Kirby Rowbotham oil filter conversion availability

[Fast Eddie]

Folks,

Does anyone know if Kirby Rowbotham is still around and still operating and doing his rather good pressurised oil filter conversions for Triumphs ?

 

[L.A.B.]

Kirby Rowbotham Oil Filter - Spare Parts?

Hello, new to the forum (and to classic Triumphs) I now have a T100R Daytona 1973 which as far as I can tell, is fitted with the Kirby Rowbotham (KR) Triumph Filter Kit (including modification to the timing cover). On my installation, the oil pipes are routed forward then pass back direct...

www.britbike.com

"Unfortunately, it turns out that KR is no longer trading..."

That was 2019.

 

[Fast Eddie]

Kirby Rowbotham Oil Filter - Spare Parts?

Hello, new to the forum (and to classic Triumphs) I now have a T100R Daytona 1973 which as far as I can tell, is fitted with the Kirby Rowbotham (KR) Triumph Filter Kit (including modification to the timing cover). On my installation, the oil pipes are routed forward then pass back direct...

www.britbike.com

"Unfortunately, it turns out that KR is no longer trading..."

That was 2019.

Thanks L.A.B.

Do you know if anyone picked up where he left off ?

 

[Chris]

Hi Nige
I will speak to Kirby & ask him

 

[Fast Eddie]

Hi Nige
I will speak to Kirby & ask him

I already spoke with him Chris… got a polite but emphatic no !

 

[Rossa1989]

Lat

Thanks L.A.B.

Do you know if anyone picked up where he left off Late t

Thanks L.A.B.

Do you know if anyone picked up where he left off ?

Oil filter kits for British motorcycles

Oil filter system for older British Bikes

www.norbsa02.freeuk.com

Could this be what you are looking for?

 

[Fast Eddie]

Lat

Oil filter kits for British motorcycles

Oil filter system for older British Bikes

www.norbsa02.freeuk.com

Could this be what you are looking for?

Thanks.

Not quite, Kirby used to do a service modifying the timing cover so the filter was fitted on the pressure side, between the pump and the crank.

 

[B+Bogus]

I always wondered at the logic of the arrangement, since it seemed reasonable to filter the return oil before it went in the tank, and wouldn't present a resistance to flow on the feed side.

I'm sure there must be good reasons behind it, but I couldn't work it out

 

[Fast Eddie]

I always wondered at the logic of the arrangement, since it seemed reasonable to filter the return oil before it went in the tank, and wouldn't present a resistance to flow on the feed side.

I'm sure there must be good reasons behind it, but I couldn't work it out

I pretty much agree.

The ‘but’ is that even with a return filter (ie on a Commando) you’ll still see sludge build up in the oil tank over time. So there is still ‘stuff’ in the oil.

Filtering between the pump and crank guarantees the crank getting the cleanest oil possible, especially if it’s as well as a return filter.

Of course, Triumph addressed this with the really quite effective sludge trap. Even with a filter in the system, a Triumph sludge trap still collect sludge.

So… now to the crux of my matter… I’m toying with the idea of modifying a Triumph crank and possibly removing the sludge trap altogether. Hence my thinking about the pre crank filtration.

 

[Triton Thrasher]

Filtering between the pump and the crank feed is good in principle, but all that high pressure external plumbing is not good.

The advantage of putting the filter in the return line is that it is simple and it does not cause problems.

 

[Fast Eddie]

FWIW Kirby didn't invent the idea. It’s basically common practice on many OEM engines. Interestingly, it is what Nourish did on their race engines.

The external plumbing issue is easily fixed by using the right components.

 

[Triton Thrasher]

FWIW Kirby didn't invent the idea. It’s basically common practice on many OEM engines. Interestingly, it is what Nourish did on their race engines.

The external plumbing issue is easily fixed by using the right components.

All good stuff, but is there an actual problem and are we actually trying to fix it?

What improvement shall we see?

 

[Fast Eddie]

All good stuff, but is there an actual problem and are we actually trying to fix it?

What improvement shall we see?

On a standard arrangement there is not really a problem to solve.

As mentioned above, I’m thinking of modifying a Triumph crank and removing the sludge trap altogether.

