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Author Topic: Cylinder head issue  (Read 412 times)

Offline Bone91

  • Posts: 26
Cylinder head issue
« on: Jul 06, 2018, 02:56:01 »
Hey there,
So i am currently attempting my first rebuild. I purchased a cb250g off gumtree for $150 about 7 years ago with a plan to restore it... low and behold, life got in the way, moved interstate so the bike went into storage at the oldies place. I have recently moved back home so figured id pull it out and tinker away at it, so far i have pulled the engine and done a complete tear down. Everything seems to be in good shape bar a hand full of things, ill post up a few photos as i would like to get some opinions on what you guys would recommend doing with the issues i have come across.



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Offline Bone91

  • Posts: 26
Re: Cylinder head issue
« Reply #1 on: Jul 06, 2018, 02:57:51 »
I am guessing the PO had welded the outside to reinforce the damage on the inside as it is on both sides. Do you think this will be an issue down the track or should i look at replacing the jugs?

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« Last Edit: Jul 06, 2018, 03:02:37 by Bone91 »

Offline Bone91

  • Posts: 26
Re: Cylinder head issue
« Reply #2 on: Jul 06, 2018, 03:01:32 »
Here i have circled the seat for the cam chain guide, i am guessing the guide came loose at some point and has bounced around causing the damage. My question is, has anyone had this issue an would it be worth having it repaired or should i be looking for a new head?

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Offline Bone91

  • Posts: 26
Re: Cylinder head issue
« Reply #3 on: Jul 06, 2018, 03:06:44 »
Here im guessing the PO has tried to smooth out the pitting on the combustion chamber, now i dont know a great deal about engines in general but the engine isnt going to run evenly if the combustion chambers arent the same size, correct?

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Offline Bone91

  • Posts: 26
Re: Cylinder head issue
« Reply #4 on: Jul 06, 2018, 03:20:53 »
Oh and this, i could be wrong but to me it looks like someone has botch welded the seat back onto the tensioner arm?

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Online MiniatureNinja

  • Posts: 380
Re: Cylinder head issue
« Reply #5 on: Jul 06, 2018, 14:43:42 »
The weld repair on the cylinder head seams fine, I would be concerned about the tensioner mount. I mean luckily heads for the cb360/cb250 are plentiful in ebay.
As for the tensioner that's just what they look like... old Japanese motorcycle welding wasn't what it is today
'82 BMW R65LS
'75 Honda CB360 - thread

Offline Sderbyshire

  • Posts: 172
  • Into Sailing, classic Triumph cars and motorbikes.
Re: Cylinder head issue
« Reply #6 on: Jul 06, 2018, 14:55:00 »
If you want to see a bodged tensioner arm, wait until i get mine out 😀

Steve

Offline doc_rot

  • DTT BOTM WINNER
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  • Posts: 1051
  • Oh the usual... I bowl, I drive around...
Re: Cylinder head issue
« Reply #7 on: Jul 06, 2018, 15:13:34 »
Here im guessing the PO has tried to smooth out the pitting on the combustion chamber, now i dont know a great deal about engines in general but the engine isnt going to run evenly if the combustion chambers arent the same size, correct?

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it looks like it was machined for a squish band? except that the bands are very unequal. weird stuff, I'd get a new head.

Online MiniatureNinja

  • Posts: 380
Re: Cylinder head issue
« Reply #8 on: Jul 06, 2018, 15:40:47 »
it looks like it was machined for a squish band? except that the bands are very unequal. weird stuff, I'd get a new head.
Its probably a cb360 head they was "repaired"

The 250 heads didnt have the squish. But the 360 ones did
'82 BMW R65LS
'75 Honda CB360 - thread

Offline Bone91

  • Posts: 26
Re: Cylinder head issue
« Reply #9 on: Jul 06, 2018, 20:28:55 »
it looks like it was machined for a squish band? except that the bands are very unequal. weird stuff, I'd get a new head.
Sorry but what is a squish band? Something maybe i could do?

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