Re: Guzzi Bore, Pistons and Cam. Bore.

Dave H. wrote:

> > http://www.sweller.dynalias.org/guzzipistons/
> >
> > What's caused the scoring, why's the carbon oily and will it polish
> > out?

> First thoughts: looking at the l/h piston, shouldn't the ring gaps not
> line up? That'd account for a lot of the oily carbon, blow-by into the
> carnkcase would push oil out of the breather and into the carb, hence
> deposits building up... the scoring in the barrel will let some more
> combustion gas past, but nothing compared to having the ring gaps lined
> up[-1]!

The rings may have lined up because of my handling of them but I can't be
certain. The evidence of any blow by would be burning on the piston.

> When you took the carbs off, were the intake ports and carb internals
> oil-misted?

No. I suspect the valve guides for the oil as these bikes are very
susceptible to having their crankcase pressurised. Since I changed the
pistons (two years ago) it doesn't suffer from it anymore.

Which is why I'm discounting blow by. Take my word for it, anyone who
followed that machine at full chat a few years ago would have had the
Royal Flying Corp look.

> The cam followers look to me like it's been run dry, is the cam badly
> scored? I had a Vauxhall that did this, an oilway wasn't drilled at the
> factory, about 1/4 inch was worn off the cam lobe in about 25K miles...
> Sounded very tappety too.

Cam looks ok but that's peering down through the follower hole.

> Looking at the scored barrels, does the cutaway in the base face
> towards the centre of the V? if'n it does, it looks like the piston's
> been rocking in the bore (a touch undersize?) with sommat hard and
> gritty picked up by the piston skirt[0] (possibly the bits of lost
> case-hardening off the cam followers?)

Could be possible.

> The scoring on the l/h piston looks a lot[1] like it's been siezed and
> left to cool, then ignored or maybe just had the rings changed

(

Piston wasn't scored when it was fitted two years ago, the bike hasn't
seized and I've not changed the rings.

> I'd be checking whether the pistons can be reused[2], they look pretty
> far gone to me, particularly the left, and the scoring... if the
> scoring will clean up with a hone, great, if not you're looking at a
> rebore and pistons, or perhaps just the replacement (same size?)
> barrels and fresh pistons

Pistons are - for all intents and purposes - unobtainable. I will see if
I can clean them up.

--
Simon

sweller <sweller@mztech.fsnet.co.uk> wrote:

> Pistons are - for all intents and purposes - unobtainable.

That's bad news. Does anyone do quality replacements? Wiseco, for
instance?

--
K1100LT 955i 750SS CB400F CD250 CM200 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60
The bells, the bells.....

sweller wrote
(snip)

>Pistons are - for all intents and purposes - unobtainable. I will see if
>I can clean them up.
>
Hope they come good.
Out of curiosity who were they made by? It's on the tip of my tongue and
is bugging me.
--
Roger Hunt

"The Older Gentleman" <chateau.murrayTAKETHISOUT@dsl.pipex.com> wrote in
message
news:1i27gdz.b84chc1shhexgN%chateau.murrayTAKETHIS OUT@dsl.pipex.com...
> sweller <sweller@mztech.fsnet.co.uk> wrote:
>
>> Pistons are - for all intents and purposes - unobtainable.
>
> That's bad news. Does anyone do quality replacements? Wiseco, for
> instance?
>
Mahle. High comp versions for cast liners too :>) Only downside is £££!

JB

On Thu, 2 Aug 2007 06:43:38 +0100,
chateau.murrayTAKETHISOUT@dsl.pipex.com (The Older Gentleman) wrote:

>sweller <sweller@mztech.fsnet.co.uk> wrote:
>
>> Pistons are - for all intents and purposes - unobtainable.
>
>That's bad news. Does anyone do quality replacements? Wiseco, for
>instance?

Probably *way* out of date now, but:

http://www.raceco.com/engine.html#Anchor-Raceco-47857

--
-Pip

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember
chateau.murrayTAKETHISOUT@dsl.pipex.com (The Older Gentleman) saying
something like:

>sweller <sweller@mztech.fsnet.co.uk> wrote:
>
>> Pistons are - for all intents and purposes - unobtainable.
>
>That's bad news. Does anyone do quality replacements? Wiseco, for
>instance?

