Carbs | Scotts Owners Club

This topic has 6 replies, 4 voices, and was last updated 16 years, 6 months ago by Deleted User.

Viewing 7 posts - 1 through 7 (of 7 total)

Author

Posts
15th December 2009 at 3:50 pm #2470

Deleted User
Participant

Hi!

Just wondering… Since the early thirties almost all Scotts were fitted with AMAL carbs. But it the earlier (two speeder) days, what was in those days regarded as the better carb?

The Binks, Brown & Barlow, Senspray, AMAC, ????

Does anyone have experience with other than the AMAL or AMAC carb on a Scott?

I use a two jet Binks on my two speeder and this works ok but is a pretty agricultural design with no needle and only two jets. And not the most economical too. But it looks great!

One of the reasons I ask is because I am planning a twin carb conversion on my two speeder and am now wondering what carbs to use. An option would be to buy two new AMAL 276 carbs. Easy to set up, a lot of parts available but also about 15 years to new for my ’23 bike. And not only to new by design but also by the fact that those would actually BE new…

I would like the conversion to be:

A: as period looking as possible
B: easily undone

Of course it would be nice if I could find another Binks to make a pair but those carbs are hard to find, especially the larger ones.

Or a matching set of brass AMAC’s, B&B’s etc.

So, any ideas on this?

Cheers,
Erik

31st January 2010 at 6:59 pm #8322

Anonymous
Inactive

Hi Eric,

I realise this is an old post but hope the info might still be relevant. I’ve got two TT reps, one with an Amal and one with a Binks 3 jet carb. I must say that the Amal one does seem to start and run better. The difference is most notable when starting, the Binks carb’ed bike seems to not draw any fuel for ages, then dumps a whole mouthful at once then its too wet to start. You have to get the throttle and air lever in just the right places. With the Amal carb’d bike it does not really matter. The other item is the Binks has no tickover screw on the slide which makes slow handchanges difficult as the engine stalls mid change!

Cheers,
Richard

2nd February 2010 at 8:46 pm #8323

Deleted User
Participant

Hi Erik
When I started out with Scotts, I had a 28 built TT Replica with a 3 jet Binks.
It was pretty worn, so I re engineered the slide to get as near as possible to new standard of operation.
If I wanted to run smoothly at lower throttle openings, it was necessary to keep adjusting the air lever to suit. At wider throttle openings it went quite well. When the three carb manufacturers Brown & Barlow, Binks and Amac combined to form Amalgamated Carburettors, the chose the Amac needle design as the one where the mixture ratio could be best controlled.
For ease of setting up and running, you can not fault their decision.
Just one point, the Scott carb runs at a high inclination and the needle does tend to drag on the brass needle jet and wear it oval. The needle jet is quite cheap and it is a sensible choice to change it every 5000 miles. I have equipment to measure their bores and the wear can be quite alarming, with a detrimental effect on mid range running, hunting, four and eight stroking etc.

3rd February 2010 at 2:37 pm #8324

richard tann
Participant

Eric

Back to basics please! I think you should explain why you are planning a twin carb conversion on a 2speeder, as you might be heading up the wrong (and expensive) path.

Richard Tann

3rd February 2010 at 2:53 pm #8325

Deleted User
Participant

Thanks guys for all the input.

The main reasons for my plans are:

– I think it would look good!
– upgrading my Binks to an AMAL or similar will give better adjustability and would probably be more economical
– two carbs would balance out the uneven filling
– it is fun to make
– and did I mention that it would look good?

Cheers,
Erik

3rd February 2010 at 3:18 pm #8326

richard tann
Participant

Eric

Even I could look good with that amount of money spent on me!

I was expecting to hear that you saw it as a cure for the infernal “spitting back” that plagues some 2speeders, and is blamed on poor manifold design. I have my doubts about that theory, but I’m not an expert.

Richard Tann

3rd February 2010 at 3:25 pm #8327

Deleted User
Participant

Well, I will probably not know anytime soon either…

With three recent large garage bills on my cars due to the bad weather the money pit is pretty empty at the moment…

I think the best way to have a go at my point two would be to fit one AMAL and see how that works. But as I have not been in the workshop since September I seriously doubt if even that is gonna happen…

I will be glad to have some maintenance done for the good season comes (if it ever does…)

Cheers!

Erik
Author

Posts

Viewing 7 posts - 1 through 7 (of 7 total)

The forum ‘General Scott topics’ is closed to new topics and replies.