Hi Richard
I do house calls for Cost ie what it costs me to get there!
Location Isle of Wight UK!
It is in my experience unlikely to do you any good going to anyone else for
this job unless they are a TWIN carb specialist with intricate knowledge of
Triumphs.
First if you don't know their state set the points and tappets to the
correct gaps, preferably do the points with a dwell meter. set the plug
gaps, then set the timing using a timing light. If this lot is ok:-
Then balance the carbs.
Disconnect the linkage between them then with the filters removed take a
piece of small bore tube, 1/8 inch ID, I use an offcut of hard plastic fuel
line as found on later Triumphs. place one end to the carb throat, and the
other near NOT in your ear and listen to the volume of the hiss, a common
miss-conception is that you need musical tuning standard hearing, not true!
You should adjust the idle screw on the loudest carb for a slower idle if
the idle is high or the screw on the quieter carb for a faster idle if the
idle is low. If the idle is correct but the balance is out a bit on each
carb is needed. Once you are satisfied that they are correct re-connect the
throttle linkage ensuring you do not move the throttle spindles and trap
them in the new position with the clamps as this will put the carbs out of
balance again. if this happens the idle will have changed, just slacken the
clamp and try again, sometimes holding the spindle in the closed position
will prevent this problem but if the spindles are worn it will introduce
other problems.
For the next bit there are a couple of methods not being one for the hard
way, I use a combination of technology. I fit two colourtunes, one to the
centre cylinder for each carb, ie 2 and 5 and a CO meter in the exhaust to
pass emissions. The other method involves the lift pin under the piston if
it is fitted to your version of the carbs, never got this to work so won't
go there! I'm sure there are others on the list who can make it work and
will happily explain it to you!
By my method you adjust each carb until the colourtune is showing you
exactly as the instructions will say, ie mainly (bunsen) blue with the
occasional yellow splash, I try to align the mirrors so I can see down each
one without moving the head and being in a position to adjust each carb
without falling in the engine. I have also found the best time for this is
about an hour before dusk, so it is light enough to see to work but not so
bright you can't see the bunsen blue as this is much dimmer than the yellow!
Be aware that changing one carb will have a small affect on the other as the
carbs are cross linked.
Once the carbs are providing the same fuel to each end of the engine I check
the CO level and adjust each carb by the same amount to suit local and age
related regs locally 2.5 to 4.5% CO which I have found attainable by all my
cars except the 2.5 PI, but including the 125,000 mile 1968 2000 MKI Saloon!
I find the colourtunes to be very accurate with little (maybe half a flat
1/12 of a turn) or no adjustment to be within the specs, 4.5 is the max for
the MOT, 2.5 is the min according to Triumph.
I hope this helps you to avoid paying for this service!
Graham.
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