Too Much Compression?

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Bilko
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Wed Mar 23, 2011 12:39 pm

Having an ongoing issue with the 250.

I've just snapped another kickstart shaft. That's the 3rd I've been through.

I'm also bending kickstart levers. 4 so far and I've only just got the Lambretta on the road.

What's my options?

RB250 with a MBD water cooled head
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dapper
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Wed Mar 23, 2011 1:06 pm

What's the squish Rob? You could always put an extra very thin head gasket in until she's run in and loosened up a bit, although I'm sure an adult will be along soon to chide me and make me sit in the naughty corner for making such a suggestion ;)
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Bilko
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Wed Mar 23, 2011 1:07 pm

1.4 mate. :(
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J1MS
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Wed Mar 23, 2011 1:10 pm

Kick it when it's off compression...

Or lower the compression, but make sure that's not going drop the compression too much first.

Rimg MB And ask what it's supposed to be with your chosen squish clearance, then check this to make sure it's correct. I've known one cylinderhead to be 17-1... even water cooled that's a bit on the high side.

Hope you sort it....

Mark.

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johnd
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Wed Mar 23, 2011 1:43 pm

What gearbox and sprockets are you using? Doesn't this have an effect on how hard it is to kick over a big engine? I'm using GP125 italian 19/46 on my 225rb and it kicks over fine.

Bilko
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Wed Mar 23, 2011 2:10 pm

GP200 and 47 X 18 Sprockets.

Phil @ MB was on standby awaiting my call.

Putting a head gasket on to lower compression a bit until it's run in a bit more.
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mark
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Wed Mar 23, 2011 4:11 pm

surely that will open your squish up making your bike run hotter?

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coaster
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Wed Mar 23, 2011 5:09 pm

mark wrote:surely that will open your squish up making your bike run hotter?
That's what I was thinking, best take it fairly easy.

Bilko
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Wed Mar 23, 2011 5:47 pm

It's just 'til it settles down, I'll not be going mad.

I've only ran it about 5-6 miles in two runs. Other than that's it only been started up at home. To lose that many kickstart shafts and levers in such a short time is insane.

Hope tthis works! :?
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mark
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Wed Mar 23, 2011 8:46 pm

It won't lose compression unless you mod the head, the bodge you are doing will not settle down. Sorry mate but after putting this much time,effort and money into this project it's mindless

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