Hi there, I have a pronblem with the engine running rough on my FJ1200, 1995.
I have put two new coils and fitted 4 new spark plug caps.
The bike starts but runs rough.
There is a lot of popping through the exhaust and it can also spit some flames.
It ran great for a short time and then started running rough again after the install of coils and plug caps.
Looking for ideas and any help/suggestions.
Thank you.
Bill.
One or more of the intake manifolds and/or their O-rings is probably cracked leading to lean condition and popping.
Quote from: balky1 on February 07, 2018, 06:42:23 AM
One or more of the intake manifolds and/or their O-rings is probably cracked leading to lean condition and popping.
Thank you, I need somewhere to start and all help is greatfuly appreciated.
Bill.
Did you try to feel the exhaust pipes after starting? If one or more are cold those cylinders are not firing. In that case, since you fiddled with electrics, start from there.
Verify the spark plug wires are routed to the proper cylinders.
Quote from: FJ_Hooligan on February 08, 2018, 12:18:52 PM
Verify the spark plug wires are routed to the proper cylinders.
BEST advise yet. Don't know why I didn't think of it. I have done the same thing on a VW with the same results.
Quote from: TexasDave on February 08, 2018, 01:40:41 PM
Don't know why I didn't think of it. I have done the same thing on a VW with the same results.
Would it make a difference on a VW?
...out of the blue.....love this place.... :rofl:
Quote from: oldktmdude on February 08, 2018, 05:59:46 PM
Quote from: TexasDave on February 08, 2018, 01:40:41 PM
Don't know why I didn't think of it. I have done the same thing on a VW with the same results.
Would it make a difference on a VW?
Not that you'd notice.
Quote from: FJ_Hooligan on February 08, 2018, 12:18:52 PM
Verify the spark plug wires are routed to the proper cylinders.
I like your answer but sadly yes they are correct.
Quote from: balky1 on February 08, 2018, 09:31:46 AM
Did you try to feel the exhaust pipes after starting? If one or more are cold those cylinders are not firing. In that case, since you fiddled with electrics, start from there.
No that I did not do BT will be playing on the weekend.
It very interesting all the possibilities. Thanx.
Quote from: Pat Conlon on February 08, 2018, 06:15:53 PM
...out of the blue.....love this place.... :rofl:
So impressed of all the response and knowledge that is out there. Really glad I made the effort to ask for help.
Thanx again.
I think the connection of the wires to the new coils and or wires to the new spark plug caps may be the problem. If you reversed the spark plug wires completely - #2 to #1, #1 to #2, #3 to #4, and #4 to #3, the motor won't start. But it will eventually backfire so loud it will make you duck for cover. INCOMING!!!
:Facepalm:
Quote from: fjbiker84 on February 09, 2018, 07:17:13 AM
I think the connection of the wires to the new coils and or wires to the new spark plug caps may be the problem. If you reversed the spark plug wires completely - #2 to #1, #1 to #2, #3 to #4, and #4 to #3, the motor won't start. But it will eventually backfire so loud it will make you duck for cover. INCOMING!!!
That one I had on my Kawasaki GPz 550 unitrak. I almost got deaf.
If popping in the exhaust and flames you have a possibility of a few different things going on.
As already mentioned, proper firing order is important. The two coils fire two spark plugs at a time. One cylinder is on compression stroke and the other is on the exhaust stroke. The one coil fire cylinders 1 & 4, the other fires 2 & 3.
But, lets start with flames. In order to have flames out of the exhaust there has to be a significant amount of un-burned fuel in the exhaust system.
Is this caused by a carb flooding over and too much fuel to burn.
Secondly, in order for the fuel to ignite, it needs an ignition source. The only ignition source will be the spark plug on the ignition cycle. Since the exhaust valve is open when the spark plug ignites on the wasted spark cycle, that is allowing the fuel in the exhaust system to be ignited.
If the firing order is correct, it is time for a compression test, valve clearance check & adjustment and then a compression check following.
From, there you also need to look at the carbies for flooding.
