Author Topic: GB is not OK!  (Read 5407 times)

Online Greybeard

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Re: GB is not OK!
« Reply #90 on: 29.05. 2018 14:53 »
depends on how much they take out, but I would say yes, ive seen somewhere that even at 5 or 6 thou you don't get piston slap...
...so it depends on your score depth
Musky advised that I should not have more than 3 thou so your thoughts on having maybe 5 or 6 thou are encouraging. Obviously I will be asking them to take the minimum out.

What about using a mechanics glaze buster; would using one of those be a bad idea or would it take out these shallow tramlines?

Online Triton Thrasher

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Re: GB is not OK!
« Reply #91 on: 29.05. 2018 14:59 »
I don’t think you’re getting a proper measurement.

A 2.75” bore with less than 3 thou clearance would probably have seized.

Online Triton Thrasher

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Re: GB is not OK!
« Reply #92 on: 29.05. 2018 15:15 »
I don’t think you’re getting a proper measurement.

A 2.75” bore with less than 3 thou clearance would probably have seized.

Scrolling back, I see you have what look like split skirt pistons, so your close clearance may be correct.   I thought pistons like that were ancient history by now.

Online berger

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Re: GB is not OK!
« Reply #93 on: 29.05. 2018 15:26 »
ive just found the book and super rocket is 5 thou shooting star 3 but when I rebuilt mine after the oil disaster 2 years ago I honed the barrels I fitted with a do it yourself honer and got a very tight 5 and nice 4 thou and its ok. I would let the honer have the pistons and tell them not to take more than 4 even if it leaves a shadow, like triton thrasher says you've got split skirts that work at finer tolerance. bit off topic but a mate rebuilt his triton [morgo barrels 750] after I told him to get rid of the lip at the bottom of his barrels and he broke the oil rings *eek*

Online Greybeard

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Re: GB is not OK!
« Reply #94 on: 29.05. 2018 15:39 »
I don’t think you’re getting a proper measurement.
A 2.75” bore with less than 3 thou clearance would probably have seized.

Scrolling back, I see you have what look like split skirt pistons, so your close clearance may be correct.   I thought pistons like that were ancient history by now.
I'm pretty sure that the bike came to me in 1973 with these +20 pistons so not surprised they are old-school. I put new rings on 6 years ago and will do again this time

Offline muskrat

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Re: GB is not OK!
« Reply #95 on: 29.05. 2018 20:45 »
G'day GB.
That'll be fine mate. 3-5 is OK for a road motor, I ran 8 in the racer. Just make sure the ring gaps are good.
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Online Triton Thrasher

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Re: GB is not OK!
« Reply #96 on: 29.05. 2018 21:25 »
Checking ring gaps is a good idea, especially in a case like this where the bore may be slightly smallish, for that close bore clearance.

Online Greybeard

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Re: GB is not OK!
« Reply #97 on: 29.05. 2018 21:30 »
Checking ring gaps is a good idea, especially in a case like this where the bore may be slightly smallish, for that close bore clearance.
Don't fret, it's on the to-do list  *smile*

Online Greybeard

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Re: GB is not OK!
« Reply #98 on: 31.05. 2018 10:01 »
I was wondering if I should pull the oil suction pipe out to clean the galleries more thoroughly. Is the top end locked into the case with a glue?
I've removed the pick-up pipe using some heat, (I was a bit concerned about warming the case near the timing side bush!). I now cannot see any point in removing the pipe as it just connects through the case with no side ports. It can be cleaned just as well in situ.

Online Greybeard

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Re: GB is not OK!
« Reply #99 on: 31.05. 2018 10:08 »
I took the barrels to a rebore shop. They've taken the piston clearance to 5 thou and the tramlines are still evident. I'm going to collect the block and try it. If that side is still smoky I'll consider a rebore. I've asked them to deglaze the other bore while it's there. Cost for the work is £31.

Online KiwiGF

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Re: GB is not OK!
« Reply #100 on: 31.05. 2018 11:54 »
I was wondering if I should pull the oil suction pipe out to clean the galleries more thoroughly. Is the top end locked into the case with a glue?
I've removed the pick-up pipe using some heat, (I was a bit concerned about warming the case near the timing side bush!). I now cannot see any point in removing the pipe as it just connects through the case with no side ports. It can be cleaned just as well in situ.

I agree. My pick up pipe was only removed so the sump gasket area could be milled flat. There was a step on my cases as they were “mismatched” cases.
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Online Greybeard

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Re: GB is not OK!
« Reply #101 on: 31.05. 2018 16:44 »
I've collected my barrel from the machine shop in Coventry. They took another skim and have now removed the tramlines. Looks good. I'll check skirt clearance when I've cleaned the barrels. Great chaps to deal with. I'll give them a mention in the Services section of the forum.

Bits have started to arrive. This picture shows SRM's contribution. These items cost £20.39, (including tax and carriage)!!

Sludge trap plugs and oil check valve spring.

Online Greybeard

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Re: GB is not OK!
« Reply #102 on: 31.05. 2018 17:23 »
Whoopy!

Online berger

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Re: GB is not OK!
« Reply #103 on: 31.05. 2018 19:44 »
i have not been to the pub,[that's tmow *countdown* *bash*] me and our kid had to freeze the bloody water pipe because stop cock knackered , good job he had freezer kits, anyway to the point, you carn't beat new toys coming through the post for your rebuilds , when you open up your packages it smells like victory, greybeard I think you would have got away with a shadow of the scores left I hope they've not taken too much like my engineer did and left me with the annoying piston slap

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Re: GB is not OK!
« Reply #104 on: 31.05. 2018 20:00 »
you carn't beat new toys coming through the post for your rebuilds , when you open up your packages it smells like victory, greybeard I think you would have got away with a shadow of the scores
Yes, I must say I'm enjoying all these parcels arriving; just like Christmas!
Quote
left I hope they've not taken too much like my engineer did and left me with the annoying piston slap
I haven't checked it yet. The engineer said he got the lines out with 5 thou skirt clearance.