86 vf500 upgrades.

I have a hunch this change is part of a larger picture which includes changes to the cam profile, carb bore and the bike's redline.

 

Don't forget, the F2 rear wheel/tire is much smaller OD than the stock 500. Just to go back to stock overall gearing you need to run less teeth on the rear.

 

I've found that the 40R has worked out great for me the bike still pulls hard to red line.

 

I don't think so, I think Honda just realized that the V4's perform better if you use their midrange more. I've found that going with taller gearing on the first gens actually makes for a better overall package.

 

This is true that these v-4's have good midrange.. but at 5000rpm the 500 is making a whopping 25hp.

Like I said earlier, the 500 just doesent have the guts for taller gearing.. it NEEDS to shift through the gears. You know there is a reason the 500 has a close ratio 6 speed and the rest of the fleet is using the 5 speed. It needs the extra help. Using a 2 down sprocket is almost the same as eliminating a gear. Remember this was engineered by a professional that knows way more about this stuff than any of us.

As far as the F2 rim goes, it is 1" smaller obviously, and like I said before when I made the switch I could not tell a difference. When I changed the rear sprocket one tooth the difference was night and day

 

Thanks for the post. Would you recommned switching a stock '84/'85 V500F to 15/43 then?

On a Dyno note: for reference, I have superimposed the charts (orig from two different articles in Cycle). Red is the '84 and blue the '86.



Cycle '86 article:

 

I changed my gearing on my old 500 to 16F - 42R (+1..-2)
I wanted to make up for the smaller F2 wheel and I wanted lower cruising revs. The bike still pulled fine.

I understand what many of you are saying regarding a 500 vs other bikes....but that's not what I'm saying.

I'm saying the VF500 isn't underpowered and it isn't a bike that needs to be driven at WOT all the time. It has such good low and mid-range it's really an effortless bike....unless you're fat or the bike is sick.

 

Well I guess we can agree to disagree.

 

Agreed. :smile:

 

Valve springs and cams are great upgrades but I believe boring the engine to 600cc is not feasible, unless you know otherwise.

I've attached a page from an article in Cycle (July, '84). Check out the right hand column about halfway down.

The VF500F is at its displacement limit according to Honda.

 

Pretty much , Have anyone tried? I think not, and Hondas safety policy , I'm pretty sure you can bore it out 2mm without running in to big problems

 

I don't have any information on this and I haven't read of someone successfully boring a VF500F engine to 600cc. It may be possible, though I suspect that it isn't.

This said, I would be more interested to learn how the team at Honda got 87 HP @ 15,000 RPM from a stock displacement VF500F engine!

 

I'm also lacking information on the subject and searchin' back 20 odd years, I need a lot of time!

 

Some wild ass jetting and one hell of an ignition curve probably some radical cams to boot same plan I have lol been thinking about sleeving it to!?

 

Sounds like a fun build!

If I could ask, are Megacycle Cams, KPMI valve springs and Carrillo Rods on this project's clipboard?

 

Megacycle cams with hardened rockers, carrillo rods thermal coat everything custom pistons from je possible sleeve the motor under cut the gear box I talked with falicon about making a crank but they would need 10 orders before they would make. Microsquirt stand alone (15,000 rpm redline) and a shit load of patience.

 

A very impressive list!

If you don't mind me asking, did Carrillo confirm that they will make a set of rods for the '86 VF500F? I know they made rods for the VF500F back in the day (if you can believe they were $108.00 each). I recently wrote to them about making a set for my '84 but I didn't get a response.

Also, what are you planning for the inner and outer valve springs? KPMI or R/D Springs?

 

The valve spring are something I haven't worked out yet thought I had something but not sure if its going to work out.as for the rods I spoke to a rep at carrillo and they can make the rods but its going to cost around 700$ Jeez the money.

 

Good to know that Carrillo will fabricate a set but I agree the price point is up there. I know of one other owner who has a set for his 500. He purchased them back in the 80s. A good investment when you compare to the current cost!

Will you be doing this work yourself or sending your '86 engine with all the trimmings to a pro-builder (aka Dave Dodge)?

 

I'll be doing all the work my self. Lol no one to blame if a piston hits me in the dick lol.