LCGB Forums

Looking at doing my first Euro next year...
Just abit perturbed by riding at altitude through the Alps and the effect on jetting.I have a phbh28.
Is there a rule of thumb or anyway I can determine which jets I'll have to change?
Cant wait....

You'll be OK, just take a small selection of larger jets 'just in case' - it's not like they'll take up any room in your luggage.
The engine might be a little down on power as you ride the Alps, it might cough & splutter a bit too but on the day you might find you don't have to touch the jets.
That's what I found with my 22mm carb.
An adult will be along in a minute to give a proper answer.

just ride thru it

I'm with Hullygully, it's a bit irritating but just live with it for the small amount of time that it has an effect. But if you wanted to, maybe just adjust the mixture screw (add more air as you go higher), the risk is that you forget to reset the adjustment and have too much air in the mix when you return to lower levels and then cause damage to your engine.

I never encountered this going to Italy in 2017 but I did to Davos in 2014. I managed to ride through it but only just. If you are jetted on the rich side, it’ll appear worse.

You get less oxygen at high level. You need to balance this with lower fuel, therefore, you should weaken your jetting.

As has been said, I’d try and ride through it but if you do grind to a halt and struggle to start it again, it would be handy to have a smaller main jet and to be prepared to drop the needle. I mention the main jet as, if you are going through some very steep inclines, you main be holding the scooter near wide open throttle in a lower gear.

For Italy, if you go through, say, the San Gottard pass rather than trying to go over the top, you should be ok. I think

Thanks for the replies.
I only posted because I read somwhere,someone holed a piston so got me thinking.