Twin carburettor balancing

Blue850

I need to get the carbs balanced on the Triumph 2000. Anyone got a carb balancer for sale/rent/loan or know anyone who can do the job, the nearer to Galway the better.

Spit62500

I bought a Gunson's Carbalancer from Tools By Post but found that it was useless. I use a small length of hosepipe to listen to the airflow in each carb mouth and find that it works just fine (with a bit of practice). You can buy a more flashy balancer for about STG £35 which is much better than the Gunsons one but the principle is the same in all cases.

The SU or Stromberg carbs are very straightforward to set up once you've sifted through all the various instructions in various manuals and its well worth learning how to set them up.

The main thing is to accept that if the carbs are worn then no amount of tweaking will fix this. If you want a Gunson's Carbalancer for free them PM me your address - it'll save me throwing it out:)

MercMad

You can make one by using a long straw and an industrial earplug !

I've always used this method with fine results............been years since I had anything interesting to listen to though !!

BeardyGit

MercMad wrote:

............been years since I had anything interesting to listen to though !!

What a nice way to put it! Carbs are something that I've always struggled with, particularly on my old suzy GSXR's. Does anyone know whether or not there's a 'bible' as such for setting up fuel systems on cars/bikes?

Gil

Spit62500

There's a Haynes manual called "Weber Carburetor Manual" which includes details on the Stromberg and SU carbs. Its worth a read but has a lot more details about Webers than the other two. Its got a handy appendix with needle charts, part numbers and manufacturers original specs as well as a chapter on fitting Webers to a VW air cooled engine. ISBN is 1 56392 157X.

Burlen in the UK do a SU workshop manual but I've found it no better than say the Triumph or Volvo Haynes manuals.

Its worth having a look around the internet as there are some good sites about maintaining and setting up SUs. There's probably lots about Webers and the more popular bike ones but I've never needed to look and I suspect that its a much more specialised ball game with other carbs.

Great idea about the straw and earplug - probably looks much more professional than a bit of green hose:D

BeardyGit

Hmmm.. Frost have a carb balancer too - Is it any good?
http://www.frost.co.uk/item_Detail.asp?productID=8697

Thanks for the pointers on the books too and sorry for jumping on your thread Blue850.

Gil

Spit62500

That's the Gunsons one that I have - I found it to give variable readings. There's a little ball that rises up and down the vertical scale but it seems to stick or something but not consistently. There's another, better type available which is shaped like a ball with a rubber cone on one side. The cone fits into the carb mouth and a marked scale inside the ball rotates to give a reading.

I'm not so sure that you need great precision to tune the more commonplace carbs. They put up with a wide variety of conditions such as cold winter nights and hot summer days where the air density can be quite different and then there's the quality of some of the petrol out there.... I suppose what I'm trying to say is that there's no point in fretting about extreme accuracy seeing as they'll never be exactly right for all conditions but they'll be good enough.

You can get them balanced quite accurately using the listening method and the colour of your plugs will tell you whether your mixture settings are right or not (you might need to fit new, clean plugs and run the car for a little while to be sure). Of course if you've moved away from a standard spec and are experimenting with extractor manifolds, gas flowed heads and the like, then you might need specialised equipment to see if its running lean at higher revs and stuff like that, but for the most part its simple enough although the manuals make it sound complicated.

Blue850

Thanks for the response, think i'll try the hosepipe method:D

Dades

Blue850 wrote:

Thanks for the response, think i'll try the hosepipe method:D

Is that where you blow in one end and make engine noises?!

Eric318

Ive got a balancing kit here. Give me your address, Ill put it in the post to you. Just promise to send it back to me (am in Dublin) with a bit of money for postage cost. Are you in a hurry?

Blue850

I'm going to see if I can get a set of good SUs for it, Strombergs leak even with new needles/ valves / gaskets / floats set up etc. or maybe I'll stick a diesel into it.

Spit62500

Do they leak all the time or just if you're having trouble starting it? They're prone to leaking when the engine won't start even with new gaskets, O rings etc (the fuel pump forces the petrol out) but normally once you get the starting problems solved and the carbs set up properly they're fine.

If you do get a set of SUs for it you should get a bit more power but its hard to find a good, unworn secondhand set for reasonable money.

Blue850

The car is very easy to start, but sometimeswhen its ticking over or in traffic, I can get the smell of petrol and usually find the underneath of one carb to be wet. I've fittted new float valves ,gasket sets, o rings etc. It doesn't do it all the time and it can be either carb. I'm on the look out for a MK2 Automatic cos the car I have was originally an auto but is now manual but the box tends to select two gears at once and jams itself in 4th and I have to take of the gearstick to reset them which is a P in the A.

Spit62500

Hard to know what could be causing it - the only things that spring to mind are an incorrect fuel pump or maybe incorrect carb needles that are much too rich at idle. I don't think that it'd idle properly if it was running that rich at idle though. I know that some Triumph engine used a spacer between the block and the fuel pump. It might be worth checking to see if your pump is mounted correctly as it'd probably affect the action of the cam on the pump if its not mounted properly.