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 Post subject: Re: Top end spruce up
PostPosted: 22 Sep 2016 22:30 
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Joined: 22 Jul 2009 18:07
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Location: derbyshire
PS I think the quoted comression ratio for this engine will be for an engine running corrected squish. Harley mass production methods will probably mean that one in a thousand will be close to this, most will probably be lower. Sounds like you got one, 95HP.


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 Post subject: Re: Top end spruce up
PostPosted: 22 Sep 2016 23:43 
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proff. patpending
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You will see, when you pull the heads, there is a 0.9mm step from the deck to the squish band. You will also see that the piston crown edge sits below the top of the barrel. If you want to make the squish 'nice', I am guessing you are aiming for 0.75mm, you will need to get the barrel as low as possible to align the edge of the piston crown with the top of the barrel. More often than not this would need you to ditch the base gaskets (and this may result in leaks further down the line), however Cometic will sell you 0.25mm and 0.5mm thick base gaskets. Next, you will want to machine the deck to the start of the squish band (approx 0.9mm) then you will want to use a 0.75mm Cometic head gasket...

However, the squish band will still not match the piston crown and the 'nice' squish clearance will only occur close to the cylinder bore, so your work is pretty much wasted... I have actually done the same, only because I had the engine in bits and I saw an injustice, but I ended up with an engine that pinked which led me to tinker with the ignition timing to get rid of it...

But... I'm with Maz on this, just refresh the heads without trying to do anything fancy. The bottom line is that if you aren't going to do the job properly (recut the squish band), don't bother. Use your time and money on something more beneficial, maybe on the missus ;) ...

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 00:53 
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pash wrote:
But... I'm with Maz on this, just refresh the heads without trying to do anything fancy. The bottom line is that if you aren't going to do the job properly (recut the squish band), don't bother. Use your time and money on something more beneficial, maybe on the missus ;) ...

:yt:

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 02:14 
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Joined: 06 May 2009 17:10
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Current ride: 99 Cyclone M2
Location: Liverpool
:D :D
I've heard others say the same, my 94.8 comes from +60 bore, wiseco pistons, mikyroony carb, US headers with V&H can it's got a race ecu and running on Vpower and maybe a capfull or 2 of octane booster :coat: ;)......

Maybe I could squeeze 95+ with a little head skimming :idea:

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 10:11 
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...not denying the bragging rights of increased RWHP, but more benefit in performance would be gained by shedding weight...

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 10:44 
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rik wrote:
...not denying the bragging rights of increased RWHP, but more benefit in performance would be gained by shedding weight...

Or upgrading suspension and brakes. Less costly to eat fewer pies, granted.

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 10:55 
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03 wrote:
rik wrote:
...not denying the bragging rights of increased RWHP, but more benefit in performance would be gained by shedding weight...

Or upgrading suspension and brakes. Less costly to eat fewer pies, granted.

lOl ... Oooo, now you're getting personal, Steve! I meant from the BIKE! ;)
But in Gus's chosen discipline, who needs suspension? ...or brakes? lOl

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 11:01 
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rik wrote:
03 wrote:
rik wrote:
...not denying the bragging rights of increased RWHP, but more benefit in performance would be gained by shedding weight...

Or upgrading suspension and brakes. Less costly to eat fewer pies, granted.

lOl ... Oooo, now you're getting personal, Steve! I meant from the BIKE! ;)
But in Gus's chosen discipline, who needs suspension? ...or brakes? lOl

Probably a reflection more of myself than anyone else actually.

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 11:27 
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03 wrote:
rik wrote:
03 wrote:
rik wrote:
...not denying the bragging rights of increased RWHP, but more benefit in performance would be gained by shedding weight...

Or upgrading suspension and brakes. Less costly to eat fewer pies, granted.

lOl ... Oooo, now you're getting personal, Steve! I meant from the BIKE! ;)
But in Gus's chosen discipline, who needs suspension? ...or brakes? lOl

Probably a reflection more of myself than anyone else actually.

There's a lot of us in that particular boat, Steve!

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 11:30 
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proff. patpending
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rik wrote:
03 wrote:
rik wrote:
03 wrote:
rik wrote:
...not denying the bragging rights of increased RWHP, but more benefit in performance would be gained by shedding weight...

Or upgrading suspension and brakes. Less costly to eat fewer pies, granted.

lOl ... Oooo, now you're getting personal, Steve! I meant from the BIKE! ;)
But in Gus's chosen discipline, who needs suspension? ...or brakes? lOl

Probably a reflection more of myself than anyone else actually.

There's a lot of us in that particular boat, Steve!

Respect the Plimsoll line...

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 11:32 
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pash wrote:
Respect the Plimsoll line...


:rotfl: amen to that brother :mrgreen:

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 15:13 
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03 wrote:
rik wrote:
...not denying the bragging rights of increased RWHP, but more benefit in performance would be gained by shedding weight...

Or upgrading suspension and brakes. Less costly to eat fewer pies, granted.


Or selling it and buying something Japanese :?

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 15:17 
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pash wrote:
Respect the Panty line...

Fixed that for ya, Nick. ;) lOl

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 Post subject: Re: Top end spruce up
PostPosted: 23 Sep 2016 17:12 
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proff. patpending
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rik wrote:
pash wrote:
Respect the Panty line...

Fixed that for ya, Nick. ;) lOl

Thanks :yup:

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 Post subject: Re: Top end spruce up
PostPosted: 24 Sep 2016 01:39 
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Bonzo wrote:
03 wrote:
rik wrote:
...not denying the bragging rights of increased RWHP, but more benefit in performance would be gained by shedding weight...

Or upgrading suspension and brakes. Less costly to eat fewer pies, granted.


Or selling it and buying something Japanese :?

Sure, but most folk here have likely already gone in the other direction? Besides, more and more nowadays you need to keep below the speed limit, meaning that a bike with close to 200 bhp is pointless for a road bike anyway. Hence improving braking and suspension might be a good way to get more smiles per miles whilst hanging on to your licence!

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