Hell to crank

[panomania]

After not cranking my 48 for a month due to rain, this weekend was sunny and 70 degrees.i thought i would take the pan out for a spin, and it has been hell to start when cold. usually after 15 to 20 kicks it will bust off but now it take 150 to 200.when it does start it hits on 1 cylinder for about 2 seconds and then the other will kick in. when idling the rear cylinder seems weak but gets strong when revved up. after the motor is warm, it starts with 1 kick and runs great. both cylinders kick over with equil compression. when cold one feels weak.
The motor has about 5000 miles on it. 80 inch flywheels, std heads, s&s pistons, andrews a-grind, mallory unilite dist and s&s super-e carb
i have checked the valve adjustment 4 times, set low speed mixture and accelerator pump multiple times and checked timing. all dead on! the plugs burn great. clean air filter. and checked for intake leaks (the wrong way) but the only way i have availible.(carb cleaner around the intake seals) all seems fine. the heads are 5000 miles new and the motor uses solid lifters. what the hell?
after cranking it i dont feel like riding it. i feel like a freaking heart attack! thanks, pano

[flathead45]

two thing to try here , first make sure theres no water in the floatbowl, second swipe a folded dollar bill through the points , the paper is just the right abrasive to clean the points they might have some smag on them

[1 star]

You may as well piss into the breeze.
Make a simple plate & test your intake fittings & nipples, the correct way. It's very easy & it actually "Tests it".
You know better than that...

[59Panman]

I could now get my bike started. I checked for spark and found that my front cylinder plug was not firing. I pulled the coil wires out and found that the wire core was missing the coil electrode by 1/16". Cut the end and reinstalled. Ok now. Just my 2 cents.


Good luck.

[DuoDave]

As you have checked everything else, it probably is an intake leak. It sounds like the problem existed previously, if it took up to twenty kicks to start from cold. I have been through the same scenario. The only answer is to persevere and make absolutely sure that you have no leaks by carrying out a proper pressure test. Cotten makes a big deal out of this because it is a big deal. It will be all worth while when you have your pan firing up after a couple of kicks from cold.
Bear in mind that you could have a leak between the carb and the manifold.

[panomania]

would you think the lower compression on one cylinder only when cold would reflect anything i need to check also? it seems like the valves arnt seating good untill the engine is warm. also the plugs burn really good. no indication of leaning out. thanks again, pano

[flathead45]

how much lower ?

there will always be a difference in an older engine, 10% I think is still ok

[panomania]

5000 miles old. im not sure about the exact compression. i can tell the front cylinder kicks harder than the rear when cold. after its warm, they feel the same. when i adjust the valves i usually pull up and down from the lifter adjuster rathen than the push rod and have a very small up and down. but i wonder if im feeling the lifter roller rather than the actual clearance?the pushrods do turn freely. could i loosen the pushrods entirely and see if if it kicks harder or would that be a problem being that both valves would be closed?

[mbskeam]

hello,
test the manifold with press. you might be suprised at what you find. I was on my old heads. the rear head was cracked at the machined spot on the intake port. at 3 psi it did its leak thing .
so after that I got the std heads.no prob so far.


as for the valve adj.
cold engine
take up looseness , you should be able to turn them with a slight drag to them. you will feel no up and down. this is my way with solids and alum. push rods. been doing this way since ive had bike. it works
I did have rear intake lifter nut back off last summer and the rear cyl. was real hard to kick thru, because the valve did not open all the way to let the cams duration and valve over lap work as it was made to do. it made a bunch more cyl pressure. in turn hard to kick thru.set it back to proper valve lash and all was good. This was a new twist in the school of panhead 101


Pano.... my engine sounds a lot like the way mine is built, but with stock dist and 74"
after siting for the winter it can be fun to kick kick kick kick kick kick and.............................................................................. .............................................................................kick kick kick
it over until it decides to start
mbskeam

[panomania]

thanks for the info. by the way, cool website and awesome purple pan.