Need Basic Info on 1981 CB750 Custom

[Stewart]

I am considering buying a 1981 CB750 Custom.  Appears to be in good shape.  I have no information about these bikes.  I have owned: 1982 KZ 550LTD,1996  Vulcan 750, 2000Kawasaki W650 (shoulda kept it), 2004 Ninja 500, 2007 Ninja 650.  Hoping you could help with answer some questions:
1.  Are they a high-maintenance bike for any particular reason?
2.  Overall performance (acceleration, handling)?  I'd like to have a bike that performs about as well as my Ninja 650 did.
3.  Any particular issues to check when buying such a bike?

Thanks,
Redbike in IL

[rrgunslinger]

Stewart wrote

I am considering buying a 1981 CB750 Custom.  Appears to be in good shape.  I have no information about these bikes.  I have owned: 1982 KZ 550LTD,1996  Vulcan 750, 2000Kawasaki W650 (shoulda kept it), 2004 Ninja 500, 2007 Ninja 650.  Hoping you could help with answer some questions:
1.  Are they a high-maintenance bike for any particular reason?
2.  Overall performance (acceleration, handling)?  I'd like to have a bike that performs about as well as my Ninja 650 did.
3.  Any particular issues to check when buying such a bike?

Thanks,
Redbike in IL

I don't think they are any more high maint than any thing else  out there.  Not high performance neither.  You did not say how much but if in good condition and it runs or turns over I would go ahead and get it if you are looking for a project bike.  Support for these bikes are still in place and many love them plus you can do this.

[TOOLS1]

They are not a high maintenance bike by any standards, but the charging system is a trouble spot on the DOHC bikes. However there are companies making heavy duty parts to replace them with. As, for performance. They were one of the fastest in their day, but nowhere near a 650 Ninja today.
TOOLS

[Stewart]

Thanks for the info.  Good to know support is available for the bikes.  The bike of which I speak was listed on Ebay.  Owner said it is ready to ride, and from the appearance of the bike, I suspect that is accurate.  Bike appears very clean, with sissy bar and rack, as I recall.  I suspect the bike's performance would be fine 90% of the time.  The other 10% is doing moderate sport riding on some twisty back roads (SW Wisconsin - Boscobel area, Wildcat Mt, Mindoro Cut, for example). It's the CB's ability to manage the 10% that has me worried.  Beyond that, the bike is just so gorgeous!  Further, I suspect I could get if for $2000, maybe less.

Thanks.

[Piute]

   If the bike is still 90% stock ,Being 10% tire's N Batt.
      2K not to bad best run real good ,S.W. Wisconsin ,Spring Green area and all south is great Watch fer deer N dang tourest,lived in Stevens Point 13 yr's,Wausau 5, Now enjoying the lower Mid West in Mo.
  Enjoy your putt and keep in touch...Stock just make it simple to know what it is.

[shinyribs]

Anything chain driven has that part of the maintenance to deal with. As far as performance goes,I am sure there are a ton of modern bikes that can out-handle the 60's and 70's models.As far as power,again they are not endowed with today's technology,but I think they have great power. More than enough to get you in trouble on and twisty road.

[LukeM]

This is a good point.  Modern technology has made bikes more reliable, less finicky, and upped the performance numbers. Fuel injection, progressive rate shocks/springs, steering dampers, tire compounds, catalytic converters, etc.

And yet, people harken back to carburetors (4 of them), loud exhaust, exposed engines, something they can modify and tinker with. Maybe it's the cost of old bikes vs. new. What sort of new bike could you get for 2 grand?  Maybe a 250cc bike, with half the performance? If memory serves, the CB750 new was about $1500, which in modern money is about 5X that.

I guess if you needed a reliable daily driver, you could buy a commuter bike, then get a relic bike for the weekends and meets and stuff.  Me, I just have the one 1984 Shadow. I travel a lot, so the Avenger usually stays at home in the garage, begging me to take it out on the weekends.  So, I do.

Sorry for the rambling.
Luke M

[sgtslag]

My father has a 1981 (or 1982?) CB750 Custom for sale, in Austin, MN.  I agree with the other folks' comments about performance:  it won't be anything like the Ninja.  Aside from that, they're pretty reliable bikes.  My Father's bike is rideable, and his asking price is only $1,200.  It has two known issues:  missing side cover, and the exhaust is loud.  It has a full fairing (can be removed, and sold), a passenger backrest, with luggage rack.  It has ~20,000 miles on it.  It has been well maintained.  If interested, PM me, and I will get you photo's, and contact information.

As far as performance on these bikes goes, upgrading the suspension with Progressive brand front fork springs, and Progressive 412 Rear Shocks will make them ride like a bike at least 20 years newer.  The cost, when I upgraded my '79 K-model, three years ago, was around $300-$400.  Do NOT get the heavy-duty springs on the rear shocks unless you plan on riding two-up, 90% of the time, as they are quite stiff.  If you ride two-up, though, they are perfect, even with stuffed saddlebags, and a full trunk!

The upgraded suspension is not just for comfort's sake.  It will improve the handling, dramatically.  It still won't ride like a Ninja, but it will handle, and ride, sooo much better.

The CB750 Custom is NOT a sport bike. Period.  It has better low-end torque, and acceleration than the K models, but I doubt it is as good as the S (sport) models, about which I know very little.  If you get a CB750 of any type, this is the place for information, and camaraderie.  Cheers!

[Stewart]

Well, I didn't buy the last bike I asked about, but am looking at another!!  Still can't decide on what I can and can't live without.  Every bike has its advantages and disadvantages.  Decisions, decisions..

[Stewart]

Also, can someone recommend a small but effective windscreen?  If I bought the bike I'm considering, I'd have to ride it about 4 hours to get home.

[Piute]

     http://www.jcwhitney.com/plexifairing-gt-windshields/p2009901.jcwx?filterid=c14185j3

[Stewart]

Would you agree with this review of the bike:
"The bike needs a large amount of throttle twisting to maintain speed uphill, caused we think by the accelerator-pump lag time. When the pump finally kicks in you find yourself rolling back the throttle to compensate for the extra speed this generates. Perhaps recalibrating the pump would cure this .

The clutch has a nice, light pull. Its somewhat narrow engagement point can combine with the light flywheel effect of the engine to produce an occasional stoplight stall. The clutch is a strong one, though; no abuse we gave it made it slip.

Our test bike had a fourth-gear problem. We had to be very careful when shifting into fourth, going up or down. From time to time when shifting from third to fourth, the lever would feel as though it had engaged fourth, when in fact it had left the transmission in third gear. Other times we would find false neutrals, whether shifting up or down."

[sgtslag]

In general, No.  Not all 750 Customs have these issues.  Cheers!