37 replies to this topic

[jpw1275]

  It depends on the extent of the corrosion obviously but if you have to remove so much material in cleaning or there is so much pitting that the seal between piston and suction chamber is leaky they will be no use.  Especially in twins where the piston drop times have to be fairly similar across the pair.  A new piston and suction chamber is very expensive and would make it cost more than getting a better pair to start with.
 
  When you assemble them make sure you are using Mini Cooper spec parts rather than Midget or similar so that everything is at the right angle when installed.  Check they aren't Midget carbs to start with as if they are you will have to swap a few parts that will not be included in a normal overhaul kit.

hi dan... with regards to midget carbs to cooper spec carbs.....other than the float angle what other differences are there? im only asking as im interested

cheers james

[Dan]

  Float angles as you say, but changing the float angle means changing the jet in turn because the jet hose is a different length in order to accommodate the bottom of the bowl being further away from the jet at steeper angles and vice versa.  Some Midget sets have a different colour piston spring I believe, and obviously the needle needs to be the right one for the engine.  The float bowl lids are not appropriate sometimes depending on what car they have come from (there are about 35 different float lids for HS carbs) and some models have very specific and odd throttle and choke levers.  It's all just the details of the build.  Only the core castings are the same between any two specs of carb really.  There are charts available from SU that show the basic components for each spec by part number which are a good starting point but the details of things like throttle lever shapes are not listed.  There are dozens of throttle levers and if you end up with one that won't work with the type of twin linkage used in a Mini then you have to phone SU to get what you want.

[GuamMini]

 

How are these installed? the holes are threaded and the screw is too long coming from the bulk head side? If I screw it from the carb side that is threaded too. These are for 1.25" Twin Su's I got them from Mini Spares.

 

Any help is appreciated

[nicklouse]

seems like you have the wrong ones. 

 

link to what you bought.

[GuamMini]

https://www.minispar...|Back to search

[markking]

Amazing in depth list. Great work.

Unfortunately it looks as though I’m going to have to remove my carbs to fit a different accelerator bracket and thought it would be worth attempting a rebuild at the same time.

Are the fuel lines used the same size as the originals?

Assuming it’s advisable to fit a fuel filter as well, I had a look on the minispares website. Their description of a 5/16 fuel line/filter is:

“A "must" on any performance engine this has 5/16" ends for competition engines where fuel lines have been increased in size. for standard 1/4" See PRO804”

Trying to order everything needed in one, postage over here to New Zealand can take a while and having the wrong parts is an even bigger pain.

So should standard hs2 twin have 1/4 fuel lines or 5/16ths?
Thanks.

Edited by markking, 21 February 2019 - 07:27 PM.

[markking]

Rightyo chaps.... thanks to this post and a few others I gave the rebuild a go.

Everything seems to be in order apart from the main reason I did the rebuild... the main accelerator bracket.

Just hving a dry run to make sure everything is as should be but I’m Not sure if I have the bracket the wrong way up.
With the acceleration cable connected I can’t open the butterfly’s fully... which means no full throttle when I’ve put them all back in the car.

I’ll upload some pics and any help would be greatly appreciated. Hate to put it all back together only then to find out I’ve done something silly.

As always thanks in advance.

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[nicklouse]

why cant you get full throttle? looks like the spindle just needs rotating away from the stop.