Monobloc vs Concentric

[Barnsey]

I imagine this topic has been done to death in the past, but I am new at this. 

  My two C15s each have a different carburettor.  One has an old Monobloc which I rebuilt and the other a brand new Concentric.

  A simple question, but, if I sell one bike and keep the other, which carburettor should I hang on to?

  I was assuming that the later concentric would be better, but lots of guys seem to feel that the earlier Monobloc was better quality. 

  BR, Ian

[limeyrob]

Once you get the carbs set up leave them as they are.
The Concentric was designed to fix some Monobloc shortcomings but it brought others.
I find the Monobloc less prone to idle circuit blockages if its standing for a while because its easier to clean and the idle jet can be removed.

[Barnsey]

I would note too that the insurance company wanted to charge me more for the concentric carb, as it counts as a modification. 

 Crazily they also charged me more because the frame was replaced back when the bike was new, even though it was replaced with the correct frame of the same period.  How is that a modification!!!?

[DAVE BRADY]

Hi,

Who are you insured with?
These are not modification and I would ask them for their definition of 'modification'.

Dave.

[Barnsey]

Carroll Nash.  Maybe I will try another insurer next time.

[rhyatt]

this cant be right to up the price for using normal standard parts !!
I can understand using non standard stuff - but I would certainly be looking elsewhere

I have used LYNBROOK for years now with my Bantams and C15s and they are sensible insurers

[Barnsey]

Thanks!  Maybe I'll give them a go next time. 

  And, I won't worry too much which carb is on which bike.  I'll just get them set up and leave them there.

[iansoady]

Carole Nash started as a good specialist classic insurer but disappeared into a corporate maw many years ago. I would recommend Peter James or Howden both of whom have been good to me. And both happily accept the Suzuki DRZ400 engine fitte to my Starfire. No quibbling about carbs......

https://www.howdeninsurance.co.uk/personal/motor/classic-and-collections/classic-motorbike-insurance/?int=11433&brand=cviandrh

https://www.peterjamesinsurance.co.uk/classics-insurance/classic-bike/