Brian,
Thanks for your input to the List and advice on my problem. Yes, the
carbs have the port for the hose. Removing the oil filler cap causes
the engine to die, so I don't think I'm pumping too much pressure to the
carbs, but I've been wrong lots of times before. ;-) This has been a
huge learning curve for me attacking the motor rebuild; I'm still only
at the tip of the iceberg as far as truly understanding how all the
parts combine to produce a solid motor.
Before I sent the carbs to Apple, I did my own rebuild ( really not much
more than o-rings, diaphragm and gaskets) and inspected both bypass
valves and found the diaphragms intact and fairly pliable. After they
were on the car was when I found the leaking throttle spindles, so I
sent 'em off to have a "professional" do them.
Based on Egil Kvaleberg's webpage for Triumph 2000 tuning, I'm going to
check out the TriumphTune catalog for recommendations for needles and
springs to see if that will give me any clues.
Once again, thanks for the advice and we folks out here in the trenches
appreciate the knowledge that you so readily share with us.
Best Regards,
D.
You wrote:
Dee,
Two possibilities for you:
You didn't say exactly how you were connecting the hoses - some
150CD's have a bung on the right hand side of the carb for an emission
hose. New rings allow a lot of blow-by until the engine is broken in
properly, this creates pressure in the crankcase that is then "pumped"
into the carbs via the emissions hose routing. If you have this type
of 150CD and you are venting this port direct to the crankcase via the
valve cover, combined with a vaccuum-robbing long duration cam, you
probably aren't pulling enough vaccuum to allow the air valve in the
carb to function properly, which may account for your increase in rpm
when you restrict the airflow.
Another possibility could be torn diaphragms in the throttle bypass
valves. These are also on the right side of the carbs and are held in
place with 3 small machine screws. Once off the carb, three more
screws open the two halves of the valve to expose the check valve and
diaphragm assembly. Air constantly leaking around the throttle plates
could also be the cause of your high idle condition.
Good Luck!!!
Brian Schlorff
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