Well, that's weird
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From: The Older Gentleman on 29 Jul 2010 18:19 Pip Luscher <pluscher(a)live.invalid.co.uk> wrote: > For the purposes of doing valve clearances, I've painted an extra mark > on the flywheel. <Nods> I did that on my Guzzis, back in the day. -- BMW K1100LT Ducati 750SS Triumph Street Triple Honda CB400F Suzuki TS250 Suzuki GN250 chateaudotmurrayatidnetdotcom Nothing damages a machine more than an ignoramus with a manual, a can-do attitude and a set of cheap tools
From: Krusty on 30 Jul 2010 05:14 Pip Luscher wrote: > On Thu, 29 Jul 2010 08:07:53 +0000 (UTC), "Krusty" > <dontwantany(a)nowhere.invalid> wrote: > > > The fact that it's a 90deg > > V-twin has no bearing on the angle between the timing marks, so I'm > > not sure why you mention that. > > I'll explain: on older engines with points, the left & right cylinder > timing can be checked individually and the engines thus have > individual timing marks for each cylinder. These marks must be at > 90deg to each other otherwise one cylinder would have different > ignition timing to the other. Sure, if the crank turns 90 or 270 deg between firing. The point I was (badly) trying to make is that just because there's 90deg between the pots doesn't necessarily mean there's 90deg between the big end journals (& therefore the timing marks)[1]. So saying "the flywheel marks are about 155deg apart. It's a 90deg Vee twin engine." doesn't really mean much to anyone who doesn't know Guzzi engines as the two don't have to be related. If that translates to "the flywheel marks are about 155deg apart. The big end journals are 90deg apart." then yes, something sounds a bit 'wrong'. Probably a drunken Italian going mad with the stamp on a Friday afternoon... -- Krusty Raptor 1000 MV 750 Senna Tiger 955i Tiger 885 Fantic Hiro 250
From: Eiron on 30 Jul 2010 05:21 On 30/07/2010 10:14, Krusty wrote: > Pip Luscher wrote: > >> On Thu, 29 Jul 2010 08:07:53 +0000 (UTC), "Krusty" >> <dontwantany(a)nowhere.invalid> wrote: >> >>> The fact that it's a 90deg >>> V-twin has no bearing on the angle between the timing marks, so I'm >>> not sure why you mention that. >> >> I'll explain: on older engines with points, the left& right cylinder >> timing can be checked individually and the engines thus have >> individual timing marks for each cylinder. These marks must be at >> 90deg to each other otherwise one cylinder would have different >> ignition timing to the other. > > Sure, if the crank turns 90 or 270 deg between firing. The point I was > (badly) trying to make is that just because there's 90deg between the > pots doesn't necessarily mean there's 90deg between the big end > journals (& therefore the timing marks)[1]. You don't actually know what a V-twin is, do you?
From: Krusty on 30 Jul 2010 05:27 Eiron wrote: > On 30/07/2010 10:14, Krusty wrote: > > Pip Luscher wrote: > > > > > On Thu, 29 Jul 2010 08:07:53 +0000 (UTC), "Krusty" > >><dontwantany(a)nowhere.invalid> wrote: > > > > > > > The fact that it's a 90deg > > > > V-twin has no bearing on the angle between the timing marks, so > > > > I'm not sure why you mention that. > > > > > > I'll explain: on older engines with points, the left& right > > > cylinder timing can be checked individually and the engines thus > > > have individual timing marks for each cylinder. These marks must > > > be at 90deg to each other otherwise one cylinder would have > > > different ignition timing to the other. > > > > Sure, if the crank turns 90 or 270 deg between firing. The point I > > was (badly) trying to make is that just because there's 90deg > > between the pots doesn't necessarily mean there's 90deg between the > > big end journals (& therefore the timing marks)[1]. > > You don't actually know what a V-twin is, do you? <points at sig> -- Krusty Raptor 1000 MV 750 Senna Tiger 955i Tiger 885 Fantic Hiro 250
From: Mark Olson on 30 Jul 2010 07:11
Krusty wrote: > Pip Luscher wrote: > >> On Thu, 29 Jul 2010 08:07:53 +0000 (UTC), "Krusty" >> <dontwantany(a)nowhere.invalid> wrote: >> >>> The fact that it's a 90deg >>> V-twin has no bearing on the angle between the timing marks, so I'm >>> not sure why you mention that. >> I'll explain: on older engines with points, the left & right cylinder >> timing can be checked individually and the engines thus have >> individual timing marks for each cylinder. These marks must be at >> 90deg to each other otherwise one cylinder would have different >> ignition timing to the other. > > Sure, if the crank turns 90 or 270 deg between firing. The point I was > (badly) trying to make is that just because there's 90deg between the > pots doesn't necessarily mean there's 90deg between the big end > journals (& therefore the timing marks)[1]. Surely there's 0 degrees between the big ends, because they're on the same journal? Otherwise why even bother to make it a 90 degree Vee? http://www.guzzitech.com/shrapnel/crank.jpg http://www.classicguzzi.com/engine_animation.gif My guess is one mark is a TDC mark, the other one is to indicate where maximum spark advance occurs for the other cylinder. Or something. If you're sure of the position of TDC from one mark, just print out a degree wheel and make another mark where necessary, which it sounds like Pip L. has already done. > So saying "the flywheel marks are about 155deg apart. It's a 90deg Vee > twin engine." doesn't really mean much to anyone who doesn't know Guzzi > engines as the two don't have to be related. If that translates to "the > flywheel marks are about 155deg apart. The big end journals are 90deg > apart." then yes, something sounds a bit 'wrong'. Probably a drunken > Italian going mad with the stamp on a Friday afternoon... You appear to be talking about Vee engines that have split/offset crankpins similar to what Honda does with their narrow angle twins in order to give them 90 degree firing intervals. |