Topic: CB350F Starter Motor Gear Slipping/Not Engaging

[jtruest]

I have a 72 Honda CB350F that I'm restoring and when I power the starter motor, it doesn't seem to be fully engaging with the inner engine gear. If I run the motor long enough, it eventually seems to catch and turn the engine over but then it slips again. That being said, it's intermittent and random. When I take out the starter motor, the gear inside doesn't look damaged and the motor shaft itself doesn't look terribly worn. See pictures below. Any help would be appreciated.

[bryanj]

Its the rollers, caps and springs inside the starter clutch that are gummed up, or at leasr 90% of the time it is

[jtruest]

Its the rollers, caps and springs inside the starter clutch that are gummed up, or at leasr 90% of the time it is

So would this starter motor rebuild kit work?
https://www.common-motor.com/honda-cb350-cl350-sl350-electric-starter-rebuild-kit

[jakec]

No. The starter clutch is inside the damper gear housing thing, that attaches to the primary drive chain. basically 100% engine rebuild to get to this area. You will have to do that or live without electric start from now on.

[jtruest]

No. The starter clutch is inside the damper gear housing thing, that attaches to the primary drive chain. basically 100% engine rebuild to get to this area. You will have to do that or live without electric start from now on.

Ah got it, thanks for the clarification. Kick start it is!

[bryanj]

I have been told that if you have small hands on the 500/550 it can be done through the sump, never tried it and i got big hands! Also never even seen a 350, we only had 400

[newday777]

No. The starter clutch is inside the damper gear housing thing, that attaches to the primary drive chain. basically 100% engine rebuild to get to this area. You will have to do that or live without electric start from now on.

Ah got it, thanks for the clarification. Kick start it is!

Has this bike sat unused with old oil left in it?

It can be cleaned sometimes.

BTW welcome aboard the forum from southern NH.

[newday777]

Have you got the bike started and running yet?
Are you keeping it in a cold garage/shed?
I ask because old cold oil is thick and effects the starter clutch springs and pawls that engage the starter chain and gears. Heat the block well and then try to see if it engages. Report back.

[Rayzerman]

Yes, it's the starter clutch likely gummed up from not being ridden much at operating temperatures, etc., etc.  You have no choice but to live with it.... start with new oil and just ride it.  Keep using the electric starter, might loosen things up... but need fresh oil to keep flushing it.
I don't usually recommend any additives in engine oil, however, you could dump in some automatic trans fluid (half a quart?) it's a great detergent....   and ride reasonably, no red-lining type stuff, take it easy, you are diluting the oil.  We used ATF as a cleaner for hydraulic valve lifters, and other things needing cleaning in engines in the old days.... Depends how long of a ride you can take, give it time to get everything well up to operating temp for a sustained time.....

[HondaMan]

It's very common for the starter clutch rollers to get too slippery when these bikes have been sitting a long time. To revive it the easiest way, just change the oil at 500 miles intervals for about 3 times in a row, and sure sure to use NON-DETERGENT oil, as that is how it got messed up to begin with: I've seen that Valvoline and Pennzoil/Quaker State oils will do this to the starter clutch rollers in the 350F quickly. Then their 'stuff' makes a slippery coat on the rollers. It takes heat and fresh oil (or removal and cleaning with solvents) to get the slippery crust off the rollers.

Get some Castrol 4T in 10w40 (wintertime) or 20w50 (summertime) from your local O'Reilly Auto store for this: after it works again I highly recommend the Bel-Ray EXL Mineral afterwards to keep it clean going forward.

[jtruest]

Wow thanks for all the suggestions. The bike had been sitting awhile and now lives in a cold garage. I will try all the recommendations and report back!

[scottly]

I don't usually recommend any additives in engine oil, however, you could dump in some automatic trans fluid (half a quart?) it's a great detergent....   and ride reasonably, no red-lining type stuff, take it easy, you are diluting the oil

I wouldn't recommend that!

