To Needle Roller or Not?

[Lukey]

Hi all, I am currently building a 1959 BSA A10 Caferacer using a SR engine. 

I currently have the following to build -

RGS Alloy Single carb head
9:1 pistons
Thick lip barrels
Large Journal Crank

I am looking to build the engine using the Eddie Dow tuning guide but I cannot decide whether I need to do the conversion to needle roller, I have heard Pro's and Cons for both and I just cant decide!

MalcsMotorbikes are building the engine and can do either!

What are peoples thoughts? The bikes going to be ridden properly!

[Bsareg]

When we were kids and the bikes only a year or three old we also rode them "enthusiastically ". Probaly without any oil changes, only "top ups" and I only remember one blow up due to a worn bush. If you're going to race it then that's a different matter. No doubt the needle roller are superior but is it really necessary for the average Joe. 

[BigJim]

Mine has the roller timing side bearing which makes it easier for someone as incompetent as me to play with the crank. Little or no worry re end float and possibly improved pressure to the big ends. If you confident with the bush setting up then it's probably worth spending the money elsewhere. Horses for courses etc. I'm glad to have done mine.
 

[Black Sheep]

Not every tale of the conversion has a happy ending. It ain't cheap either. Our A10 bought in 1972 is still on a plain bush, as has the A7 bought in 1978. Neither are treated gently.
The plain bush has a much greater contact area and load carrying capacity than a needle roller one.
THe choice is of course yours.

[JulianS]

Had the SRM needle roller/end feed conversion done in 1985 and thoroughly recommend it.

No problems with settng end float or poor quality bushes.

[metalflake11]

No question in my mind the conversion is the way to go.

Correct me if I'm wrong, but didn't the racing department invent it when they needed reliability for bikes that would be ridden hard?

Personal experience tells me it's far better too. I had mine done nearly thirty years ago, and the bottom end has been apart just once since. It's no hobby bike either, I have no other form of transport.

Granted I spoil it rotten with oil changes, but it's the best money I ever spent. 41 years, same bike, same rider, 13 without the conversion the rest with, along with the S.R.M oil pump and oil pressure relief valve I'd do it again if it was twice the price it is.

I'd be interested to hear the bad endings Black Sheep has come across concerning the conversion?

[muskrat]

G'day Lukey.
+1 for the conversion. Did my A7SS when racing it (now my A10 Cafe). I re-did it once after a blow up (nothing to do with the conversion).
The plunger is coming down for a rebuild soon and will be treated to the same.
I ride all my bikes hard so need them bullet proof. But in saying that the plunger is still going despite the 8 thou" slop in the main bush. I just run 70wt oil to take up the gap 
Cheers

[chaterlea25]

Hi Lukey,
A google of your bike shop, read through their website and a trawl trough their faceache page
does not reveal anything about their machine shop and experiences of BSA bottom end conversions ??
Just an observation ?

John

[Rocket Racer]

When I read the mention of needle rollers I jumped to the assumption of for the gearbox or camshaft rather than the combination bearing conversion.
If relating to the timing side bearing, my 10 cents worth is I have run both plain timing side and combination bearings and get my local engineer to make the changes.
There is no doubt more investment is required for the combination bearing but it results in more peace of mind. For a warmed up motor with clean oil and general (to hard) use a plain bush is fine. I ran a white metal bush on my race engine initially and while it did fail in its second season it did no damage and was being run to 7500. 
I have a low mileage road rocket motor on stock rods which is just getting a fresh bush, but also have several combination bearings on the shelf for the A7SS race motor and potentially this motor in a year or two if I change my mind.

[Clive54bsa]

Lukey, I've done 2 motors with the conversion and 1 without. In hind-sight, which as we all know is 20-20, I shouldn't have wasted my money. I my case I probably do less than 2000 miles a year and change the oil probably 3 times in that period, However if yours is a daily rider and you ride it hard sometimes, perhaps one could justify it. I did have a bearing failure once after 7000 miles, and after tearing down the motor, I removed the bearing and sent it to SRM. 3 months later they kindly sent me another bearing with a note saying a 1% failure rate was acceptable.

[orabanda]

I agree with Clive.
All of my bikes have timing bushes, except for one with the needle roller conversion (not my choice; however I was given the SR & it came already converted).
Given the relatively low miles I ride each bike, and the addition of an oil filter, they will all outlast me.

Invest a little bit of money in an oil filter (which SRM don't recommend BTW!?!?!?), rather than a lot more for the needle roller conversion.

Richard

[Sav]

Knackered A10SR engine was rebuilt by known competent engineers, subsequent problem was the bushes used were made of putty, six months later - crank full of white metal.

Trip up to Aberystwyth to visit SRM for the needle roller conversion and the engine has been rock solid for ten years.

Cost an arm and a leg for me but if you have the engine apart already obvious where my vote lies!

[Triton Thrasher]

Lukey, I've done 2 motors with the conversion and 1 without. In hind-sight, which as we all know is 20-20, I shouldn't have wasted my money. I my case I probably do less than 2000 miles a year and change the oil probably 3 times in that period, However if yours is a daily rider and you ride it hard sometimes, perhaps one could justify it. I did have a bearing failure once after 7000 miles, and after tearing down the motor, I removed the bearing and sent it to SRM. 3 months later they kindly sent me another bearing with a note saying a 1% failure rate was acceptable.

A 1% failure rate on all the bearings would soon bust the factory.

[MrShifta]

Not sure if the factory did the first end fed cranks on A10's,  I certainly did the first on my RGS in late 1983, It had been done before by using exterior plumbing but I designed mine all internaly.  Bob Stevenson of Spondon Engineering welded the seal block in place but the rest I did in my own workshop. I had the advantage of having a tool and bearing company and Ina was a supplier to us. With their help the combination bearing was found to replace the timing bush. 

Prior to then SRM did not do conversions for A10's but within weeks of the Classic Bike article about my RGS with its picture on the front cover ( March 1984) they adverised they could now do the A10's.

I have just started rebuilding a 1954 GF and intend once more doing a conversion, If I can remember what and where to drill :-)

My RGS was sold some years later and the last I heard the conversion was still working perfectly  37 years later.

I did mine out of technical interest not necessity,  I am sure tens of thousands of A10's run perfectly alright but I note on here that the failures mentioned were all of bushes, you pays your moneys and takes your choice, as they say !!!   

[Truckedup]

 I dropped off engine parts at the mechine shop yesterday....I decided a bearing conversion wasn't needed....I pressed in a Kibblewhite  bushing with the intentions of have the bushing line honed for the best fit.....The price quoted was high due to set up time anf making jigs...The shop does all types of high performane work, not just bikes. they have done A65 flat track vintage racers, all had bushes,none line honed and supposedly none blew up
   Sometimes dreams of perfection are crushed by the reality of cost and being 73 years old.