Oil Mod for 1984 VF750F

It turned out to be a broken water hose clamp

 

Finally installed the oil modon vf750f and i say that sounds and feels better.

 

Yep, they always do!

 

Top end oil modifications, when done correctly, do not cause this - that is a myth.

 

It seems a better pump might be a better option? Does anyone know if one is available?

 

The pump was not part of the problem - so it won't be part of the solution. There is nothing wrong with the oil pump on those bikes. The problem: the design was changed before going into production. Specifically, the pickup for the heads was switched from the main oil gallery (you can still see the casing feature where it was supposed to be) to the area of the gearbox. That is the problem, fix it and you will be fine.

 

As an original owner of an 83 VF750, I was intrigued by Greg Pullen's account in "Honda V4 - The Complete Four-Stroke Story" (an excellent book, with much research):


"With the early V4s, the problem was camshaft wear - in an ironic twist- was blamed on the decision to use the 'less troublesome' threaded tapped adjustment rather than shims. In essence, the problem was that the camshafts could rock in their bearings if the tappet adjustment was incorrect, or if the top and bottom castings that had the camshaft bearings machined into them were not a good match. Honda did not match components to get the best fit from the inevitable variations in mass production, instead trusting to the precision of their new machinery to avoid such variations. In addition, rough castings could lead a mechanic to 'feel' he had the tappet correctly adjusted and secured by a locknut, when in fact further tightening was needed.


As a result, camshafts and cylinder heads continued to wear catastrophically. ——— At first, Honda believed the solution lay in improved oil ways, and they pressed ahead with V4 road bikes in an even higher state of tune, with disastrous results. ——— Because the V4s woes stemmed from unmatched components, some engines were affected far more than others, and some not at all; it depended on how poorly the components matched one another when they came together on the production line."


So there you have the real problem, with no logical fix.

 

Unfortunately this doesn't line up with the facts collected over many years. The cams were never the problem. In fact, many times the cams looked pretty decent while the rockers got destroyed.

Many "fixes" were attempted to address the items below without affecting the ultimate outcome. The only solutions have been either 1) hardwelding the rockers or 2) a modified oiling system. Both are possible and one or the other should be implemented to ALL early VF's.

 

I am sure the are other contributions factors as well and a lot of myths. I put a heli-coil in the cam journal top half for the cover bolt today (my cams look fine) and noticed the cam journals could not have been line bored as a unit, because they sit lower than the edge of the casting, giving some credibility to having to "match" (or not to match) components. I think I remember seeing rubber half moons on some other bikes so that journal could be machined as a unit from one side.

Based on Greg Pullen's sources at Honda, I am sure he did his due diligence on research, it's a good book to have, it covers the entire gamut of the V4's.

 

This is coming from a Honda engineer that has a lot of knowledge about the cams. Check out his home page.

http://www.motorcycleproject.com/text/v4_cams_what.html

 

Now this is a well written article. I would vouch for this explanation before all others.


cheers

 

Excellent article, I don't think it negates the matching problem, it clearly shows the wear caused by mass production standards.
Photos are also very similar to some 8th gen caliper piston problems! Poor materials.

 

I also agree with the premise of this article. I have a '84 VF700F that I put 49K miles on before switching to a VFR800. The few times that I had the valve covers off, I noticed very slight pitting here/there (lobes/followers) that never seemed to get any worse. I ran Mobil 1 MC oil in her. I still have her, and if I ever get motivated enough to put her back together, I intend to ride her again ...

ACE

 

I think the most important thing aboot swiping oil is to verify what the oil pressure is before and after the mod and see if it is a number you and your lower end can live with when done. Not checking the oil pressure with a mechanical gauge and just installing a kit all willy nilly is just suicidal behavior. Oil pressure on a heat soaked engine may not be quite what you think. I have done several Mega Cycle cams and followers but would never consider an oil kit.Once again just my two pennies.

 

Mike Nixon is the bees knees on all this sort of stuff, whatever he says you can guarantee it is correct and not just with these V4's

 

I just thought I would add a little something to this whole thing. Over the years I have done a number of the “Oil Modifications” using the “Tap into the main oil galley” method. I did a number of them back when the bikes were new in the dealership and I have done a couple more recently. I have to say that none of the bikes I have ever seen with that modification have ever had camshaft or follower problems. When the bikes were being raced by Honda, HRC had decided that modifying the oil feed to the cyl heads was important. All the factory bikes had it. The very first ones actually used a double banjo bolt off where the pipe comes from at the tranny. That didn’t last very long and they then went to using the spot on the bottom of the main oil galley thereafter. If you were looking at one of the HRC factory manuals you will see the lines and things all shown in the diagrams with part #’s. I guess if it was good enough for HRC and the factory bikes it was certainly good enough for me.
The motor that is in my HRC project build I am using an oil pump from a VF1000R and the deeper sump to hold more oil. And I have done the oil modification from the main galley. The complete HRC kitted motor I recently acquired (out of a former AMA privateer Superbike) already has the modification done to it. So again for me if it is good enough for the factory race bikes I think it is good enough.
Just my .02

 

What I would like a definitive answer to is this question......

Is the megacycle cam/followers weld a for sure, once and done, permanent fix? I really am enjoying my 1st gen 700 and if this is a permanent fix for $1,200 I'm up for it.

 

crickets......