Starting Issues (Starter or Starter Clutch)

My bike is a 81 XJ650 Maxim. I bought it not running and converted to a "bobber." after cleaning the carbs I was able to get the bike running and test drove it around the block. Minimum running time since I got her going.


Unknown: Mileage and Oil. No tach/speedo and unsure of what kind of oil is in it.

Problem: The starter seems to be "slipping." It reminds me of a Bendix falling/slipping off of a flywheel in a car. It makes a distinct grinding/crunching sound. It seems to be giving about a "quarter turn" to the engine before it "falls off."

Troubleshooting: New fresh battery reading above 12v. All connections are good and clean. No significant voltage loss due to weak battery or bad connections or wires. I ran a direct wire and bypassed starter solenoid and starter button and had the same results. Bench tested starter out of engine and it spun what seemed to be fine. I was not able to put a load on it outside of the engine. Pulled all 4 plugs with starter in engine and the sound disappeared. Put 2 plugs in and still no sound. 3 plugs gave me the sound. So it seems to be making the sound under load greater then 2 pistons making compression.

Question: I can't create the sound with starter on the bench, is there any other tests I can do on the starter (isolated, out of the engine) to determine it good? Then I can focus on the starter clutch. Does the starter clutch, when failed, fail at all RPMS or under load? Or is it possible for it to function normal under a light load and fail under heavy load. I don't know enough about how it works however to determine it bad. I have a basic understanding of it.


Thanks for reading and helping this newbie motorcycle rider out. Its my first bike.

 

STARTER CLUTCH REBUILD PARTS:

sms6) OEM and aftermarket parts to rebuild your STARTER MOTOR CLUTCH DRIVE. Yamaha used a "centrifugal clutch" type of drive system to engage and disengage the starter motor drive from the engine gear, and over time the springs, spring caps, and roller pins that provide the engagement action can fail....which is terrible, as these are a real pain to replace, and always require dis-assembly of the upper and lower engine cases.

However, there are a few alternative methods that might (or might not) save you some incredible effort and allow you to "dodge a bullet" and repair your starter clutch system in an easier manner; but, the success of such methods really depends upon whether the clutch failure is due to mechanical wear or damage to the pins, caps, or springs (in which case, you MUST somehow get in there and replace those items), or, if the caps and pins are merely "seized" in the starter clutch hub due to accumulated varnish and sludge, etc.----and in such a situation, then you might be able to clean out the mess and restore the clutch to an operational condition.

Methods a) and b) below address the problem of "sludge-seized" component pieces. Method c) deals with the problem of damaged parts. Note that if any of the major components are damaged---the clutch hub, or any idle gears or sprockets---then the engine is going to have to come out and taken apart to allow access to such larger pieces.

a) Pull the starter motor.....or, even better, the alternator shaft housing.......and shoot lots of solvent (seafoam, carb or brake cleaner, etc.) directly onto and into the Starter Clutch Assembly. Then, drain all of your engine oil and refill with fresh oil. Run the engine while on the centerstand until it's warmed up, drain the oil again, and fill with fresh oil. If the starter clutch was just sticking, this method may wash away enough of the accumulated gunk and set you on your way.

b) Next, it may be necessary to actually run a solvent in with the engine oil in an attempt to loosen any engine oil sludge that has accumulated over time, and locked the starter clutch roller pins. Of course, such solvent should be run in the engine with the bike on the centerstand, and not any under load!!! Then drain and flush this solvent-and-oil mixture, refill with fresh oil-only, run on the centerstand again, and then drain and refill with fresh oil-only again......now you can ride it again. You want to make DARNED SURE that you get all of the solvent-saturated oil out of the crankcase before you put the engine under load, and risk chewing up engine bearings, etc. with solvent-thinned oil!


AND, be aware that a failing battery and/or a starter motor with a shorted winding or excessive carbon build-up on the commutator, or even burnt contacts in the starter solenoid, can reduce current to the starter motor to a point where it can't produce enough torque upon the starter clutch, and thus mimic starter clutch failure symptoms (that "bag of rocks" sound and an engine that doesn't turn over), so be sure to eliminate those as potential problems before digging into your engine!


