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1275 timing/ carb pistion sticking

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R

RonR

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While trying to help a friend time the 1275 engine in his recently acquired Bugeye, we could not see or feel any indication on the pulley indicating the TDC notch. We looked and felt around the entire circumference of the pulley.

Does anyone have any suggestions what may have happened and how to correct these things?

Also, one of the HS2 carbs’ piston needle binds up after centering the jet and tightening the nut. Loosening the nut allows the piston to fall with the “clunk” sound. However, even with the nut lose the needle seems to be sticking as upon acceleration of the engine, this piston does not raise nearly as quickly as the other carb piston. I assume that needle is bent and we should replace both the needles and jets in each carb.


Thanks.
Ron
 
If it has a dampner pulley, then you should have a little slot on the bottom @ TDC. Also, you can take out the spark plugs and valve cover to get a reasonable idea as to where you are hoping to find it.

Pat
 
You can try switching the carb pistons around for better matching. Can even try lightly polishing the sticky one. That is assuming the needle is straight.
 
Visit YouTube and search for John Twist's (University Motors) videos on matching SU carb pistons. He'll quickly walk you through how to match the carb pistons.

You may wish to drop the jet completely out so you can remove the guide tube, crush washers, and bearing nut. A washer "may" have developed a distorted top surface that's kicking the jet off to the side when you make that last little bit of tightening of the bearing nut. You can dress the washer flat on some wet/dry paper on a flat surface and try using it again.

Remember that you will be lowering the jet by 2 turns of the adjusting nut to achieve the initial "start" setting before setting the mixture properly. What I'm about to suggest may not sound "correct" to purists, but if the needle binds a tiny bit but moves freely when the adjusting nut is backed out 1 turn, you're probably still "OK" with that degree of centering.

For the timing issue, you may want to visit Jeff's web site: https://www.advanceddistributors.com (look under the Products tab)
He sells a pointer and calibrated pulley tape/decal that will move the timing marks "up top" so you can see them easier.
 
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