Rear cylinder not cooperating
- Thread starter Atti2ude
- Start date
Atti2ude
Member
There wasn't a change in valve train noise so figured the pushrods were in adjustment. Each cyl took about 5 revs to hit 250 which is good but is that a conclusive test?
bearman
Active Member
It is very conclusive. If the rear took two additional revolutions to reach the same pressure then that would mean that the rear cylinder isn't as mechanically heathy as the front, like maybe a stuck or broke ring or dirt on one of the valves or maybe a pushrod out of adjustment and not holding the valve open long enough. But the fact that they operate nearly identical means that your problem is most likely NOT mechanical.
Another thing that I can think of for your problem is one of the wires or connectors from the ignition to the coil might be bad. See if you can test the continuity/resistance from back of the igntion connector to the coil on all three wires (with the wires still connected) and see if there is any difference, they should all three be the same. Be sure to wiggle the wires and connectors around to imitate engine vibration.
Another thing that I can think of for your problem is one of the wires or connectors from the ignition to the coil might be bad. See if you can test the continuity/resistance from back of the igntion connector to the coil on all three wires (with the wires still connected) and see if there is any difference, they should all three be the same. Be sure to wiggle the wires and connectors around to imitate engine vibration.
Atti2ude
Member
Found a bent pushrod
Perfect riding weather and bike is still down. No local knowledge where I'm at so been doing a lot of reading on the forum trying to figure out the hell's going on. Removed the pushrod tubes and found the rear cyl exhaust pushrod is slightly bent. I'm sure this is contributing to the problem but what would cause this?
I did a few more videos so you can see how the rear exhaust valve train is clearly troubled. In both videos you will notice that the movement is sluggish in comparison to the others, especially when the valve is closing. Before I start pulling things apart, it would be nice to know whether to target the rocker box or lifter. Any suggestions??
Rear cyl exhaust valve; rocker box view - YouTube
Rear cyl exhaust valve; push rod view - YouTube
Perfect riding weather and bike is still down. No local knowledge where I'm at so been doing a lot of reading on the forum trying to figure out the hell's going on. Removed the pushrod tubes and found the rear cyl exhaust pushrod is slightly bent. I'm sure this is contributing to the problem but what would cause this?
I did a few more videos so you can see how the rear exhaust valve train is clearly troubled. In both videos you will notice that the movement is sluggish in comparison to the others, especially when the valve is closing. Before I start pulling things apart, it would be nice to know whether to target the rocker box or lifter. Any suggestions??
Rear cyl exhaust valve; rocker box view - YouTube
Rear cyl exhaust valve; push rod view - YouTube
JeffM
Active Member
Todd, i know we spoke while out fishing today, but after see the You tube vid's i did not see your pushrods turn.
My old 80 cu evo had Edelebrok heads, S&S adjustable, roller rockers and black diamond oversize valves and if i remember rightly when i pulled out the plugs and hit the start button the pushrods turned slowly, to me your pushrods look too tight.
Someone else chime in if you think i may have imagined it.
I adjusted my push rods up till they touched then up 1 -2 turns and lock them off.
Never had an issue with 105 hp in an EVO.
As we said today maybe 2 new lifters and rods, cheaper than a head job.
My old 80 cu evo had Edelebrok heads, S&S adjustable, roller rockers and black diamond oversize valves and if i remember rightly when i pulled out the plugs and hit the start button the pushrods turned slowly, to me your pushrods look too tight.
Someone else chime in if you think i may have imagined it.
I adjusted my push rods up till they touched then up 1 -2 turns and lock them off.
Never had an issue with 105 hp in an EVO.
As we said today maybe 2 new lifters and rods, cheaper than a head job.
Slick-Dog
Active Member
Thats wild a buddy of mine has a 05 chop and it always sound it like it had a flat spot in it... but when reved up it went away...hummm I`LL HAVE HIM CHECK THEM OUT!
It's easy to overlook the obvious.
chubs
Guru
Ain’t that the truth!! When we have a problem with our bike, it’s. Always “. Oh no ! This is gonna be major expensive “ and we usually find that the last thing we’d think about is the problem!
08 Ridgeback
New Member
I'm having the same issue now... Did you ever figure out the direct issue here? One cylinder is great and the other hits about every 15 seconds or so. Compression is good on both.
chubs
Guru
You might check the plug wire connections at the coil, or maybe even swap them and see if the misfire switches cylinders. New plugs? My 02 does that when the plugs get a little fouled.
