Vizard's suggestion is a good one for an SU in good nick -- wind the mixture nut all the way to the bridge, then out 12-14 flats (2 - 2-1/2 turns). That puts the mixture in the 'right' region.. it won't be spot on, but if the needle and jet are in good condition (which they should be on a rebuilt motor) then it'll be safe.

I've done that with my twin 1-1/4's and my colourtune says it's no more than 3 flats out either way.

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Simon

The adventures of an owner builder in the Tallarook Ranges

what about if it's a weber

It has been jetted as per the specs vizard suggests in his book for basic settings. If I just sit there and quickly get the idle right will this be ok?
Or, am I better off just pulling out my old SU and doing your trick for running in?

Surely someone has put a webber on a newly rebuilt engine

I'm no expert but I watched someone adjust the idle jets on mine and it was basically screw them both down all the way then back up 1 - 1 1/2 turns. That apparently puts them somewhere around the right mark.



I"m happy to be told otherwise .......

Cheers,
BC.

Yes thats a good starting point and then fine tune from there.

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http://www.youtube.com/watch?v=nDMkVq1jRGU

The way i go once the engine is in and ready to be fired, dissy in roughly the right place, carb or carbies roughly adjusted........
remove coil lead and low tension wire from coil, build up oil pressure, then let it rest for a few minutes then repeat this process 3 or 4 times
fit coil lead and low tension wire back on coil
fire up engine and let engine idle for a few minutes and check for leaks (coolant and oil) now engine has some temp as well.
drive car (max rev 3,500 rpm, try not to use 4th gear, and if you have to stop at intersections used 2nd to take off) to nearest steep hill, try and climb hill in 4th gear for extra load but depends on incline you may not get to the top in 4th so change to 3rd gear.
repeat 5 or 6 times or untill you get bored with the hill
now engine has had initial bedding in fine tune carbs and check timing.
do 500 kms from initial start up, not going over 3,500 rpm
after 500kms are up, change oil & oil filter, retension head, do rocker clearances, check point gap, timing carb/carbs check for leaks.
drive car hard without going silly and losing licence using full rev range (best if you do this on kil as previously mentioned
have fun doing it

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http://www.youtube.com/watch?v=nDMkVq1jRGU

A Gunsons Colourtune really is your friend here, as long as the engine starts you can very quickly get a fairly accurate tune (maybe 1 minute).

Personally I don't think I could tune a carby without one

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Noli Illegitimi Carborundum

Are these things easy enough to use?? I've never used one ... never even seen one being used!! Have NO idea WTF a Gunsons Colourtune is???

get the picture

C heers,
Skender.

VERY easy to use... have a look here Skender

http://www.ausmini.com/forums/viewtopic.php?t=18175&highlight=gunsons

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did I tell you that I won a trophy?

I found the cheapest place to buy it was the MG site in the UK especially if you get 2 or 3 other items as well - it reduces the overall postage per item.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

"fire up engine and let engine idle for a few minutes and check for leaks (coolant and oil) now engine has some temp as well. "

never let a new engine idle. You'll quickly kill the cam. The cam must be run in for 20 minutes at around 3500rpm.

Don't let it idle at traffic lights too for the first miles

With the advent of modern machining the old running in is really a thing of the past, back in the dim dark ages when the blocks/heads and cranks were brand new some settling of the material and casting or forgings could/would take place as the engine went through its first heating and cooling cylces when you drove the vehicles, as the components are far from new these days and have alrweady settled it is only the machining that is new and if the engine builder checks all the clearances and tolerances as he puts it together its pretty much right to go from start up. Yes build up oil pressure before you startbut do not let the engine idle for a couple of minutes on first start, give it a couple of quick revs to start bedding in the rings or they will glaze the bores and you have wasted a lot of money for nothing, run in the cam as per the grinders /manufactirers advice but as GR says drive it like you stole it because he well knows that the biggest problem is glazed bores, any crank/bearing problems should not exist if you have checked clearances before yoru final build

Ro;;sroyce used to throw there engine blocks out into a paddock for a couple of years to allow them to age settle but most manufactures jus cats machined and built so they needed a break in period and now 30 plus years on you don't need the break in perriod with a engine rebuild

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Roundies and Clubbies(except vans) are both ugly that is why I have Midas and a van
1293 Mini Midas Bronze,1275 Clubman van