Hi all, my '92 750T has I have noticed sometimes jumps out of gear once the bike is hot. The gearshift doesn’t feel as positive as it gets warmer, and then sometimes when I am fairly sure it’s ‘in’, when the power is put back on, jumps out.
Also the bike is very snatchy at around 2K rpm. In traffic second/third gear is uncomfortable to say the least. I know I have backlash in the transmission, though I rang the chap at NBS and he thought it was within limits. Also I am not sure the carbs are absolutely spot on, close but not perfect. And the ignition is an ancient RITA.
I am not sure if this is a combination of everything.
Come the Winter I would certainly think about rebuilding the rear drive and associated components.
Any thoughts ?
Cheers, Tony.
Never been inside a bevel box. I would be tempted to parcel it up and give it to Nigel. he does an overhaul for about £130 or so I think. Ian D had his done recently and will be able to tell you better.
Sounds like it needs a good dose of looking at to sort the various annoying issues. Tackle them one at a time.
Off the top of my head:
The gearchange pawl may be out of adjustment, do the small blocks have that adjustable centring pin?
Also is gear pedal running out of available travel, could be linkage adjustment needs looking at.
Snatchy: too much slack in throttle cable? Shortening it to minimum often helps.
Transmission backlash: always is some, due to driveshaft splined couplings etc., will never get rid of it. Very much doubt it’s as simple as all due to play between the bevel box gears.
Ian D is chuffed to little bits with Nigel’s service.
I will have no doubt about using him again should I need to.
Thanks for the comments, I shall check the service manual and see what can/cannot be adjusted. All my other bikes are off the road with one thing and another, so shall have to persevere with mainly just tinkering for now !
After a brief ride this afternoon I am coming to the conclusion that erratic running of the engine, (K&Ns fitted) around 2K is the main culprit.
“erratic running of the engine, (K&Ns fitted) around 2K is the main culprit.”
That sounds like a carburation issue. Normal guidance is plus 10% increase on the main jet size and have a good play with the mixture settings on the pilot jet system after fitting K & N’s
Yep, you’ve inadvertently recreated the not-very-smooth running of a modern emission-strangled EFi bike! 
If this happened since fitting the K&N’s then be wary of too-weak mixture at wide throttle… could turn out to be expensive… bigger jets me thinks.
There could well be carburation set-up issues.
I am reminded of something about the small blocks exhibiting a flat-spot in the rev range? in certain circumstances? Memory fails to recall any details…
K&Ns fitted by the PO, but he didn’t re-jet. No problem, he never rode it !
I re-jetted, if anything it may be a little on the rich side, though plugs look a nice colour, only the outer rim is sooty. Wide open she goes like a rocket ship. Idle isn’t very stable, but not horrendous.
At the Kickback show last year, I talked to the guys from Corsa Italiana and the one with the 'tache and ponytail told me over the years he had seen a number of 750’s that had K&N’s fitted, and they never ran well. He even reckoned that he saw several bikes again and again that got sold on by disgruntled owners. I must admit my first one back in the early Nineties had the standard air box, and ran very nicely.