Re: Parts car and Mikuni Question (archive)

yay! I got myself one hellufa parts car today! The guy selling it rear-ended someone and just wanted to get rid of it. even though it may not look like it, it drives great and is super fast! Yay! (Gloat, Gloat) =)
my only problem is that the car won't idle quite right. It Idles rough and at about 2000 rpm. I'm thinking it's the carbs (Mikuni 44PHH). I was wondering if anybody could steer me in the right way in how to tune these things? any help will be greatly apreciated

time for me to brag so here is what is on the car:
Engine: 284 or 286 Cam Blueprinted 9.5:1 compression piston - w/ devise rings hardened and polished Crank lightened and hardened rocker arms 44 mm mikunis high pro electronic ignition mechanical advancement distributor New everything when Ireland engineering built the engine
Suspension:
Suspension techniques sway bars all urethane bushings replaced everything Eibachs sport shocks (Japanese company, but NOT koni)
Brakes:
steel braided brake lines tii wheel cylinders in rear big vented brake kit from Ireland Engineering in the front new tii master cylinder all the other parts i forgot to mention have replaced two day old shoes in the rear
Drivetrain:
5-speed trans. new clutch when the engine was done and slave cylinder and clutch master cylinder shortend drive shaft limited slip diff. 3.91
Others: Electronic fuel pump Battery is mounted in the trunk VDO gauges (water, oil temp and battery) new front tires with 200 hundred miles one them bottle cap rims 74 gas tank ( it is a little more gas pump friendly)
There is more but I can't think of it right now
Thanks again for any info with the carbs,
Seth Ragona
'71 shell
'72 Parts car (runner for now)

I have 44's on a tuned 1602. My experience is that I never think about them and the time (15yrs) gets away from me and a little TLC is required.

First check that your jets are srewed down firmly, just remove the little covers on the top of the carbs and use a very large screw driver to seat them. A second problem could be that your linkage has worn. Not a problem, just need to make sure that both throttle shafts leave the stops on the slightest throttle input at exactly and I mean exactly the same time. Pull the linkage with the cable so the shaft will settle into it's normal wobble in the plastic bushing just like from the gas pedal actuation.

Mikuni's (as all other carbs) have tiny holes just above the throttle plate closed position for idle and just a hair bellow the closed position for transition driving. If the plates don't open exactly together you expose one set of these tiny transition holes in one of your carbs first. This cause uneven running at cracked throttle. At open throttle a 64th inch more open won't mean squat but at transition it means a lot.

Since you just got the car, get 2 cans of carb cleaner for each carb and pull them one at a time and pop off the float float bowl cover and the accel pump cover and clean the hell out of it. The inlet to the float bowel has a sleave filter clean it carefully. With a little caution you won't need new gaskets. Note the little holes in the bore right at the butterfly valve closed position. Spray these real well.

Clean the accel pump, there are two parts bolted to the carb body the actuator cover and the body of the pump, pull both off and make sure the ever so small little brass subsized BB is still pressed into acces hole in the check valve tube. Can fall out and you will over look it in the gunk from your cleaning effort. If it has fallen out press it back in firmly.

Don't adjust anything just close it back up and replace the inline fuel filter.

Drive on and in 10 years you will have to do it all over again. Have fun.

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