PDA

View Full Version : cb125T am I missing something here?



dangerous
13th September 2008, 21:46
Ummm, ok well its kinda like this... I forgot how it goes back togeather LOL

Na not quite but I do need the knolage of the other 125T riders.
The cam in the twin, does it just have suport at each end?
the head looks like it should have jurnals to suport the cam in the center each side of the cam chain, but the cam has a rough casting about 5mm wide and it tapers down steaply.

Am I missing something here or do the inner suports on the head and caps not do anything leaving cam suport at each end only?

Shadows
14th September 2008, 00:11
I would say the cam is only held up at either end. Note the lack of notches in the centre.... another pair of journals there would just spin around.

The rough cast area is a bit of a giveaway too. I reckon you're on the right track.

dangerous
14th September 2008, 08:10
The rough cast area is a bit of a giveaway too. I reckon you're on the right track.

Yeah I think so cos I dont have any spare parts... how ever I picked up another head yesterday from a wreckers and it still has the 1/2 shell jurnals sitting in the center shiney sclops, weird cos all 3 of my cams from diferent modle twins all look the same :blink:

T.W.R
14th September 2008, 10:06
Have a nosy here D :niceone:

It's a online schematics for the CB125T

http://www.cmsnl.com/honda-cb125ta-australia_model16555/partslist/

I've got a service schedule for these but the diagrams aren't clear enough to show what you're after

Skunk
14th September 2008, 10:31
Just bearings at each end D. Nothing in the middle.

Buddha#81
14th September 2008, 10:40
Nothing in the middle.

Much like whats between the ginernuts ears.:wacko:

gav
14th September 2008, 11:19
Have a nosy here D :niceone:

It's a online schematics for the CB125T

http://www.cmsnl.com/honda-cb125ta-australia_model16555/partslist/

I've got a service schedule for these but the diagrams aren't clear enough to show what you're after
Yeah good site that, was about to post the same. Oh well might as well ...
http://www.cmsnl.com/honda-cb125t-general-export-kph_model16526/partslist/E04.html

speedpro
14th September 2008, 13:38
I don't have any experiance with the innards of a CB125T (them being one of those pussy 4-stroke things) but your cam doesn't look like it belongs in that cylinder head. It "looks" like your cam has tapered thrust journals either side of the chain sprockets to keep it from floating too far sideways but the head appears to have normal bearings in the same places.

The other thing that caught my eye is how little valve stem is projecting above the collets and retainers. If that was mine I would be having a very careful look and measure to ensure that the rockers are actually acting on the valve stems and not touching the other bits. You WILL drop valves if they do touch.

k14
14th September 2008, 13:40
I don't have any experiance with the innards of a CB125T (them being one of those pussy 4-stroke things) but your cam doesn't look like it belongs in that cylinder head. It "looks" like your cam has tapered thrust journals either side of the chain sprockets to keep it from floating too far sideways but the head appears to have normal bearings in the same places.
The two heads of my CB engines have exactly the same design so not sure why it is like that. Pretty sure honda didn't use that cam or head for any other engine so can't think why it is like that??

timg
14th September 2008, 15:58
Ummm, ok well its kinda like this... I forgot how it goes back togeather LOL

I have a Haynes workshop manual for it if you wanna borrow it? That your tractor parked outside Repco this morning?? Cheers.

Skunk
14th September 2008, 19:48
I don't have any experiance with the innards of a CB125T (them being one of those pussy 4-stroke things) but your cam doesn't look like it belongs in that cylinder head. It "looks" like your cam has tapered thrust journals either side of the chain sprockets to keep it from floating too far sideways but the head appears to have normal bearings in the same places.Nah, it's odd but it's the right cam in the right head. Nothing missing, nothing wrong. As K14 said, odd but correct.

Agree with your comment about the valve stem not showing much above the collet though.

dangerous
14th September 2008, 19:54
I have a Haynes workshop manual for it if you wanna borrow it? That your tractor parked outside Repco this morning?? Cheers.

yeah wouldnt mind ta, when you in town next... and yes that was my MOTO GUZZI V11 LEMANS NERO CORSA, I was after a universal for the axualary drive for the combine harvester... prick :cool:



The other thing that caught my eye is how little valve stem is projecting above the collets and retainers.
LOL, sorry SP, dont look that close thats my spare head I just used it as an example... let me flip it over and you will see those two valves aint the happiest.

gav
14th September 2008, 20:47
LOL, one you prepared earlier? :buggerd:

nudemetalz
14th September 2008, 21:27
yeah wouldnt mind ta, when you in town next... and yes that was my MOTO GUZZI V11 LEMANS NERO CORSA, I was after a universal for the axualary drive for the combine harvester... prick :cool:



...and you know how often I get mine called a bloody "tractor" :argh::angry2:
They're all only jealous !!!

speedpro
16th September 2008, 16:41
LOL, sorry SP, dont look that close thats my spare head I just used it as an example... let me flip it over and you will see those two valves aint the happiest.

That will not affect how much valve stem extends past the collets and retainer which is a function of those two items. Do you have any little marks on the outer edge of the retainers or are the collets shiny/marked on the top edges that are visible? That will be evidence that things aren't right and the valves are being allowed a bit of freedom resulting in the carnage in the photo. Opening pressure from the cam or tappet must be applied to the valve stem and the closing force of the spring applied through the retainer and collets to the valve. It's an easily made mistake if custom valves or cams are being used. The underside of the rockers can touch the outer edges of the retainers which can unload the collets allowing the valve to rattle around a bit, or a lot.