[Tracksnblades1]

Try using some Vavoline restore oil.. yes it’s synthetic, Originally developed with Cummins under a different name..
The new formulation can clean “restore” low tension oil rings in modern engine by removing all
Sludges and buildups on rings and pistons..It can work wonders on high hour heui injectors too.

I’m sure it’ll easily clean up your starter sprag clutch too….

Read the reviews. It is known to really clean the sludge out quickly so change your filter frequently especially if your bike has been neglected of oil changes or by inferior oils..

https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwiDkovqzcGLAxXyWv8BHeBdKIIYABAAGgJtZA&co=1&gclid=EAIaIQobChMIg5KL6s3BiwMV8lr_AR3gXSiCEAAYASAAEgIiQ_D_BwE&ohost=www.google.com&cid=CAASJeRo825D-T9iVkHM7KfvQHIBW6u-Vw4nJXR0fplqZ6khDBtIpaE&sig=AOD64_3RwONuPG5w1UuHbKU9T0yyj4zZQw&q&adurl&ved=2ahUKEwiG2IPqzcGLAxUWvokEHW7kBlgQ0Qx6BAgKEAE

The Vavoline Cummins diesel version is called Premium Blue. It comes as a mineral oil or as a semi or full synthetic blends.. Like Vavoline Restore and all diesel oils it is a very high detergent oil similar to T4 Rotella…

https://www.facebook.com/erniemarksrepair/videos/comparison-of-the-foaming-produced-by-hd-versus-non-detergent-oil/815467295175633/

Modern oil blends have come a long way…

[dave500]

I have been told that if you have small hands on the 500/550 it can be done through the sump, never tried it and i got big hands! Also never even seen a 350, we only had 400

Ive done the 500/550 ones,i put a full thread on here how to,its not hard but not easy but better than a full motor strip down,im guessing the 350 and 400 is similar?but can it be done?Id go for changing the oil over a few times,and with the sump dropped can you blast kerosine into that area and maybe free it up if its only sticky springs and rollers?with the sump dropped you might find bits of spring and roller?who knows,Id drop the sump and have a look.

[jtruest]

I have been told that if you have small hands on the 500/550 it can be done through the sump, never tried it and i got big hands! Also never even seen a 350, we only had 400

Ive done the 500/550 ones,i put a full thread on here how to,its not hard but not easy but better than a full motor strip down,im guessing the 350 and 400 is similar?but can it be done?Id go for changing the oil over a few times,and with the sump dropped can you blast kerosine into that area and maybe free it up if its only sticky springs and rollers?with the sump dropped you might find bits of spring and roller?who knows,Id drop the sump and have a look.

This is all great advice. I'll try dropping the sump and having a peek. Thanks for the help!

[Little_Phil]

I'd try the other suggestions about oil first.
I've done a 550 through the sump. But I had the engine out and upside down to do it as it's fiddly.

[Herr Supersport]

FYI:

http://forums.sohc4.net/index.php/topic,122084.0.html

Cheers, Daniel

[jtruest]

FYI:

http://forums.sohc4.net/index.php/topic,122084.0.html

Cheers, Daniel

The video he posted where he ran the starter and it not turning over the motor is what mine sounds like when it doesn't engage, although mine engages sometimes and turns over...which leads me to believe its gummed up.

[jakec]

In order to get the damper housing (with starter clutch attached) out of the engine, you would have to remove the primary shaft, then be able to wrestle the housing out of the primary chain. I don't think this is possible, never mind the amount of space for your fingers, but the primary chain is too tight and has too much grip on the gear... I would seriously doubt it's possible.

Actually looking at a pic online (of a 400) maybe it is doable... doesn't look any harder to get to than the 550.

Since it's a 350f, if you already had it upside down on the table like this I would go for the rebuild, you probably need to replace tensioner parts.. you want to be sure to do that every 200 miles anyways..