Spray it directly into the bendix, I would also check for debris that sometimes gets stuck between the starter and bendix. Just remove the starter, once out clean any debris and check also the teeth of the back of the bendix, if they are damaged it needs to be replaced.
Just to be sure your starter isn’t the problem, test it by placing the body of the starter on the negative end of the battery, then connect the positive end of the battery to the starter cable. (Something like this https://youtube.com/shorts/6AevQ_cNXqI?si=5swI_tQHVpxMVKT_ ) If it doesn’t work try another battery (make sure your batteries are properly charged) If nothing happens your starter is at fault, if it works then your bendix is.
To remove the bendix you need to basically disassembly the whole clutch group, which requieres especialized tools. In this case better have it serviced by your local shop.
Auto parts store doesn’t have triflow to spray in the gear. Should I use WD40 or should I use brake parts cleaner? I’m thinking WD40 because I want the teeth to be lubricated.
Also, how am I supposed to remove this bolt to take the starter motor off when there isn’t enough clearance to get an allen key in there?
UPDATE: nuclear option was taken, allen key was a casualty. Bolt is off, but I probably shouldn’t even have taken it off. I misunderstood the overhaul manual and tried to pull the starter motor away from the bendix (towards the left side of the kart) when instead I should have just taken the whole assembly off in one piece towards the rear of the kart as shown in this video of a mini rok:
Next, I plan to remove the 4 bolts shown at 0:23 of my video and then tap the starter motor+bendix assembly off with a rubber mallet. I’ll probably take then engine and mount off the frame at this point. I should have done that at the beginning. Would have made this job a lot easier.
As many have mentioned, the bendix mechanism is not remaining engaged and holding the starter pinion engaged to the flywheel. There can be a few causes.
Low battery cranking current. Jump start from the car to test it using 12Volts only (not if your car runs 24volts)
Wiring loom losses (feel for hot joints).
The starter motor itself is lacking punch. If you are game you can try cleaning the commutator and replacing brushes.
Chain lube getting into the bendix glueing it up.
And I have also seen a cracked retaining washer in the bendix causing it to fail.
The bendix has a tiny centrifugal clutch in it which keeps it engaged until the motor starts. Keep it clean and only ever use very light oils such as WD40 on it.
Also, the only way to truly test it is under load on the engine. You’ll probably find yourself putting it on and off a few times so clear the workbench and move anything else that’s getting in your way.
Disassembling the bendix itself (part 154 in your diagram) can be very hard. Removing the circlip to remove the pinion is tricky and frustrating.
I used to intermittently have this exact issue when I was running Ka100’s, found a guy who said its an easy fix, pulled off the bendix cover on the sprocket side of the engine, exposing the bendix part that links with the crank (or something idk) (part 154), got some degreaser, and sprayed it all out, the whole bendix, whilst just pushing and pulling the bendix to get all the dirt and grit out of it, and once it was relatively clean, just put the cover back on and it fired right up. I always noticed it was failing after either running in the wet, going off, or just sitting for a long time, and eventually, it became a routine thing at the start of a day (just giving it a spray down), and never had any issues since. Not too sure if somebody has said it, but its a painful issue to have with an easy fix, so hope this helps!
Edit: its not so much dissasembling the bendix, so much as it is pulling the cover (part 158) off, and cleaning the inside without removing any more
Thanks guys. I took the engine off the frame and haven’t touched it since. I’ve been busy fixing my fence and other projects around the house. I will post another video once I get back at it and expose the bendix. I will remove part 158 and attempt to clean part 154.
I cleaned out the bendix with WD40 (wiped the area around the bendix with paper towels after this video as well). It was a bit dirty, but not gummed up or stuck, so I don’t have high hopes that this will actually fix the problem. Reassembly to follow, and I’ll try to start it again.
Sometimes if the black plastic bendix cover has been repeatedly over-tightened, it will distort and bind the bendix and not allow it to spin quickly enough to engage fully. I see this fairly often with Swifts and KAs. The only way to check this is to remove the starter motor, and install the bendix with the cover on and see if it spins freely in its housing.
I have the opposite problem with my sons rok VLR, went to start the kart and the bendix got stuck, it will not go back in. I will disassemble everything this week and see if there’s dirt and grime in there.
Update: I took the kart to my mechanic and he troubleshot it with me. Bendix was fine. Starter motor was spinning slowly/weakly. We tried different batteries, different wirimg harnesses, and replacing the brushes/contact kit in the starter. Nothing worked. Had to buy a new starter. Works perfectly now.
Side note: how do y’all keep your batteries charged? What kind of charger do you have and how often do you charge it/how long do you leave it on the charger for?
Glad you figured out your problem. I would like to figure out the issue. Maybe a dry inner bearing or a dirty commutator. Not a cheap fix.
As for the battery, I have used both a Battery tender trickle type charger and a full size car type charger that has a 2amp switch. Both work fine. I will usually put it on for an evening once between races (usually every 2 weeks).
I did some research a few years ago when it was time to replace my trickle charger. I found for the money, the NOCO Genius G1100 was a very good buy. It can charge 12V and 6V, it works on Flooded, AGM and Lithium batteries. It has a fully automatic 7 step charge/trickle function as well as a descaling function for older batteries (not had much success with that). It is not ideal for charging a Full Sized Car Battery, but serves well as a trickle charger on them.
I didn’t want something with too high of an amp rating so not to shorten the lifespan of the battery, but enough to fully charge my kart battery in two hours. At the time I paid $60 for it, now when I looked it up it at $100. F’ing Inflation !!!
Bumping because kart now won’t start again, but this time for a different reason. Kart was starting right up at the track this past weekend until the last session of the day. I hit the starter button and nothing happened. A couple guys at the track tried to help me. Battery sparked off well when they connected the terminals. No issue there. They tried bypassing the starter switch with a screwdriver, and that didn’t fix anything either. While they were fumbling around with the connections, this wire fell on the ground loose! We couldn’t figure out where it came from or where to plug it into…
…there are two ends coming off the magneto on the left side of the engine. I plugged one into this rubber booted connector (going to the battery) and another into the empty male plug near the sparkplug wire as a ground…
Everything seems to be plugged in now, but still nothing when I hit the starter switch. What am I missing? I’ll post a video in the next post so you can see the whole setup.
Here is a link to the manual that includes pics and diagrams of the wiring harness:
You don’t need the kill switch pigtail for it to start, only for it to shut off.
More than likely needs starter brushes or a starter if it was working and then suddenly it wasn’t. Did you try an external starter to see if it would fire with that?
When you replaced the starter did you silicon the brush leads? If you have a rough track that is a must. I would eliminate the kill switch first, they are known to be troublesome, but since the wire was not even connected it is likely not your issue. Do have a voltmeter? It would be handy to see if you are getting voltage to the starter when the button is pushed and that your battery has the required voltage. You mentioned “sparking off”? What do you mean by that?
Like mtbikerbob says, Check if 12v is getting the starter motor. If it is > dud starter.
If it isn’t, work your way from the battery to the starter motor with a multimeter and see where power is, or isn’t, making it to.
