valve question
#13
RE: valve question
The head can be removed with the motor in the frame. Some clues to valve or seat damage are carbon build up, discoloration, melted or cracked metal. You can do a leak down (compression) test before pulling it apart. If there is damage you will have lower compression or a rapid pressure loss compared to the other cylanders.
Here are a couple of examples of head/valve damage.
[IMG]local://upfiles/23095/DC59AF9BBE63444580C9D3CBCD7DA70B.jpg[/IMG]
[IMG]local://upfiles/23095/B7FDE7AABD364822B1D7FEBAC457F7B5.jpg[/IMG]
Here are a couple of examples of head/valve damage.
[IMG]local://upfiles/23095/DC59AF9BBE63444580C9D3CBCD7DA70B.jpg[/IMG]
[IMG]local://upfiles/23095/B7FDE7AABD364822B1D7FEBAC457F7B5.jpg[/IMG]
#14
#15
RE: valve question
Yup. Looks like you are running lean. Exhaust valves look like they have been hot. Clean up your heads and valve seats, as well as the top of your pistons. Rejet the carbs so you are getting adequatefueling at high rpm. New plugs wouldnt hurt either. Hopefully you caught this before there is too much damage.
#16
RE: valve question
Alright cool. I've got a stock exhaust system here, can I just swap to that for awhile and enjoy quiet without worrying much?
I'm glad there doesnt appear to be much damage. Today I'll pull the valves out and clean em up inside just to be safe and make sure everything is good.
I'm glad there doesnt appear to be much damage. Today I'll pull the valves out and clean em up inside just to be safe and make sure everything is good.
#17
RE: valve question
Stock carburation and exhaust wont cause any more harm. Make sure you clean both the valves and seats. With those deposits on the pistons and top of the combustion chamber there must have been chunks coming loose. Were you getting carbon deposits at the tail end of the exhaust or black smoke when you rev it?
In any case good luck getting it cleaned up and reassembled. Keep us posted.
In any case good luck getting it cleaned up and reassembled. Keep us posted.
#18
#19
#20
RE: valve question
I couldnt find anything on that. but I found a dental pick that works to scrape a lot of the carbon out of the exhaust port and from the valves. HOLY CRAP. it makes sense why it wasnt running well now, there was so much baked on carbon on the valves facing the pistons, and a lot in the exhaust ports too, like a small handful that I've gotten out so far. unbelievable. once I get everything back together it should run a LOT better I hope.