Hayter Harrier 2 Dog Clutch Adjustment

[REC 2]

Hi all

 

I have a Hayter Harrier 2 and I am mindful of needing to keep the dog clutch correctly adjusted. How do I check the adjustment of the clutch given that the red plastic sleeve prevents me seeing the engagement/condition of the clutch?

 

I presume that adjustment is done by the nut on the threaded post next to the operating fork.

 

Thanks

[Wristpin 400]

Before attempting clutch adjustment you should check for, and if necessary eliminate end float on the engine’s Auxilliary Power Take Off shaft. Assuming that your Harrier has its original engine the chances are that it has a couple of mm of in and out movement this makes any attempt at dog clutch adjustment fairly futile. When dog clutch Harriers were in common use I made an unofficial modification to reduce / eliminate the end float buy inserting a shim washer onto the APTO shaft within the engine sump. The shim that I used was in fact a Qualcast part number and with a bit of practice the operation could be done through the “ port hole” without removing the engine sump.

That said, I may be able to find Hayter bulletin on the correct adjustment procedure for an APTO with minimal end float. If I can find it I will post it later.

 

[REC 2]

Many thanks for the information. There is indeed some end float. I will get the porthole cover off and check the shaft diameter for the shim. 

 

I assume you still had to get the engine off the deck or remove the driven half of the clutch to move parts along the shaft,  or did you keep everything in situ?

[Wristpin 400]

Engine off makes life easier 

The shim / thrust washer is a Suffolk / Qualcast part F016L08500 and was used on the 30,35 and 43 cm cylinder mowers  on the top shaft by the spherical bronze self aligning bearing. A possible source is the Gateshead Garden Machinery company who bought up all the old stock when Bosch disposed of the Atco, Suffolk and Qualcast brands. Another possible source is Jon Cruse at the Hailsham Mower Centre : he specialises in obsolete stock.

When you open the port hole you will see a bronze gear retained with a roll pin. If you are careful and angle the gear so that there is some clearance behind the roll pin, you can tap the pin through just enough to clear the shaft and release the gear without the pin falling into the engine . The shaft may then be withdrawn and the gear lifted out. You will probably see a recess worn  into the thrust face of the gear  - that's where the shim goes. If, when you offer it all up and and the shim is too thick , don't try to force the pin back in  but carefully reduce its thickness on an oil stone. You don't want the shaft to bind through total lack of end clearance.  

I always used to replace the roll pin with a Spirol pin which had more resistance to overload shearing and meant that any overload sheared one of the exterior roll pins. An issue in this metric age was sourcing an imperial diameter Spirol pin   - use too thick a one and the boss on the bronze gear will split around the pin hole.

[REC 2]

Thanks for such a detailed guide, I'll see how I get on.

 

Just have to see how getting the friction disc off the crankshaft goes...I have a nearly new can of plus gas...

[Wristpin 400]

Getting the disc off can be difficult and really stubborn ones need a lot of heat on the boss and that means oxy- acetylene. 

Try turning the machine upside down ( drain oil first!) removing the blade bolt and then filling the hole with Plus Gas  ( diesel is good and cheaper!) and leaving it to soak , topping up as needed, for a couple of days.  A home made puller will hep.

Going back to the end float on the APTO shaft perhaps I should have said that if removing the disc is an issue , 20/ 25 thou  is probably acceptable . 

Clutch adjustment as follows. Set the cable adjuster on the handle bar lever mid way. Pull the APTO shaft outwards to take up the float, with the clutch lever locked in the disengaged position,  adjust the fork using the fulcrum nut so that the two dogs are just touching then turn the nut one turn plus two flats to move them apart. Make sure that you keep the APTO shaft pulled outwards. This should ensure positive engagement and disengagement even if the APTO shaft is wandering about a bit.

[REC 2]

Thanks for the clutch adjustment details. Hopefully I'll get a chance to look at it this weekend; will update when done.

[REC 2]

Update as I finally got round to starting this job after ordering a new clutch cable as the original was frayed. Hopefully the photos will be helpful to anyone else doing this job

 

I was pleasantly surprised when the friction disc slid off easily after a week's soaking in Plus Gas, so the engine was duly removed. There are some signs of rounding and wear on the clutch dogs but hopefully this job will arrest any  further wear a bit.

 

Keyhole cover removed and bronze gear exposed.

 

 

 

As the gear was a fairly tight fit on the shaft I initally thought the roll pin was still holding everything in place  so unfortunately ended up knocking the roll pin right through. Fortunately it was rescued with long nosed pliers. You can just see it siting on the gear below the APTO bush

 

Then discovered the pin had sheared. So I've decided to take the sump off to check the other half is not in there somewhere

 

 

[REC 2]

Not too difficult to remove the sump and I was pleased to find that the what I intitially thought were snapped bolts were just locating pins. Predictably the gasket didn't survive the sump being removed! Looks like the shimming of the shaft won't be before time...

 

 

General view of inside the crankcase but no obvious sign of the other half of the pin. I'll be getting the dentist's mirror in there

 

 

So just need to order a new roll pin (3/16x15/16" looks ideal but I'll probably have to get 7/8" or 1") and a new sump gasket to finish the job. The only question I do have regarding the clutch adjustment is that it seems to be impossible to remove the red sleeves over the clutch when everything is in place so do you determine when the dogs are touching by feel?

 

[Wristpin 400]

What ever you do , make sure that you account for every bit of broken pin. One of my customers didn’t bother and a couple of hours later had a split crankcase. When we were doing them , if the pieces of did not = a whole pin, the sump came off and the whole thing was flushed out over a clean stainless roasting tin (gastronorm, from a catering supply co!!) until every bit was accounted for. Bits even got up inside the piston. To make more room the cam shaft pulls out easily if you rotate the crank to just past TDC on the power stroke to relax the valves. The crank and cam are marked for correct timing on reassembly.

 

[REC 2]

Luckily the pin had snapped clean in two, and was only underneath the crankshaft counterweight. Also found the clutch was loose on the shaft so punched the pin out which came out in several pieces so new pins for both ends of the shaft ordered!

 

Compared to the Honda GV150 engine that my old Haytertte had, the B&S doesn't seem as well made; I was quite surprised that most of the shafts are running direct in the aluminium castings. Also wasn't impressed that the APTO gear has to be removed to get at one of the sump bolts!

Edited May 19, 2019 by REC

[Wristpin 400]

Good that you’ve got it sorted.

I don’t want to start a Briggs v Honda thread but would just say that there are millions of old BS engines giving good service, surviving  on minimal maintenance, and my experience is that Hondas don’t put up with that for long.

 

 

[REC 2]

After a long wait the new roll pins turned up so finally back together with all end float eliminated.  Unfortunately I now have the opposite problem of a dragging clutch.  Even if I fully slide the two halves of the clutch apart by hand I  cannot get it to fully disengage. 

 

I have tried moving the engine around slightly on its mounting holes without any improvement.  Could adding too many shims have possibly caused this? From what I can tell, inserting shims should not have caused the dog on the engine to move away from the engine casing. In addition the engine turns over easily so I'm sure I haven't caused any binding. 

 

 

[REC 2]

Managed to sort it, the drive chain was running slack, which caused poor alignment of the shaft the clutch is on.

 

There was a fair bit of end float on my engine, I ended up using 5 M13x0.3mm shims to eliminate it so the job is defintely worth doing. Hopefully the photos are useful for anyone else doing the same job.

 

Thanks for all your help Wristpin.

Edited May 28, 2019 by REC