Lely Lotus 770 Rotor Timing

[The_Swede]

Evening all,

Came by one of these a few weeks ago (from a clearly less than sympathetic previous owner).

It has clearly had a bit of abuse followed by a botched repair involving rotors being dropped then replaced 'out of time' leading to tines hitting each other.

We've had it all apart and re-timed each of them them 'by eye' thereby improving things massively but cant seem to iron out the last couple knocks - is this just a quirk of the machine or is there a set procedure we should be following - timing marks hidden somewhere etc?

Cheers

 

[Dry Rot]

I've a four rotor Stabilo which is similar. I found the best way to time the rotors was to mount the machine on the tractor, then knock out the roll pins holding on the wheels, then using a short length of scaffolding and a hydraulic jack, it is easy enough to raise the dishes until they are meshed with the crown wheel and pinion. Then a bit of trial and error to get the timing right, mark that position, and reassemble.

 

[The_Swede]

Similar methods applied here thus far (once some very seized assembly's had been freed up that is!)

Looks like a continuation of the process then....

Thanks

 

[The_Swede]

Turned out 30 acres earlier - been beforehand and semed fine but during use still some intermittent clanking resulting in the breakage of several tines.

I notice a fair amount of backlash in one of the rotors that showed tine breakage, around 30 degrees as a rough estimate... would this be enough to potentially cause the intermittent collisions / breakages? I'm sure this rotor isn't jumping a tooth as it were as it is remaining in time with the next one along...

Will drop the saucer and have a look inside tomorrow but thoughts from the outset anyone?

 

[bobk]

Time it from the middle and work out , pretty simple unless it's bent .

 

[Dry Rot]

Just put mine together this afternoon (Stabilo which is similar).

The bearing at the end of the shaft needed replacing, also there was up and down movement to the saucer, so I replaced all three bearings including the two on the short vertical shaft under the saucer. I have to admit I knocked the roll pins out a couple of times before I got the timing right! But there are are only four rotors on the Stabilo, so no big deal.

I put the arms up in the folded position, then knocked the roll pins out on that shaft. The wheel assembly and spacer can now be slid off and, if you fold out the arms, the saucer will drop off. So I stick a screwdriver in the hole where the roller pin for the wheel assembly was, then fold out the arms. The saucer will now drop down, but be stopped by the screw driver. Adjust the timing, mark the position of the saucers, lift the arms and reassemble with due attention to your timing marks!

If there are more than one saucer out of timing, I'd start from the middle and work out.

 

[bobk]

Just put mine together this afternoon (Stabilo which is similar).

The bearing at the end of the shaft needed replacing, also there was up and down movement to the saucer, so I replaced all three bearings including the two on the short vertical shaft under the saucer. I have to admit I knocked the roll pins out a couple of times before I got the timing right! But there are are only four rotors on the Stabilo, so no big deal.

I put the arms up in the folded position, then knocked the roll pins out on that shaft. The wheel assembly and spacer can now be slid off and, if you fold out the arms, the saucer will drop off. So I stick a screwdriver in the hole where the roller pin for the wheel assembly was, then fold out the arms. The saucer will now drop down, but be stopped by the screw driver. Adjust the timing, mark the position of the saucers, lift the arms and reassemble with due attention to your timing marks!

If there are more than one saucer out of timing, I'd start from the middle and work out.

That's how you do it .

 

[The_Swede]

Clear on the process, issue is it only seems to be 'out of time' intermittently and then only when in work though?

 

[bobk]

Clear on the process, issue is it only seems to be 'out of time' intermittently and then only when in work though?

Must be jumping a cog then .

 

[The_Swede]

I'll get the dish off for a look then, was certainly cheap enough and worth saving but the previous homes maintenance... deary me.

 

[bobk]

I'll get the dish off for a look then, was certainly cheap enough and worth saving but the previous homes maintenance... deary me.

Parts prices from lely are fairly frightening .

 

[wr.]

Might there be a key sheared off allowing a gear to rotate on a shaft when under pressure?

 

[Dry Rot]

I took about a bucket full of grass out of the rotors of mine -- each! There was scarcely any movement in the bearings on the wheel shaft of mine but it was enough to allow the saucer to move up and down about an inch. That movement has disappeared with new bearings.

I think if a lot of grass gets in there, with a bit of wear, it can easily force the gears to jump a tooth. There are spacers about that locking ring. I bought a selection and kept adding them until it was quite tight but I could still get the roll pin in. A short length of scaffolding pipe is handy for knocking the ring on.

 

[The_Swede]

I'll have to get it fully apart and assess, what is baffling me re the timing discussion is that if it is 'jumping a tooth, sheared the key or similar then I'd have thought over the course of a few hours work this should cause collision with the rotors on both sides of the offending one not just the one as it is at the moment.

Basically looking from behind the machine left hand three are absolutely fine, its first on right hand side and the next on right that seem to occasionally clash but then also no issue with the very outside right hand one.

 

[The_Swede]

Parts prices from lely are fairly frightening .

We're talking bought at hundreds not thousands for the machine so bit of wriggle room yet, I hope!

 

[Dry Rot]

I think the bearings cost about £8 each from the local bearings place. They are fairly standard. The keys and spacers can be bought off Ebay for a couple of quid, so don't fret! You do have venier calipres, don't you? I just took the old bearings in and the man behind the counter measured them. IF it's the crown wheel and pinion, I think they cost around £200 (but I don't think it will be).

 

[balerman]

Turned out 30 acres earlier - been beforehand and semed fine but during use still some intermittent clanking resulting in the breakage of several tines.

I notice a fair amount of backlash in one of the rotors that showed tine breakage, around 30 degrees as a rough estimate... would this be enough to potentially cause the intermittent collisions / breakages? I'm sure this rotor isn't jumping a tooth as it were as it is remaining in time with the next one along...

Will drop the saucer and have a look inside tomorrow but thoughts from the outset anyone?

Must be a fair bit of wear in the UJs,30 degrees is a fair bit of movement,and the hook tines don't allow for much slack cos of the angle they are at ie you can get away with more slack with straight down tines.Our lely 675 runs completely silent when in the air,but will clank occasionally when in work,not enough to break tines,oldish model but not done a huge amount of work.I would say maybe 10-15 degrees of movement on ours.

 

[The_Swede]

Thanks - will be apart tomorrow so I'll report back!

 

[Dry Rot]

Have fun getting the roller pins out! Had to take mine to the local engineers.

 

[Pan mixer]

I had intermittent clanking - nothing out of time but careful disassembly of a few of the tine- arms revealed very small bends where they had been wedged with a wodge - straightened them carefully in the press and no problem now.