CB750K8 Project

[martin_uk]

Started to have a look at engine in detail.

Head had valve jammed open even with cam shaft removed.

Cylinders have corrosion markings where piston seized and rings seized in pistons.

2015_0105mountingbrake0044 by nitram2010, on Flickr

2015_0105mountingbrake0047 by nitram2010, on Flickr

2015_0105mountingbrake0048 by nitram2010, on Flickr

Will need a rebore.

Bought a set of original NOS pistons and rings on Ebay before Xmas, but not yet arrived, seller says they are oversize but not sure yet what size.

[martin_uk]

Pistons arrived today pn 13105-392-000 and rings 13051-300-024

Although they are the flatter top ones.

Pistons are marked 1.00 so whilst maximum normal range, wont have worries that wont be big enough 

Seems a bit of a shame going straight to max oversize as my bores are not that bad.

Also found some interesting info on oversizes on CSMNL site

"Which piston and piston ring oversize should I use?

Here is some important information on how to determine which piston oversize one should order.

With the piston ring one has to look at the 4th position in the part number. The value of the 4th position refers to the following oversizes:

1 => std.
2 => 0.25
3 => 0.50
4 => 0.75
5 => 1.00

Consider this ( fictional) part number: 123256789012345. With this example the 4th position is 2, meaning an oversize of 0.25

For pistons, the 5th position in the part number refers to the same oversize table. "

http://www.cmsnl.com/help/faq/14_honda/#f94

This means the rings match the pistons 

[martin_uk]

Started to strip seat, but needs work on pan as well 

CB750K8 purchased eb by nitram2010, on Flickr

2015_0107seat0002 by nitram2010, on Flickr

Obligatory cracks 

2015_0107seat0004 by nitram2010, on Flickr

2015_0107seat0005 by nitram2010, on Flickr

2015_0107seat0007 by nitram2010, on Flickr

[UK Pete]

Do you think you can salvage it martin

[martin_uk]

Busy week for parts arriving.

Carbs from Ebay purchase arrived.

Dont look too bad.

K8 carbs before$_57 by nitram2010, on Flickr

K8 carbs before$_55 by nitram2010, on Flickr

2015_0107carbs0011 by nitram2010, on Flickr

2015_0107carbs0002 by nitram2010, on Flickr

2015_0107carbs0001 by nitram2010, on Flickr

2015_0107carbs0009 by nitram2010, on Flickr

[martin_uk]

Do you think you can salvage it martin

Will give it a try 

[martin_uk]

Big thank you to BigAl who sent through wiring loom multi connectors (on approval)  that actually match the original

Be aware that alot of the connector suppliers dont have the correct ones.

The original wiring was bad, the loom off Ebay a bit better,  connectors seem to crumble in the US.

May end up going for Alan's harness rebuild, just depends on state of internal wiring when I cut and strip back.

2015_0107conn0001 by nitram2010, on Flickr

2015_0107conn0002 by nitram2010, on Flickr

I better get on and start fixing 

[martin_uk]

Just about to go into my rather chilly garage when another parcel arrived

If you want to know what £102.71 worth of mostly repro parts from DSS looks like 

2015_0107dsparts0001 by nitram2010, on Flickr

Reminds me of a lucky dip 

2015_0107dsparts0005 by nitram2010, on Flickr

pair of mirrors

2015_0107dsparts0007 by nitram2010, on Flickr

Clutch and choke cables, throttle tube, side stand rubber, choke bracket

2015_0107dsparts0008 by nitram2010, on Flickr

Brake pads and shoes.

2015_0107dsparts0009 by nitram2010, on Flickr

and the bill

[Bryanj]

You can check the ring size easily on the ring as it will have the oversize close to the ends, o/s pistons should also be marked

[martin_uk]

Cleared my bike lift and got the freshly powder coated frame in place.

I find the foil backed insulation board quite handy to protect frrom damage.

2015_0112frame0004 by nitram2010, on Flickr

Started by cleaning all threads with a tap.

2015_0112frame0014 by nitram2010, on Flickr


I have found that unless you do this, the remnants of blasting medium and powder coat can cause threads to jam.

Fitting the centre stand is much easier before the swinging arm is fitted, as you can fit the spring tilt the stand up and slide the pin in as most of the tension is off the spring. Check the pin fits in stand and brackets first and may need a gentle tap with sofy mallet. Certainly beats the other methods of fitting spring.

2015_0112frame0019 by nitram2010, on Flickr

Swinging arm fitted, make sure brake arm is forward of this.

2015_0112frame0020 by nitram2010, on Flickr

Not what I wanted to find 

2015_0112frame0029 by nitram2010, on Flickr

Someone has tried to force a nut with wrong thread on top shock absorber mount and damaged thread.

Honda use alot of fine M10 bolts with pitch of 1.25 instead of standard 1.5

Would have preferred to find and fix before frame was painted.

I dont have a M10 fine die and it may have been difficult to get aligned, so use a thread restorer file, didnt have a metric one but 20 tpi seems close and was able to clean up threads and fit correct nut.

2015_0112frame0048 by nitram2010, on Flickr

 

[MarkCR750]

Martin, I have a K7 seat in pretty good condition (I think the seat pan is spot on from memory), your welcome to it for the price of postage if you want it, cheers Mark.

[Trigger]

I put bolts in all the treads before it gets blasted and goes of for powder, save a ton of work later.

[martin_uk]

Martin, I have a K7 seat in pretty good condition (I think the seat pan is spot on from memory), your welcome to it for the price of postage if you want it, cheers Mark.

Mark, Thats very kind of you, have sent PM

[martin_uk]

The brake torque arm fixing on brake plate was a pain to remove as head of bolt turned due to wear and recessed so you cant get a spanner on it.

Bought a new bolt and hoped it would be held by back plate.

Had to centre punch plate in the end to hold in place.

2015_0112frame0050 by nitram2010, on Flickr

[martin_uk]

Fork ears from the US.

2015_0112frame0001 by nitram2010, on Flickr

There is a wear lip on indicator mounting section, as far as I am aware the indicators mount over the projection so unsure how the wear lip formed?