How can 2 bikes be so different?

[Lobo]

Just an honest question here regarding my 750K2 vs a friend’s K1. Mine, whilst not quite concours, is good as new... erm, because it almost is. (as David Silver & eBay could verify 😂). Every moving thing is regularly greased, oiled etc, the ride is quiet & smooth.

My mate’s K1 is a bit tired. It needs love, and is awaiting a resto. It’s not particularly ‘joyful’ to ride, and the motor feels that it’s not quite breathing right. The plugs btw a nice light brown; the engine doesn’t burn oil.

Today we serviced it iaw Honda specs. New air filter / plugs / carb rubbers. Tappets set @ 0.05/0.08mm, (electronic) timing(s) verified correct at full advance RPMs, and the carbs balanced (at 2000RPM) via quality vacuum gauges. All easily achieved, and in truth little adjustment needed: the engine seems ok. It continues to start on the button & idles cleanly.

Despite the above his bike (still) just doesn’t pull as strongly as mine. Any suggestions to what we might have missed.... is it simply that it generally feels rough and it’s all in the head??? 
(he’s running K2 pipes on it, but with K1 baffles as I recall)

Ta.

[taysidedragon]

I think you answered your own question. If your mate's bike is tired , there must be wear and tear in the top end.
Carbon buildup on the pistons and valves, valves leaking?, worn cam maybe? Are the jets standard or been changed?
Could be a lot of things. Difficult to know without opening up.

[SumpMagnet]

Under the circumstances....if I had spent a load on a full rebuild, and my bike ran and rode like a tired unrestored example, I would wonder why I had bothered.

[McCabe-Thiele (Ted)]

It could be that they were both different when new - when I was in the car trade I often noticed two identical models of car would perform and feel quite differently depending sometimes on how they were run in. Strangely enough the ones that were driven hard by salesmen from day one often retained the edge but sometimes ended up with noisier engines !

We put it down to the manufacturing tolerances of engines - I believe that's how engine blueprinting led to more powerful standard engines that stuck to the regulations for rallying such as Group A Regs. 

[philward]

Ref pipes, not sure the earlier bafles will fit in 343 pipes? Could be wrong