Honda Twins banner

1 - 20 of 30 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
Hi All. First time poster here. I have a 72’ cb450 and I’m pretty positive that the starter clutch is broken. When I press the starter button, the starte spins but the clutch mechanism doesn’t engage. It whines, chirps and rattles a bit, but doesn’t crank the cylinders. So I know I need to rebuild the starter clutch. I have the Honda factory refurb kit and the flywheel puller, but I just am not 100% certain on the process. I have the clymer manual and the exploded parts diagram which helps, but I can’t find anything online or in print that shows the procedure. Can someone shed some light on this procedure for me? Thanks in advance!
 

·
Premium Member
Joined
·
5,550 Posts
Step one - Toss Clymer in the trash

Step two - download Honda factory service manual for the 450s here

There is a section about how to take that side of the engine apart to inspect and repair the clutch. Most times the rollers are not being pushed into place because the springs and the caps are stuck in their bores. Just taking things apart and cleaning them fixes the issue. I would make sure to inspect the torque on the screws that hold the clutch to the rotor and lock-tite or stake them back if they are loose at all.

I will also move this thread to the correct forum section since this is the baby twins area.
 

·
Registered
Joined
·
2,381 Posts
It’s very easy, at least something is�� you will need new pins, rollers, and springs. An eBay seller has the whole kit for like 50 bucks. The parts look like something from a bic pen. The only challenge is keeping the parts aligned inside the rotor during reinstallation. You will need a rotor pulling tool/bolt which is like ten bucks. Be mindful of how the parts are lined up before you remove the old ones. Honestly, it’s not hard or time consuming. Use the Honda shop manual, as recommended. Post an update so we know it’s completed.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #6
Thanks for the help and insight. i appreciate it. As per the clymer manual its as old as the bike and came with the bike so if money was wasted it wasn't on the clymer... That being said I do already have the rotor puller bolt and the clutch kit from common motor.

So today, armed with those parts and print outs from the PDF shop manual (thank you Frogman) I went to install the kit. Once I removed the crank case cover, I discovered that the starter clutch wasn't the biggest issue with my starter. The fact that there was no damn starter chain or sprocket on the starter is the bigger problem.

I was unable to source these parts as new from anywhere. If anyone knows where to get a starer chain from please let me know. In the mean time I have ordered a used sprocket and chain off of ebay,

Not to be deterred from making some progress today I figured that while I had the case off I may as well install the new clutch parts so that I don't have to trouble shoot that later. However, I was unable to get the damn flywheel off. I was able to get the mounting bolt off by wrapping a shop rag around the flywheel and using some giant channel locks to hold it but i was not able to hold the flywheel in place with this method once i started to use that rotor pulling tool. The amount of torque required to twist that bolt in was way more then the amount of force I was able to put onto holding the flywheel.

I of course googled the hell out of this and found lots of nifty flywheel holding tools that would not work on this flywheel. Can anyone tell me what the heck to do here? thanks again.
 

·
Registered
Joined
·
13,085 Posts
If you put a wrench on the rotor puller bolt and hit it with a hammer a few times, then briskly tap on the end of the rotor puller bolt with the hammer a couple times, then back to the wrench again, and repeat until it comes loose - that method has worked for me, as well as gently using an electric or air impact on the rotor puller bolt and alternately tapping on the bolt with a hammer. A strap wrench will hold the rotor still too if it's clean
 

·
Registered
Joined
·
2,381 Posts
Ancient....is correct. I cannot explain but you tap it with a hammer and the rotor just gently moves out. No chain?! How did that happen?? Just pay close mind to how the starter clutch pieces are arranged, as they can be fit different ways but of course, only one way is correct�� perhaps instead of getting just the chain take some time and get the whole assembly. I do know starter motor rebuild kits are less than thirty bucks. Does everything else work correctly and the bike started ok before???
 

·
Premium Member
Joined
·
5,550 Posts
If it's really that stuck you can pull the clutch side cover and use a penny in the crank/clutch gears to jam up the crank well enough to hold things. Pennies are soft enough they won't hurt anything if you happen to mash it through.

Far as new gear and chain highly doubtful that you will find them. Maybe David Sliver Spares may have them. I wouldn't worry about installing used chains, they probably will last longer than the rest of the bike.

Sent from my SAMSUNG-SM-G891A using Tapatalk
 

·
Registered
Joined
·
8 Posts
Discussion Starter #10
I am not sure what happened to the chain and sprocket. It came to me that way. However i am thinking it must have been something catastrophic because the old crankcase cover was cracked from the inside out right above where the starter sprocket is.

The starter motor currently works. obviously I can not tell how well it works as it has no chain and sprocket. All I know for sure is that when the starter motor button is pressed it starts whirring. Is it worth it to just rebuild the starter too? or just wait and see? i think i know the answer.

As per the bike starting. It starts and runs using the kick starter, however I am pretty sure that the coils are bad. I placed the sparkplug electrode against the cylinder head and it gave me a week yellowish spark and the sparking was intermittent, as in it was sparking every 3rd or 4th kick. They are new plugs, new boots and old coils. I will just replace them and eliminate that as an issue.
 

·
Registered
Joined
·
13,085 Posts
Do you have the sprocket on the starter motor? If so, I pretty sure I have the other sprocket and chain from one of my spare engines
 

·
Registered
Joined
·
13,085 Posts
Not sure if I have the smaller sprocket but I'll check if you need it. Also looks like the o-ring around the nose of the starter motor is out of the groove, it will weep oil out of there if not taken care of and now is the time to do it
 

·
Registered
Joined
·
8 Posts
Discussion Starter #14
Thank you for the offer Ancient. I have ordered a sprocket and a chain off ebay, its set to arrive friday or saturday. I have only seen a small blurry picture of the parts on ebay, so if they turn up junk or clapped out I may take you up on it. And in reference to the o-ring are you referencing the part that i have traced over in red in the image below? Isn't that a retainer spring clamp? Am I missing something in the picture?

CB450_STARTER_DETAIL.JPG
 

·
Registered
Joined
·
8 Posts
Discussion Starter #16

·
Registered
Joined
·
13,085 Posts
yep, that's it - the left cover is still on mine so I couldn't look at it. Obviously been a while since I looked at a starter motor... :D
 

·
Registered
Joined
·
8 Posts
Discussion Starter #18 (Edited)
Just an update and a thank you to all you guys who helped me out. I bought an old starer sprocket and chain off ebay, installed it and it's all good. I managed to get the fly wheel off thanks to a giant strap wrench from home depot whilst tapping the end of the flywheel puller with a hammer. worked like a champ. The starter clutch was jacked. all three screws that held the clutch to the flywheel were sheered off clean, those 3 little spring tensioned pins had the tops of them worn completely off. all fixed now and it starts like its brand new. (I suppose the brand new set of coils helps)

Thanks again! on to the next problem. Here is a photo of my 450 as she sits in the hot sun.

IMG_0569.jpg
 

·
Registered
Joined
·
13,085 Posts
Hopefully you staked (or used Loctite on) the screws that hold the clutch to the rotor so it won't happen again. Glad the remnants of the screws came out easily, somehow the holes in the rotor weren't jacked up as a result
 
1 - 20 of 30 Posts
Top