OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Reel Lawn Mowers, Atco & Villiers etc. Is it possible to bore out clutch drive hole to 3/4" from 5/8"?

Hi folks,

My 17" Rover 45 clutch has a 5/8"(16mm) drive bore and I want to replace the engine with a Honda or even a new B&S.
There seems to be more engine options and stock levels with a 3/4" (19mm) drive shaft.

Does anyone in Perth do that kind of boring out alteration to the clutch?
The current drive on the Rover 45 uses a 5/8" keyed drive shaft from a 3.5hp B&S.
The clutch is in great condition, just the engine has lost power and burns oil.
I'm kind of fond of the Honda engines.

Hi Phantoma,
A good place to start looking for a fitter and turner is to ask at a local bearing shop, they usually know somebody retired who can do that sort of stuff in their shed

Thanks Norm, is it something a handy person could do themselves?

I still have an old drill press. I could screw it to a wooden bench and use some of my big G-clamps to secure the clutch housing in position.
I'd have to buy a 19mm hss drill bit but you can get a short shank one for $15. The key slot would be shallower afterwards but I could grind the keys down to fit.

Hi Phantoma,
Drill will move around too much, it needs to be done in a lathe or mill. All you will do by drilling it is having to chase around and buy a new clutch

Thanks Norm,

I won't be trying that then.

Definitely wouldn't try with a drill - if you slightly imbalance the clutch you will do everything from crack the frame rails, prematurely wear the bearings (clutch and driveshaft) and potentially put more strain on the pto side bearings of the new motor.

I would suggest ringing trident mowers in swan view

Otherwise a new 3/4 clutch half is $100. If you are dropping 450 on a new briggs or even more on a honda, 5/8 shouldn't be too hard to find.

Thanks Tyler for the info on Trident mowers.

I'm leaning towards a Honda GP160 which apparently only comes in 3/4" drive shaft. I can get hold of new one for $397 from the Honda Shop or a used one in excellent cond for $260.
The Honda GX range are pretty pricey.

the gp160 is a good engine - seen/worked on one that is on a pressure washer at a truck depot. used by 50 different people, has had diesel through it, water through it and it still goes well.

please put a photo of a gp160 and a briggs cr950 side by side - they are pretty well identical. pretty confident that you can't directly get a cr950 from briggs but if you can find one in used good nick its an option. I have a cr950 on a pressure washer (actually a rs950 but same thing) goes well, can be a little hard to start if the weather is a certain temp (but its probably because of the pump resistance).

also have a 127cc briggs xr, very decent motor. Bottom dollar for one of them around here is $425

I bought a new 3/4" alloy clutch half from these guys : https://www.reelmowersolutionswa.com/

Did the job. I have a lathe and figured I could bore out the 5/8" clutch, but it had a cotter pin and I couldn't be bothered with the faffing about to bore it out and drill/tap for grub screws.

I've kept the original Briggs and 5/8" clutch half "just in case", but the Robin that replaced it is a much more agreeable motor.