SOHC.co.uk Forums > CB750

Best workshop manual cb750

<< < (2/3) > >>

Martin6:
I don't notice any issue with the gear change. Better than my modern BMW boxer. Probably not a high benchmark  :)

It's definitely the front wheel and only on bigger lean angles at speed. I have refurbished the front shocks, including replacing a bent stanchion, plus new steering bearings. I have Hagons on the rear, which are a huge improvement and modern Avons front and rear, feel pretty good. Despite less squat than with the previous rear shocks, I think the front : rear weight balance is probably causing a slightly too light front wheel on acceleration.

K2-K6:

--- Quote from: Oddjob on January 28, 2024, 11:53:39 AM ---The dry sump was a poor idea, giving a notchy and loud gearchange, the main reason I didn't like the 750 over the 500 which has a gear change like a knife through butter.

--- End quote ---

The dry sump has absolutely nothing to do with how the gearbox runs and works. Lubrication is even pushed through it via takeoff from return /scavenge side of pump.

The two engine, although they may superficially look similar in layout, are very, very different in overall design.

The smaller engine uses more reduction going into transmission, runs hyvo chain (consequently low oscillation space on input route from centrifugal characteristic , even when chain is knackered) with gearbox running at lower speed and needing less final drive reduction.

The 750 has no mitigation for its primary drive chain (slack is slack on this one) larger clutch inertia on the end of that chain in conflict with crankshaft to effectively have a more nuanced remote flywheel effect. Gears have reduction ratio on exit of box to drive sprocket and still need fairly large rear sprocket to complete drive train. If there's any final drive compromise on 750 chain, lubrication, adjustment, tight spots etc it'll play havoc with gear change quality.  The change is quite "industrial" in quality, but works well with all components finely fettled.

Dry sump on any engine is all about getting oil away from spinning crankshaft and ensuring completely reliable supply side to lubrication, thats all.

Honda learnt a lot between these two design, the 750 relatively crude and with excess weight etc (they didn't develop or repeat this design ) the 500 was logical in moving to hyvo chain for refinement and with lighter components. The dry sump "effect" is done on these by making the sump deeper to keep the oil out of the way of other components, essentially followed by many other four stroke engine design even today.

The 400 shows probably a little more of this design concept in having that drop down sump with all the exhaust pipes routed to one side of it, this now seen in many production engines.

Spitfire:
The genuine one as the main reference and the others to fill in, but this and the US site for starters when you have a problem.

Cheers

Dennis

Oddjob:
Whatever the cause Nigel that really loud thunk as it went into first gear is pretty awful. Imagine sitting at the lights in the 70s, people are admiring you from the cars around you, you smile and nod and generally bask in the glow of having a really nice bike, then you select first and everyone looks away, embarrassed for you, what a clunker they are thinking, whereas the 500 just slides into gear next to you and smiles the smile of knowing he or she has the better bike.

Martin6:
No one is looking, they never were. We may hope they are, but they're really not. Nowadays their phones are much more interesting.  :D

Navigation

[0] Message Index

[#] Next page

[*] Previous page