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A A A A Author Topic: 650 starter clutch boss - possible reconditioning option  (Read 3323 times)

jhovel

I have 2 off 650 starter gears with the typical "hammered" marks on the clutch boss. They seem to be beautifully made and near indestructible in the 500s. SO I'm investigating getting them precision ground back to smoot. The indentation turned out to be less than 1/2 thou deep (~0.0125mm). That means the diameter would reduce by around 1/1000" to be smooth again.
Advice I had is that they are most likely through hardened and therefore would not not loose surface hardening in the process.
I'm currently getting a quote for making a precision mandrel and grinding them.
The price is likely to be very attractive if I get 10 or more done (to drefray set-up costs).
Does anyone else have any 'hammered' starter gears that have failed in the 650s (or 500s) they are willing to have reground (or let me have them for postage costs for regrinding for future use by the members)?
They cost a fortune new when available and will eventually make 650s too expensive to keep going. So I'm trying to find a solution in advance....

cxichy

Sounds great Joe.  Thanks for doing so much investigation and planning and design.

Every time I think I'll have to bite the bullet and take the engine out to fix my starter clutch, it comes good for a month or so.  At this stage with other committments, I won't be doing anything till after the 2009 VJMC.  Alan



Hann

Joe,when my 650 driven gear needed replacing i used a 500 one from an older type engine - they`re usually in good condition,much easier to source and a direct replacement (slightly different design the only difference);




jhovel

Hi Hann,
I have a spare 500 one to fit in my engine tonight or tomorrow.
I have one of each of the top two in your photo - both found in 650s. THe spare 500 I have is the same as the top one. What model is the bottom one out of?
I'm just checking out our options for the future.... and I hate throwing things away that can be recycled...  :)

Hann

Joe,the top two were from Euro motors and the bottom one (which is the one i used) was from an early type CX (CDI) - we call `em Z/A/B`s,i think you call `em `Shadows` ? (the Plastic Maggot type!!)

Hann.
 2coolsmiley

jhovel

OK, I have a quote to do the 'reconditioning' (regrinding) of these starter clutch bosses:
to get one done would cost $110, to get 10 done $350 = $35 each.... That sounds like a good option to me!
Anyone interested?
If we can get 10 together (posted to me here), I'll go ahead with this as a trial and post them back to their respective owners.

For interest sake: they are listed as NLA (no longer available) in all catalogues I could find for all CX/GL models and last indication of prices were around AU$200...

cxichy

I'm interested Joe.  I'll take the starter clutch out of the Bejing bike and if it needs reconditioning get it to you for later fitting to my Black Beauty.  Am I right in thinking that it won't matter if more than 10 customers sign up?    Thanks for arranging all this.  Alan

jhovel

No, Alan, more than 10 will be just fine - might even drop the price further!

That's 3 - anyone else?

Honey

Hi Joe

will check if i have one which should be in the parts section of the shed and if so will send it over to you

Mel

slipchuck

do you have a pic of the damage? and what exactly does a very shallow indent like that do to the starter clutch?
the reason I ask is because my eurosport is waiting for camchain parts and the rollers in the starter clutch.
BTW, grinding does change the hardness as any type of heat does.... the grinding has to be done with lots of coolant... the worst that could happen is the part might ware out a bit faster.

cheers

randy

cxichy

Thanks for revitalising this thread randy.    Since lasting posting on this thread,  I now have a starter clutch boss which looks like the cx500 one (bottom one in Hann's picture) as a spare which could be reconditioned ready for the black beauty.

cxichy

..... and what exactly does a very shallow indent like that do to the starter clutch?
....
cheers

randy

If you want to know what indentations in the boss and/or bad rollers and/or weak roller springs sound like, check out the first part of this utube video.


[ Invalid YouTube link ]

jhovel

Randy,
I'll try and take a sharp photo of one of the stuffed starter bosses. Will be a bit tricky, because the shallow dents are barely visible - have to get the lighting or flash just right.
The dents make the roller bounce and skip, rather than jamming tight and turning the flywheel. It does sound terrible! Like someone inside the crankcase hitting the case with a hammer from the inside....
The surface on these bosses are gorund after hardening in the first place, so replicating the grinding process a second time won;t change the hardening - as long is it is done properly and without creating heat (as you say). Only about 1 or 1.5 10th of a millimetre (0.1 to 0.15mm) will have to come off to get below the bottom of the indentations.

So far still only 3 likely candidates to do - 7 more to go before I'd be going ahead....

slipchuck

gee I was pointed to this video caus' it had a bad cam chain :)
I just bought new rollers, springs etc. the old ones didn't look like they are worn. how much smaller are they when they wear out? .001"? .005"?

also, if anyone has a pic on how the pin sits against the dowel like roller could you please post it. mine fell out when I popped it off.

cheers

randy

cxichy

gee I was pointed to this video caus' it had a bad cam chain :)

....cheers

randy

I'm almost certain that the video I pointed Randy to

[ Invalid YouTube link ]

 is an example of a bad starter clutch.  And it seems to me that the cam chain condition/tension is not apparent from the video.  Anybody else got an opinion?  Alan

phantomcxmenance

both,I reckon you can hear the cam chain rattling around but that starter clutch sounds awfull

jhovel

I know this thread went dead about 5 years ago.
However, in the interim I have built a relationship with several people who have cylindrical grinders - in fact I have one myself, which still needs restoring.
So getting these starter gears reground is no longer a big cost factor. A small nominal charge for me to buy the operator a slab in exchange for a bundle of starter gears will probably do. Add to that postage both ways and the idea sounds like a good proposition.
Does anyone have any damaged/worn starter gears they want ground - even for spares - in particular for 650s?
Let me know and post them to me and I'll get them ground - along with my 3 spares.

ACE

Hi Joe,
As you know mine has exactly that issue. It is still in the bike though and works fine until it sits for a week or so...then you have the issue until it gets some new fuel and fires up. I bought a new starter kit with rollers etc...I thought that was going to be the problem? I will be interested in your offer...but maybe when winter comes round!
Chris

hamilton

Marvelous idea Joe, there wont be any problem grinding that deep as if they are only case hardened it will be at least 1 mm deep, maybe more.
They can be ground in the lathe with a tool post grinder [ which i havent got but would like] using a stub mandrel turned [and not disturbed ]with the piece lock tited on, to be accurate a new mandrel should be made for each unit ground, at least with my lathes and my expertise level. Ralph.

PS this post may have answered a problem noise heard by 8ballbenny so i will let him know in case he hasnt read it, he goes away with work for a month at a time, would you believe it we know his Grandmother, small world aint it.

jhovel

Ralph, you are right about the principle of the toolpost grinder.
Proper cylindrical grinders are about 100 times as rigid and accurate and have driven centres and large wheels. Mine is about 400kgs of cast iron....
I would not attempt this on a toolpost grinder. We probably only need to take off a few tenths (a few dozen microns).

hamilton

Yep Joe, never having used a toolpost grinder i am sure it would be one hub in the bin, hadnt thought much about rigidity, could cause more chatter marks than the rollers did, perhaps i will save my pocket money. Ralph

fab

Ralph, you are right about the principle of the toolpost grinder.
Proper cylindrical grinders are about 100 times as rigid and accurate and have driven centres and large wheels. Mine is about 400kgs of cast iron....
I would not attempt this on a toolpost grinder. We probably only need to take off a few tenths (a few dozen microns).
how did you go joe, did you end up doing any of these for sale, I know its a very old topic.

 


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