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Author Topic: Having an issue seating the cylinder block.  (Read 246 times)

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Offline juntjoo

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Having an issue seating the cylinder block.
« on: November 09, 2018, 11:37:42 am »

Anyone have experience or just a tip on what I can do here?

-Ben

82 Nighthawk 650

I just wanted to own and ride a bike. instead I became a (amateur)mechanic.

Offline Tim2005

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Re: Having an issue seating the cylinder block.
« Reply #1 on: November 09, 2018, 03:10:59 pm »
Are they the original dowels at the ends of the block? It looks like they are a bit too long. Either that or they haven't dropped into their holes well and the block is hanging up on them.

Offline juntjoo

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Re: Having an issue seating the cylinder block.
« Reply #2 on: November 09, 2018, 03:24:03 pm »
Thanks. I didn't take the block off originally but the pins were already sitting in the crankcase so I just assumed they were completely sealed. Tomorrow when I get back at it I'll check the holes in the underside of the block and try to fit them I manually/individually.
-Ben

82 Nighthawk 650

I just wanted to own and ride a bike. instead I became a (amateur)mechanic.

Offline Scott S

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Re: Having an issue seating the cylinder block.
« Reply #3 on: November 09, 2018, 08:25:59 pm »
 Make sure you seat the cam chain tensioner properly or you'll be back in there again!
'73 CB500/550
'71 CT70
'14 Triumph Scrambler

 and too many projects...

Offline 754

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Re: Having an issue seating the cylinder block.
« Reply #4 on: November 09, 2018, 09:08:17 pm »
Dowels are easily damaged , when trying to remove them.
 My favorite way to pull them is with a tap.
 Is it the cylinder that came off that motor ?
 Did you try to remove dowels  and scar them or make them oval ?
Can you lift it high enough to get your little finger in to feel for damage..
 Don't put to much pressure on that crank bolt.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline juntjoo

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Re: Having an issue seating the cylinder block.
« Reply #5 on: November 11, 2018, 09:52:03 am »
Dowel pins https://imgur.com/a/8PVDCMU

I didn't scar them or anything. Currently after my last attempt at wiggling the block on they're settled in pretty good. I'd need to use a tap to get them out but I wonder if they're the culprit. The block was just lifted off I presume. I didn't feel any obstructions underneath, nothing obvious. Tried tightening down a bit but I'm scared. As I should be. I have a proclivity to break things. I think I'll get that reverse tap and get pins out then try just to make sure...

Will that little tear in the (new) gasket there cause problems? That wet spot where it tore was from some gasoline. Is there something I should smear in there?
« Last Edit: November 11, 2018, 09:55:23 am by juntjoo »
-Ben

82 Nighthawk 650

I just wanted to own and ride a bike. instead I became a (amateur)mechanic.

Offline juntjoo

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Re: Having an issue seating the cylinder block.
« Reply #6 on: November 11, 2018, 10:08:05 am »
http://imgur.com/a/0wA9YBn

I guess no using a tap to get it out. That's for oil correct?
-Ben

82 Nighthawk 650

I just wanted to own and ride a bike. instead I became a (amateur)mechanic.

Offline juntjoo

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Re: Having an issue seating the cylinder block.
« Reply #7 on: Today at 09:06:53 am »
9mm ID/10mm OD https://imgur.com/a/zuCEeBA

If I'd been the one who took it apart it I'd know if these oil dowel pins are original. I'm going to imagine so and that in fact I'm supposed to press them in by tightening down the whole thing but I don't know for sure. Maybe I have them upside down? If I remember correctly one pin was already in the block and I just put the other one in to fit the same way and it just easilly fit in. I remember it was tapered, or stepped down in diameter and I put the smaller side in. I think I'll need a special tool to remove them at this point. Already scuffed one up a bit too much. Are these supposed to be pressed I tight as heck? Are the block and head supposed to fit easily or require pressing the pins in?
-Ben

82 Nighthawk 650

I just wanted to own and ride a bike. instead I became a (amateur)mechanic.

