too hot cont.

[arc40s]

Question is how do I free up sticky EX valves. engine runs and pops in muffler bad.

[slowforty]

50/50 acetone and auto trans fluid. Pour lots down the cylinders down the spark plug holes. Wait a long time, patience is your friend. try and turn it over after a day or so. cover the spark plug holes to prevent a huge mess.[ dont ask me how I know.] repeat an needed.

[arc40s]

Engine has only about 3K miles on new rebuild so should not have any varnish on valves stems. Feel it may have gotten too HOT and galled valve stems in split guides. I did add quart of M. Mystery oil to crank case and bout 6 oz to gas. I have not run very long since so may not have had chance to work. Just concerned it will blow muffler apart before MM gets results.

Guess real solution is to pull heads and valves & guides to see what if any damage was done. pain to pull all off over fat fenders.......

[flathead4rd]

Why not pull the intake first to see what's going on with the valve train. A lot easier than pulling the heads. Might be able to free up a stuck valve from there.

[Willit Stop]

I'm not much of a mechanic but I'd do a compression check first.It would tell you which valve/s are stuck.If the compression is good in all cylinders,it may be a spark problem. Just a guess. Good luck.

[Ken/Alabama]

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Could be ignition problems.

[arc40s]

I did run compression check.
#1was 120#
#2 was 130#
#3 was 125#
#4 did not check due to hard to get gauge straight

#5 was 120 #
#6 was 120 #
#7 was 110#
#8 was 120#

[arc40s]

What would cause poping in muffler or exhaust that relates to plug or ignition?

[Willit Stop]

Guessing again.....crossed plug wires,bad dizzy cap,faulty distributor,bad wires to name a few. If some of the valves were stuck,I don't think the compression would be as high as it is.I don't think your problem is internal.

[alanwoodieman]

what engine? could be a bad rotor button grounding out on the helmet shaft? cross firing due to bad plug wire--found one in the metal loom one time--out of firing order

[Keystone 34 3w]

If you are running 12v coil, some of the "original replacement" plug wires can't tolerate the extra high voltage and will cross fire inside the conduits. You can actually see glowing in the tubes at night when this occurs.

[Chuck Sea/Tac]

Vaccum leak ?

[Tinker]

I'll throw in a couple more things for fun... rich fuel mixture and retarded timing.

Hows the plugs look? Unused fuel gets expelled into the exhaust system and ignites.

Retarded timing can also add to any overheating issues and your popping issues.

Just a couple more internet guesses/thoughts.




.

[APDAVE]

Also coil and condenser con cause this problem! Dave

[richard crow]

do you know what cyl is causing it. run eng short one plug at a time. when you short the causing cyl back fire should stop. now with eng warm do a leak down test.harber freight sells a test kit it,s cheag & comes with inst.if it test good follow the above sugestions

[Tinker]

Originally Posted by APDAVE

Also coil and condenser con cause this problem! Dave

I just looked at your previous thread about a hot/over heating coil.

I might suggest talking to bubba one on one and get your ignition looked over. I installed one of their conversion setups (with points) on a friends 50 with a merc 8ba motor. Made a world of difference. Fix it and forget it.

If the engine is over heating not just the coil then maybe look at timing.