The 3 piston has hit one valve at high rpm. BUT It still started easily.Since the rebuild I have not been able to start my fj1100 :cray:. I just had my cylinder head resurfaced and valve job;also replaced one broken valve. I can't think of anything. Cams are timed right,groundings and connections are fine (I think.) I'm not an expert mechanic. Everytime I try to start it it pops as if it's going to start. After that my plugs are wet with fuel. :scratch_one-s_head: . I'm running out of ideas.
Have you done a compression test after the rebuild ?
Are all 4 plugs flashing a strong spark?
Quote from: fjman on January 09, 2011, 06:51:45 AM
The 3 piston has hit one valve
I believe you have identified the problem. If it were my bike I would first
check the compression and verify the problem, if it is a valve clearance problem (bent valve) I would check the valve lash (probably impossible to verify with a bent valve) and remove the cylinder head. Options; thicker cylinder head gasket or replace cylinder head. I would be inclined to replace the cylinder head if the cylinder head has been shaved too much.
Rebuild fixed the bent bits, i presume.
Simple troubleshooting applies, man.
Define the no start. Does it have power? Fuel in the appropriate places? Makes farty noises? Makes no noises? Blows fire out either end? Cranks? etc, etc, etc. There's a bit of a walkthrough on many of the common problems someplace around here, but with a fresh rebuild, tbh I'd imagine you've just got something assembled a bit wrong. Pops like it's going to start but won't catch? Spark wires going to the right coils perchance? Can it be sussed if it's all the cylinders popping or just one trying? More info is good info.
Comp check is a good start, spark check is a good start, plugs getting stinky with fuel sounds about right.
clear the cylinders , remove the spark plugs and use compressed air to clear out any unburned fuel or oil.
tighten the gap on your plugs to .020 and go for restart.
try to start on the choke only with throttle closed.
getting the fj to fire up after a rebuild is a bitch.
Have you got the plug leads on the right way..(Firing order..)
Cheers
even though I blew one valve prior to the rebuild the engine was still running.It still started easily. I replaced it with a thicker head gasket. Also replaced one valve. The #3 Piston's surface was not really damaged bad. Is there another way to check compression? I don't have a compression tester :cray: . 4 Plugs have a moderate spark. Not really strong;not really weak. I was thinking about working with the float level of the carbs.
Firing order is right. IF you crank it manually I hear hissing sounds.
While cranking hold your hand over one of the carbs. Make sure it is sucking and not pushing your hand away.
Where did you get a "thicker" head gasket? I have heard of this many times, but have never witnessed one.
My other concern since the inception of your post(s) is that a piston hit #3 valve and only one. If the piston hit the valve it shouldhave hit both of them, so that doesn't make sense that one one was bent. In my experience if the piston is hitting the valve it has also hit the head distorting the chamber and the valve seats renderring the head useless.
Make sure you have the cams install correctly and not 180 out which if the carbs are pushing instead of sucking that would be the problem.
Randy - RPM
I had my gasket custom made. I brought it to this shop that makes gaskets. I had one made for my Jeep Laredo and had no problems. The damage to the head was minimal. hence I had it resurfaced. The valve seats were not damaged. Sorry for the lousy picture. This is the only picture I have with my phone. (http://fjowners.com/gallery/1/1156_11_01_11_5_07_24.jpeg)
I'll check the cams tomorrow. How do I know if the cams are 180 and out? :unknown: :wacko1: All I did was align the dots on the bearing caps and find TDC mark on the Pick up.
In theory you should be okay if you've aligned the dots right, and the pickup is in the right spot. Otherwise the pickup would be in the right spot and the cams would be exactly upside down. Now, ensuring the pickup is in the right place first might be a good start. Got a manual? It's all pretty clearly put forth in the GYSM and the Haynes, probably the clymer too, but I'm using that right now to keep my desk from wobbling and don't want to check :)
Quote from: andyb on January 11, 2011, 07:56:38 AM
In theory you should be okay if you've aligned the dots right, and the pickup is in the right spot. Otherwise the pickup would be in the right spot and the cams would be exactly upside down. Now, ensuring the pickup is in the right place first might be a good start. Got a manual? It's all pretty clearly put forth in the GYSM and the Haynes, probably the clymer too, but I'm using that right now to keep my desk from wobbling and don't want to check :)
Exactly, the pickup doesn't care where it is so it can be 180* out and still run fine. If it is a dual pick-up coil the you have to align it to the proper P/U coil. The key way slot which is just barely visible at the rotor bolt must be at 12:00 for TDC.
If you crank it and is pushes your hand away there are 180* out of time.
Randy - RPM