Engine oil?

[Triton Thrasher]

Read the spec on monograde oils, it is produced/designed NOT to carry particles. It will carry it a short distance, but the bike is designed to rid it of them before it starts a fresh cycle
Multigrade would be effected by centrifugal force, but it is more likely to hold on to some particles due to its inherant design function......Hence the need for a filter.

Oil being mono or multigrade shouldn't be directly related to detergent content. Am I right in thinking there was detergent in oil many years ago, when these old bikes were still being built?

Do you suggest that monograde oil will not "carry particles" the few inches to a filter, but will carry them right round the system to the sludge trap, or am I misreading?

Roughly, I have ran the same engine for 10 years on multigrade without a filter- 2 engine bottom end re-builds. 10 years WITH a filter- 1 bottom end re-build. Straight oil and no filter for 14 years and no bottom end problems at all. I must quantify that with the fact S.R.M. did the bottom end last time, and also did the end feed conversion.

I don't think anyone would say filters are a bad thing, or deny that an end-feed conversion can extend crank life.

[bsa-bill]

Am I right in thinking there was detergent in oil many years ago, when these old bikes were still being built?

Yes - as has been said already oil for diesel engines was/is high in detergent, I flushed my 61 Flash with it (around 63) it then wet sump'd, not saying the oil caused it but it hadn't done it before and never did it again

Do you suggest that monograde oil will not "carry particles" the few inches to a filter, but will carry them right round the system to the sludge trap, or am I misreading?

the sludge trap would take out some of the crud some of the time the rest carried on back to the tank where some more of the crud would some of the time settle out at the bottom of the tank.
Not a very precise system but coupled with frequent oil changes more than adequate for the use that most of the bikes BSA sold were used for - short journey to work and back

or deny that an end-feed conversion can extend crank life.

Given the age of most of our bikes you could well argue the original crank lubeing set up is good enough, SRM's excellent end feed maybe a good thing for large mileage riders for many of us though it's a pity SRM couldn't come up with something to extend the riders crank life

[Triton Thrasher]

Given the age of most of our bikes you could well argue the original crank lubeing set up is good enough, SRM's excellent end feed maybe a good thing for large mileage riders for many of us though it's a pity SRM couldn't come up with something to extend the riders crank life

Yeah, I think the conversions may be more relevant to Unit twins.

[metalflake11]

I don't think anyone would say filters are a bad thing, or deny that an end-feed conversion can extend crank life.


 S.R.M. would. In fact, using any kind of of filter, or use of multigrade oil will invalidate the guarantee.
Yes, you did misread my post. The part of my post you quoted says 'it will carry particles for short ditances.'  The highest mileage and longest period of time wthout trouble has been without using a filter and monograde 40's.
 I don't bang a drum for any choice of oils or filter use or not, it's their bike and they can run it on what they like. But, when an established firm who have built thousands of engines and guarantee their work tell me something, I listen up. The filter is still fitted to mine but no longer connected to the oil supply, it would take minutes to plumb it in but 10,000's of thousands of miles following their advise to the letter stops me doing it.
                        Rob

[Triton Thrasher]

 S.R.M. would. In fact, using any kind of of filter, or use of multigrade oil will invalidate the guarantee.

Well, when SRM explain what's wrong with filters and/or multigrade, I might pay them some attention.

[ShaunMac]

Thanks everyone. Safe to say that their's quite a few varying opinions on oil! 
Cheers,
ShaunMac

[metalflake11]

There is Shaun, but few on here would suggest anything but none/low detergent multigrade with a filter or straight 40's without. That's it in a nutshell, so take your pick.