Author Topic: Dorothy III - CB750 (Read 103624 times)

MCRider · « **Reply #325 on:** October 01, 2015, 06:41:52 AM »

Quote from: 70CB750 on October 01, 2015, 03:22:08 AM

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 · « **Reply #326 on:** October 01, 2015, 06:44:50 AM »

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

MCRider · « **Reply #327 on:** October 01, 2015, 06:57:02 AM »

Quote from: 70CB750 on October 01, 2015, 06:44:50 AM

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 · « **Reply #328 on:** October 01, 2015, 07:34:30 AM »

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

70CB750 · « **Reply #329 on:** October 01, 2015, 07:36:49 AM »

Quote from: MoMo on October 01, 2015, 07:34:30 AM

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 · « **Reply #330 on:** October 01, 2015, 07:39:07 AM »

Quote from: MoMo on October 01, 2015, 07:34:30 AM

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 It must be withdrawn.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 · « **Reply #331 on:** October 01, 2015, 07:45:46 AM »

Quote from: 70CB750 on October 01, 2015, 07:36:49 AM

Quote from: MoMo on October 01, 2015, 07:34:30 AM
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 · « **Reply #332 on:** October 01, 2015, 07:48:44 AM »

Quote from: MoMo on October 01, 2015, 07:45:46 AM

Quote from: 70CB750 on October 01, 2015, 07:36:49 AM
Quote from: MoMo on October 01, 2015, 07:34:30 AM
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 · « **Reply #333 on:** October 01, 2015, 03:21:31 PM »

Quote from: MoMo on October 01, 2015, 07:45:46 AM

Quote from: 70CB750 on October 01, 2015, 07:36:49 AM
Quote from: MoMo on October 01, 2015, 07:34:30 AM
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 · « **Reply #334 on:** October 01, 2015, 05:00:27 PM »

Quote from: Stev-o on October 01, 2015, 03:21:31 PM

Quote from: MoMo on October 01, 2015, 07:45:46 AM
Quote from: 70CB750 on October 01, 2015, 07:36:49 AM
Quote from: MoMo on October 01, 2015, 07:34:30 AM
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 · « **Reply #335 on:** October 02, 2015, 04:30:05 AM »

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

70CB750 · « **Reply #336 on:** October 02, 2015, 04:31:41 AM »

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 · « **Reply #337 on:** October 02, 2015, 04:40:39 AM »

The underside.

70CB750 · « **Reply #338 on:** October 02, 2015, 04:42:15 AM »

Quote from: MCRider on October 01, 2015, 06:41:52 AM

Quote from: 70CB750 on October 01, 2015, 03:22:08 AM
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 · « **Reply #339 on:** October 02, 2015, 04:47:28 AM »

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

calj737 · « **Reply #340 on:** October 02, 2015, 04:52:34 AM »

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 · « **Reply #341 on:** October 02, 2015, 05:05:25 AM »

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 · « **Reply #342 on:** October 02, 2015, 05:50:53 AM »

Quote from: 70CB750 on October 02, 2015, 05:05:25 AM

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 · « **Reply #343 on:** October 02, 2015, 05:59:43 AM »

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 · « **Reply #344 on:** October 02, 2015, 06:29:35 AM »

70CB750 · « **Reply #345 on:** October 03, 2015, 07:45:32 AM »

Cleaned pistons.

70CB750 · « **Reply #346 on:** October 03, 2015, 07:47:43 AM »

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 · « **Reply #347 on:** October 03, 2015, 07:51:09 AM »

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 · « **Reply #348 on:** October 03, 2015, 08:18:58 AM »

Crankshaft out of the way and safe.

70CB750 · « **Reply #349 on:** October 05, 2015, 04:49:48 AM »

The engine stand needed some additional fabrication.

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Author Topic: Dorothy III - CB750 (Read 103624 times)