Cat SX - Struggling to mesh pinion & spur

[Verde]

Ive just set up a used sx I bought, but Im struggling to fine tune the spacing between pinion and spur gear. It's either too loose or too tight and I can't find a simple way of adjusting it. I read an old thread regarding the same problem, but it didn't get to the bottom of how it was solved, despite changing lay shafts and bearings.

Any advice welcome.

Jason.

[andy-aj]

Put a piece of paper between the spur and pinion, then move the motor/pinion upto the spur and lock up the motor screws. Roll the spur to get the paper out. Then roll the spur over and see where the tight spot is, and mark it with a bit of tipex or pen. Re-adjust with the paper and the marked tight spot inline with the pinion.

[john333]

It's not got motor screws, the motor is clamped around its circumference.

Make sure the motor holder slides freely backwards and forwards without the motor in, then what I used to do was fit the motor in and only nip it with the clamp screw relatively loose still. Get the mesh so it's quite loose by sliding the motor back towards the spur, finally tighten the motor clamp screw tighter and it should bring the pinion closer to the spur......

......well it did in mine anyway

[Verde]

Thanks fellas. When you said the motor mount should slide it rang alarm bells. I've studied manual and realise there are four adjustment screws. Unfortunately the previous owner seems to have over tightened the two m3x10 screws that go through the chassis and the hex head is too worn to get grip. Ahhh, the problem just got worse.

[andy-aj]

Sorry Verde, didn't think about motor clamp sliding, ( thank's for poinyng that out John) as opposed to motor bolts doing the securing, but you get the point regarding the paper I guess.

[john333]

Thanks fellas. When you said the motor mount should slide it rang alarm bells. I've studied manual and realise there are four adjustment screws. Unfortunately the previous owner seems to have over tightened the two m3x10 screws that go through the chassis and the hex head is too worn to get grip. Ahhh, the problem just got worse.

Damn, that's a pain! :( in my days as an engineer I would have used a pin punch and small hammer to knock the screw anti-clockwise to loosen it, or use an imperial driver (sorry don't know what size) which is a tiny bit bigger than the metric one and might loosen it off for you.

[Verde]

Andy, no worries... I still learnt something from your reply so thank you. John, luckily my Brother-in-law is an engineer and sorted the problem in no time - the screws are M3/10 pan heads and I think he did something similar to what you said. Once I pick the car up the motor ring should slide freely - fingers crossed.

Thanks again,
Jason.