My starter clutch have started to fail once in a while and I have ordered new rollers, springs and roller caps from CMS. They had the rollers and the springs in stock, but they have the roller caps in a back order, and they expect to ship the parts at the end of this month.
However, a quick question for Volker; I seem to remember that Robert said he removed and rebuilt his starter clutch without taking the engine out of the frame, by just removing the oil pan and sliding the starter clutch assy out from the bottom of the engine? Any thoughts about that?
Starter clutch
Re: starter clutch
Hi Ibsen,
I also remember that. I think Robert did it with the engine out but without splitting the crankcase. But it should also work with engine in frame if you can pull the primary cam. Possibly this requires removing the right lower frame part. I also weakly remember he told about partly disassemble and reassemble the starter clutch inside (at least pull the gear wheel). I once failed to get it out however I just tried it all in one part.
But are you really sure it is the starter clutch? First thing to do is to check whether the starter transmission gear has still all teeth. Remove the starter and turn the engine backwards to watch the teeth passing the starter hole. Well, if it is the starter clutch, it may not turn then.
BTW, at the beginning of last year, my starter clutch failed a few times. It never did that again (or before), so a standing time may be responsible and riding may heal it.
I also remember that. I think Robert did it with the engine out but without splitting the crankcase. But it should also work with engine in frame if you can pull the primary cam. Possibly this requires removing the right lower frame part. I also weakly remember he told about partly disassemble and reassemble the starter clutch inside (at least pull the gear wheel). I once failed to get it out however I just tried it all in one part.
But are you really sure it is the starter clutch? First thing to do is to check whether the starter transmission gear has still all teeth. Remove the starter and turn the engine backwards to watch the teeth passing the starter hole. Well, if it is the starter clutch, it may not turn then.
BTW, at the beginning of last year, my starter clutch failed a few times. It never did that again (or before), so a standing time may be responsible and riding may heal it.
Thanks.
When the time comes I will try to take off the pan and see how it looks. If it can't be done that way, I will take the engine out of the frame.
And yes I'm pretty sure it's the starter clutch. It only fails once in a while when the engine is cold. It never happens when the engine and the oil is warm. And when it fails the starter engine and the gears are spinning, but the clutch won't catch. It got better when I changed the oil to a semi synthetic oil, Castrol GPS 10/40. And it could just be that it will get better as the temperatures are rising outside.
But I have planned to take out the starter and check the starter motor and all the gears at the same time.
When the time comes I will try to take off the pan and see how it looks. If it can't be done that way, I will take the engine out of the frame.
And yes I'm pretty sure it's the starter clutch. It only fails once in a while when the engine is cold. It never happens when the engine and the oil is warm. And when it fails the starter engine and the gears are spinning, but the clutch won't catch. It got better when I changed the oil to a semi synthetic oil, Castrol GPS 10/40. And it could just be that it will get better as the temperatures are rising outside.
But I have planned to take out the starter and check the starter motor and all the gears at the same time.
Hmm, sounds really like starter clutch. Cleaning the starter from time to time is a good idea. But before taking apart anything else I would do a long trip at changing revs to get the engine heated through. When the starter clutch still fails afterwards, one can be sure not to open the engine unnecessarily.
I have tried that, and the problem only appears at start up when the engine is cold. What I haven't tested is if the battery can't spin the starter motor fast enough. But that really shouldn't have anything to do with it if the starter clutch works properly. When the starter clutch are good, it will lock up as soon as you start to spin the gear on the primary shaft, like when you turn the engine backwards by hand.
I agree that turning speed should not matter, I did not mean to say cleaning the starter will help with your problem. I just think it is a good idea to get out the black wear from time to time. 
From my experience of last year, I guess there is a chance that something got stuck from standing which may get loose again from a time being centrifugalized in hot oil. When you already did several rides including a longer one, the chances to have it vanished without further work decrease.
From my experience of last year, I guess there is a chance that something got stuck from standing which may get loose again from a time being centrifugalized in hot oil. When you already did several rides including a longer one, the chances to have it vanished without further work decrease.
Yes, I think you are right about that. I had a small hope that it might be as you say, but new oil and the riding I have been doing so far doesn't seem to have changed anything. Btw, I have been out riding today, a 120km ride, and at the first start up the starter clutch failed to catch on the first two attempts, then it worked as it should. I stopped several times during the ride and the starter worked flawlessly each time.
Any ways, till the parts arrive I will keep on riding.
