Villiers mains roller bearings with plastic cage

[Stuart Baskill]

I have a new roller main bearing for a 9E or 2T fitted with a plastic cage for the rollers.Is this ok to use? I bought it for a 9E but my old fashioned idea is that plastic melts !! (I thought that the Shuttle using ceramic tiles was also a bad idea but I was proven wrong).Has anybody used one and was it ok?

[druid]

Plastic cages

Stuart,
I've just built a B44 motor with a plastic cage main bearing, mainly because I had a new one to hand. I would have preferred a metallic cage but I thought I'd try it (not done so yet).
Looking through the net it appears that the two main problems are longevity and overload capacity. In marginal lubrication conditions, such as a lean running 2 stroke might encounter, the plastic cage can deform more than a metal one. Not so much a problem with a 4 stroke with its own oil supply.
The question of longevity is less relevant. We are talking about a 30% reduction in life but as this means that you'll have to change the bearing every 20 seasons instead of 30 seasons it's not a problem.
Speak to the Guru, Bearingman, I don't think he's a lover of Polyamide cages.

Druid

[Stuart Baskill]

Stuart,
I've just built a B44 motor with a plastic cage main bearing, mainly because I had a new one to hand. I would have preferred a metallic cage but I thought I'd try it (not done so yet).
Looking through the net it appears that the two main problems are longevity and overload capacity. In marginal lubrication conditions, such as a lean running 2 stroke might encounter, the plastic cage can deform more than a metal one. Not so much a problem with a 4 stroke with its own oil supply.
The question of longevity is less relevant. We are talking about a 30% reduction in life but as this means that you'll have to change the bearing every 20 seasons instead of 30 seasons it's not a problem.
Speak to the Guru, Bearingman, I don't think he's a lover of Polyamide cages.

Druid

Thanks for your advice.I just wish that I had been smart enough to check it when I bought it.

[PeteNev]

Roller Bearing

If you are still worried on Ebay there is a new old stock Hoffman bearing R125 on auction it ends tomorrow 8-19 pm with a heavy bronze cage. It is listed under Villiers item no 270951659831 they are in exellant condition i know i purchased the one this seller auctioned last week
Hope this useful
PeteNev.

[John Wakefield]

If you miss the one on fleabay Villiers Services do them http://villiersservices.co.uk/index....roducts_id=161 but at twice the price, but they are new though.

[Bearingman]

Stuart,
I've just built a B44 motor with a plastic cage main bearing, mainly because I had a new one to hand. I would have preferred a metallic cage but I thought I'd try it (not done so yet).
Looking through the net it appears that the two main problems are longevity and overload capacity. In marginal lubrication conditions, such as a lean running 2 stroke might encounter, the plastic cage can deform more than a metal one. Not so much a problem with a 4 stroke with its own oil supply.
The question of longevity is less relevant. We are talking about a 30% reduction in life but as this means that you'll have to change the bearing every 20 seasons instead of 30 seasons it's not a problem.
Speak to the Guru, Bearingman, I don't think he's a lover of Polyamide cages.

Druid

Hi Stuart,

Sometimes I miss things...I far as my motors go I only use steel cages or the machined bronze cage for the roller bearings. Cost are all over the map, so it pays off to get quotes from your suppliers. I'm pretty certain for what we do, the plastic cages would be o/k, I'm not sure what the effect would be on the cages regarding the new fuels though. I have a supplier who uses plastic cages for ceramic hybrid bearings with good results, but these could be used in a oil bath application and not premix. Best bet is to use what the OEM used and be done with it. Steel or bronze...you can't go wrong...just watch out for the Chinese crap flooding the markets...BTW...a lot of these come in unmarked...or as they say neutral markings.

I hope this helps.

Regards,
Kenny Sykes

[ADickerson]

Just as an aside to this post, on Villiers singles I replace the Mains roller with a double row ball. They are about half the price and in my experience offer better support to the timing side crankshaft. Other than that I can only agree with advice and comments made so far.

