Main Motorcycle: Triumph TR7
Join Date: Feb 2012
Location: Norwich, England
Other Motorcycle: T140
Extra Motorcycle: Most of another T140
Thanks for posting Kirby's link Dr Fene, I'd have done so myself if I knew how! Kirby is a very nice bloke who really does know his stuff when it comes to Triumph twins - not a Monty Python or Benny Hill character at all!
For many years I've been convinced that poor lubrication and, in particular, poor oil filtration are the main causes of premature wear and failur in British bike engines. It seems to stand to reason, the lubricant that's keeping metal from metal must be free of any abrasive particles or it'll act as a grinding paste. Not only that, but the particles will clog the oilways and the sludge trap, which can lead to complete starvation to the big ends. Look at any Japanes 4 stroke: they have proper, full-flow paper filters that stop even very small particles. And these Jap engines last a lot longer without major work than their British counterparts. If the only way to assist engine longevity in Brit bikes is to change the oil every 1000 miles, well that's just ridiculous, as well as very expensive. And it just shouldn't be necessary: oil lasts much longer than that if it isn't polluted with rubbish that should have been filtered out.
As far as I can tell, the Kirby Rowbotham conversion is a tried and proven ststem. I know someone who has had this conversion on their T140 for nearly 15 years, no problems, and cleaner oil. It makes sense to me, filtering the oil not only under pressure but in the line between the pump and all engine components. Any crap entering from the tank goes through the pump and straight into the filter: after that, if the filter's doing its job, only clean oil enters the crank.
The only drawbacks I can see are the fact that this system has several more joints and quite a bit more tubing, all of which could potentially lead to leakage and oil feed / oil pressure loss, if any joints or sections of tubing failed. Having said that, I don't see why the likelihoof of failure should be any higher than with the standard setup, as long as all pipes are carefully routed and shrouded from chafing, and as long as all joints are properly made.
I hope I'm right because this is what I'm doing on my TR7. Am I really the only person on this forum to be using this system?
Last edited by JohnA; 03-31-2012 at 08:14 AM.
Reason: Got name worng 1st time!