VF500F - Top End Modifcations - Tech Questions

Discussion in '1st & 2nd Generation 1983-1989' started by invisible cities, Dec 27, 2010.

  1. invisible cities

    invisible cities New Member

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    “We can rebuild him. We have the technology. We can make him better than he was. Better...stronger...faster.”

    I've been giving some thought to a top end rebuild on my spare set of VF500F heads (from an '85).

    My goal is to build a top end that can handle revs in the 11k range. In part this is based on a Dyno chart originally published in Cycle back in the day:

    [​IMG]

    From what I have been able to garner from other posts - the issue with breaking the safety seal and reving past 9K is the potential for valve float leading to the retainers failing due to a 'slide hammer' effect.

    With this in mind I am planning on sending a spare set of heads to a spring manufacturer (most likely KPMI) to see if they can supply a performance set.

    [​IMG]

    My question is twofold:

    The first part is, if I install performance springs am I opening up an issue of having more wear on other components in the valve train?

    Second, should I look into installing a top end oiling modification to add a bit more insurance for the valve train or is this going to create an issue of lack of oil for the main bearings?

    I'm not sure if anyone here has done a spring modification on a VF500F or on another VF model but I would welcome any thoughts or suggestions.

    Thx!
     
    Last edited: Dec 27, 2010
  2. squirrelman

    squirrelman Member

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    Your suspicion is probably right that stronger springs will increase wear on cam lobes and the alloy camshaft holder bearings.

    Also, increasing rpms can bring out other issues like con rod bolt strength or rods themselves.
     
  3. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    I'll be watching. Sounds quite interesting. I say give it a shot and see what happens. If the lobes fail, another donor motor is just a day away on craigslist. My .02 is to leave the oil kit alone. She'll be pumping plenty of lube at 10k+ RPM. Run clean synthetic with frequent changes to deal with the low RPM low oil volume.
     
  4. JamieDaugherty

    JamieDaugherty New Member

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    Something to think about is that it's a misconception that performance valve springs have to provide more force. While this is true sometimes it's not an across the board rule. You have to calculate what the springs need to provide for the given rpm and mass of the moving parts. It's not rocket science but still pretty tough to do. It's been my goal to design a set of springs for the past two years but I just haven't had the time. I too have a spare head that I sent off to a guy who used to build Kasey Cahne's engines (before they started buying Yates engines and shut down thier engine operations). He's not gotten back to me yet, and it's been almost a year. That's something I've gotten used to over the years. If there is anything I can do to help let me know. Maybe we can make it an "open source" type of collaborative effort.

    Top end oiling modicuation = a must have.
     
  5. invisible cities

    invisible cities New Member

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    In conjunction with the top end oil modification should I also look into switching out to an '86 oil pump (w/ an '86 oil pan and '86 exhaust headers/collector) to get a bit more oil capacity?

    I am concerned that a top end oil mod may starve the main bearings.

    On this note, is there a step by step tech guide out there as the oil mod kits are NLA from DMr?

    Thx!

    Parts needed to install the 1986's higher capacity oil pump:


    #2, used '86 oil pan (OEM part no. 11210-MF2-710)
    #3, gasket (OEM part no. 11315-KE7-000- same part number for all years)
    #9, used '86 pickup tube + 2x #26 bolts to mount this
    #22, oil seal, pipe (OEM part no. 91315-MF2-711)
    #4, used '86 oil pump and check valve assembly
    #19, O-ring,14.7X3.7 (OEM part no. 91308-MA6-005)
    #13, oil pipe - this part can be reused (shares the same part number for all years)


    Also needed are the mounting bolts for the oil pan - M6x1.0x28mm (OEM part no. 96001-06028-07)

    [​IMG]

    '86 exhaust pipes and collector

    [​IMG]

    Schematic from the '84 FSM


    [​IMG]
     
    Last edited: Jan 5, 2011
  6. JamieDaugherty

    JamieDaugherty New Member

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    I don't think the pump is any different, just the bypass valve. It's a separate part. The bypass just allows more max pressure. Dont forget that at lower revs the pressure would likey be below the blow-off limit anyway. The oiling system changes were done to help bottom end lubrication, something I've never known to be a problem with the earlier years.
     
  7. invisible cities

    invisible cities New Member

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    Thanks for the post.

    I haven't heard of these issues on the VF500F.

    Not to say that a few bottom end issues were not there but I had read that the crank/bearing issues were resolved very early in the production run and that a Factory recall covered this.

    From the Dyno chart above and given the 12,500 red line (on the '84/'85) I am hoping that 11k will be okay on these components.

    As noted, holding to 9k is good insurance for keeping the stock valve springs from staging a coup but by improving the valve train you can harness an extra 10hp btwn 9k and 11k on these models.
     
  8. invisible cities

    invisible cities New Member

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    Thanks Tink.

    I'm still puzzled by the caveats regarding a top end oil mod. Some owners say that it is must have (as noted here) others say it is not required or worse not to install one as it can harm the bottom end.

    I will keep you posted on what I find out.

    If it doesn't cause an issue with oil starvation I think it is worth doing but I need to find out a bit more about what all is required.
     
  9. invisible cities

    invisible cities New Member

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    Thanks for the post.

    Would this switch out be beneficial if installing a top end oiling mod?

