Synchronising Mk1 Concentrics

[Howard]

I've been having problems synchronising my Mk1 concentrics, mainly bacause I threw the air cleaners in the bin and went back to the lovely long bellmouths. I don't know about the rest of you, but my fingers aren't long enough to reach the slide, and sticking a drill under the slide was not very accurate either, to say the least.

I finally had a Ureka moment today. It may sound drastic, but I took off the float bowls and the jet blocks and measured the length of needle hanging through. Set both needles the same, checked at various throttle openings and it's now absolutely spot on!

Ok, now tell me this was in MPH 29.

H

 

[deejay499]

You could also get both slides disappearing at the same time at the top on full throttle. A torch makes this easier. Never done it your way but it sounds good.

 

[vibrac]

Unscrew the belmouth on the lower one poke in a finger and look the top one in the mouth
works every time on the big Egli racer
and the belmouths are just right for bath plugs unlike the comets TT that never seems to hold its 'bungs'

 

[Howard]

I've done this twice now............. Adjusted the timing on Saturday, went out for a quick spin to check, and a throttle cable broke! The new twistgrip I fitted last year has a corner in the throttle cable guide. Is it just me, or is there a load of **** parts on the market. I put a new indicator/headlamp switch on, and that shorted after 1000 miles. I've just taken off new petrol taps because I can't stop them leaking (old ones work fine but not as shiny).

DJ - Slides are full open at the same time - one check you can do by sight.

Vibrac - Bellmouths are Araldited on. I once nearly lost one, so I "tweaked" the allen screws and distorted the carb mouth. Now I use Araldite, and a gentle "tweak" on the screws.

H