Any ways, till the parts arrive I will keep on riding.
Hi guys!
As much as i can't say exactly what is happening with this particular clutch, I'm feeling like an expert when it comes to get this baby out. I did it now at least 4 times (was testing different springs for rollers ) and now from beginning, to running engine after assembly it takes me 2,5 hrs of work.
Below I will try to put it as simply as i can....
Drain the oil from the pan.
While draining, strat removing screws from the clutch cover.
take out the clutch cover, take out the clutch basket
here's a little problem - you need special tool to unscrew the washer to take the clutch out - fastest way is a socket size 24, dremel (or other similar cutting thing) and fashion it yourself. You will need it sooner or later. In order to unscrew this washer you need to block the gears. I found that the fastest way was to put bike on a sidestand, put it in gear, step on the rear brake, and push on the wrench.
this thing out, now unscrew, and remove oil pan. You may want to take away the sump as well - its just pushed into place, and may fall out, when you fiddle with the starter clutch later on.
now, you need to take out the primary shaft. Unscrew 3 bolts that hold the metal plates (one goes as high as the neutral gear thing) and take this all out. You will see which ones.
take out the shaft - it requires a bit of push but once started it comes easily out. Watch out, there's a bearing on it. Just remember to keep it there when putting things back on
and now, thourgh the hole, you see the REAL thing - it is a fairly big cog, with holes in it.
take out the ignition cover, so you can rotate the engine easily using another 24 wrench
have handy a torx 30 head. with this torx you must unscrew 3 screws that hold the starter clutch to the rest of the system. This is the trickiest part. You must do it THROUGH the holes in this cog. You can position each screw by turning the engine by hand - slowly. Another trick - wasted a lot of time 1st time - unscrew AND take out those screws one by one. To do this, you must put a flat screwdriver (from underneath) between the cog and the next part of the clutch - this is the one where all springs and rollers are. This tiny bit of space will enable you to take the screw out (and in later on). You may want to help the screw to pop out with the screwdriver.
Now that the screws are out, the whole assembly (cog and the rollers part) should gently drop down - put a bit of cloth underneath, just in case.
In my case, when this clutch started to slip it was the little push-pins, which heads were "swollen" a bit (fron hitting the roller i presume) and were not moving freely enough - they were jamming inside their holes. Next time, it was the springs inside those push pins - they got warped, and stopped pushing the rollers into place. Since I didn't have real possibility, nor time , nor money to order original parts, I did a drawing of the push pins, went to a local metal workshop, and ordered myself 6 pieces of push pins. Price was 10U$
With slightly smaller diameter (to allow really good movement) and from much harder material (I hope).
I had an event with the springs - I thought, I will put stronger ones, so it will be more secure grip. Yes, it was. Too much of a grip actually. After starting the engine i could hear the rollers rolling heavily on the elements. So, switch off, disasemble, and put new springs.
Springs story - I tried ballpen springs - were very good in diameter, but material quality was poor - they didn't last long, got warped very fast. Again, I decided to do them myself, and now i have a perfect set - I did them from a H steel guitar string. Just right on strenght. G string came out a bit too strong.
Putting things back together - fairly straightforward, just few tricky things.
You must place the clutch correctly - there's a steel pin that transfers the actual power. I found that easiest was to turn the engine so, that the hole for the pin would be at the lowest point of the turn. Then it's easier to slide in the cog wheel and to fit the pin into place. Once you have it there, its time for those torx screws. Again, screwdriver to have some space and put them through the holes in the cog. And then its plain assembly till the end.
Now i realize that this may be a bit clumsy description. heres another one from SOHC4 forum. Bit shorter, I admit...
It can be done! Not only have I done it, but a few weeks ago Steve Tenenbaum and I did his. You don't even have to take the engine out of the bike. Here's how:
1. Remove oil pan, clutch cover, & clutch. The clutch "requires" a special socket from Honda, but I made it out of a 1" diameter steel plumbing pipe and a dremel. Follow the manual's instructions, but don't disassemble the clutch, just take it out.
2. Loosen the two bolts holding the primary shaft in and slide it out. The starter clutch is bolted to the primary drive chain gear, so the chain will keep it from falling out.
3. There are three bolts that hold the starter clutch to the primary gear - you need a Torx 30 head to get them out. You can see them through the hole the primary shaft slid out of. It's tricky, because you have to go through the holes in the starter gear to get to the bolts, and you have to loosen all three before taking it out because the bolt head won't fit through the holes in the starter gear.
