sprint carb balancing

[jiffy]

guys trying to get my sprint carbs balanced,done the usual as reccomended in the haynes,ie warmed it up,cleaned the needles and pots etc,played with the carb jet adjusters,the problem is that the forward carb hisses more than the rear one and cant seem to get them to hiss at the same rate,also checked the usual plugs points dizzy,timing leads etc,also checked for leaky pipes,still a little lumpy but not much mainly at tickover,any ideas??thanks jiffy
i have looked for posts regarding balancing but cant seem to find any
but sure this has comr up before

[DavePoth]

The principle adjustment for the balancing is the idle screws. Down will cause more suck from that carb, up less. Adjust the mixture to standard, and then only adjust the mixture again if you can't get it to idle at a sensible speed with both carbs sucking the same amount of air. Anything between around 600 and 900 rpm is livable with, I try to get mine around 700-750.

[jiffy]

how do you adjust the mixture,dont see the usual mixture screw like you have on other carbs

[DavePoth]

What year is your car? Later cars had "adjustment proof" carbs...

[jiffy]

its an N plate

[USASPRINTMAN]

First: Make sure the choke is pushed fully home
Second: Check that the fast idle screws are off the carbs
Third: Make sure the throttle shaft actuators are set properly and not touching the forked part of the carbs
Fourth: Warm up the engine and remove the air cleaners
Fifth: Check the misture by pushing up on the pins on the sides of the carbs.
Sixth: Set the mixture by turning the jet nuts up or down as needed. Waxstats can also be adjusted.
Seven: put a hose up to your ear and the other end into the front of the carbs. Turn the idle screws until the hissing sound is about the same.
Eight: Readjust the idle until it is around 800 or so RPM.
Nine: Reinstall air filter.

Most important thing here: Make sure the linkage is adjusted properly. You will never get your carbs set properly if ALL the linkage isn't right.


Richard Truett

[Jon Tilson]

at the archive which should contain several totally brilliant posts (no prizes for guessing by who) on how to set up tiwn SU's.

Its a waste of time if ignition isnt spot in and there are no manifold air leaks from perished hoses and carb moutings.

Tune one carb at a time by seperating the throttles...undo the clamp bolt on the cross shaft. Turn the carb off with the idle screw and it will barely hiss at all. Tune the other at 1000 rpm. by adjusting the mixture. Into the carb body is weaker, down is richer. Snore....I've fallen asleep. Read the old posts.

Jonners

[Dollyboy]

my webers are balanced very nicely on the shelf in my garage

[USASPRINTMAN]

dolly:

Are those nicely balanced Webers on the shelf in your garage connected to an intake manifold, and would said set-up be for sale for a totally obscene amount of ca$h?

Richard Truett

[Mad Mart]

But you don't like Webers Richard!

[Dollyboy]

Richard - sorry m8, these nicely polished items are for project orange, as is the manifold...

i could upset you by telling you how I came by them, but that would be very harsh, and I wouldnt want to make you cry!

( )

[USASPRINTMAN]

But every man has his price.
I sure would love to have that Weber set-up for my TR7 Sprint, which, thanks to some great advice from here, will be getting an SRT91 Cam from JigSaw.

Richard

[DavePoth]

Richard,

We've gone over the merits of various carbs, and the consensus is that the Webers are only really necessary for full on race cars. A nice set of HS8s will provide almost as much flow, and better driveability.

[USASPRINTMAN]

Dave:

I can only come up with Rover 2000TC HS8s, which the TriumphTune manual says not to use.

I don't think any other British cars sold in the states used the other type of HS8s.

I do have a pair of Rover HS8s and a manifold open out for them and the club's alloy spacers. Maybe I will patrol eBay UK until the proper set of HS8s comes up for sale.

Thanks,
Richard

[Mad Mart]

Webers are only really necessary for full on race cars

I'll have to disagree DP. I'm not sure that "necesssary" comes into it. I have them on my track car which I drive a hundred odd miles sometimes to get to a circuit. It drives beautifully! even at low revs...and then there's the induction noise.

http://mysite.orange.co.uk/honda-s2000/ ... lory06.WMV

not that old one!