Mikarb jetting sorted
Posted: Mon Jul 28, 2014 11:02 am
Hi all, thought I would post which jets I arrived at on my 2003 Sixty5, hoping it may help anyone whith similar set up.
As bought last year it ha the air recirc gubbins removed and a cone filter fitted. However it was still on standard jetting, and the air bleed tube from manifold left on and open to atmos.
I first blocked this tube off, I ordered and fitted the the one piece rubber inlet manifold from the earlier bikes, because the cable adjuster was resting on the underside rear of fuel tank. The shorter manifold cured this.
After experimenting with jetting I arrived at the following;
Pilot, one step up.(can't remember size, 27.5?)
Slide, 2.5
Needle jet, PO, one step richer.
Main jet, 125.
The bike now starts easily and ticks over smoothly, providing excessive choke isn't used, and picks up on throttle cleanly. It pulls through the gears and cruises easily at 55/60.
That main jet may be a fraction rich, but a 17.5 was too lean, as shown by the engine picking up when choke was momentarily closed. I would prefer a little richer than leaner, especially in this warm weather.
Next step is fitting Boyer electronic ign I have sitting in garage. BTW. Boyer don't include any form of fixing for the box, not even a sticky pad to fix it inside toolbox or air filter box. Soon made up though.
As bought last year it ha the air recirc gubbins removed and a cone filter fitted. However it was still on standard jetting, and the air bleed tube from manifold left on and open to atmos.
I first blocked this tube off, I ordered and fitted the the one piece rubber inlet manifold from the earlier bikes, because the cable adjuster was resting on the underside rear of fuel tank. The shorter manifold cured this.
After experimenting with jetting I arrived at the following;
Pilot, one step up.(can't remember size, 27.5?)
Slide, 2.5
Needle jet, PO, one step richer.
Main jet, 125.
The bike now starts easily and ticks over smoothly, providing excessive choke isn't used, and picks up on throttle cleanly. It pulls through the gears and cruises easily at 55/60.
That main jet may be a fraction rich, but a 17.5 was too lean, as shown by the engine picking up when choke was momentarily closed. I would prefer a little richer than leaner, especially in this warm weather.
Next step is fitting Boyer electronic ign I have sitting in garage. BTW. Boyer don't include any form of fixing for the box, not even a sticky pad to fix it inside toolbox or air filter box. Soon made up though.