Compression tester & whats this?

[Symon]

Hello, Just a quick question. What size adapter do i need to do a compression test?
And while taking the bike apart i found a tube leading to the carbs, but someone has blocked the other end with a nut.
Whats it for?

[CaNsA]

Does that goto the carbs or the airbox?
Looks like a breather/drain to me.
Take the bolt out and see what comes out.
I reckon a watery/oily gunge.

[Symon]

Yeah it go's to the carb, I took the bolt and a little drop of fluid come out. It smelt abit like petrol but was oily. And do you no what size adapter i need for the compression tester?
Cheers

[RedexRobB]

Thats looks more like the carb heater circuit to me.

[Danman109]

agreed, looks like carb heating,

This tube just runs warm coolant through the carbs to keep them warm in winter and helps to prevent carb icing.

i've blocked mine off both ends and removed the rubber pipes with brass looking connectors because it makes it easier to fit and remove the carbs + i wont be taking it out in winter so im not gonna get carb icing!