Author Topic: 750 K1 project  (Read 4641 times)

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: 750 K1 project
« Reply #15 on: April 09, 2018, 04:53:29 PM »
Et Voila!  :). Good job you guys know what's What ! These two have come out quite easily...which is more than I can say for some the fasteners so far! Can't budge the exhaust stub screws !
Blimey, you are a very lucky chap. Graham would faint with shock if he had them come out that easy but, like he said previously, your engine looks a million dollars compared to some of the ones we get through here  :'( :'( :'(
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Crispy

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Re: 750 K1 project
« Reply #16 on: April 09, 2018, 05:03:39 PM »
Yes I'm beginning to realise that it's not bad after seeing some of the project threads...still it's a big  but enjoyable learning curve for me ....and I've learned loads today...🙌

Offline Bryanj

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Re: 750 K1 project
« Reply #17 on: April 09, 2018, 05:29:29 PM »
Big thing is all oilways scrupulously clean along with gasket surfaces, a tiny amount of gasket material in an oilway will wreck the top end

Offline Trigger

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Re: 750 K1 project
« Reply #18 on: April 09, 2018, 05:43:02 PM »
Et Voila!  :). Good job you guys know what's What ! You had me worried then with talk of 're-engineering'  :o These two have come out quite easily...which is more than I can say for some the fasteners so far! Can't budge the exhaust stub screws !

How the hell did you get those out without grabbing hold of the nipple ?  Or have you flattened the nipple ?
 I have made so many special tools to get those out.

Offline Crispy

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Re: 750 K1 project
« Reply #19 on: April 09, 2018, 05:55:40 PM »
Big thing is all oilways scrupulously clean along with gasket surfaces, a tiny amount of gasket material in an oilway will wreck the top end
Cheers Bryanj
After reading your post I've just spent a few minutes blowing air down all the holes in the cylinder head and seeing where it comes out ...to give me an idea of where the oil ways run...and to make sure they're clear. It is difficult to keep everything clean though, I power washed the motor before I started stripping it down but there's still dirt everywhere. I can now understand why some of you have separate clean and dirty workshops.
« Last Edit: April 09, 2018, 06:18:25 PM by Crispy »

Offline Crispy

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Re: 750 K1 project
« Reply #20 on: April 09, 2018, 06:25:08 PM »
Et Voila!  :). Good job you guys know what's What ! You had me worried then with talk of 're-engineering'  :o These two have come out quite easily...which is more than I can say for some the fasteners so far! Can't budge the exhaust stub screws !

How the hell did you get those out without grabbing hold of the nipple ?  Or have you flattened the nipple ?
 I have made so many special tools to get those out.

I think my nipples are ok! 😬
Although I did grab hold of them with a pair of long nose pliers! I didn't put too much pressure on them..gave them a waggle and out they popped!
« Last Edit: April 09, 2018, 06:29:44 PM by Crispy »

Offline Crispy

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Re: 750 K1 project
« Reply #21 on: April 09, 2018, 06:45:22 PM »
Finished my seat off today with the logo and strap, pleased with how that turned out and also butchered a spare socket to make a valve removal tool which worked really well. I know it's not a big deal but it was very satisfying to get them all out with it!  ::)

Offline Crispy

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Re: 750 K1 project
« Reply #22 on: April 09, 2018, 07:16:25 PM »
Got another question...having removed the valves, there are only 4 valve stem seals ..on the inlet valves ..although the exploded parts diagram shows them on both inlet and exhaust.. Is this because it's an earlyish motor?

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: 750 K1 project
« Reply #23 on: April 09, 2018, 07:27:24 PM »
Yes, the early ones don't have exhaust valve seals.
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Trigger

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Re: 750 K1 project
« Reply #24 on: April 09, 2018, 07:34:08 PM »
Et Voila!  :). Good job you guys know what's What ! You had me worried then with talk of 're-engineering'  :o These two have come out quite easily...which is more than I can say for some the fasteners so far! Can't budge the exhaust stub screws !

How the hell did you get those out without grabbing hold of the nipple ?  Or have you flattened the nipple ?
 I have made so many special tools to get those out.

I think my nipples are ok! 😬
Although I did grab hold of them with a pair of long nose pliers! I didn't put too much pressure on them..gave them a waggle and out they popped!

Those are in perfect shape, more evidence that that motor has never been apart before  ;) To clean the jets, soak in thinners for a couple of days and dig with a thin bit of wire (from a wire brush) before blowing out with a airline.

Offline Crispy

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Re: 750 K1 project
« Reply #25 on: April 09, 2018, 08:47:30 PM »
Et Voila!  :). Good job you guys know what's What ! You had me worried then with talk of 're-engineering'  :o These two have come out quite easily...which is more than I can say for some the fasteners so far! Can't budge the exhaust stub screws !

How the hell did you get those out without grabbing hold of the nipple ?  Or have you flattened the nipple ?
 I have made so many special tools to get those out.

I think my nipples are ok! 😬
Although I did grab hold of them with a pair of long nose pliers! I didn't put too much pressure on them..gave them a waggle and out they popped!

Those are in perfect shape, more evidence that that motor has never been apart before  ;) To clean the jets, soak in thinners for a couple of days and dig with a thin bit of wire (from a wire brush) before blowing out with a airline.

👍

Offline Crispy

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Re: 750 K1 project
« Reply #26 on: April 15, 2018, 10:09:39 AM »
I've measured my cylinders, pistons and ring gaps, (see pic)  Measurements seem to be only just within tolerance, out of round and taper seem ok. What do you think folks? ...will I be ok using the cylinders and Pistons as they are Just replacing the rings ?

Limit for cylinders is rebore if diameter is greater 61.1mm
Limit for piston is replace if diameter is less than 60.85mm

My measurements seem to be very close to these limits although they are within them.  :-\
« Last Edit: April 15, 2018, 10:13:09 AM by Crispy »

Offline Trigger

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Re: 750 K1 project
« Reply #27 on: April 15, 2018, 10:17:10 AM »
I've measured my cylinders, pistons and ring gaps, (see pic)  Measurements seem to be only just within tolerance, out of round and taper seem ok. What do you think folks? ...will I be ok using the cylinders and Pistons as they are Just replacing the rings ?

Limit for cylinders is rebore if diameter is greater 61.1mm
Limit for piston is replace if diameter is less than 60.85mm

My measurements seem to be very close to these limits although they are within them.  :-\

By your measuring, it looks like piston 2,3,4 won't fit the bore as the pistons are bigger  ;)

Offline Crispy

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Re: 750 K1 project
« Reply #28 on: April 15, 2018, 10:29:29 AM »
🙄....damn!! I'll do them again!! 😂

Offline Crispy

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Re: 750 K1 project
« Reply #29 on: April 15, 2018, 10:45:43 AM »
Ok here's another attempt..these are the averages of several readings....it's a long time since I've done any maths!! 😂

Just realised that the pistons are measured at the skirt...mine are very tight in  the bore of the cylinder at the top!
« Last Edit: April 15, 2018, 11:02:19 AM by Crispy »