Kitchen Garden Forum

Hi,i wonder if anyone can help,i purchased a second hand atco commodore there is quite a lot of slack in the drive chains,is there any means to adjust the slack out.neil

in general there are two methods of chain tightening
either an adjustable roller pushing the chain out of line or provision to move the cogs and shafts further apart on their mountings.
if the chain is really worn past the limit of whatever adjustment is available it may be possible to remove two links to shorten it.
ive had to shorten the main drive chain on my lawnflite mower cos it had stretched past the limits of moving the axle back.

Hello Neil,
The Commodore appeared first in about 1984??.. and must have gone perhaps about 1995??....its chassis for B14, B17 and B20 was derived from the previous model series....however on the Commodore the clutch action was reversed for both engine clutch and traction clutch to give a dead mans handle operation rather than the previous pull clutch lever to stop the drive on the earlier model. (Commodore B12 was derived from Suffolk Punch 30DL with single chain)

I only worked on a couple of Commodores...as they came out towards the end of my time in the mower world...however I would suspect that the adjustment would be similar to the earlier model.???

The first chain, engine to cutting cylinder, may well have an adjustable arm with a nylon slipper pad on top of the chain...this arm can be adjusted to tension the chain...I believe it had an extra stay/slide?? on the Commodore due to it not staying as adjusted on earlier model. What is important to remember is that as you adjust the cutting cylinder to bottom blade, in regular wear take up, you move the cutting cylinder away from engine sprocket hence the chain tightens..and if left unchecked it gets dead tight and trashes chain, bearings etc. Do check for any tight spots and make the adjustment to about 1/2 inch lateral movement at that point even if it means the chain is slacker at other positions...Mower shaft ends often run out of true due to previous inflicted damage..hence the tight and slack spots.

The intermediate chain, 2nd chain, and the final roller drive chain, 3rd chain,..on the previous model to Commodore adjusted both together by slightly loosening the centre shaft of the traction clutch...I seem to recall the spanner went right at the back of the whole unit with I think? a captive nut? at the back of the chassis plate..the whole unit is moved in a slot...then the fun starts..as you had to find a position that suits both chains...and then when you tighten it you find one is suddenly slack ..again adjust to the best you can acheive..again being aware of tight spots as if chains run too tight then the traction clutch plate bearing face will be wrecked....Now I stress this was the previous model...but suspect Commodore would follow similar.??.at least on early models..

Do not undo the traction clutch screws to investigate unless absolutely necessary..there are 52 ball bearings on the plate just waiting to run and hide under the workbench..

All good mower service agents will stock chain on a roll should you require new..

Do take care in any repair work...always best to remove and earth spark plug lead to avoid inadvertant start up....mowers may seem basic stuff at times but can and will "bite" you all the same.

Although Commodore is now an old model I would think all service agents would still be familiar with them.. http://www.atco.co.uk then the Atco Owners link then Service Agent search facility.

All the best,
Clive.

Hi,thanks for your reply have had a look and there is a belt that drives from engine to cutting cylinder with a tensioner roller.I can see the nut behind the clutch i think i will have to modify a spanner to fit.How is sprocket unscrewed off cutting cylinder to remove cylinder for sharpening,is a special tool required.thanks.

Hello Neil,

Ah...much newer version of the model then than ones I came across

Out of curiosity is it a toothed drive belt or just a V belt as the first drive.??

Toothed belt drives on Qualcast/Atco had not appeared during my time in the mower world except for one re imported ex services Suffolk Punch that lived locally...export machines to Germany had toothed belts before types home in UK..

I was aware of later models changing but never got to see them....
...because after a bad time when the company I worked for closed...then followed by some exceedingly good fortune....I left the mower world to become a gardener


If it is like the previous model.??? then I reckon I had a slightly cranked spanner to get It to fit into place behind the clutch unit...I am getting windy of my ageing info now...in case they changed the adjustment idea too.!!

Again ...on previous Atco model.!!..the then double chain sprocket for the cutter end was screwed onto the cutting cylinder...left hand thread if memory serves me correct??...so all the time it was driving it was tightening....hence mighty hard to shift...with wooden shaft into cylinder and big peg spanner.

Sadly I don't know if the later version that you have unscrews similarly.??...perhaps some more up to date info may surface or perhaps run your quest past a local agent rather than cause any damage.??!!....if only via clues from a parts book.

All the best,
Clive.

Hi,it has a toothed belt