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"B" etter performance

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Bob Claffie

Bob Claffie

Jedi Knight
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"B" etter performance

I moaned a lot last fall about the lack of acceleration with my '72 B. Acquired a set of HS4's this spring and finally put them on a couple weeks ago. WOW, hard to believe it's the same motor. Good acceleration and hill climbing ability (not quite as good as my son's but respectable). Problems? yes! Throttle and choke shafts from the old HIF's were about 1/2" too short causing a weeks delay and today realized the HIF carbs had tapped holes to hold the air cleaners on and the "new" HS4's have clearance holes! Needless to say I don't have the required brackets for the replacement carbs. Tomorrow a trip to the hardware store for longer bolts. Was the change over worth it? You betcha. Bob
 
Re: "B" etter performance

Bob:

Do you attribute the difference to the design of the carbs or were your HIF4s acting up, worn shafts, wrong needles, or...?

Just curious because I have a later engine with HIF4s and just came back from a trip in Georgia in the hills and had absolutely no problems staying at speed except when I got into the steeper hills just in the mountains, but no shock there.

I hadn't heard a report like this before, but if there's that much of a difference it might be something to consider for the future.

-- Scott
 
Re: "B" etter performance

Bob: Interesting story. I have heard that the HIFs are about the most complex carbs SU made because of the emissions stuff they had to engineer into the system.

Point is everything is working well now!
grin.gif
 
Re: "B" etter performance

Scott: Hard to say what was wrong with the HIF's. They had been cleaned and the floats set correctly and the mixture and balance right on, using a unisyn but they had absolutely no low RPM response. Wouldn't idle under 1200 and nothing happened until 1500 or 2000, and then it ran out of steam around 4500. Cruising was effortless and hills weren't really a problem unless relatively steep. I was at the point of pulling the front of the motor apart to make sure the timing was correct from the rebuild or possibly change to an earlier camshaft. About 10 years ago I had another '72 and it ran fantastically well, so whatever was the problem appears to have been unique to this particular pair of carbs. Bob
 
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