[TR] TR4A - Tuning Update 2

G.D. Huggins guy at genfiniti.com
Sun Dec 15 15:03:34 MST 2013


Second update on my efforts to super-tune a TR4A.
Loved the story from Jonmac concerning the efficacy of what I am attempting.

In the last update, I spoke of how the timing varies significantly, always
"jumping" to the advance side.
After checking about everything, I determined that all was mechanically and
electrically well.

Suspecting the dizzy advance mechanism was somehow slipping into advance
sporadically, and being the experimental type, I determined to retard the
I statically timed the engine, then retarded to 4 degrees BTC, and the engine
runs smoother than ever!
I can retard more without giving up power under load, but start to get some
backfire through the carbs.

Running HS6 carbs with "TW" needles and red springs.
Mixure nuts are 7 points down, giving me 21 Hg of vacuum at ~800 rpm.

I was surprised that retarding would help.
Might try coming down a bit more later, adjusting the carbs as needed.


Guy D. Huggins
1965 Triumph TR4A
CTC 63569LO

Online project diary at http://www.genfiniti.com/triumph

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