Offline 754

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Re: Having an issue seating the cylinder block.
« Reply #8 on: Today at 10:01:41 am »
I just use a tap, twist them out  but I have many sizes,
 Btw that does not look like most dowels   thicker wall, can't be the size you listed.
They generally have to be tapped in, some go easy.
 But if you pulled  them or part way and they are cocked a bit, it will take some extra tapping to get them sliding in.
 Make sure they are smooth.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Phoenix

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Re: Having an issue seating the cylinder block.
« Reply #9 on: Today at 10:34:13 am »
If it were me, and I've been there, I would pull of the jugs and measure the pin length and pin depths.  Ideally, check the fit w/o the pins.
Ed Spengeman
Indy
1971 CB750K1 (Stock)
1973 CB350 Twin  (Gone)

Offline juntjoo

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Re: Having an issue seating the cylinder block.
« Reply #10 on: Today at 10:41:42 am »
I just use a tap, twist them out  but I have many sizes,
 Btw that does not look like most dowels   thicker wall, can't be the size you listed.
They generally have to be tapped in, some go easy.
 But if you pulled  them or part way and they are cocked a bit, it will take some extra tapping to get them sliding in.
 Make sure they are smooth.

http://partstream.arinet.com/Mobile/UT9QOkNB9cTAfbSJvd9VecST4zy8a0T2hjnStblpb433l6aSssMlA_BkW1KQ5y_jLXlY6ANpm_BmcM17qQdedSxglo0MyUNQOm8I9PvYvhFRpebPQJWj7kuqbAq7A1P30.html#/Mobile/2i3esvi_J4GMMAyOe7dXTVH6NQIzLpj5muN_NtyzkcYvPovZLGkJvvtPkb8UhdBLoN_xrd9_YlTHUPwUJM2VEOlAWfObXVuRH-ggFDLX92A1.html

"oil control valve" and now I'm thinking I put them i upside down if what this diagram seems to show. I think I gotta get my hands on a special tool. May check with my mechanic who's working on my truck atm. Good time to go check on it...
-Ben

82 Nighthawk 650

I just wanted to own and ride a bike. instead I became a (amateur)mechanic.

Offline The Lone Builder

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Re: Having an issue seating the cylinder block.
« Reply #11 on: Today at 01:11:47 pm »
I went through a very similar story; on a 750K2 so don't know if it's the same. See the story here:
http://forums.sohc4.net/index.php/topic,168350.msg1950253.html#msg1950253

First, I agree with 754 that those dowels don't look like originals - certainly not like the 750 ones.

If you ahven't got a right size tap, a drill bit will do the same job.

The main thing I learned was to make sure both the bore and the outside of the dowels are clean are smooth. Then measure teh depth of both sides and get a dowel to fit.

Good luck.

Sean
CB750 K2 - A work in progress
CB750 K1 - The less, said the better!
CB450 K1 - It's black.
CB400F Supersport - It's rusty!

Offline juntjoo

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Re: Having an issue seating the cylinder block.
« Reply #12 on: Today at 02:02:16 pm »
I went through a very similar story; on a 750K2 so don't know if it's the same. See the story here:
http://forums.sohc4.net/index.php/topic,168350.msg1950253.html#msg1950253

First, I agree with 754 that those dowels don't look like originals - certainly not like the 750 ones.

If you ahven't got a right size tap, a drill bit will do the same job.

The main thing I learned was to make sure both the bore and the outside of the dowels are clean are smooth. Then measure teh depth of both sides and get a dowel to fit.

Good luck.

Sean

Thanks. No, I'm sure at this point that I put them in upside down as the pic in the fiche page I linked to above shows them(oil control valves) them oriented with the narrow side up. I put mine in down hence the tight/stuck fit. I stuck them via rubber mallet  - cylinder head. With the narrow ends of these up I can see how they wouldn't interfere with the holes in the underside of the cylinder head. Silly mistake. Destined to make them til you do these jobs several times til you know each part. First time going this deep into this machine. Now I know what an oil control valve looks like. Speaking of which, I've dropped some rtv debris in the engine scraping the mating surfaces. Not much but I ought to change and flush the oil right? Flush with what? I've r/heard how those pieces get stuck in oil passages like of these valves, which I now can see how junk could block them then no oil to cylinder head ouch.

If anyone has any ideas on pulling these oit(without damaging), gripping them really. I'll ask mechanic tomorrow. He's also a machine shop so he should have an idea/tool. I can get around them with pliers and electrical tape to protect but can't physically grip them enough. I'm not too familiar with many vice gripping tools like higher end pliers like those Irwin vice grip ones. Are they much more mechanically advantageous than standard pliers? I've always wanted to grab a pair. What do you use to get the best hand grip on something this little and difficult to grab?
-Ben

82 Nighthawk 650

I just wanted to own and ride a bike. instead I became a (amateur)mechanic.

 

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