Once unbolted it should drop out, and you can see what's wrong with it. On mine and Steve's both, the three holes in the edge of the clutch-outer were warped, and the springs behind the roller push-pins were mangled. Here's a link to the parts, and this site uses the same diagrams the dealers do:
http://houseofmotorcycles.bikebandit.co ... ematic_vie w.asp?schem_dept_id=213328§ion_dept_id=1§ion_dept_name=OEM+% 28Stock+Parts% 29&dept_type_id=2&model_dept_year=1981&model_dept_mfr=Honda&model_dept _id=206277&model_dept_name=CB650
It took us about 2.5 hours to change out Steve's and neither of us have had any problems since the operation. The parts can be expensive, but if you look on eBay you can sometimes get lucky. Email me if you have any questions, and if you live near St. Louis, MO I'd be glad to help out. Good luck!
In any case - I wish you luck, (it's easy, really) and don't hesitate to ask. At least this is a place where I feel solid knowledge And making those parts yourself was no big deal, really!
Regards!
As much as i can't say exactly what is happening with this particular clutch, I'm feeling like an expert when it comes to get this baby out. I did it now at least 4 times (was testing different springs for rollers
) and now from beginning, to running engine after assembly it takes me 2,5 hrs of work.
Below I will try to put it as simply as i can....
Drain the oil from the pan.
While draining, strat removing screws from the clutch cover.
take out the clutch cover, take out the clutch basket
here's a little problem - you need special tool to unscrew the washer to take the clutch out - fastest way is a socket size 24, dremel (or other similar cutting thing) and fashion it yourself. You will need it sooner or later
. In order to unscrew this washer you need to block the gears. I found that the fastest way was to put bike on a sidestand, put it in gear, step on the rear brake, and push on the wrench.
this thing out, now unscrew, and remove oil pan. You may want to take away the sump as well - its just pushed into place, and may fall out, when you fiddle with the starter clutch later on.
now, you need to take out the primary shaft. Unscrew 3 bolts that hold the metal plates (one goes as high as the neutral gear thing) and take this all out. You will see which ones.
take out the shaft - it requires a bit of push but once started it comes easily out. Watch out, there's a bearing on it. Just remember to keep it there when putting things back on
and now, thourgh the hole, you see the REAL thing - it is a fairly big cog, with holes in it.
take out the ignition cover, so you can rotate the engine easily using another 24 wrench
have handy a torx 30 head. with this torx you must unscrew 3 screws that hold the starter clutch to the rest of the system. This is the trickiest part. You must do it THROUGH the holes in this cog. You can position each screw by turning the engine by hand - slowly. Another trick - wasted a lot of time 1st time - unscrew AND take out those screws one by one. To do this, you must put a flat screwdriver (from underneath) between the cog and the next part of the clutch - this is the one where all springs and rollers are. This tiny bit of space will enable you to take the screw out (and in later on). You may want to help the screw to pop out with the screwdriver.
Now that the screws are out, the whole assembly (cog and the rollers part) should gently drop down - put a bit of cloth underneath, just in case.
In my case, when this clutch started to slip it was the little push-pins, which heads were "swollen" a bit (fron hitting the roller i presume) and were not moving freely enough - they were jamming inside their holes. Next time, it was the springs inside those push pins - they got warped, and stopped pushing the rollers into place. Since I didn't have real possibility, nor time , nor money to order original parts, I did a drawing of the push pins, went to a local metal workshop, and ordered myself 6 pieces of push pins. Price was 10U$
With slightly smaller diameter (to allow really good movement) and from much harder material (I hope).
I had an event with the springs - I thought, I will put stronger ones, so it will be more secure grip. Yes, it was. Too much of a grip actually. After starting the engine i could hear the rollers rolling heavily on the elements. So, switch off, disasemble, and put new springs.
Springs story - I tried ballpen springs - were very good in diameter, but material quality was poor - they didn't last long, got warped very fast. Again, I decided to do them myself, and now i have a perfect set - I did them from a H steel guitar string. Just right on strenght. G string came out a bit too strong.
Putting things back together - fairly straightforward, just few tricky things.
You must place the clutch correctly - there's a steel pin that transfers the actual power. I found that easiest was to turn the engine so, that the hole for the pin would be at the lowest point of the turn. Then it's easier to slide in the cog wheel and to fit the pin into place. Once you have it there, its time for those torx screws. Again, screwdriver to have some space and put them through the holes in the cog. And then its plain assembly till the end.
