Couple of bits of help

[v58fuy]

Guys,

Firstly I'm not slagging the N5 in anyway, because I bloody love mine, it's great.

However, does anybody else suffer from main shaft play - front to back, and left to right NOT up and down?

Also, am still getting the odd one way lock-up, despite having blown all grease out, lightly oiled and then sanded the sleeve completely smooth - is this still affecting others?

Lastly, my OS55 runs well and is currently set with idle a little leaned, mid at 1 1/4 and main at 1 1/2 turns - and yet it still seems rich particularly in the mid/low end region (tried leaning the low out more and it was better, but then wouldn't start well from cold).

David

[jamiem]

I've got no play in my main shaft at all, the only thing it can be I'd have thought is bad mainshaft bearings. If they have worn it could cause it, and also I guess if they have gone that bad they could lock up and wear the plastic bearing blocks, also causing this issue. I get the very occasional one way lock up, but not had it for ages. Not sure if anything has changed on the newer kits though, I'm sure climb-out could advise on this one.

[debrooker]

Hi David,

I have no main shaft play either in mine.

I can't comment on the one way as I have only done one auto, and it landed safely.

I do (don't wish to hijack your thread) have a cause of low head speed wobbles, so will be removing the button head to see if that helps - as Matt Botos has commented on.

[Britflyer]

There can only be 3 real areas for the play to develop.

1) Play between the mainshaft and bearing (this could be a tolerance issue with the shaft or bearing). If this is the cause generally removing the shaft will show a witness mark on the shaft where the shaft has been rocking in the bearing. Raptors used to be bad for this, even wearing a groove into the shaft eventually!

2) Damaged Bearing that is breaking up internally.

3) Play between the Bearing and the Bearing Block (this would seem unlikely for a plastic bearing block setup though).

When you rock the mainshaft can you see where the play is? If you have enough play that you can feel it then you can probable see it if you look for it.


On the engine front, the N5 has quite a low slung tank, which isn't ideal. Compare the tank position between the N5 and a Trex. The Trex tank outlet is pretty much bang inline with the middle of the carb, whereas the N5 is below. Which means going from inverted to normal way up will have a greater effect on the N5. I fitted a header tank inline with the carb and uniflowed my main tank, which allowed my Novarossi to run much more consistantly, therefore allowing the needles to be tuned better.


Paul

[ROSSCO]

Hi David,

I have not noticed any play in the mainshaft assembly on mine but i will check it and see if it has any. I remember back in the day when flying Raptors that the bearings would wear the plastic in the frames causing a similiar issue to what your describing. We used to rectify it by running a bit of CA or epoxy in the grove that accepts the bearings in the frames so that once set it would just give a little more grab on the bearings and remove the play. You could try a similiar method to see if it removes the play, if it does then maybe repalce the plastic bearing blocks or go for the metal ones. I actually prefer the plastic ones as i find them easier on the bearings.

I will check mine though and let you know.

With the Auto-Hub, since i did my modification to the sleeve and bearing by grinding and polishing the sleeve outer surface and then removing all the grease from the bearing and cleaning with solvent, then relubing with Tri-Flow i have had no further issues with the auto-hub locking up.

My OS55 has been running great with the Hatori SB55 and i've got the needles pretty much spot on now but it did seem slightly on the rich side at the bottom end, i've had to lean the idle needle very slightly to give a smooth idle but it's running like a champ at the moment!! I run my setup with an OS bubbleless clunk at the moment, i was running a fuel Magnet in there but it degraded on the field and the only thing to hand was an OS Bubbleless clunk so it got fitted and i've left it in as it seems to be working well.

[v58fuy]

Guys,

Thanks for all the replies, as I said overall I am very happy indeed with my N5.

I will do some more investigating into the main shaft play, it may be a combination of things i.e. main shaft a little undersized, small play in bearings, and small amount of play in the bearing blocks.

The one way bearing is definitely better since I blew all the grease out (looked a bit odd at the petrol station I bet), and sanded the sleeve - just still get the odd lock-up.

My 55 pulls really well but I think it's probably still a little rich across the board, might play with this next time out.

David

[v58fuy]

Guys,

Has anyone found a cheaper source for the main shaft/clutch bearings - 10x19x6 seems an odd size, generally 10x19x 5 or 7mm but not 6mm, Synergy bearings are £10 each.

David

[Tony15]

try here Simply Bearings Ltd ~ Oil Seals SKF FAG TIMKEN KOYO NTN NKE TRULOC Needle Rollers Taper Rollers Rod Ends Oilite Bushes Loose Balls O Rings Grease Plain Thrust

[v58fuy]

Same problem they dont list 10 x 19 x 6mm

david

[Droid]

Have you actually measured your bearings to check they are 6mm?? Will it make a difference if you fit the larger width 7mm??

[beeflyer2]

Have you actually measured your bearings to check they are 6mm?? Will it make a difference if you fit the larger width 7mm??

Yes, the upper main shaft bearing is indeed 6mm width.

[Eckchaz]

I just checked RcBearings.co.uk for you and they dont list the 10x19x6 either?? They only do a size either way as you mentioned and also checking on the N5 Manual.. the 10x19x6 is correct?!

My 55 runs well but again a tad on the rich side only because mines been eating bearings previously but it still pulls very well

[Droid]

Yes, the upper main shaft bearing is indeed 6mm width.

OK but could it be supplemented with a 5 or 7??

My N5 will be here next week so i could look at it then.