OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Victa Lawn Mower Frames Victa Imperial - Parts

hi guys i have to replace the drive sprocket on the cylinder of my 16" imperial and will be getting it all ground.

my question is would i be able to get a sprocket anywhere and would there be a replacement bed knife available or would they be able to re grind it as it is in fairly good condition.

cheers

Hi Gizmo, I have done a little research for you for the cutter sprocket....Unfortunately spare parts are very thin on the ground for the Imperial....I have found none listed anywhere.

Maybe the cutter sprocket that is fitted to the Morrison/Masport Olympic 500-600-660 may be the same diameter and pitch that is required....but I am only guessing. You may have to source one in New Zealand where they are manufactured in Hastings.

Re: the bottom knife blade, the engineer that does the spin-grind will be able to make one for you if necessary, or regrind yours if it is serviceable.
You should also take the sprocket to him and ask his advice...he may have a good idea or able to fabricate one.
As time goes on, these machines are going to be harder and harder to service, due to the lack of spare parts.

Hi deejay

Once I manage to remove the sprocket I think I will do as you mentioned and see if I can get one engineered it seems as much as I try to search for parts the less I seem to find. Such a shame.

Yes Gizmo, it is a shame...but at least some members here, like yourself, are keeping the dream alive for future generations to see.
Please let us know how you get on.

cheers deejay

with the quick crafting of a sprocket spanner its now off, im pretty sure from what i can see a sprocket from a olympic 500 should fit perfect. only thing is the victa sprocket is a 12/23 tooth and the olympic is a 10/23 which might be the straw that breaks the camels back!

Hi Gizmo...maybe grumpy will chime in here and give you some advice...I'm not sure of the ramification 2 less teeth would cause...

gizmo, reducing a driven sprocket from 12 to 10 teeth without changing the drive sprocket would increase the output speed by 20%. This is not an impossible amount for the cutter drive, at least if the cutter is running without contact but it does move the cutting speed away from the optimum. More importantly though, that is a double sprocket, and the other part of it must be driving something. Whatever it is will be driven 20% faster as well - and it looks to me as if it includes the drum, so your mower will be wanting to canter around the yard bouncing off obstacles while you struggle vainly to keep up. To avoid this you have to either run the engine slower (which has the advantage of reducing the cutter speed, but it will also reduce available engine power) or slip the clutch considerably more than usual.

Realistically, if your Imperial has a Victa 2 stroke engine it probably has far more power than a cylinder mower can use, so running it 20% slower than intended is probably more or less feasible. You'd have to try it for a while and see.

im thinking at this stage ill get a new sprocket engineered the mower is way to fast as it is dont want to be getting dragged round the yard!

If you are getting a sprocket made, why not get 14 teeth and slow the mower by 14%? You'll need a longer chain of course, but the old chain is bound to be worn out anyway by the look of the sprockets.

great idea grumpy! i will be heading to the engineer tomorrow hopefully its a goer. my question is which part of the sprocket would i be loocking to change to a 14 tooth, the 23 or the 10.
(the 10 tooth goes to the drum)

gizmo, let's just be sure I've understood the picture correctly, because the chain is not fitted in the picture. Is the 12 tooth sprocket driven directly by the motor shaft sprocket? That is what I've thought was happening, but if I'm wrong, and the motor shaft sprocket drives the bigger sprocket behind the 12 tooth one, then the 12 tooth is actually a driving sprocket, not a driven one, and a 10 tooth sprocket replacing that 12 tooth would actually slow the drum drive by 17% without changing the speed of the reel. That would be exactly what you want.

Can you post a picture with that front chain installed (from the engine shaft to the reel) so we can see which sprocket it drives, and we will end up with a sensible archive?

ok the first picture is with both the chains on

the second is with the chain from the motor to the reel

Thanks gizmo, my guess that the engine sprocket drove the 12 tooth was wrong, it drives the 23 tooth that is behind the 12 tooth. The 12 tooth drives the clutch and the drum. That means the 12 tooth is a driving sprocket, not a driven sprocket, so having fewer teeth on it slows down whatever it is driving.

If you fit the NZ sprocket, and it has 23 teeth on the back and 10 teeth on the front, you will slow the drum by 17% without having any effect on the reel speed. That sounds like exactly what you want. Imagine it, the NZ guys actually fixed Victa's mess-up and made their mower work better than when Victa made it. We may have to suppress this information, or the NZers will become insufferable.

Haha true grumpy!, that makes it very easy then hopefully the masport boys in fishwyck can help me out. one more step closer to it being back up and running.

Hi gizmo, and thanks to grumpy for sorting out the ratios for us.
So it looks like Victa were employing the Ransome unit before the whole shebang was shifted to NZ. Good work to Morrison to sort out the speed problem....or could it have been Scott Bonnar??...as it was badge engineered as a Scotty...could they have had input to the engineering side?
Guess we will never know for sure.
gizmo, please let us know how you get on mate,

A History Record is now available for the Victa Imperial.
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=72511


This topic is now Closed and Locked.