Now i realize that this may be a bit clumsy description. heres another one from SOHC4 forum. Bit shorter, I admit...
It can be done! Not only have I done it, but a few weeks ago Steve Tenenbaum and I did his. You don't even have to take the engine out of the bike. Here's how:
1. Remove oil pan, clutch cover, & clutch. The clutch "requires" a special socket from Honda, but I made it out of a 1" diameter steel plumbing pipe and a dremel. Follow the manual's instructions, but don't disassemble the clutch, just take it out.
2. Loosen the two bolts holding the primary shaft in and slide it out. The starter clutch is bolted to the primary drive chain gear, so the chain will keep it from falling out.
3. There are three bolts that hold the starter clutch to the primary gear - you need a Torx 30 head to get them out. You can see them through the hole the primary shaft slid out of. It's tricky, because you have to go through the holes in the starter gear to get to the bolts, and you have to loosen all three before taking it out because the bolt head won't fit through the holes in the starter gear.
Once unbolted it should drop out, and you can see what's wrong with it. On mine and Steve's both, the three holes in the edge of the clutch-outer were warped, and the springs behind the roller push-pins were mangled. Here's a link to the parts, and this site uses the same diagrams the dealers do:
http://houseofmotorcycles.bikebandit.co ... ematic_vie w.asp?schem_dept_id=213328§ion_dept_id=1§ion_dept_name=OEM+% 28Stock+Parts% 29&dept_type_id=2&model_dept_year=1981&model_dept_mfr=Honda&model_dept _id=206277&model_dept_name=CB650
It took us about 2.5 hours to change out Steve's and neither of us have had any problems since the operation. The parts can be expensive, but if you look on eBay you can sometimes get lucky. Email me if you have any questions, and if you live near St. Louis, MO I'd be glad to help out. Good luck!
In any case - I wish you luck, (it's easy, really) and don't hesitate to ask. At least this is a place where I feel solid knowledge
And making those parts yourself was no big deal, really!
Regards!
Hey Buber, thanks a lot! I owe you a case of beer pal! 
I did suspect that it should be possible. A friend of mine managed to overhaul the starter clutch on his Kawa Z650 the same way (the starter clutch on the Kawa is the same system, and with same problems as the CB650), but since Roberts post about the issue is long gone I wasn't sure.
And even if it is some fiddling, and it should take me 5 hours, it beats taking the engine out of the frame and splitting the crankcase.
I have ordered new rollers, springs and pins, and hopefully they will fix the problem. The price wasn't too bad either, a total of €24+shipping.
I owe you a case of beer pal!
I did suspect that it should be possible. A friend of mine managed to overhaul the starter clutch on his Kawa Z650 the same way (the starter clutch on the Kawa is the same system, and with same problems as the CB650), but since Roberts post about the issue is long gone I wasn't sure.
And even if it is some fiddling, and it should take me 5 hours, it beats taking the engine out of the frame and splitting the crankcase.
I have ordered new rollers, springs and pins, and hopefully they will fix the problem. The price wasn't too bad either, a total of €24+shipping.
Hi,
can be done. In the meantime I have done it with the engine in frame, I had a lifting platform at a DIY shop that helped though.
in reference to the parts catalogue, page 78, the only real trick is to loosen screw 29 and slide out the shaft 14 just so much that the starter reduction gear 13 can be moved away a bit to have more room to take the starter clutch out. (I know you have the catalogue, Ibsen )
Robert
can be done. In the meantime I have done it with the engine in frame, I had a lifting platform at a DIY shop that helped though.
in reference to the parts catalogue, page 78, the only real trick is to loosen screw 29 and slide out the shaft 14 just so much that the starter reduction gear 13 can be moved away a bit to have more room to take the starter clutch out. (I know you have the catalogue, Ibsen
)
Robert
Hi Robert, it's good to see you around. And thanks for the tip. Yes, I have the catalogue. 
I had prepared myself on splitting the crankcase and go by the book, but then I remembered that you posted about this issue on the old 650 forum. Not that splitting the crankcase is such a big issue, but it is much more time consuming. Doing it your and Bubers way I just need a rainy day.
And thanks for the tip. Yes, I have the catalogue.
I had prepared myself on splitting the crankcase and go by the book, but then I remembered that you posted about this issue on the old 650 forum. Not that splitting the crankcase is such a big issue, but it is much more time consuming. Doing it your and Bubers way I just need a rainy day.
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