Hi all, hoping some experienced members here, specifically with the old Cox cone/friction drive systems, can help me diagnose what's going on with my New Generation.
To give some history on my machine, I purchased it for a couple hundred bucks over a year ago, was told by previous owner it's only good for parts as engine is "worn". Ended up putting on a new head gasket, adjusting valve clearances, couple new belts, blades, and it's effectively been my primary mower on a 10 acre block all this time. Apart from occasional repairs on deck, or new belts, etc, it hasn't missed a beat.
Until recently, it started with intermittent shuddering/slipping when going up steep inclines, and would be fine otherwise... but progressively got worse to the point where even on flattish ground, if it was under a bit of load it began shuddering, only when going forward, more noticeable when I really had to engage forward peddle with some pressure... if I eased off pedal a bit wasn't as bad... but got to point where it became unusable.
Cone was pretty worn down, and plates not making full contact and a bit grooved... so figured just needed new cone and plates some machining. While I was at it, I also changed out bearings on clutch plate shaft as well as bearing on the cone pulley... and also changed drive chain out for a new one.
Problem is, after doing all this, the bloody shuddering issue is still there. Even worse perhaps.
The only clue as to what might be causing it, is when I jack the rear end up off the ground, and push pedal down so plate touches the cone, when I manually spin the wheels/shaft, I can only hear the plate making contact with the cone for a small portion of it's rotation. I'd got the plates professionally machined to match the new cone, and based on the marking left on plate after running it a little, it does appear to be making full width contact on both plates. So I thought well maybe somehow the clutch plate shaft has slightly bent or something (even though seemed incredibly hard to imagine how that could happen)... so ordered a brand new shaft, put it in today... and the damn problem is still there. I'm pretty much out of ideas on what could be causing it.
Anyone else had an issue like this? or any ideas at all on what could be causing it?
Thanks Bruce, however I've had the manual since day 1 of getting it -- I do refer to it very often when sourcing parts or doing repairs, for example I did use it to find the correct part numbers when sourcing the new bearings and clutch plate shaft, but unfortunately it's no help with figuring out the root cause of this particular issue.
Had another try at diagnosing the problem today... Pulled off the chain to isolate the shaft only, in case any issue with cogs, but problem remains. With the rear jacked up and pedal pushed forward just enough to see crack of light between right plate and cone (ensuring it makes no contact with cone to rule out any movement of the cone/pulley/clutch arm assembly), I can visibly see the gap grow/shrink very slightly on each rotation. And also same deal between left plate and cone.
So I have to assume the shaft/plates are not rotating perfectly true which is what's causing the shuddering issue... Only it's odd that it only shudders when driving forward, not in reverse.
But having already gotten shaft replaced, bearings replaced, and plates professionally machined... I'm still at a loss at what else could be causing this? Is it possible the plates are slightly wonky? Or something else I'm completely missing?
In case anyone else has similar symptoms... it was the small cog/sprocket. Thought it was okay but turns out was worn down just enough that with the new chain, under load, it started slipping teeth.
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