Why? Because the ‘normal’ place for a Triumph crank to break in race use is through the sludge trap access hole.

When you look at one, there’s no wonder, the threads create stress risers and if that’s not enough, the massive centre punch ‘whack’ certainly does, sometimes several of them on an old crank!

My thinking is to machine out the thread to a smooth bore, cut a chamfer to remove all centre punch damage, press in a purpose made plug and weld it in (laser welding to avoid any heat issues).

I reckon that’ll make for a MUCH stronger crank.

So, if I ever get around to this, the idea of a pre crank filter appeals. But, I do agree that with a filter in the return, and by using modern detergent oil, it’s certainly not a deal breaker.

 

[B+Bogus]

I pretty much agree.

The ‘but’ is that even with a return filter (ie on a Commando) you’ll still see sludge build up in the oil tank over time. So there is still ‘stuff’ in the oil.

Filtering between the pump and crank guarantees the crank getting the cleanest oil possible, especially if it’s as well as a return filter.

Of course, Triumph addressed this with the really quite effective sludge trap.

So… now to the crux of my matter… I’m toying with the idea of modifying a Triumph crank and possibly removing the sludge trap altogether. Hence my thinking about the pre crank filtration.

I removed the sludge trap from my T140 crank and fitted the OIF sump plate B25 filter along with a Morgo rotary pump. The Norton spin-on filter is probably superior, but either way it's better than what left the factory.
Another aspect of the KR version is the pump is running both feed and return in unfiltered oil, whereas the other way means only the scavenge is pumping unfiltered oil.

 

[Triton Thrasher]

I agree about doing away with the sludge trap.

Crankshaft oilways should be angled so that suspended carbon black is not trapped, but passes through the big ends.

 

[Triton Thrasher]

Why? Because the ‘normal’ place for a Triumph crank to break in race use is through the sludge trap access hole.

When you look at one, there’s no wonder, the threads create stress risers and if that’s not enough, the massive centre punch ‘whack’ certainly does, sometimes several of them on an old crank!

Yes I think you could make a stronger crankshaft.

 

[Fast Eddie]

I removed the sludge trap from my T140 crank and fitted the OIF sump plate B25 filter along with a Morgo rotary pump. The Norton spin-on filter is probably superior, but either way it's better than what left the factory.
Another aspect of the KR version is the pump is running both feed and return in unfiltered oil, whereas the other way means only the scavenge is pumping unfiltered oil.

I run one of the ‘Charlie’s’ kits on my T140 too.

My ‘fancy crank’ idea wouldn’t be in an OIF though, so a filter in the return would be the only good option there.

Did you get the crank re-balanced sans sludge trap ?

 

[B+Bogus]

Did you get the crank re-balanced sans sludge trap ?

Oh yes!
It's running +0.060" Powermax pistons and a light '68 flywheel. I re-balanced it the old school way and it's the smoothest Triumph I've ever had.
It's very quick for a street bike, but I wouldn't race it without replacing the flywheel with a steel one.

 

[Fast Eddie]

Oh yes!
It's running +0.060" Powermax pistons and a light '68 flywheel. I re-balanced it the old school way and it's the smoothest Triumph I've ever had.
It's very quick for a street bike, but I wouldn't race it without replacing the flywheel with a steel one.

Interesting!

Are the flywheels universally interchangeable between 120s 140s etc?

I like the lightweight flywheel too. You’re obviously a hooligan of good taste !!

What cams you got in it?

 

[B+Bogus]

Interesting!

Are the flywheels universally interchangeable between 120s 140s etc?

I like the lightweight flywheel too. You’re obviously a hooligan of good taste !!

What cams you got in it?

Yes the flywheel is a straight swap - I happen to know a guy who has a spare
Standard inlet cam, exhaust cam with inlet profile, ISTR them being either Spitfire or Thruxton profile? Memory isn't what it was when I built it.
Head ported & flowed to take 32mm carbs.
It's still remarkably tractable at low revs, and ticks over like a standard T140.

I did get hold of a Tracey Hurricane style tank/seat a few years back which would have suited it well, but I'm getting a bit old for that kind of bling.