Cam lobe flattening '85 VF500

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.

 

Vf 500's have double springs. Nothing new there.

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.

 

Aren't we on the same page?

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.:thumbsup:

 

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.

 

Where do you get that energy?

Why don't you get some for me next time you are out. One thing is for sure, you get things done fast. :thumbsup: 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.:biggrin: I bet you don't 49 mpg anymore, after you open up those jets and passages.

 

Where do you get that energy?

Why don't you get some for me next time you are out. One thing is for sure, you get things done fast. :thumbsup: 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.:biggrin: I bet you won't be getting 49 mpg after you open those jets and passages?

 

ouch you can see the flat spot in it :frown:

 

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

 

Dodge's Website

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?

 

We have been using Vfrf2's thread

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 :thumbsup:

 

If you did gang the ECS lines of the 4 Carbs?

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.