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Messages - StevieWonder

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1
CB750 / K0 CORRECT MIRRORS
« on: November 05, 2019, 08:52:34 PM »
When did the handle bar mirrors change from Acorn nut adjustment to friction swivel ball? The Parts Catalogue indicates that all K0s had Acorn nuts, but maybe it was only the early models? Mine is a May 1970, Frame No 1036***.

2
CB750 / Re: CB750 K1 Tool Kit?
« on: October 31, 2019, 05:17:51 PM »
You may already have a list, but if it helps the K0 User Manual lists the tool kit items as shown in photos attached, perhaps the K1 does also? Probably isn't too different.


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CB750 / Re: TORQUEING REAR AXLE
« on: October 21, 2019, 04:10:19 PM »
Just to complete the story. A rear axle wheel nut tightened to 67 ft/Lbs can readily be removed with a size 10 shoe and the standard tool kit hex spanner with extension. Just undo the footpeg nut a few turns.

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CB750 / Re: TORQUEING REAR AXLE
« on: October 20, 2019, 10:46:31 AM »
Thanks Green1, I hear what you say, car wheel nuts can be difficult to remove. However, the rear axle suggestions provided (stand on it/ use a long leaver) would likely result in an over-tightened axle nut hindering removal and even if you could loosen the nut, changing a bike wheel at the roadside is hardly an option. Though I will try and undo the correctly torqued nut with the standard tool kit shortly and advise.

Evidently over 50-years and some 400,000 CB750K examples, there have been few if any problems associated with tightening the rear axle. It seems to withstand over-tightening and under-tightening, supported by the chain adjusters. I just want to tighten it correctly and now I can.

5
CB750 / Re: TORQUEING REAR AXLE
« on: October 19, 2019, 09:29:21 PM »
Thanks for your opinions. My initial appeal was for help in torquing the rear axle without removing the exhausts, but none of the suggestions provided certainty that it would be correctly tightened. Having devised a solution I thought I'd share it. There are only a few torque settings on the CB750, so in my opinion these are important and in fact my rear axle was too loose. I now have confidence that it isn't and future chain adjustments can be done correctly and conveniently. Correct me if I'm wrong.

6
CB750 / Re: TORQUEING REAR AXLE
« on: October 19, 2019, 06:36:47 PM »
Thought I'd try a slightly more elegant solution. Pete the policeman/ fork leg not required. Found a 24/17 mm hex ring spanner from a YAMAHA tool kit (nice quality to be fair). Drilled and filed a square 3/8" hole near the 24 mm end to take the torque wrench. Set a 90 degree configuration as per pic. Loosened, but did not removed foot peg nut, to increase clearance. Tested existing torque and found previous guesstimate to be 48 ft/Lbs - good job it's still running in! Gradually increased torque, as wasn't sure spanner was robust enough, but it was. Set at 67 ft/Lbs, unfortunately smack between split pin holes! Estimate next split pin hole alignment will far exceed max torque 72 ft/Lbs.

At a latter time. I realised that there are 2-holes for the split pin through the end of the axle at 90 degrees to one-another and the second one was lined up.

7
CB750 / Re: K0 CORRECT DATE OF MANUFACTURE
« on: October 15, 2019, 10:37:23 PM »
Excellent! Thanks to all but especially James, my bike sits between the two frame numbers quoted for 05/70 machines.  ;D ;D ;D

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CB750 / K0 CORRECT DATE OF MANUFACTURE
« on: October 15, 2019, 06:41:18 PM »
Can anyone please help me identify when my bike was manufactured. Unfortunately the VIN plate on the steering head has been removed - maybe for respray, It's a K0 with frame number 10369**. I think it would be around May 1970. Perhaps there is a listing of frame numbers and dates out there or I'd be very grateful, if someone with a similar frame number and intact VIN would advise.

9
CB750 / Re: TORQUEING REAR AXLE
« on: October 12, 2019, 03:55:49 PM »
Trying to tighten the rear axle nut to the correct torque as based upon the kind advice provided by Nurse Julie and Bryanj – ‘Stand on it’ and ‘use the tool kit flat hex ring’ – I got all technical and calculated the bar length required to produce 65 ft Lbs torque.

Torque (ft Lbs) = Lever length (ft) x force (Lbs)     all calcs assume force at 90 degrees to lever.

65 ft Lbs = Lever length x 1 fat b*****d (182 lbs) stood on it.

Lever Length =      65         .
                    182   

Lever Length = 0.357 of a foot ~ 4.25 inches about the length of the tool kit hex ring, without the extension would produce the 65 ft Lbs of torque required, if I stood on the end of it.

So I stood on the unextended hex ring and ……………………. It loosened the nut!

So to tighten the nut to 65 ft Lbs, if I use a bar lever of 10” (0.834 ft)

Force =        Torque   .
                Lever Length

Force =         65       .
                 0.834

Force = ~ 80 Lbs   or 5 Stone 6 Lb   but I don’t know what that feels like?

So if I use 34” of 22mm copper pipe to extend the tool kit hex ring – I know the bend in the bar reduces the force slightly.

Force =                65     .               =  ~ 23 ft Lbs     I know what that feels like.
                   2.834 ft (34”)

So tightened axle nut, but now the hole for the split pin doesn’t line up!

Note to self: Next time take off silencers #3 and #4; torque up properly with a socket; use washer shims to align split pin hole; paint in use split pin slot in axle nut. On next chain adjustment tighten to align split pin.

Did I get that wrong? Any better suggestions? :-\

10
CB750 / TORQUEING REAR AXLE
« on: October 11, 2019, 01:35:55 PM »
Does anyone know, if the rear axle bolt can be torqued up without removing silencers/mufflers #3 and #4?

The 24 mm axle nut has a torque setting of 58 – 72 Ft/Lbs, which in itself calls for significant leverage and more than an open ended spanner.

However, I have found that with the silencers supported and the pillion foot peg/ silencer support withdrawn the additional space around the rear axle nut is still insufficient to fit a socket or a crowfoot spanner/wrench and attach the torque wrench.

As the axle nut must be regularly accessed to make drive chain adjustments, surely there is a technique to set the torque with silencers in place?

11
CB750 / Re: Correct Front Wheel Hub K0
« on: October 10, 2019, 10:23:15 PM »
No not one of the transition K0s with the with the better rocker arm linkage for the carbs, she's a die cast from the US.

12
CB750 / Re: Correct Front Wheel Hub K0
« on: October 10, 2019, 04:52:20 PM »
Thanks for the link Ash, mine looks very similar to the photos therein.  :)

Hi Jamesh, photo front front attached shows 90 degree backplate.

13
CB750 / Re: Correct Front Wheel Hub K0
« on: October 10, 2019, 02:30:26 PM »
Fitted the new bolts today and torqued up fine (21 ft/Lbs).

All seems good, but not sure now about the disc and other gubbins, questioned by Ash. How do I tell?

There is a 'W17S' mark on the disc and it looks similar to the aftermarket part on DSS site. Pictures attached if anyone can identify please?

14
CB750 / Re: CB750 K0 Front Sprocket Case Protector
« on: October 08, 2019, 10:57:16 PM »
That's right, my Mum loved the boil in a tin stuff.

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CB750 / Re: CB750 K0 Front Sprocket Case Protector
« on: October 08, 2019, 06:03:25 PM »
I'm hoping to stop any engine oil flying around the rear by holding it in the fully closed position, then regularly apply proprietory chain lube.

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