Cam lobe flattening '85 VF500

Exactly. The online part of the equation makes it impossible to know if the warehouse has inventory. Honda's parts system is a little screwy, but it's getting better.

I get a permanent discount (I'm setup in their system) at my dealership. When you factor in shipping they always beat online places. And guess what? They are making money by selling me parts. It's really handy for them when I walk in and go behind the counter and enter my own order into the computer too. It's sort of like Norm on Cheers actually.


tinkerinWstuff - The idea of metal pieces floating around is not really something you want to think about, I understand. However, that's what the filter is for! I've had several V4's with top end issues and have never seen collateral damage that I could trace back to pieces of the rockers and cam lobes.

 

Wow that's scary. If you look at the oil system diagram you'll find that the only oil that is filtered is going to the mains and rod bearings. The rest of the oil for the trans,cams and piston rings is unfiltered! Also not knowing if the filter went in to by pass mode (no filtering) at anytime you really don't know what those bearings are like. Those small metal particles does an oil pump wonders let alone the other parts of the engine.

As Dirty Harry asks, do you feel lucky, well do ya? How long do you want to keep this bike running? The only way to tell is to take the motor a part and have a look see and at least clean it out. Having metal particles still in there after all that work and money is really back yard IMHO. Good luck.

 

FYI - there is no oil going directly to the piston rings. They only get indirect splashing which comes via the filtered portion. Since there is only one pump and most of the flow goes through the system you can figure it all gets filtered.

As previously mentioned, I've had a bunch of V4's and several have had top end issues when I got them. After repairing the top end , I later on split the cases on a couple of them for other reasons (gearboxes, mainly). I found no damage what so ever from "metal pieces floating around. I'm not saying that it's impossible, just not likely.

Seriously, you are better off with new oil and filter than opening the Pandora's Box that comes with pulling down an engine that old. You would likely run into parts availability of some sort. You call it a risk, but I feel that it's a very small one.

 

It's more complicated than just building lines. Whatever you make would have to be checked to ensure that the bottom end pressure is not affected and that there is enough oil going to the top end. The latter is not much of an issue with a main oil gallery type mod, but the system design is not a "no brainer".

There is no check valve in the oiling system to the top end. The stock system does not pump up very quickly, that's one of the problems.

 

As mentioned, it's a page from my old site that I've posted back to the server just for reference use. The current content of my site is at Daugherty Motorsports - Motorcycle Suspension Performance and Modification .

 

Not any longer. I'm totally slammed with suspension, wheel swap, and other CNC machined parts work right now. I was selling these kits for zero profit, and since 1) my time has some value and 2) I'm more busy now than I can handle I had to make the tough decision. It really was difficult, I believe in the top end oiling modification and my bikes have it installed. I sold a bunch of those kits and it was the first VF part I ever offered, so it was a little sentimental too.

I've got TONS more stuff than what I list on my site. I think currently I've got over 20 items for each size/model of early VF. Some of these are just too expensive for the majority of people, so I don't bother showing them on my site.

 

Your Compression test. What did it tell you?

What did taking compression on the "front range of Colorado" tell you? You are at 5000 Ft. That's approximately one mile high or nearly 1.6 Km above sea level. That makes your average local barometic pressure @ 0.83 of sea level pressure. If there were a way to calculate cylinder pressure using a straight ratio of atmospheric pressures then you should have gotten approximately .83 times 175 psi when you checked your Vf 500. That would be 145 psi on all cylinders. Even at the lowest allowable quoted pressure (142 psi) you should have read 118 psi. Worried about the condition of the "works". Don't stop at a compression test. Get a leak down test. Problem is you need an outside pressure source. So you need a friend who has a compressor. That's going to be a fair difficulty at 5000 ft. You need a very efficient air compressor to be able to get up to 175 psi or above. You will probably have to be content with 140 or less psi from the compressor. No matter, a leak down test is mostly about audible noise anyway. What you want to do is listen with the cylinder at TDC on the firing stroke (valves closed) for the passage of air. If it's a valve you will hear air rushing at the carb or the exhaust pipe of the errant cylinder. If it's the rings you will hear it at the crankcase filler blowing down past the rings. If its a bad gasket you will get bubbles in the coolant tank or noise or bubbling at the joint of the head gasket. There are parameters for how long it takes (time) for a full load of pressure introduced into a cylinder being tested to leak down a certain percentage. The tool will tell you the parameters to watch for.

I have to concure with Jamie on the "bits of metal" getting into the main and rod bearings through the filter unless the filter has been damaged or left on for too long, cloged tothe point that the oil is no longer being routed through the dirt clogged filter. As for the plumbing problem to get oil to the cam shafts and head in general, I have to say that there are an awful lot of old V4 machines from the early 80's still running around without auxillary oil lines on them. I own 5 of them. And my son has another three 500's. They have various problems but not excessive cam wear out. Maybe they are among the lucky few which had intelligent owners who did not let them run at ldle for extended periods of time before getting on and reving them up so as to get the oil pressure at the transmission up and squirting oil onto the cams. If your 500 is a "front slope bike" then maybe a previous owner, the one who amassed the majority of the miles on the bike, used to let it idle for extended periods after long cold Colorado nights in the garage or maybe outside in it. The oil had turned to molasses over night and it just couldn't make that climb up the oil pipe to the cams because the pipe was full of freezing oil until the head got hot.