[whitehillbillies]

Interested in this Mod,as I am thinking about putting a rebuilt crank into my 32A trials engine with the added lead weight. Is it a straight swap ???? what is the bearing size and number ????
The rebuilt crank is the old origional bob weight type, replacing the fullcircle one, I rebuilt it with, several years ago. The flywheel side of the fullcircle one has a slight bend, I will try and measure the run out, so tends to cause a bit of vibration, when it was full road registered. Also one of the alloy plugs in the flywheel, became loose, and fell out, luckly did no damage, and I could hook it out, once the barrel was removed. I have now put it back to Trials spec, removing lights, speedo, etc.
Has any one had much success straightening cranks ????
thanks for you comments.

whitehillbillies

[riflegreen]

The double row bearing was always used with the Alpha full circle crank , the only mod was to remove the circlip that held the N205 outer .

Works perfectly with the standard crank , gives more support and lasts longer.

Have at the back of my mind it was a 2205 bearing ???.

Chris

[ADickerson]

The double row bearing was always used with the Alpha full circle crank , the only mod was to remove the circlip that held the N205 outer .

Works perfectly with the standard crank , gives more support and lasts longer.

Have at the back of my mind it was a 2205 bearing ???.

Chris

Removing the circlip only, aligns with my experiences too Chris. I've just been on a bearing website and a 25 x 52 x 18(I think that's the size) double row bearing starts with a 4205 number, so your memory is holding up pretty well spot on if so.
Regarding crank run out, when I had a similar problem with my MDS I simply applied a DTI to it(with it assembled in the crankcases) then dressed it up with a combination of dry stone and lapping the flywheel in until it ran true. It may seem a little archaic but I had no other means at my disposal and successfully reduced the run out from .0035" to less than .001"! Been OK since!

[340villiers]

Hi, The bearing required is a 4205, delete the circlip in the crankcase, but you will have to machine 3mm from the shoulder on the t/s crank. The new bearing is 18mm wide the old 15mm. The worst thing Villiers invented was their hammer tight spanner, put them in the bin, they twist the crankshaft out of balance very easily, always support the flywheel itself and do not use the drive side nut when tightening/undoing the flywheel nut. The Villiers cranks are good to true up, but should not be run in a engine out of balance! Be selective and ask for the crank to be trued up to within 0.0015" you can get them to 0 runout but it takes time, the vibration is very much reduced.

How can a tight arsed Scotsman add pictures with out spending £22 ???

Regards Willie

[Bearingman]

The double row bearing was always used with the Alpha full circle crank , the only mod was to remove the circlip that held the N205 outer .

Works perfectly with the standard crank , gives more support and lasts longer.

Have at the back of my mind it was a 2205 bearing ???.

Chris

Hi Chris,

You're correct on the basic number...

The 4205 is a double row European width ball bearing. The 2205 roller is the same dimensions as the N205, but as wide as the 4205 (18mm width)...more load capacity...

The 2205 series only comes with the inner ring (race) removable on both sides or one side, so you have to check before ordering. The proper number is NU2205. This would allow the inner ring to be fixed to the main shaft, still allowing the cases to be split like the N205. The 4205 which is a non-separable bearing would make it more difficult to split the cases, because it would be pressed on both shaft and bearing housing.

Man that really hurt! I hope I made sense to everyone!

Kenny Sykes

[riflegreen]

Willie ,

" How can a tight arsed Scotsman add pictures with out spending £22 ??? "

You can't

Why machine 3mm off the crank ?, I never had to & I fitted a few .

Thanks Kenny , the ones I used must have been the 4205 , had to heat the R/H case up to go over the bearing .

Chris

[340villiers]

Hi Gents/Chris

The plus side of fitting the wider bearing allowing it to sit further inboard in a far better fashion, the bearing sits almost flush with the inside of the crankcase (as per drive side case). The shoulder on the t/s crank is some 5mm wide from the crank web, machining 3mm off leaves 2mm this almost matches the drive side of 1.4mm, also reducing the shoulder down to 25mm better supports the inner bearing race.

The down side of allowing the bearing to sit to the outside is,(1)the inner race is only supported for 14mm on the shaft,(2)you are almost blocking off the oil hole supplying the seal/bearing,(3)you will also need to reduce the spigot on the inner timing cover,(4)the spigot is also then weakened at the oil seal location.

Best Regards Willie

[whitehillbillies]

so for the odd trial and a bit of green laning the origional N205 will do ?????
Adrian, what for my Scottish would I have bought off of you 20 years ago ???? you were listed in Leading Link, I think.... scottish front guard stay, or scottish stand, or the points conversion. Its just the name has rung a bell.

whitehillbillies