One more thing, if for some reason the camshaft timing is off, you can have these types of problems.
Randy - RPM
Quote from: racerrad8 on February 09, 2018, 10:22:25 AM
If popping in the exhaust and flames you have a possibility of a few different things going on.
As already mentioned, proper firing order is important. The two coils fire two spark plugs at a time. One cylinder is on compression stroke and the other is on the exhaust stroke. The one coil fire cylinders 1 & 4, the other fires 2 & 3.
But, lets start with flames. In order to have flames out of the exhaust there has to be a significant amount of un-burned fuel in the exhaust system.
Is this caused by a carb flooding over and too much fuel to burn.
Secondly, in order for the fuel to ignite, it needs an ignition source. The only ignition source will be the spark plug on the ignition cycle. Since the exhaust valve is open when the spark plug ignites on the wasted spark cycle, that is allowing the fuel in the exhaust system to be
If the firing order is correct, it is time for a compression test, valve clearance check & adjustment and then a compression check following.
From, there you also need to look at the carbies for flooding.
One more thing, if for some reason the camshaft timing is off, you can have these types of problems.
Randy - RPM
Wow, if I Wasn't in the shit before I sure am now. I will take all in And be very busy for a couple days (years) so again Wow and thank you.
Quote from: balky1 on February 09, 2018, 09:43:11 AM
:Facepalm:Quote from: fjbiker84 on February 09, 2018, 07:17:13 AM
I think the connection of the wires to the new coils and or wires to the new spark plug caps may be the problem. If you reversed the spark plug wires completely - #2 to #1, #1 to #2, #3 to #4, and #4 to #3, the motor won't start. But it will eventually backfire so loud it will make you duck for cover. INCOMING!!!
That one I had on my Kawasaki GPz 550 unitrak. I almost got deaf.
:bomb:
Just an update on the engine running.
I removed the muffler and ran the bike, it was loud but a whole lot smoother.
I bought the bike with a 4 into exhaust system and I don't think the tuning was done.
I will either put on a standard system or get the bike tuned.
Thank you to all who have tried to help me.
I have been impressed and grateful of all the help.
Thank you,
Bill.
Quote from: Bill Pine on February 24, 2018, 06:51:36 PMJust an update on the engine running. I removed the muffler and ran the bike, it was loud but a whole lot smoother. I bought the bike with a 4 into exhaust system and I don't think the tuning was done. I will either put on a standard system or get the bike tuned.
Thank you to all who have tried to help me. I have been impressed and grateful of all the help. Thank you,
Bill.
Bill,
I have V&H 4-2-1 headers on my FJ. I do not believe "tuning" could cause
or cure the problem that you report. I believe that the muffler was just allowing unburned fuel to collect inside the pipes, until there was enough to detonate. Removing the muffler did not fix the problem, but now there was no place to collect the unburned fuel, so, no detonations. I believe the standard exhaust system would have exactly the same problem, but maybe quieter.
When you start the bike from dead cold, all four pipes should get hot at the same rate. You will need to work fast, but start the bike from cold, and touch each pipe in order, repeatedly. Keep that finger moving, from one pipe to the next. As they get hot, SKIP any pipe that gets too hot too touch, and only touch the others. Sight unseen, I would bet that one pipe will stay cooler much longer than the others. That would be the cylinder with a problem. It may have a bad plug, or bad cap, or a bad high-voltage wire. You may have one carb with a bad needle-and-seat, or a bad carb float (or a bad float setting). Beyond all that stuff, the next thing might be to do a compression check. I believe that "tuning" right now would be a waste of money.
A spray bottle with water will help you save your fingerprints.
Quote from: FJ_Hooligan on February 25, 2018, 09:22:27 AM
A spray bottle with water will help you save your fingerprints.
I have had the filters off and ran the bike and found some spitting from carby #4 I am going to run it again without the filter box attached briefly but there was some spitting from the back of the carb.
I bought the bike second hand and it had been messed with and as per the previous owner's comment "I tuned the carbies on the bench" so they're fine.