I think you need to redo the compression test. This time make sure you have a fully charged battery to spin the cylinders with. Use a fully charged car battery as a jumper or get one of the battery chargers with a 75 amp starting function built into the charger to spin the starter. Buy it where you can return it after you use it for this one test if you can't afford to buy. Make sure you have the throttle open/wide open when you make the test. Try to make the compression test in the warm indoors or outside when it's not very cold, say in the sunlight afternoon, after a brilliant warm and sunny Colorado autumn day. Remove all spark plugs prior to making the test.

If you don't get the compression up to 130-140 psi get a local garage/mechanic to do a leak down test. Try to get them to let you participate. Try to get to hear the air passage noise yourself. Out here in soCal we have a retail business called 'Harbor Freight' that sells cheap Chinese made tools. You can buy a leak down tester tool for around $40. If its on sale it will sell for $30. Try to find a similar store around your part of Colorado. Then all you need is access to a compressor.

Ask the mechanic what he thinks compression taken at 5000 ft above sea level should be. Not just regarding your cycle, but for any car/truck/cycle/lawn mower that is tested at that altitude.

I think you have a viable motor. I think the low compression was a bad test run. I don't know about your cam wear problem and the issue about the soft followers. I think you might get away with just doing the head work. Another thing you could do is check oil pressure at the pressure sender tap and at the banjo fitting that feeds the cam oiler line. If you have a Harbor Freight or a store like it they can also sell you an oil pressure testing outfit for around $30. If you really think you have contamination in the main and rod bearings then you really need to check oil pressure at the oil sender tap. You have to have the motor running and warmed up to do an oil pressure test. The banjo fitting at the transmission requires a special fitting for oil pressure testing. I took the bolt off of mine and drilled and taped it for a npt or its european equivelent pipe thread. I believe the Honda uses the european pipe thread. You can get the right tap at a hardware specialty store or maybe Harbor Freight carries them as well.

Don't give up on the bike yet. You might find out that its viable if you can replace the worn cam and the followers.

 

I've considered that. The problem is that if you give someone info and they screw it up then you get blamed. It's happened to be a couple of times before... lesson learned the hard way.

 

Its gonna snow hard in a month or so!

Hey TinkerinWstuff,

It's going to be a long hard winter slog coming up soon. You need to get that Cycle in a nice warm garage where you can sort things out. You want to see if its worth your time and hard earned cash before you sink arm and leg into the morass of a complete motor rebuild. You have a nice shinny new compression guage. Trust it. Get a buddy to loan you his and check your gage against his guage if you are suspicious. Or get a second compression guage at a store where you can put it back in the box it came in and return it (Walmart) and check out what the second one gets for a result for comparison.

Next, ask a local mechanic what he expects pressure to be on a car or truck when he does a compression test at 5000 ft. If he says 100 psi on all cylinders is common place on a car that runs on regular gas (most cars and trucks) I'd go with what you got. You are averaging 106 psi on all four of the Vf cylinders. You might be able to improve the low cylinder with the cam fix. And while I am thinking about it, if you have one cam lobe worn out then the others may also be faulty. If you have a worn out cam your valve will be open less time and the opening will be restricted so that will result in a lower compression reading. Your cam problem is restricting air flow into the cylinder with the problem cam. If you have one problem cam you probably have 2 or 3 or 4 problem cams. They all get lubricated from the same pipe and well.

My guess is that if you can't get compression to improve to say low 130's without a squirt of oil in all cylinders you have a stuck pig that is never going squeal again. So drive the Vf 500with low compression, you can fill it with regular instead of premium and you'll still look good when you ride. :smile: You can spend a lot of money on parts/gaskets/this and that and what do you have in the end? A Vf 500 with a racy chassis and a plastic body. You might want to go for something bigger and faster if you have to tear it apart/ say a VFR or a Ninja that does not run. Besides, after you get the real low down on compression readings at 5000 ft you can take your compression guage with you and check out the next bike before you buy it ( take a fully charged battery with you). Most guys are willing to let you do a compression test before you buy because they are curious themselves and don't have the money or time to get someone to do it for them.

There was another thread in the WORLD where a guy got two bikes for free and ended up with a good black (repainted) Vf500f. But he got it for free and he traded away the second bike for junk yard parts in San Diego. If you are going to shell out for parts you need to consider that you could be buying parts for a different more desirable bike (newer) for about the same price as the Vf500. So go slow and think about it. I gotta run to the junk yard this am. Big 1/2 price sale on the weekend at pick a part.

DKC

 

tinkerin, why spend tons of money and effort on an old bike that you intend to keep only a short time? That bike is not very desirable for the reason(s) Jamie noted. And I can speak with some experience because I also own a 1st Generation with serious design flaws (same problem with the rockers/cams and crappy cam chain tensioners). Frankly, if I were you I would just ride the bike until it craps out and move on to a 2nd Gen VFR. Well, I would just dump it now BEFORE it craps out, but that's just me.

 

Keep us informed how it works out. There are several websites showing how to install oiling kits. Jamie and others have already mentioned that cam scoring is a consequence of worn out rockers, so you're probably looking at new rockers and perhaps cams. I considered fixing up my 1984 VF750F, and started with a new shock, but I lost interest given the bike's serious design flaws and the money it would have taken to rectify them - or to forestall the inevitable.

 

Just some info I thought you might like to know:
When I check a few years back, it was actually cheaper to have megacycles to reweld my '86 cams than to buy new ones (just under $600 at the time). I was also looking for a race cam profile, but I'm sure he does stock. But I think to have the rockers done is just as much as the cams. So about $1200 for all the cams and rockers. I would get a hold of megacycles and see what they say. I was looking at building a race engine, so if you are only going to send the actual damaged parts it may be much cheaper.

Jamie, am I wrong in remembering that the reworked cams lasted longer than stock?

Just my 2 cents.
Rich