why are only two cyliners firing? (not a coil problem)
 

okay... i am stumped

I rebuilt my engine completely. down to replacing the crankshaft bearings. no screw was untouched. also i completely rebuilt my carbs. and returned them to the settings they were at when i got the bike (non-running condition)

here is a video of it "running" for the first time on saturday.

http://i23.photobucket.com/albums/b3...h_MVI_2845.jpg

So i put some gas in the bike and fired the bike up. well.. it turns out the left two cylinders are not firing... at all. the header pipes dont even get warm.

so... i tried to diagnose the problem

1. Not a bad coil. the two running cylinders are not on the same coil.
2. Not the wires. Used a spark tester and am getting a strong consistent spark on the bad cylinders
3. Dont think it is fouled/flooded. pulled both the plugs, and they did not look fouled, but didnt check to see if they were sparking. they are brand new NGK iridium plugs
4. didnt check to see if they were sparking cause they smelled like gas, and didnt want a small fire. so.. it seems the cylinders are getting fuel. also it smells strongly of gas and it backfires (usually just when starting) when the bike runs.. so i am guessing that comes from the unburned fuel.
5. also i am getting some smoke...?

it is the two right side cylinders on a CBR 600 F2 that arnt firing

please help!

i didnt do a engine rebuild but had a similar problem with my old bike, since you did a full rebuild im sure there is some cleaner/oil/grease/whatever in places its not supposed to be which would be a good reason why it is smoking till it gets burnt off, on the no fire question i would double check to make sure the carbs are sync'd and the choke isnt stuck open, but firstly i would do a simple check, turn the gas off or disconnect the line and try to start the motor only let it turn over about 5-7 times so not to foul the plugs, do this a few times to get the excess gas out of the cyclinder, it will prob pop and back fire or even run a little till the gas left in the cyclinders is gone, if it starts let it run out of gas and then crank it a couple more times to make sure its all cleared out, then rehook up the gas line or turn it back on and try to fire it up.

Check spark on the bad cylinders, the iridium plugs are hard to foul but its an easy check, might as well write it off, and then check compression if none of the stuff stretch said works.

knifemaker, i saw your build on CF and your bike looks sweet. sorry to hear you're having problems with the motor

as far as the vid... sounds like its in the top end. sounds like a very loud valve tick. are you sure the valve timing is right? pop the valve cover off and make sure the timing marks line up right with the timing marks on the crank. if that all lines up, pull the cam shafts off and pop the lifters off of the valves and make sure the valve retainers are there along with the shims being in the right place.

i built an engine a lil while ago, and it sounded almost exactly like yours, very loud valves, and it was only running on 2 cylinders, and my valves were warped and the retainers were popped out. i ended up buying a new head and it did solve the problem.


edit: go through the simplest things first before you check the actual valve timing so that you can completely rule out spark and fuel.
double edit: i've had plugs that looked fine before but they were still fouled. you can't always tell just by the way they look. easy way to tell is move the plugs around and see if they misfire follows the plugs. then you'll know.

i think i may have found the problem.. the PO had the wires in the wrong spot. mine are (i am pretty sure) 1-3 2-4 while they should be 1-4 2-3 which would mean 2 of them are connected to the wrong coil.. which would explain the good spark, the gas, but no combustion.

https://img717.imageshack.us/img717/1782/f2coils.png

I certainly hope that the problem is the wires, however, i will check out the valves too. i kinda need to dial in the shims for the head. they were on the tight side of tolerance on the exhaust side and on the loose side for the fuel side. would that account for the ticking?

well you are right about the coils going to 1-4 and 2-3.


i was just listening to your vid and it sounded like mine did. however, definitely get the coils and spark plug wires in the right spot. keep us in the know man. always do the simple stuff first!



edit... yes... that's what would account for the loud tick... my new head ticked at first, and then got progressively quieter in the first 50 miles on it. its not as quiet as my fighter's motor, but it's not too noticeable anymore.

yep! it fixed it... it kicks serious butt.
http://i23.photobucket.com/albums/b3...h_MVI_2870.jpg

Haha, you came here for tech help too knifemaker?

ohhhh yeah. worked too. lol. what help do you need?