Is this right?

alien.46.uk · Could Be A Chat Bot Joined: 24 May 2006 Karma :

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Err, no. But how many base gaskets have you got on there?

All the best

Keith
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alien.46.uk · Could Be A Chat Bot Joined: 24 May 2006 Karma :

Just over 1.0mm of gaskets, as it says it need 1.0mm squish ...

This is the kit they said i needed so i dont get it ...

Is this completely wrong or is it a case of too many gaskets?

Luke.
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2007 Kawasaki ZX10R :: 1998 Kawasaki ZX-9R - SOLD
1998 Yamaha FZS600 Fazer - SOLD :: 1994 Aprilia Pegaso 125 - SOLD

0ddball · World Chat Champion Joined: 15 Jul 2005 Karma :

I'd be wanting at least 2 full threads showing once the nut is fitted.

I don't think it means that type of squish Laughing

It's probably refering to the gap between the rim of the piston and the cylinder head deck at tdc.

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

1mm squish is the distance from the edge of the piston to the edge of the head when the piston is at TDC.

Normally you should be using a 0.3mm or 0.5mm gasket. Which explains ~0.5mm of the stud shortness. Remember that it will seat a bit further than that,

Not seen that kind of issue before though.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

Paddy Blake · World Chat Champion Joined: 29 Jun 2006 Karma :

As a rule you need 6 theads and that looks to short.The base gaskit looks
like it is to thick.

Paddy.

cestrian · World Chat Champion Joined: 24 Jul 2006 Karma :

That base gasket looks almost as thick as the 'Mitaka' lettering, wayyyy to thick.
Maybe I'm getting old but I've never seen a gasket like that before, and certainly never that thick.

gavin · World Chat Champion Joined: 05 Jul 2005 Karma :

an old cheap tuning trick was to add a second or third base gasket, and assemble the head to the barrel with instant gasket to restore the squish, raising all the ports and getting more revs and power.

you should really only have one gasket in there. assemble the engine and measure the squish at at least 4 (preferably 8 ) points around the top of the piston, by feeding a length of solder in through the plug hole and turning the engine over by hand, so the piston squashes the solder. measure the thickness of the squashed solder with a digital vernier and take an average of the measurments. you should ideally be looking for about 0.7-0.9 mm, but it depends on the bike a bit, generally its smaller on smaller pistons and bigger on bigger pistons. but you should be ablke to find an appropriate squish clearance for your bike if you search.

cagiva gezzer · World Chat Champion Joined: 17 Mar 2003 Karma :

Download a manual. Rolling Eyes

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"because one stroke isnt enough and four strokes waste two"

alien.46.uk · Could Be A Chat Bot Joined: 24 May 2006 Karma :

You've said that before cagiva and as i've said they dont have the manual for mine downloadable ... Probably because they're so rare or because they were never sold in the UK or something ...

Anyways, im pretty sure [now i know what it means] the squish is right, judged by eye and some feelwer gauges squished onto the top of the barrel ...

I dont know what to do about the barrel though ... Im pretty sure its right because it fits fine everywhere else although the gaskets were a little too big ...

It's just that fact that the bottom is soo god damn thick ... and wide ...

Luke.
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2007 Kawasaki ZX10R :: 1998 Kawasaki ZX-9R - SOLD
1998 Yamaha FZS600 Fazer - SOLD :: 1994 Aprilia Pegaso 125 - SOLD

six · Trackday Trickster Joined: 29 Sep 2006 Karma :

slightly off topic, but could anyone tell me what a gasket is? lol... I was just reading through and I don't have a clue what any of it is about! hehe

sorry for being thick!

Tom
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Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

The Aprilia manual tells you to use a pipette to measure the combustion chamber volume with the piston at TDC.

By the way, never knew this before but it seems that Haynes have finally got round to doing a manual:-

https://www.haynes.co.uk/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=10001&productId=38953&langId=-1

The Pegaso was imported to the UK (in small numbers) and the engine is basically the same as the AF1 / Tuareg / Tuareg Rally engines. Aprilia sold seperate manuals for the engine and for the rest of the bike (bike manuals are pretty rare).

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

You can't have measured the squish until the whole lot is torqued down and the head is on. You certainly can't do it with a feeler guage.

As has been said, those base gaskets are WAY too thick. A thicker gasket increases the squish, a thinner one reduces it. Standard gasket paper is 0.4mm (roughly 1/64"). You can cut your own out using gasket paper or thin card.

