Motor won't turn over - Honda TRX Forum
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post #1 of 12 Old 08-11-2018, 12:19 AM Thread Starter
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Motor won't turn over

I have a brand new starter, solenoid, and battery. Power is getting to the starter but the motor won't turn over. I took the starter gear cover off and it free spins clockwise and catches counter-clockwise. I thought maybe it was the starter clutch at first but not so sure now knowing that it still catches when trying to rotate CCW. It was running just fine then died all of the sudden a couple of weeks ago. Any suggestions?

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85MM 11:1 Weisco Piston
Stage 3 Hotcam

01' 400ex - Frame up resotoration
85mm Weisco 11:1 piston w/ xr400 gasket
Stage 2 Hotcam
Sparks Racing Carb
Six Sigma Jet Kit
HMF Full exhaust
CMF Air box - No Lid
K&N Air Filter
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post #2 of 12 Old 08-11-2018, 01:44 PM
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When you say the motor does not turn over, what is your definition of turning over?

To me, if the crankshaft is turning, the motor is turning over - if the motor is turning over, but not starting, then we have eliminated the starter and starter clutch. If you have the spark plug in and hit the starter button, the solenoid closes, the starter motor spins, but the flywheel does not turn, then the motor is not cranking over and the starter clutch needs replaced. But if the flywheel turns and the piston is not going up and down, it probably has a sheared flywheel key and the flywheel is just spinning on the crankshaft.

This can all be checked with the two plugs removed from the flywheel cover - NOTE: THE FLYWHEEL COVER AND STARTER REDUCTION GEAR COVER MUST BE IN PLACE WHEN THE STARTER MOTOR IS ENGAGED OR THE ENGINE COVERS MAY BE DAMAGED. If the flywheel turns and the bolt securing the flywheel to the crankshaft turns when the starter is engaged, it's safe to assume the crankshaft is turning. If you take the spark plug out, put your finger in the spark plug hole and use the starter and it blows you finger off the hole, it's somewhat safe to assume the crankshaft is turning and the engine has compression. The only way to know if the engine has sufficient compression to start is by checking compression with a compression gauge. Typically 120 to 150 psi compression is adequate.

I hope I have explained this in a way that you understand what I'm trying to describe.
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post #3 of 12 Old 08-11-2018, 03:32 PM Thread Starter
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Thanks for the reply. The solenoid closes, starter motor attempts to spin but makes a loud "clunk" for a better term. I pulled the starter cover off the side and noticed that it attempts to turn the motor but the gears are not moving. Could it be the starter clutch not allowing the flywheel to turn? I've started with the cheapest fixes (battery, solenoid, & starter) now I'm moving to the bigger fixes. Thanks

01' 400ex - Frame up resotoration
85mm Weisco 11:1 piston w/ xr400 gasket
Stage 2 Hotcam
Sparks Racing Carb
Six Sigma Jet Kit
HMF Full exhaust
CMF Air box - No Lid
K&N Air Filter
CMF Oil Tank
Oil Cooler Mod
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post #4 of 12 Old 08-11-2018, 05:43 PM
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Take the plug out of the crankcase cover on the LH side - it will expose the bolt holding the flywheel on - put a socket on the bolt and try turning the crankshaft at least one full rotation counter clockwise. You can't engage the starter motor with the cover over the reduction gears off the engine, it will cause the gears to bind and possibly break the inner cover.

If you can rotate the crankshaft with a wrench, then the motor turns over - then you just have to get it to crank without a clunk.
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post #5 of 12 Old 08-11-2018, 06:00 PM Thread Starter
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It does turn over completely turning the flywheel bolt with a socket. Any other suggestions?

01' 400ex - Frame up resotoration
85mm Weisco 11:1 piston w/ xr400 gasket
Stage 2 Hotcam
Sparks Racing Carb
Six Sigma Jet Kit
HMF Full exhaust
CMF Air box - No Lid
K&N Air Filter
CMF Oil Tank
Oil Cooler Mod
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post #6 of 12 Old 08-11-2018, 06:06 PM
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I need to have it in my shop

I can only guess you have a bad ground, weak battery or tight motor
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post #7 of 12 Old 08-11-2018, 06:11 PM Thread Starter
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It's a new battery, not to say its not weak but that should eliminate it. I tested the Vdc its pushing 12+ volts. I'll double check the ground wires. What do you mean by tight motor though? How do you remedy that?

01' 400ex - Frame up resotoration
85mm Weisco 11:1 piston w/ xr400 gasket
Stage 2 Hotcam
Sparks Racing Carb
Six Sigma Jet Kit
HMF Full exhaust
CMF Air box - No Lid
K&N Air Filter
CMF Oil Tank
Oil Cooler Mod
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post #8 of 12 Old 08-11-2018, 06:50 PM Thread Starter
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Ok I did some poking around, after my last response I decided to try to turn it at the flywheel again. This time is bound up in the CCW rotation. I could hear something in the valve cover so I pulled it off. This is the third C rocker arm that has busted in the same place. This time it damaged the camshaft so I'll need to replace it as well. Do you know what could be causing this piece to break off constantly? I pushed the starter button with the valve cover off and the motor turned over completely. This must have been the root of the problem however now I have a new problem I am not sure how to fix.


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01' 400ex - Frame up resotoration
85mm Weisco 11:1 piston w/ xr400 gasket
Stage 2 Hotcam
Sparks Racing Carb
Six Sigma Jet Kit
HMF Full exhaust
CMF Air box - No Lid
K&N Air Filter
CMF Oil Tank
Oil Cooler Mod
minga001 is offline  
post #9 of 12 Old 08-11-2018, 06:53 PM
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A fully charged 12v battery has 13.2 volts - when I say weak, put a meter across the battery terminals and hit the starter button, the voltage should not drop below 9 to 10 volts - anything less than 9 volts, its a weak battery. You can test by using jumper cables to a car battery - if the engine turns over normally, then the battery is the problem.

By tight motor, if it takes more than about 10 ft lbs of force to turn the engine with the spark plug out, then it's tight - the force needed to turn will vary with position of the crank and whether on compression or exhaust stroke, but on the down side of the compression stroke (from tdc to bdc) very little force is needed to turn - it should almost turn on it's own.
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post #10 of 12 Old 08-11-2018, 06:58 PM
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Pretty simple - the rocker arm could not open the valve - either out of time and the valve was against the piston or the valve is seized to the valve guide and can't move - yeah, I'd say you found the problem, now just have to figure out why.
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