ALSO, TAKE NOTE OF THIS EXPERIENCE FROM ANOTHER XJ-OWNER:

"If there is not enough grip between the plunger and the roller, it can skip, causing the grinding, clacking noises you hear. I have been told by a Yamaha mechanic with over 20 years experience that it is very possible for some synthetics to greatly increase the chances that this will occur......"

So this weekend I drained the synthetic out, put some cheap 20W50 in, and rode it for a little while. Then I drained the cheap oil out and put Castrol GTX 20W50 in and the starter does not malfunction anymore, not even once! I cant believe it! I guess these bikes were not made to run synthetic---I'm sticking with conventional oil from now on."


c) If none of the above solutions work, then it might be time to do the dirty deed. If you read this thread, you'll get a good idea of what challenges you're up against.

http://xjbikes.com/forums/index.php?threads/1700

When you finally get the starter clutch assembly out of the engine and available for rebuild, we suggest that the central hub unit be inspected carefully for any damage or cracks, and replaced if needed. Here is a common problem that you need to look for (scroll down for the image of the cracked hub):

http://xjbikes.com/forums/index.php?threads/18676

There’s only one way to repair a starter clutch that’s bad without splitting the engine cases, and it ain’t pretty:

http://xjbikes.com/forums/index.php?threads/48348


By the way, if you do decide to split the engine open and perform open-heart surgery, you might as well replace the primary chain and guide while you're in there, as those are also "wear items" and will cause problems if and when they start failing!


Starter Clutch Components and Operation:

The general layout of the starter motor clutch system is as follows (it differs slightly between the various engine types, but overall, here is what is happening):

a) the starter motor gear operates upon a PRIMARY IDLER GEAR (which is supported on its own shaft)....

b) which in turn spins the another INTERMEDIATE IDLER GEAR attached to the rear side of the STARTER CLUTCH ASSEMBLY.

c) This entire "starter clutch assembly" consists of the above intermediate idler gear and a CENTRAL HUB UNIT which contains the centrifugally-operated springs, caps, and roller pins which lock the starter clutch operation to the starter motor. Failure of both the hub unit itself (it can develop hairline---or larger----cracks over time) as well as wear or seizure of the springs, caps, or roller pins accounts for 99.9% of all starter clutch problems and failures.

d) The "central hub unit" is attached via rubber ABSORBERS operating on the STARTER WHEEL to the starter clutch OUTER COVER, and this outer cover has a DRIVEN GEAR which is operated by the PRIMARY CHAIN, referred to in technical manuals as the "Hy-Vo" chain. Hy-Vo Chain is a unique type of Silent Chain. Hy-Vo stands for High Capacity, High Velocity, and Involute Tooth, and it is a registered trademark of Borg-Warner Automotive, Inc.

http://chain-guide.com/applications/1-6-3-inverted-tooth-chain.html


e) The starter clutch assembly rides upon the same shaft that drives the alternator.

f) If you are going to have the starter clutch assembly out of the engine and available for rebuild, we suggest that the central hub unit be inspected carefully for any damage or cracks, and replaced if needed. Here is a common problem that you need to look for (scroll down for the image of the cracked hub):

http://xjbikes.com/forums/index.php?threads/starter-clutch.14924/

Also take note that if the hub is not cracked, there is some good advice about re-conditioning the hub that you may wish to follow.

If the hub is secure, then always replace the springs, caps, and pins, as well as the rubber absorbers used within the starter wheel.

http://www.xjbikes.com/forums/threads/complete-xj650-rebuild.81981/page-2#post-500076

 

^ what he said.

Do the oil change/ spray the clutch with solvent route first.
JASO MA compliant oil only.

 

Thanks for the responses fellas. I appreciate it.

I will work on changing the oil and spraying the clutch route. It may be a couple weeks before I get to it but it will be done and I will report back here my results.