up those jets and passages.

[DKC'sVFR]

Why don't you get some for me next time you are out. One thing is for sure, you get things done fast. So you are out freezing your but off now? Good work and I do mean work. Just standing up in that kind of weather is work, especially at 5000 ft. I hope that bike is as fast as you are. I bet you won't be getting 49 mpg after you open those jets and passages?

[tinkerinWstuff]

the MPGs might take a hit. It seemed that the floats were just a touch lean. The dimension in Clymer was .240 and it seemed they were set closer to about .280. I set them back to .240 which would richen the fuel mixture. At my altitude, a leaner mixture would be good but considering the surging issue I figured I'd set it to the book.

It ran a lot better. I didn't get to work it too hard because my tail light was out (if it's not one thing it's another...) and I didn't think I should venture far from home after dark.

It still seemed like there might have been a little bit of a surge under mid-to-high rpm and varying loads. It just felt like during certian RPM ranges, she would dig a lot harder than others but not completely fall on it's face like before. I'll get a better feel for it today but I still need to sync the carbs and that could help.

[tinkerinWstuff]

It's been a while but here are the pictures of the bad cam and rocker. Not sure if the camera was able to capture the scoring like I wanted but here they are anyway.

[matt1986vf500f]

ouch you can see the flat spot in it

[DKC'sVFR]

Originally Posted by tinkerinWstuff

It's been a while but here are the pictures of the bad cam and rocker. Not sure if the camera was able to capture the scoring like I wanted but here they are anyway.

Am I correct in assuming that the parallel lines in the approximate middle of the cam lobe are the score's on the lobe? I have seen that and worse on my son's '84. I also have an '85 500 C with about the same amount of scoring. Your picture is a little out of focus so its a bit fuzzy, right? If I can see the two parallel lines does that mean that there is a lot more damage on the lobe? And can you verify that you paid $40 for the cam and follower just to compare prices around So Cal with North Co.

Another question, did the tappet noise go away or significantly reduce when you made the cam/follower switch?

Thanks DKC

[tinkerinWstuff]

The lobe is pretty well focused but I had to use a very shallow depth of field on the camera in order to get in that close. That's why the rest of the picture looks out of focus.

Yes, the lines there at the peak of the lobe are the scoring, there are more than two lines but it doesn't show well on the photo. The rest of the lobe has a perfect finish. I was surprised that the rocker didn't appear to have more wear. The far rocker for intake valves on cylinder 4 was also starting to show wear but it hadn't started to transer to the cam lobe yet.

The salvage yard wanted $100 for the whole cylinder head. He wanted $50 for the intake cam and both rocker arms. I talked him down to $40 on the cam. I doubt he would have gone down to $40 but I also bought two used exhaust pipes while I was there for $35/pair.

Upper end noise is significanty reduced. There was a tremendous amount of valve noise when I first put this project back together. I think a lot of that had to do with the fact that the previous owner attempted to gap the valves and probably didn't do it right. I used the method on Dodge's website of a .003 feeler between the lobe and rocker while running the tappet adjuster screws down the valve. Obviously, I adjusted all the valves while I was in there.

[invisible cities]

Thanks for the update and for posting the photos. You mention, in your post, a valve adjustment method on "Dodge's website". Do you have a link for this?

[tinkerinWstuff]

Originally Posted by invisible cities

Thanks for the update and for posting the photos. You mention, in your post, a valve adjustment method on "Dodge's website". Do you have a link for this?

SabMag

regards

More fun info and reading here:

Classic Honda VF - V4 Sabre Magna Interceptor

[DKC'sVFR]

If you look on the "wierd" thread by Matts1986vf500f you will find a discussion of removing the Evaporation Control System that pertains to your cycle.

[matt1986vf500f]

Originally Posted by DKC'sVFR

If you look on the "wierd" thread by Matts1986vf500f you will find a discussion of removing the Evaporation Control System that pertains to your cycle.

holy rusted metal batman thats the shortest response you've ever wrote

[tinkerinWstuff]

Originally Posted by matt1986vf500f

holy rusted metal batman thats the shortest response you've ever wrote

LOL!!

[DKC'sVFR]

If you did connect the lines of the four ECS ports together the carbs with the lowest pressures in the inlets to the cylinders (downstream of the throttle plates) will suck air fuel mixture from the cylinders with higher inlet pressures. This could be the source of some surging. Just block each of the ECS ports on each carburetor off (by itself). Don't interconnect them. Then you should rebalance the carburetors.

[tinkerinWstuff]

Originally Posted by DKC'sVFR

If you did connect the lines of the four ECS ports together the carbs with the lowest pressures in the inlets to the cylinders (downstream of the throttle plates) will suck air fuel mixture from the cylinders with higher inlet pressures. This could be the source of some surging. Just block each of the ECS ports on each carburetor off (by itself). Don't interconnect them. Then you should rebalance the carburetors.

I interconnected mine, as I said in an earlier post, because it was the easiest way for the time being. Until the next time the carb assembly is removed, this is the easiest way. This was done AFTER there was already surging, not the cause of it. As a matter of fact, I believe the performance of my ride has improved.

I disagree that the performance would be any different with them interconnected because the hocky pucky thingy does the SAME THING. Only the valve opens and allows the vacuum tube coming up from the canister to be open to the ECS ports.

And why would balancing have ANYTHING to do with interconnecting the ECS lines? Balancing is adjusting the butterfly valves in the carbs and the ECS ports are between the butterfly and the slider. No affect on balance - engine vacuum is measured at the ports in the cylinder head between the intake valves and the carb butterflys.