Travelling Su Carb guru!!

[Bassman]

Hey folks, do you know anyone around the Doncaster area, that is any good with SU carbs? Me Harley flathead 45 chop is off the road right now as it quit. I bought an amal carb and if its better that can go on it instead... if anyone knows someone good that can come here and fix it, that would be great... obviously i would pay them for it...
Don't want much do I?
:D

[dracken1]

i'm in doncaster in 2 weeks time. delivering a trike frame and shell.
we'll be stopping for a couple of days with misses daughter in kings road wheatley.
how far is that from you?

the su carb is it one of those damn hif ones?

[Bassman]

Hi mate,
The carb is an old mini one that has the seperate upright float chamber on the left of it... The bike has always popped and banged a bit, reckon it has always run a bit rich...
I have also bought an Amal carb for it to try, but that needs a manifold adaptor making up.
I need this sorting fairly quickly as i have to get some pics of it asap, and some of them need to be riding pics..
Wheatley is just up the road from here, I live in Scawthorpe, maybe two miles away...
Reckon you could spare the time mate? :D

[dracken1]

no prob just hope that the wind is not coming from that demoulders :D

[Bassman]

hehe.. I will make sure the wind is blowing scented beer type smells!!
Let me know when you will be around?
Cheers mate, look forward to meeting you.
Keith :D

[Mad Dog]

SU's aren't as difficult to set up as some people make out.

First thing is to ensure that the needle and jet aren't worn - easily replaced.
Then check that there is 3-in-1 oil in the dashpot.
You can undo the jet and lift and drop the needle to centre the jet, then you can raise or lower the jet to alter the mixture - a process easily done with a Colourtune plug in one of the heads.

I've always wondered if the old Reece-Fish carbs would work well on a HD, we used to use them when racing Mini-Coopers, they had a horizontal sliding needle/jet and performed better than the SU.

Get hold of 2 books - "Mini Tuning" and "More Mini Tuning" by a bloke called David Vizzard. The gas flow and carburation techniques are very relevant to the Harley Engine.

You can also put a "Turbulator" in the inlet between the carb and the manifold - it spins the fuel/air mixture making better atomisation and thus a better burn rather than chucking large droplets of fuel through the cylinder head which end up unburnt in the exhaust.

[dracken1]

i remember fish carbs :)
simple and reasonably efficient.
can't remember the last time i saw one though.
but as md stated the biggest prob with su's is needle and seat wear.
plus what needle is fitted, someone may have changed it to a richer one before you had it.

we used to use atf as a damper fluid

[Bassman]

Hi folks..
The bike ran fairly well, but started to pop and bang, especially when cold...
When the bike broke down , i pushed it back home... bloody heavy things Harleys!!, checked the fuel was getting to the carb ok, and put a bit more oil in the dashpot, and the bike started first kick,, ran for a minute and then quit again... so i reckon it must be the carb..
I was recommended to get an amal carb as they are supposed to be better than the old su's on an old bike... The one i have is a monobloc 376 from an old brit twin. 1inch model... so it should be ok i suppose...
Being kick only, it can be a pain if the bike is hard to start and run...but thats half the fun i guess eh!! :rolleyes:

[Mad Dog]

Could be 2 things.

Firstly the jet/needle worn, or needs re-centering. The mixture does go off to rich as they wear and age, quite common.

Secondly, check the float and the gasket around the float bowl, if this leaks it can flood the carb.

Also check the manifold connection coz when thay leak air in, the vtwin engines get a mind of their own.

Better to be rich rather than lean though.

[dracken1]

heres a few links that might help you
http://teglerizer.com/sucarbs/
http://burlen.co.uk/
http://www.riveraengineering.com/

burlen are now the main uk su dealers

[Bassman]

Some good info on those sites M8...
They make it sound so simple don't they!! If it was that easy I would be riding the bike right now, instead of looking at it...!! :D