CB performance manifold plug size ?

Hi, sat at home about to order some 90° NPT fittings for the manifold servo hose and the balance pipe but cannot remember is it 1/8 or 3/8 size I need to get ? It is for the type 4 engine with the CB manifolds and ICT carbs. If anyone could give me the answer it would save me having to wait till Monday to check .Thanks

 

I’d go for 1/4” NPT, which gives you about a 1/2” 13mm hose. 3/8” NPT is mighty big.

 

Thanks for the reply back. The manifolds are already pre tapped by CB and come with straight fittings but would prefer to tidy it all up with 90° bend type.They have supplied some balance hose but it does seem a bit narrow with a I.d of 8mm ? 1/4 NPT sounds right just need to find the 90° fittings to accommdate the 13mm I.D servo and breather hose.

 

Worth looking on the web to check the NPT thread ODs. I'd think it would be 1/4" - all the fittings on my CB breather box were tapped 1/4" NPT.

The bore ID of the fittings (and OD of the hoses) seems to vary between manufacturers - some have narrow bores, some wider. Drove me nuts when I was trying to find suitable breather fittings. In the end, I just bought a few different ones to find which worked best.

These folk have a wide selection...

http://www.ebaystores.co.uk/Hose-Fi...10091018&_sid=135462148&_trksid=p4634.c0.m322

 

Thanks for that and will look into it. Did you think the 8mm I.d hose seem a bit narrow or doesn't really make much difference as long as the manifolds are connected to each other?

 

Don't know. Maybe someone with ICTs can comment.

 

Got to the CB Performance site, RTFM ...
A 1/4 " hose on 1/8" fittings...
It only is there for idle balance, when flow rates are low.

Opening it up too much may provide a more accurate simulation of the problems of using a single centre mount carb.