Two fucking fifty says you do not let that engine builder out of your sight. 600 miles might as well say 60k.
.... then It's a bent pushrod.
Bear, you schooled me right there to count my pushrod's rotations if both comp match the same numbers.
2ude, the coil buy. Coil out of both plug wires have to match equally. I can flip a coil so as to hide the plug leads between the cylinders, or the two plugs reversed and the L plug angle end to throw a beauty cover over it. Can't be the coil, get it? Both have to die is the wired crossing inside.
Sooty plug because not enough time to exit the spent; where the spent is mixed with fresh and not so much power. Stroke counts the Bear action is the lag of opening wider. When pulling the plug [which is private btw so no see] but see how 250psi and very little unspent still fires off? No coil needed. No ignition needed is the hindsight.
This be a Sticky Bear, if not in the mental toolbox. Any V8, Tri, BSA, HD, etc. Push comes to count them off.... How beautiful is that Stick He <<<
2dude,
Good question... you'll have to answer that.
So my guess is, 600 miles and now you start swapping out parts. That says to me, that bent valve was up to WOT point is the finger now pointed at you. Here is your rebuild and no charge for the bent exhaust rod? Not out the door, right?
Bad boy, did you think what I have to put the brakes on and now... it sure did not bend the valve if tag meets float. Here comes the hindsight?
Home he here would rawhide some rod back to a straw and install. Then I'd somehow leverage a push more on the rocker arm, where the rocker has the exhaust at full open. How much more travel can you get, or is the valve hitting the piston now? Peek in the plug hole maybe?
The rocker arm is more a feel how much between those two tag points and spin the rod with a few flats to shrink the rod some. That or mill the ex pocket down on the piston.
Good question... you'll have to answer that.
So my guess is, 600 miles and now you start swapping out parts. That says to me, that bent valve was up to WOT point is the finger now pointed at you. Here is your rebuild and no charge for the bent exhaust rod? Not out the door, right?
Bad boy, did you think what I have to put the brakes on and now... it sure did not bend the valve if tag meets float. Here comes the hindsight?
Home he here would rawhide some rod back to a straw and install. Then I'd somehow leverage a push more on the rocker arm, where the rocker has the exhaust at full open. How much more travel can you get, or is the valve hitting the piston now? Peek in the plug hole maybe?
The rocker arm is more a feel how much between those two tag points and spin the rod with a few flats to shrink the rod some. That or mill the ex pocket down on the piston.
08 Ridgeback
New Member
I've changed plugs, coils, plug wires, plugs and continuity checked wiring and nothing. I've also performed compression tests. When running it yesterday, I pushed on both compression releases while it was idling. The back cylinder where I'm having the issue seemed weak. Do you guys think it could be the compression release not working properly?
Ridge,
Let's look at compression two ways.
1. We usually just wait for the needle to stop and we now have the number, hand tester wise.
2. Leakdown, we can pull the pushrods, rockers, and rocker cover off.
3. Both ways show the same compression number.
While we watched you matching 2ude, the variable is... go check the rod bend.
This way, the comp release will show that difference too and you'll know either way if the comp needs a new one... seeing both comp numbers match. Rod or Release, right? The bird killer.
Set the valves at their own stroke positions so you can spin the one for something like this, or where the position you want to adjust the rod as well. 2 birds here too.
Remember EOIC. Watch EX OPEN... then STOP>>> spin the intake rod. Watch IN CLOSE... and stop there before it moves the other way>>>> spin the ex pushrod. Said another way: you are moving the intake open and once it begins to close, stop and that in between meaning.
Let's look at compression two ways.
1. We usually just wait for the needle to stop and we now have the number, hand tester wise.
2. Leakdown, we can pull the pushrods, rockers, and rocker cover off.
3. Both ways show the same compression number.
While we watched you matching 2ude, the variable is... go check the rod bend.
This way, the comp release will show that difference too and you'll know either way if the comp needs a new one... seeing both comp numbers match. Rod or Release, right? The bird killer.
Set the valves at their own stroke positions so you can spin the one for something like this, or where the position you want to adjust the rod as well. 2 birds here too.
Remember EOIC. Watch EX OPEN... then STOP>>> spin the intake rod. Watch IN CLOSE... and stop there before it moves the other way>>>> spin the ex pushrod. Said another way: you are moving the intake open and once it begins to close, stop and that in between meaning.