Main Motorcycle: Triumph TR7
Join Date: Feb 2012
Location: Norwich, England
Other Motorcycle: T140
Extra Motorcycle: Most of another T140
This is getting to be an interesting debate! Just to explain why I felt the need to have two filters, this is because when I bought the bike as a running project, the (or a) previous owner had had the frame blasted & powder coated. That worried me from the moment I discovered that fact. I rode it the 20 miles home, via a pressure washer, then stripped it down to the last nut & bolt. No sign of grit damage in the engine, most probably due to there having been a B25 (or 'Charlie') filter in the bottom of the tank. It was very dirty but not blocked.
I thought I could feel some grittiness when I ran my finger round the inside of the oil tank, so I pressure washed, then steam cleaned the tank, them swilled it out 3 times with paraffin. Then continued to worry about the possibility of grit left in there.
I decided quite quickly to go for a Kirby Rowbotham filter, having done some research (including starting this thread). I was originally going to fit a new mesh strainer to the tank, but grit worries kept haunting me and I decided that fiting a new B25 filter wouldn't do any harm - and would at least ensure no damage to my nice new Morgo oil pump. So that's what I did. I must admit it does seem a bit unconventional, and I wouldn;t have done this if I'd felt confident that there could be no trace of grit in the frame. I will inspect the B25 filter very carefully when I remove it (soon), and if there's no trace of grit, I'll revert to the standard strainer.
I take the points above re. the K.R conversion involving extra high-pressure oil plumbing that could spring a leak, and with very messy results if it ever did. I would feel happier with this system if it had more positive connectors (eg: screw-in rather than push & lock connectores), and armoured oil lines. I might try to modify it myself in that direction, but I've heard from several others who have used this conversion just as it comes for years without any problems.