'86 VF500F, Cycle, April '86

A fun read on the 'new' 1986 VF500F.

 

Wow! Lot's of flashbacks seeing that. I had that issue and read it many times wondering if I should trade mine in. The words all looked familiar to me as I read it! Amazing what the mind stores (and doesn't, lol) Thanks for sharing.

 

Glad you enjoyed reading the article.

I thought it was interesting to note the '86's reduced inlet-port diameter and milder cams with less duration, overlap and valve lift along with the changes to the shape of the combustion chamber. This answered a few questions I had about the differences between the '86 and the '84/'85 models.

I'm still a bit puzzled on how the larger 32mm carbs are a good upgrade on the '86 - it seems to me that the engineers at Honda went to great lengths to redesign the engine and that it would be best to keep the 30mm carbs on the '86.

Also it does seem like Honda was really working towards reshaping the powerband to lower the rev's working the range down from 10k-12k to 6k-8k. I wonder if this is in part based on the known issues surrounding the VF500F's valve train - i.e. valve springs and valve stem ends.

 

Thanks for the article.

I was wondering the 2 same things.

 

Part 1 - as article says, the better top end makes it faster on the track

Part 2 - Bike engineers go back and fourth between mid/top during model evolution all the time. In this case I don't believe that it has to do with the top end issues, merely a desire for a better responding motor for 95% of users on the street.

 

Totally agree they were looking to increase the midrange torque,,,still lowering the redline makes me suspect that they had some concerns about premature wear at higher rev's.

The 500 pulls strong right to redline and you can feel the engine has more to give - so I can see where an owner could get themselves into some trouble.

I purchased a used set of heads ('85) and I am going to give some thought to a rebuild. This is an 'on the clipboard' project as I have a few things going right now - gas tank restoration and off the plate carb rebuild.

Still, it is fun to think about what the Honda engineers were working on back in the day!

 

For reference, here are the torque and horsepower Dyno charts for the '84 and the '86.

'84 VF500F



'86 VF500F



Overlay of the two charts:



The '84 chart is an excerpt from an article in Cycle July 1984 and the '86 chart is an excerpt from Cycle April 1986.

 

This definitely brings back the memories. When this bike came out, I was in high school and had a picture of it hanging up in my locker. As a matter of fact, I had the 750 and 1000 hanging up there with it as well. Honda should bring back a bike like this. There has got to be a market for it.

 

There is and they are all buying the Ninja 250, 400 and 650's and SV650's. Honda is missing out here!

 

...now you got me going: Come on Honda! Bring us back a bike like the VFR750's and VF500's. Forget about the VTEC and bring us back a sporty, comfy and sharp bike. The new full-fairing ZX1000 Ninja is going to sell like mad. You're missing out Honda!

Bring over the awesome CB1000R. You have left the naked market high and dry since abandoning the 919 after 2007. The Z1000 is selling well here, so will the CB1000R!!! It's doing well in Europe for three years now. Wake up! (note: I hear that Honda Canada and US are seriously considering this).

Rant over.

 

What the heck is that? I kinda like it, a little. It's different anyway, and very simple. Reminds me a bit of a Thruxton or the new Norton in some respects.

 

Funny you should mention Honda competition to the Ninja 250. I just read about the new 2011 Honda CBR250R today! Now if they come out with a 500cc version...

Soup :: Wow! Honda Announces All-New CBR250R! :: 10-27-2010



Dan in Naperville, IL
1986 VF500F
1999 VFR800

 

CB1100R prototype.

Not a V4 engine but very interesting nonetheless!

 

1100!!? That would be awesome! Sign me up!

I heard they were dumping the dinky 125, but that is the fist pic i have seen. Nice VFR 1200 inspired styling. I believe that Kawasaki isn't doing the 250 any more. It's now a 400! Honda's playing catch up...

Invisible - sorry for the thread derailment!

 

Looks like they listened to me!! They must read VFRWorld! Honda just announced that they are bringing the CB1000R to North America.

2011 CB1000R Overview - Honda Powersports

 

Some serious mojo Michael!

If you could please channel a few thoughts for a North American release of a 400cc or 500cc V4 - vintage endurance racing inspired - Honda, this would be most appreciated.

 

If you take a look at the dyno charts you will see where the 86 has a very small advantage in HP from 5500 to 8500 rpms and a bit more TQ. Looking around the 7500 rpm area is the largest in both over the 84 motor. Now look at those same specs from 9000 to 12000 rpms. Right at 11500 the 84 has quite a bit (for a 500cc) more of both. What you gain from the 86 in the mid range is out weighted in what the 84 makes in the upper rpms. That's only good if you use those upper rpms.

Part of that is carburation. Most stock engines whether car or bike are under carbed from the factory. Bikes are a lot less but still under carbed. Seeing Honda wanted more mid range they chose smaller carbs along with the intake cross section and IV. That being said, by using the larger carbs you might drop a tad (not much if any) in the 6-8k area. Where as you should really pick up above 9k with more air flow. You have to remember most engines,even modified NA ones, will never reach 100% VE (volumetric efficiency) in air flow of what the carbs are rated. By going with the larger carbs you will increase the VE a tad in the higher rpms and not lose much in the mid range because the cross section of the intake and IV remains the same,smaller than the 84. It's a compromise using the best of the two, sorta speak.

I doubt you would feel the mid range loss, but would feel the upper range gain. Now look at your gearing vs rpms. When you redline then shift where does the next gear start in the rpm band? If it's around 8-9k or more you will go faster going thru the gears in a drag race or exiting a corner. You have the opportunity to play around with the different sized carbs and see/feel for yourself as long as both sets are setup correctly for your engine. Where do you want your most power?

Honda chose a compromise for stronger street/traffic response at street speed/rpms by going smaller on the intake parts. Not sure what their goal was but you can change that if you want and still be close to what they have with better top end with the 32mm carbs. Depends on what you want from the bike. Your the designer now.

 

Well noted, thank you for the post Grey.

I have an '84 VF500F with a spare set of '85 heads, that from visual inspection look to be in good condition.

I am giving some thought to upgrading the '85 heads that I have (after careful 'service limit' inspection) with a new set of springs from KPMI. I am also considering installing a top end oiling kit to help with the cam and rocker wear issues - though there is still some question about reducing the oil pressure and whether the top end oiling modification is a safe thing to do.

My goal being, to to get the rev's up - safely - into the 11,500 range, as Honda had originally intended for '84.