On Thu, 19 Nov 1998, Jim Jones wrote:
> Adjusted my SU H6 carbs on the TR4A. In adjusting mixture, I could not get
> the front carb to do anything. Lifting the piston had no effect.
> Adjusting the jet seat had no effect. Appeared as though there was gas
> coming out the seat, but it runs very rough when cold and somewhat rough
> even when hot. My guess is that it has to do with the float or the
> butterfly valve. Which one is most likely and what should I look for?
You're probably not getting gas thru the main nozzle.
The easiest thing to check is the butterfly. Remove air filters, lift
piston all the way up with thumb, peer down carb bore, activate throttle
(with engine OFF, don't want to have anything come fireballing out into
your face)
My bet would be on the float though. Are you sure you have H6? On a TR4A
you will probably have HS6 unless someone has retrofit a TR4 set on. I
have (ornery) H6s on my TR4. They are basically the same, apart from the
float bowl fittings and the locations of adjusters.
Take the lid off the float bowl and look inside. Your needle might be
stuck shut or something else might happen.
The float bowl functions much the same way the reservoir on a toilet does.
For (unhealthy) carbeurator practice, take the lid off the john
and observe what happens. Fluid level rises, float rises, shuts off fluid
flow using some sort of valve mechanism. The intended purpose is
different, of course (do not use a carbeurator in the bathroom), but the
principle is the same. The float bowl must supply the accurate fuel level
so that on level ground, you've got gas going into the carb. If you've
just got gas, go back to the bathroom.
Check the float level as per the instructions in your favorite manual (I
don't have any of mine beside me at the moment). It is probably set too
low OR there is something impeding the float, causing it not to fall back
down and let the valve open.
If you haven't done so, install a clear inline fuel filter. Helps to know
if there's any crud in the gas lines. Most fuel related problems are due
to contaminants in the gas.
-Malcolm
* There is a FAQ for this list! Its temporary home is:
http://www3.bc.sympatico.ca/walker/triumph/trfaq.htm
|