Having now sorted my carby the next fix needed on my 1976 AG 175 is the clutch. It is working in that I can engage and disengage via the clutch handle but under load it is slipping badly. I have zero experience in clutches so before I go straight to pulling it apart I thought I should first ask the brains trust here what I should do? Is it best to just pull it apart and inspect, identify needs of either new plates or adjustments, or is there other things to check/do first? Should I be ordering parts before I even pull it apart - I mean is it standard practice just to put all new plates in when redoing a clutch? Any advice before I make my first move would be really appreciated!

Thanks
Ian

There are a few things that can cause a clutch to slip , other than the clutch itself .
Using a car type oil in your gearbox for one . They have a number of friction additives ,
that often play havoc with a wet clutch on a motorcycle .
The clutch cable , and / or lower adjuster down at the engine , may be bound up with
dirt / grease , and may not release properly . The nylon gear on the lower adjuster can split too ,
which could also cause it not to release properly . There is an adjustment which should be made
at the engine adjuster , which is detailed in service manuals .
Until you've gone through all these checks , I wouldn't be diving inside the engine .
However , if that's needed , there are really only three components .
Friction plates are checked for thickness , specs in manual .
Steel plates are checked for flatness , laying on a glass surface will show that .
Springs are checked for free length , specs also in manual .
If you do wind up replacing worn clutch friction plates , then the adjuster down
at the engine , will need to be reset .
Good luck .

Early 175's in US all had metal worm gears... after 1973, no worm gear at all... not too familiar with the AG175... the pictures I've seen look like it has the 69-73 style engine with the worm gear and clutch adjustment in the side cover we got in the US.

Good advice to check adjustment first...

Only thing to add is make sure you get the right disks. Yamaha clutch disks often fit many models and are sometimes made in different thicknesses. I came across a 175 that had brand new disks with a badly slipping clutch. Disks were 2mm thick but were supposed to be 3mm... correct disks fixed the problem.

Ag's were pretty soft in the spring [by memory] but the rubber spreader rings aggravate slipping & should be biffed out. They sit between each steel or in other words they sit under the fibers & assist in spreading the clutch but [in my pinion] they're not necessary & only make a slipping clutch worse. Plates are probably glazed up by now so new fibers & give the steels a scratch & she'll be good. Not sure how you can check the springs compared to new ones out of another model for tension comparison, but new CT3 springs might be stronger being the same motor but a bit more powerful so maybe stronger springs required [guessing]. Anyway--cable must be nice & free & operating worn that the cable puls. Your one will have a nylon outer worn i think. Here's a link to a much later AG but still shows the ring cushion 'No7'. Couldn't find a parts pic of the older model but this popped up so near enough for the purpose to show you. & in the second link the nylon worm is No29 if you scroll the pic down a bit.

yamahaoemparts.com.au/partFinder/fiche/y...175/clutch#ficheZone

yamahaoemparts.com.au/partFinder/fiche/y...175/clutch#ficheZone

Ok guys - finally started on the clutch. I checked cable and could really not find any issue so dove in and pulled engine cover off.

The nylon gear looks ok. - photo attached.

So here is what I’m looking at - I guess I go ahead and remove clutch and do a full inspection. Anything else I should do first?


I’ll need to source new gasket, new screws etc as it wasn’t easy to get to this stage but now I’m in I want to give it my best shot!

Ian

Those five Phillips screws holding the clutch basket on are TIGHT! I can see I could easily strip these. Any tips on removing them without resorting to vice grips, easy outs and other such methods? I’ve not stripped them but can see it could easily go that way. Impact river I guess is next option?

Impact driver.
www.grainger.com/product/1AT29?cm_mmc=PP...iEy:20200514110444:s

That's top-of-the-line, and for that price it should be gold plated. But you get the idea. Put the bit holder on the business end, put the screw driver bit in the screw head, whack it lovingly with a 16 oz hammer. The driver twists and the impact makes the bit grip the Phillips grooves.

Best tool in the box = impact driver
Especially if you plan to work on motorcycles.

Edit:
First tool in the box = Hammer

Taking your life in your hands using an impact driver on those as the posts snap off if ya get too brutal. Best bet 'i think' is to get a NEW impact tip the right size not a size under--& put it in an 8mm TBar Handle. drop a leather belt into the crank/ clutch gear to stop it turning. "i use a bit of alloy but don't want to teach you bad habits". Straight push while turning & it'll crack free. Think they're only a 5mm thread like very early DT1's but hope they're 6mm. also hope they're not locktited in which would be unlikely--but.

If i bracket something it doesn't show when i post. Often does it--not sure why. Did it again & brackets off & works.

If those screws are that tight, I'm surprised they aren't broken! They don't need to be more than "snug" and are easy to break when tightening...

Don't ask me how I know...