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Discussion Starter · #1 ·
so im coming home last week and the bike starts running like crap. its like its being held back and doesnt sound right.

i had a charging issue in the past and so i checked the batt juice and got @11V.

charging the battery and some tinkering and she seems good. several short rides later and all is good. so i leave to go to a cruise in this afternoon. not 1/4 mile from the house and she starts acting "held back" and the sound is a kind of hollow sound. so i struggle down the road a half mile or so trying to get the rpms up to see if that brought her out of the funk but to no avail. pulled over. checked for spark and it was present, pushed in the tickler and fuel comes out just fine.
i decide to go home so i kick it about 200 times to no avail. not even a hint of turning over. i noticed some "smoke" coming from the hole in the side of the carb on the tickler side. i try to push start it but nothing so i start the mile push home. thers a nice downhill on the way so i coast down it and on a whim kick it into first and pop the clutch and after much sputtering she fires up and runs (poorly) and i limp her the last 1/4 mile home.
a check of the battery reveals...11v. ***? any ideas?

the other issue. i recently replaced the throttle cable and now the slide gets stuck in WOT sometimes. i pulled the slide out and cleaned everything with carb cleaner last night and was having no problems this morning but while i was involved in the above saga, it happened again. i was able to get the slide to go down with some fiddling with the choke.


im letting it cool down now so i can go and on her later.
any beneficial advice will be rewarded with a cold beverage of your choice next time i roll through your town.
 

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Pushrod,

What ignition system are you running? Points, RITA, after-market EI (eg Boyer)?

Battery at 11V indicates you still have a charging problem. Was that measured with engine running, or with everything off? Check all connections between alternator and battery, including rectifier and fuse. I can send you a doc on all the checks you should be doing if you email me. Engine running at 2000rpm should have 13.8V or a little more at battery. Everything off should have around 12.5V on battery.

What make of carb are you running? Sticking carb slide on Amal can be caused by overtightening the mounting nuts, warping the carb body slightly. Also check/lube cables.
 

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Discussion Starter · #3 ·
oz, thanks for the help:

first lets talk about my setup: im running stock points. also running a tympanium unit instead of the reg/rect/zener. im running 6 over high comp pistons that were in the bike when i bought it. im 550ish miles off a top end rebuild that was peformed by a lovely welsh gentleman with lots of experience, and i babied her the first 300 miles.

just got back in from some investigating:

no compression, upon rebuild there was 165psi each side, now i can crank by hand. kicking makes a woosh sound in the head. took off the exhaust valve cover and things look to be moving normally and felt no air. roll started it again so a mate of mine could hear/see and it was too hot to look at the inlets. it sounds very much like air is blowing back into the airbox. the bike has a very hollow sound when running. my friend said blue smoke came out after i roll started it. she will not idle.

im getting 11v all the time it seems. a new stator is on its way as that was my original thought.

i have messed with the carb a little the last few weeks. new throttle cable was put on. also yesterday i pulled the slide out and moved the clip down 1 notch on the needle because i was running a little lean. i cleaned everything with the carb cleaner and reassembled. i think the sticking slide may be the choke is catching because moving the choke lever back and forth seems to free it up. i havent messed with the mounting nuts at all.

my first ride out this morning was to see if moving the clip had helped and to be honest i wrung her out a little more than usual. i had been having issued with the motor not wanting to rev over 4.5k rpm so i hit 6 this morning after a few minutes of easy riding for warm up and once i was satisfied that the revs had freed up i rode fairly tamely back to the house with no issues. she idled in the drive for a few minutes and then into the garage. a few hours later she kicked over with plenty of compression and away i went until the power drop described above.

my fear is that one of the inlet valves is stuck open.
 

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Discussion Starter · #4 ·
more investigation today.
needle was very bent when i removed the slide today. :(
i removed the intake valve cover and everything moves fine. i pulled the plugs and watched all the valves oven and close.
my next thought was rings. i couldnt see anything on top of the pistons through the spark plug hole. i drained the oil and found some very tiny pieces of metal,maybe 10 to 20 tiny flakes. a check with a magnet revealed them to be aluminum.

could this be valves out of alignment? i tried to feel for air coming out somewhere but found nothing.
 

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Do a leak down test. If there are bent valves, you probably will hear air passing without even looking at the guage.
 

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Discussion Starter · #6 ·
thanks for the advice. i dont have a tester, but i will get one.
 

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Discussion Starter · #7 ·
decided i was getting in over my head and called the welsh mechanic who rebuilt the top end for me. took it to him yesterday and he checked the compression and found both cylinders down. he checked the valves and said they had tightened and muttered about the ethanol in gas in this country. this got back a little compression but not what it had been. he asked to keep the bike to pull the head off. the possibilities he mentioned were:
head gasket.
cracked piston.
burned valve/scored seat.
 

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I was just going to suggest that it sounded like a classic case of the valves being out of adjustment when you mentioned the sounds you were hearing from the intakes.

You CANNOT properly straighten a carb needle, you need new ones. I'll bet the carb was over-tightened and needs to be polished out with 0000 steel wool to get the carb slide freed up.

I'll bet all it needs is a proper re-torquing of the top end, then a re-adjustment of the valves.
 

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Discussion Starter · #9 ·
paul i totally understand about the needle, i had planned on ordering a new one but when i called steve he said he has them at his shop. I told him about that and the sticky carb slide as well.
 

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Discussion Starter · #10 ·
been a few weeks since an update, i was in NY/NJ for work and just generally busy. my mechanic pulled the head and found the head gasket had split between the cylinders so thats where my compression went.
new gasket is on, said he had to button up a few last things before it done. he also told me he sonic cleaned the carb and replaced the needle.
should be back on the road this weekend.
 
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