Topic: Dorothy III - CB750

[MCRider]

How do you get out the spring pin that holds the kickstart shaft? Number 9.

ITs a bear. Many threads on this, when I did mine a few years ago. Settled on a small vicegrip; squeeeze what bit of the pin you can reach and tap up on the vice grips. Once it moves, reposition the VG to grab a little more and repeat.

[70CB750]

Thanks!  I will take my time, left it aside yesterday.

[MCRider]

Thanks!  I will take my time, left it aside yesterday.

Oh yeah, I remember now. Once setting the vice grip, I used a long screwdriver (maybe it was a tire iron) to pry on it. There was some point that made an obvious fulcrum. Once it moves, reposition the grips and repeat.

[MoMo]

Certainly are worn.  Won't a pin punch drive that out?  Remember I have a later model trans complete...Larry

[70CB750]

Certainly are worn.  Won't a pin punch drive that out?  Remember I have a later model trans complete...Larry

Right!  You do.  I suppose they are compatible 1970 - 1975, right?  I will buy it from you.

[MCRider]

Certainly are worn.  Won't a pin punch drive that out?  Remember I have a later model trans complete...Larry

That pin can only go one direction. If you tap on it it stops against the floor of the hole its in. It must be withdrawn.

I think I'm remembering correctly.

[MoMo]

Certainly are worn.  Won't a pin punch drive that out?  Remember I have a later model trans complete...Larry

Right!  You do.  I suppose they are compatible 1970 - 1975, right?  I will buy it from you.

K7/8 trans, maybe someone knows compatibility issues, I don't...Larry

[70CB750]

Certainly are worn.  Won't a pin punch drive that out?  Remember I have a later model trans complete...Larry

Right!  You do.  I suppose they are compatible 1970 - 1975, right?  I will buy it from you.

I will check into it.  Maybe invidual gears can be replaced only.

K7/8 trans, maybe someone knows compatibility issues, I don't...Larry

[Stev-o]

Certainly are worn.  Won't a pin punch drive that out?  Remember I have a later model trans complete...Larry

Right!  You do.  I suppose they are compatible 1970 - 1975, right?  I will buy it from you.

K7/8 trans, maybe someone knows compatibility issues, I don't...Larry

The sprocket shaft is different, The K7-8 is longer if I remember correctly. It could be used but the chain will not align correctly with the rear sprocket.

[MoMo]

Certainly are worn.  Won't a pin punch drive that out?  Remember I have a later model trans complete...Larry

Right!  You do.  I suppose they are compatible 1970 - 1975, right?  I will buy it from you.

K7/8 trans, maybe someone knows compatibility issues, I don't...Larry

The sprocket shaft is different, The K7-8 is longer if I remember correctly. It could be used but the chain will not align correctly with the rear sprocket.

If the gears are the same , it'd be a cheap fix for Prokop as I'd sell real cheap

[70CB750]

I will do my reaserch and get back to you, Larry.  I could be only swapping gears, keeping shafts.

[70CB750]

I took apart the head, Frank was right. knee mill is the easiest way to compress valve springs, it worked like a charm.

In K0 style, no guide seals on intake side - I removed two already here.  Loved the tight fit of under the spring washers, they were hard to remove because of tight tolerancies.

[70CB750]

The underside.

[70CB750]

How do you get out the spring pin that holds the kickstart shaft? Number 9.

ITs a bear. Many threads on this, when I did mine a few years ago. Settled on a small vicegrip; squeeeze what bit of the pin you can reach and tap up on the vice grips. Once it moves, reposition the VG to grab a little more and repeat.

Got it out yesterday, vice grips and twisting motion worked easy enough, thank you.

[70CB750]

This was my Robinson Crusoe moment; somebody worked the intake the way Hondaman describes in his book.

[calj737]

perhaps an answer as to why #4 would not synchronize equally with the others? A DIY porting job that created unequal port flows. Apologies if you previously stated the rebuild specs, but what is the intention on the motor? Stock rebuild or "turned up" a touch?

[70CB750]

Could be the porting job; also I remember once she ate the pin from the carburetor choke flap door; I found only the flap inside the carburetor but there are no siginificant nicks on valve or valve seat.

Plans for the engine:  if possible I will only hone and install new rings, depends how worn out cylinders are; with only minor improvements such as aftermarket tensioner and replacing worn out parts.

She had all the power I cared to use and more 

Now the valves have dimples where the tappet adjuster pushed on them, I may need to replace all the valves.

[calj737]

Now the valves have dimples where the tappet adjuster pushed on them, I may need to replace all the valves.

Ouch! If the prices of those is anything like the 5xx models 

[70CB750]

Not sure how much 5xx go for, but the SuperSport engine was the worst - valves, springs, retainers and guides plus 2 Neway cutters.

Looks like CycleX can fix me for reasonable price:

ENV-015    $149.00 per set of 8 (4 Intake and 4 Exhaust)

[calj737]

$40@

[70CB750]

Cleaned pistons.

[70CB750]

This is how one of the rings came out, looks like the little piece was riding there quite happily for a while, the break surface is not fresh.

[70CB750]

Oil rings - I never seen oil rings like these before.

And the inner and outer rings were all lined up, meaning the gap was open.

[70CB750]

Crankshaft out of the way and safe.

[70CB750]

The engine stand needed some additional fabrication.