The trip to Junction 33 turned out to be a thoroughly annoying setback. Several small mishaps before it even got on the dyno set the tone and should have been in indicator of things to come. The bike has a massively over-rich problem from around 4k to over 6k and Andy can't sort it with the carbs. His view is that it's something in the induction that's causing a 'blockage' which is stopping air entering. Eventually this clears when the revs have got past it but I'm stumped as to what the problem could be. Roger was there too and he's got no idea either.
The A/F chart is below and the one from my old engine as a comparison. I've written everything I can remember from the runs plus the differences between my old, fit, engine and this new one. Answers and suggestions on a postcard please to:
Thoroughly despondent,
c/o anyone looking to buy a few Storms in bits,
at hunting ebay for local bikes that just run,
next to "I'm too old for this sh1t".
The top green line is as received and it's mega lean at the top end plus rich on the pilots. Blocking the main air relief circuit made that better but the rich condition was horrific (pink). The three other, overlapping lines, are with smaller pilots, larger mains, plus a trial with a more restrictive air filter. The larger mains sorted the lean top end but made the richness in midrange worse, so there was no point going bigger to get the top end right. At best it made 72 ft-lbs of torque and less than 120bhp. Way off my old engine and what Roger and I were expecting from this engine.
Engine differences :
Stg 2 Mori cams on the new one vs stg 1 Yoshi on the old one
Std valves vs +1mm inlet and +0.5mm outlet
Mori pistons vs JE
Mori carbs and needles vs stock cards with Dnyojet needles
Mori vleocity stacks vs two short stock ones
Air box and carbs the same exhaust
I know all these changes add up but I can't see how they have made such a huge difference when Roger has had good results with this sort of build before. All I can think of is that the valve timing is off, but that surely wouldn't make such a huge difference without the engine eating itself. Another thought is that the choke circuit on my carbs is blocked off but could be open. That, in my head, would give something like this but we didn't explore it on the day as I thought the choke circuit was deleted on these. Roger has confirmed choke was an option so I'm going to check tomorrow but if it's blocked I've no idea what to do other than stripping and checking everything. Which I can't face right now and I've a nasty opposition to throwing good money after bad.
New engine
Old engine