Amal Monobloc Carburettor

I am giving the top end of my Ariel Red Hunter an overhaul.

Also an opportunity to overhaul the carb.

The threads at the top that the top ring threads onto which hold the cap (and slide/choke assembly) in place are badly worn.

Over the years I have had to resort to a few turns of ptfe tape inorder to get the threads to grip each other.

So, any suggestions about how to repair, who might do repairs, has anybody been successful in repairing etc, etc.

Suggestions gratefully received.

A number of years ago, I did bore the body 'round' and sleeved the slide with brass, and that is still good.

Try Martyn Bratby, he maybe able to help.
Failing that its another body.

If you let me know the size, and which hand it is I may have a spare body

Neil

Maybe talk to Burlens?

Martyn Bratby. Name rings a bell. Got a contact detail for him?

Burlens. Doesn't ring a bell. Again, got a contact detail?


Thanks.

OK. So found Burlen Fuel Systems. Looks promising. Will mail them in the morning.

Martin Bratby THE COACHOUSE WORKS LIMEPIT LANE HUNTINGDON CANNOCK STAFFS WS12 4PA 01543 572583 FAX 01543 876202

Pulled from Old Bike Mart

For the cost of repairs you may as well replace the carb entirely, you will notice the difference.
As far as i now monobloc bodies aren't available separately.
Burlen are quoting weeks for delivery at present.
I use surreycycles.com they normally will despatch within hours, cant fault their service.
#

Progress so far.

Contacted Burlen. Only via website contact page. No reply as yet.

Spoke to Surrey Cycles on the phone. Very helpful. Can assemble a new monobloc is 1-2 days, jetted to my requirements. Where are these new bodies being cast, and is the metal better than the 'monkey' metal, zinc alloy, that the originals were made from?

Found Autocycle Engineering advertising in the Old Bike Mart. Phoned them. Again very helpful and offered a quite honest opinion. They have some undersize threaded rings which sometimes are a quick simple answer. They also have a method to 'swell' the body at the top in the thread area, and combined with an undersize threaded ring works. But, when I mentioned that the body had previously been bored 'round' and the slide sleeved in brass he hesitated. However he said that he would look at it for me.

That might be my first route, as the slide is still a good fit in the bore of the body, and the carb does perform well.

NeilDD. I looked in the OBM August issue and could not find Martin Bratby. Which issue and which page please?

I put his details in post #5

dr nosh said:

Progress so far.

Contacted Burlen. Only via website contact page. No reply as yet.

Spoke to Surrey Cycles on the phone. Very helpful. Can assemble a new monobloc is 1-2 days, jetted to my requirements. Where are these new bodies being cast, and is the metal better than the 'monkey' metal, zinc alloy, that the originals were made from?

Found Autocycle Engineering advertising in the Old Bike Mart. Phoned them. Again very helpful and offered a quite honest opinion. They have some undersize threaded rings which sometimes are a quick simple answer. They also have a method to 'swell' the body at the top in the thread area, and combined with an undersize threaded ring works. But, when I mentioned that the body had previously been bored 'round' and the slide sleeved in brass he hesitated. However he said that he would look at it for me.

That might be my first route, as the slide is still a good fit in the bore of the body, and the carb does perform well.

NeilDD. I looked in the OBM August issue and could not find Martin Bratby. Which issue and which page please?

Click to expand...

The new ones are made of high quality materials. You are probably thinking of the ones that were made in i think it was Brazil and the main casting was porous.
Doing all that machining will cost you a fair bit towards the cost of a new carb, an expensive way to find out if it works!
I can highly recommend Surrey cycles, i have a trade account with Burlen but i still use Surrey.

Martin Bratbury used to have a stand at the two Stafford shows. When I say stand it was more like a Caravan with Martin ( black fingers) doing his magic on carbs. My old SS80 C15 , had a slide and body with MB engraved on it. He also rebuilt my Pals 1920 side valve carb , a really talented guy.

Good progress.

Autocycle Engineering www.auto-cycle.co.uk swaged the top of the body, cleaned/re-cut top threads and supplied an undersize threaded ring. Princely sum of £20.

Recommended.

I found that www.feked.com (Who bought all the Sammy Miller stocks) were cheapest for a new Monobloc at £175, jetted. (Surrey Cycles £208, Burlen £207). That was going to be the route if the refurb failed.

<a data-flickr-embed="true" href="https://www.flickr.com/gp/188977856@N04/Sz0v25" title="Carburettor Refurbished 3"><img src="https://live.staticflickr.com/65535/50316915513_42e77f26a2_z.jpg" width="480" height="640" alt="Carburettor Refurbished 3"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

<a data-flickr-embed="true" href="https://www.flickr.com/gp/188977856@N04/kyNd9s" title="Carburettor Refurbished 1"><img src="https://live.staticflickr.com/65535/50317580766_79e29e1965_z.jpg" width="480" height="640" alt="Carburettor Refurbished 1"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>


And by the way, had the barrel off as well during this top end overhaul. Ring gaps are all good, measured at the bottom unswept area. Just going to fit new rings.

Honed

<a data-flickr-embed="true" href="https://www.flickr.com/gp/188977856@N04/jSN0p3" title="Bore Honed 1"><img src="https://live.staticflickr.com/65535/50316910103_53332a3031_z.jpg" width="640" height="480" alt="Bore Honed 1"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>