    In example, if there is a larger quantity of oil in the system (deeper oil pan) is there less chance for oil starvation when installing the top end oiling kit?

    '84/'85 vs '86 (photo: sirepair, Yahoo VF500 Group)

    [​IMG]
     
  10. invisible cities

    invisible cities New Member

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    Side note to the above:

    The '86 oil pump looks to have larger impellers (photo: sirepair)

    [​IMG]

    [​IMG]
     
  11. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    I forgot about your previous thread where you were investigating the '86 pan and pump. Nice :thumbsup: The increased pan volume coupled with the deeper pan and cooling fins..... benefits kind of speak for themselves.

    My statement regarding avoiding the oil mod comes from threads here where, even the sellers of such mods admit it is a tight rope walk between lower end and top end. You can read on this forum where the sellers of these mods say this is such a technical balancing act, that attempting to discover the secret formula of hose and orifice on your own will most certainly end in catastrophic destruction.

    Couple that with the fact that there are many 500s, taken care of with kid gloves, that last a very long time - without any mods. There is also much reading here that states the killer of the top end, regarding the oil part of the equation, is in low RPM where oil flow is at its lowest. Many say don't let the thing idle more than necessary and bump up the idle setting slightly. Further, the biggest symptom 500 owners are worried about is cam wear - which is the result of a combination of factors - oil supply being only one.
     
  12. invisible cities

    invisible cities New Member

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    Well noted. Thanks for the post.

    I wrote to Dave Dodge awhile back and he pretty much said the same thing - it is very much a balancing act and one that I am hesitant to take on without a proven track record.

    In the e-mail from Dave he also mentioned that the '86 has a better oiling system which got me thinking about switching this out (per my previous thread).

    From the photos above you can see the '86 impellers are more stout. This in conjunction with the deeper pan and larger cooling fins does seem like a good upgrade for the '84/'85 contingent.

    I wonder if this would also help if/when adding a top end oiling kit?

    Dave mentioned that the stock '84/'85 system couldn't handle a top end oil mod,,,but can the '86,,,?
     
  13. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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  14. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    Here's the other thing I think you have to consider with regard to the top end oil mod:

    Why do you suppose it is that no one sells this thing any more? Really, how hard is it to put together a little braided tube, some banjo bolts, and an orifice or two? If it's too much of a pain in the ass to put together and sell for a couple bucks, why do you suppose there's no thread out there with a bill of materials and some instructions?

    I mean really, if we're all just here to help people (I feel like that phrase should be linked to another post somewhere... :confused:) then you think someone by now would have put "help" over "making a buck" and made some really cool "how to" thread on the subject?

    Unless maybe the thing is a disaster and was responsible for destroying more motors than helping them?

    I'd stick with your idea on the '86 pump and pan.
     
  15. invisible cities

    invisible cities New Member

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    Thanks for the post. I'm working on the '86 pump now - found one on eBay and am waiting for the mail to arrive.

    I do think a top end oil modification can work - but I don't think it is a simple tap the galley and run some lines kind of modification. The proper amount of restriction (i.d. of the external lines) would be key here, IMO.

    I had read awhile back that HRC ran a top end oiling mod on the VF500F but I haven't been able to find any documentation on this. I wonder if this is indeed true and what other modifications they did - i.e. the larger pump and pan,,?
     
  16. creaky

    creaky New Member

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    I've been following these threads that refer to top end oiling issues. Has anyone actually run a VF500F engine with the valve covers off to observe the oil flow at idle?
     
  17. invisible cities

    invisible cities New Member

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    I have not,,,but more intel can be found here:

    Yahoo! Groups
     
  18. stewartj239

    stewartj239 Member

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    IC - for what it's worth, I installed a top-end oiling kit on my 500 back in 2004 when I was restoring it. From all the research that I did, I couldn't find any conclusive evidence that this bike needed one though. The conclusion that I came to was that the basic engine design of the 500 is similar to that of the 1st Gen 700/750 that was definitely plagued with this problem. Therefore, it is logical that the 500 could also be affected. However, it seems that the 500 was less prone to the problem than the bigger bikes. As a matter of fact, I don't think I remember seeing any evidence where somebody had actually encountered this problem on a 500. In the end, I put one on my bike as a "feel good" measure. I thought that I'd rather be safe than sorry. In contrast, my brother also has a 1986 VF500 that he still uses which has 30K+ miles on it. It has no top end oiling kit and it also has no issues. If you know of any resources that contradict the research that I did, then I'd love to know about as I still question whether it was worth the $250 investment.
     
  19. JamieDaugherty

    JamieDaugherty New Member

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    I, personally, have seen damage done to a 500 engine from improper lubrication. Others have as well, and I think there were some photos posted up on this (or another) forum recently showing the typical damage.

    Just as my Yahoo Group post suggests, I don't get too shocked anymore when people try to justify that their bike is somehow not affected. The bottom line is that if your bike is a VF or VFR made prior to 1989 then it's affected. I used to just say "VF prior to 1987" but a member here found some rocker damage on his 1986 VFR750 this year so I've had to adjust that statement!
     
  20. stewartj239

    stewartj239 Member

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    Thanks for the clarification. That's what I was looking for. It looks like putting the kit on my 500 was the right way to go after all.
     
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