With a brand new barrel and head, you'd only normally need one gasket. May need more if the head had been skimmed/lapped a fair bit.

So, you would need to fit it with ONE paper gasket. If you still don't have enough stud showing, contact the place that sold you the barrel and ask them about it because something has gone wrong somewhere, maybe their design needs slightly longer studs fitting? Once you have the barrel bolted down, fit the head.

The way I was taght to measure squish was to make a 'ring' of solder slightly smaller than the diameter of the bore and lay this on top of the piston. Then fit the head, torque it down, turn the engine over once by hand and remove the head again. Now measure the bit of solder. The thickness of the solder = the squish. Gavins technique sounds easier though.

If the squish is too small, fit another base gasket. If it is too big, skim a bit off the top of the barrel/head.

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

six · Trackday Trickster Joined: 29 Sep 2006 Karma :

alien.46.uk · Could Be A Chat Bot Joined: 24 May 2006 Karma :

Well i've taken them all off and put the smallest one on and there isn't even enough thread showing to fill up the bolt ...

Im going to get slightly stroppy with the company as i've asked them three times to clarify this is the right kit as i need this bike on it first run-in on Tuesday as from this week i cant get a lift to college anymore ...

Hmphh ... I even thought to myself last night [Whilst slightly pissed] that this was going too well because i was enjoying it too much ... Something always stops me ...

That haynes looks interesting Kickstart, i know its the same engine, but its a totally different bike, lol ... Think ill pass on that one and keep browsing for the Rotax 123 Manual then base the body on the old 650, lol as its the ame frame ... Also noticed the '98 ETX is vertually identical parts wise, so that isn't too bad ...

Anyway, ill give it another check and see whats going on, i think they've just made the base to thick as i dont think it being too wide will effect, might look odd and add weight, but internally it matches up ...

Rolling Eyes

Luke.

____________________
2007 Kawasaki ZX10R :: 1998 Kawasaki ZX-9R - SOLD
1998 Yamaha FZS600 Fazer - SOLD :: 1994 Aprilia Pegaso 125 - SOLD

cagiva gezzer · World Chat Champion Joined: 17 Mar 2003 Karma :

https://www.laverdaman.co.uk/

God knows what the bike is a mix of.

If you're not sure about how the two stroke engine is meant to work, take a look around sites like

https://www.eric-gorr.com/

www.macdizzy.com

Or buy one of the two stroke books - jennings / bells - .

Or, shock horror, ask on a Aprilia site?
____________________
"because one stroke isnt enough and four strokes waste two"

gavin · World Chat Champion Joined: 05 Jul 2005 Karma :

just spotted something odd about that barell.......usually the bolt lands (mating faces) are machined down a bit. this is done to locate the flange of the nut properly.

the ones on that barrell arent, and they dont even appear to be flat in relation to the studs. if that is the case, even if you get it to do up, the nuts wont sit right, they will touch one side first and bind on the threads. maybe you have a barell that didnt get fully machined Shocked

Whosthedaddy · Super Spammer Joined: 11 Dec 2005 Karma :

How does it compare to the old one?

If the gasket is much thicker then theres the problem as it does nt look a very good fit in my opinion, it does nt seem to follow the contours of the casings. Surley, like mentioned before, it should be paper thin, not several mm thick?

If the new part is the top end then is this different, as the studs in the existing block have not shrunk overnight and maybe the new part is not suitable for the bike.

Comparing new with old takes 2 minutes and will tell you insantly whether there will be problems Rolling Eyes

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Paddy Blake · World Chat Champion Joined: 29 Jun 2006 Karma :

Can you show us a picture of it with one gaskit on it as it may be possible
to lossen the bolts a bit where they go into the engine and so long as you
have a good amount at the engine end it could fit together.

I dont know what way that sounds to you maybe someone can say it right

Whosthedaddy · Super Spammer Joined: 11 Dec 2005 Karma :

cagiva gezzer · World Chat Champion Joined: 17 Mar 2003 Karma :

Paddy Blake · World Chat Champion Joined: 29 Jun 2006 Karma :

The studs may be unscrewed slightly giving you more threads to tighten a nut onto to Wink

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stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

gavin · World Chat Champion Joined: 05 Jul 2005 Karma :

makes me wonder if its for a different version of the rotax motor...