85 VF500 jet kit?

air filters - slight detour

On a side note - does anyone have the 'rest of the story' on K&N air filters?

A Honda Factory Mechanic I know frowns upon them. Beside the need for re-jetting for little gain in HP, his take - 'more air, true, but at a price' - noting that more particles can get through and damage the engine.

I would appreciate any thoughts!

 

i have yet to see any other number to suggest mine is low if you could get me real world number and not what the claimed hp rating we might have somethin then

 

mid 50's

True real wheel horsepower is in the mid-50's when using the larger 32mm bore carburetors. The '86 dropped down a bit but this model year should still be above the 50 HP mark.

Based on posts I have read on the Yahoo VF500F Owners Group.

 

when my bike was dyno it had no slip-ons on it and most likely dirty carbs, who knows why its that low i'll be dynoing it again in the spring so ill found out if it comes close to the 50 mark

 

slip-ons

Good deal - I'm sure you'll get things dialed in and I look forward to reading what you find out.

On a side note - I've read that slip-ons actually rob power or at the most - after re-jetting - they'll even out to stock horsepower.

 

no like my factory mufflers where not on it at the time

 

You Dyno'd it without a complete exhaust??

You can toss those "baseline" numbers out the window :tongue:

 

well to make a long story short i i had a leaking header gasket pull it all down fixed it and i screwed up the gaskets for the slip-ons and the atlanta bike show was like a couple of days away abd bikebandit couldnt get them so i said screw and rode it up to atlanta with out them :thumbsup:

 

In your defense those Muffler gaskets are a PITA

 

It looks like I'm a little late to the party.

Honestly, I would try just simply shimming the needles first. The stock main yet is ok even with a 4-1 header. The mains are not lean with the stock setup, and a 4-1 doesn't require much more fuel on the top end. In some cases I've had to bump the jets up one size, but that's it.

Jets are common and cheap, as are washers from the hardware store. A jet kit can help make optimum power if dialed in properly, but you can get 90%+ without one most of the time.

 

jet sizing

Good advice, thank you for the post.

Regarding the stock main jets, you note that they are fine even for a 4-1 header. Are you refering to the stock #90's?

 

Of course, it all depends on the rest of your setup and the year (carb version). For most of my bikes I've found that the stock main jets are pretty close. With other changes, such as an aftermarket air filter, you might need to go up one size.

Without special equipment , reading the plugs is the only way to know where you are with top end jetting. There usually isn't one 'special formula'. The best you are going to get is a good starting point to begin your tuning from.

 

jetting

Well noted, thank you.

I'm still a little puzzled though why the '84's 32mm carburetor was released with #102F/#105R main jets while the '85's 32mm carburetor is set up with #90's front and rear. The '85 set-up seems like a significant reduction from what the stock engine can handle.

Honda must have dialed in the '84's 32mm carburetor for the larger mains - perhaps as part of the change the '85 carburetor also has different jet needles and emulsion tubes - to go with the smaller #90 main jets?

 

Now, if your carbs are dirty, just cleaning them should make your bike run richer, right? My problem is when my bike gets hot, it wouldn't stay running, I don't thing its the pulse generater (sp) cause as long as I hold the throttle it will run, just wont hold an idle. I'm thinking it may be running lean cause of the F1's and K&N filter. I have yet to pull the plugs though.

 

your pulse generater's most of the time fail on the top end

 

I have a Hindle 4-1 I can get for cheap locally....but I don't wanna get it for the reasons of having to muck with the carbs.

 

So the bike would stall while cruzing down the street?

 

What's "cheap" ?