4 stroking

[Wrench]

My Whizzer Motor Bike would get vapor lock. The carb was too close to the cyl. So I used a 3/4" carb intake spacer and a heat resistant plate between the carb and the spacer. Now no vapor lock.

BTW I ride air cooled carb M/Cs I don't have any problems at higher altitudes in the mountains or in the desert when it's over 100*F

Pic of my Whizzer M/B carb spacer and heat resistant plate

 

[berdomb]

Carb spacers often help vehicles ive read.... Get the carb away from the hot engine.
But some problems are related to a fuel pumps back from before they put the fuel pumps in the gas tank.

I imagine on a bike , with a small black tank sitting in the sun..... On a hot sunny day that tank and carb can get way hotter than ambient temperatures baking in the sun. Probably not inconceivable that someone could have some problems at some point in time. I have a small 9.9 Yamaha four-stroke outboard.. the fuel pump is driven mechanically Yamaha revised the fuel pump on it at some point in last 25 yrs so that is now water cooled. So recently instead of just rebuilding the gasket kit etc I installed the new revised fuel pump for $100 I never had a problem but other people apparently did occasionally, I learned about it when I started googling it after seeing that the fuel pump had been revised to be water cooled.