My thought exactly. A knowledgeable piston shoppe can source a piston
for almost anything, even if it's made for a totally different engine.
--
Dave
GS850x2 XS650 SE6a

Teach a man to fish and he and his pikey mates will have the
river cleaned out in a day.

	#1
sweller	Re: Guzzi Bore, Pistons and Cam. Bore. Dave H. wrote: > > http://www.sweller.dynalias.org/guzzipistons/ > > > > What's caused the scoring, why's the carbon oily and will it polish > > out? > First thoughts: looking at the l/h piston, shouldn't the ring gaps not > line up? That'd account for a lot of the oily carbon, blow-by into the > carnkcase would push oil out of the breather and into the carb, hence > deposits building up... the scoring in the barrel will let some more > combustion gas past, but nothing compared to having the ring gaps lined > up[-1]! The rings may have lined up because of my handling of them but I can't be certain. The evidence of any blow by would be burning on the piston. > When you took the carbs off, were the intake ports and carb internals > oil-misted? No. I suspect the valve guides for the oil as these bikes are very susceptible to having their crankcase pressurised. Since I changed the pistons (two years ago) it doesn't suffer from it anymore. Which is why I'm discounting blow by. Take my word for it, anyone who followed that machine at full chat a few years ago would have had the Royal Flying Corp look. > The cam followers look to me like it's been run dry, is the cam badly > scored? I had a Vauxhall that did this, an oilway wasn't drilled at the > factory, about 1/4 inch was worn off the cam lobe in about 25K miles... > Sounded very tappety too. Cam looks ok but that's peering down through the follower hole. > Looking at the scored barrels, does the cutaway in the base face > towards the centre of the V? if'n it does, it looks like the piston's > been rocking in the bore (a touch undersize?) with sommat hard and > gritty picked up by the piston skirt[0] (possibly the bits of lost > case-hardening off the cam followers?) Could be possible. > The scoring on the l/h piston looks a lot[1] like it's been siezed and > left to cool, then ignored or maybe just had the rings changed ( Piston wasn't scored when it was fitted two years ago, the bike hasn't seized and I've not changed the rings. > I'd be checking whether the pistons can be reused[2], they look pretty > far gone to me, particularly the left, and the scoring... if the > scoring will clean up with a hone, great, if not you're looking at a > rebore and pistons, or perhaps just the replacement (same size?) > barrels and fresh pistons Pistons are - for all intents and purposes - unobtainable. I will see if I can clean them up. -- Simon

	#2
The Older Gentleman	Re: Guzzi Bore, Pistons and Cam. Bore. sweller <sweller@mztech.fsnet.co.uk> wrote: > Pistons are - for all intents and purposes - unobtainable. That's bad news. Does anyone do quality replacements? Wiseco, for instance? -- K1100LT 955i 750SS CB400F CD250 CM200 SL125 GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 The bells, the bells.....

	#3
Roger Hunt	Re: Guzzi Bore, Pistons and Cam. Bore. sweller wrote (snip) >Pistons are - for all intents and purposes - unobtainable. I will see if >I can clean them up. > Hope they come good. Out of curiosity who were they made by? It's on the tip of my tongue and is bugging me. -- Roger Hunt

	#5
Pip Luscher	Re: Guzzi Bore, Pistons and Cam. Bore. On Thu, 2 Aug 2007 06:43:38 +0100, chateau.murrayTAKETHISOUT@dsl.pipex.com (The Older Gentleman) wrote: >sweller <sweller@mztech.fsnet.co.uk> wrote: > >> Pistons are - for all intents and purposes - unobtainable. > >That's bad news. Does anyone do quality replacements? Wiseco, for >instance? Probably way out of date now, but: http://www.raceco.com/engine.html#Anchor-Raceco-47857 -- -Pip

	#6
Grimly Curmudgeon	Re: Guzzi Bore, Pistons and Cam. Bore. We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember chateau.murrayTAKETHISOUT@dsl.pipex.com (The Older Gentleman) saying something like: >sweller <sweller@mztech.fsnet.co.uk> wrote: > >> Pistons are - for all intents and purposes - unobtainable. > >That's bad news. Does anyone do quality replacements? Wiseco, for >instance? My thought exactly. A knowledgeable piston shoppe can source a piston for almost anything, even if it's made for a totally different engine. -- Dave GS850x2 XS650 SE6a Teach a man to fish and he and his pikey mates will have the river cleaned out in a day.