Honda 500 single

[jim parrott]

Hi everyone can any tell me who's the go to man for tunning these Honda Xl 500 motors I'm off to the Dyno tomorrow to see what the stock motor is making with standard exhaust and the after market ones

[ken platt]

The XL is a very simple motor to work on , so simple anyone with a set of spanners can tune them .

That`s why there is so many in Air Cooled

Unless you have NEVER worked on a bike , then you might struggle .

When you get the figures say what make of dyno you used .

[jim parrott]

Hi been on the dyno today with the xl the best run of five in stock trim 29.3 bhp swap std exhaust for the twin after market ones servrel or more runs later after changing the jets and trying the different size cones supplied with the exhausts to reduce the outlets ended up at 34.7 bhp

[jim parrott]

Friend of mine as spoken with Steve Dobbie today at Donnington regarding the use of xl 500 standard frame not a problem good to ahead 👍

[ken platt]

Assume the noise level was 105 DB or under .

[jim parrott]

Hello ken unfortunately this is something l haven't tested the silencers are fairly large compared to the old one on the dyno the bike didn't sound much louder

[ken platt]

All you need is a bit of porting , a 10 or12.5 to 1 piston , a Phil Joy cam his 110 gives 54 Bhp , his  44 cam 58/60 Bhp ,

a 40 to 44 mm carb . job done .

The above figures re Bhp are for Dynojet , knock 4 to 5 Bhp off for Dynopro .

Simples .

[Spike Livingstone]

Friend of mine as spoken with Steve Dobbie today at Donnington regarding the use of xl 500 standard frame not a problem good to ahead 👍

Why would you?
Surely the geometry is all wrong for a race bike?

[Andy Guy]

Spike.

Plain and simple. He has one and getting on the circuit takes place over having the best gear and no money to enjoy it.

I say go for it Jim.

Nige I seem to recall you using a flat top piston in one of your engines. What compression were able to get?

[jim parrott]

Hello ken l don't know how accurate our noise testing device is but the bike measured 100 db right side 103 db left @ 5,000 revs and thanks for advice on the engine we are sending the camshaft and cam followers to Web cam in the states to be welded up and then reprofile

[jim parrott]

The bike chassis its self should be fine with new yokes forks swing arm and suspension units the new geometry is based on a 2016 moto 3 KTM

[Andy Guy]

Sounds interesting Jim. Are the ktm frame dimensions commonly available?

[jim parrott]

Hi Andy the guy who's doing the frame fab as a mate and his lad races one in BSB but where not starting with that untill the motor as been sorted l will post all the frame mods as we go

[Steve Adlem]

Hi Andy the guy who's doing the frame fab as a mate and his lad races one in BSB but where not starting with that untill the motor as been sorted l will post all the frame mods as we go

So Steve Dobbie OK'd the use of the standard frame, or did your mate tell him which modifications you are planning?

[Andy Guy]

What Steve Dobbie doesn't know won't hurt him. Its perfectly acceptable to modify a frame anyway.