I have a V50 Monza (well, it has PE prefixed engine and frame numbers, although it looks like a roadster - tank, seat, side panels etc.). I’m testing it out and getting used to it.
It’s lovely at low revs, and sounds fantastic. It feels very very eager and accelerates quickly from the off, but the trouble is it feels unhappy at much over fifty. It’s reading about 5000 rpm at sixty mph but it feels very busy, like it wants a higher gear, but it hasn’t got one, that’s it. And I don’t think it’s got a lot left.
I’ve been reading stuff about different gearings, but if mine is a standard Monza box (and I don’t know if it is), I wonder if it’s just the nature of an old engine which is a bit shattered.
60mph at 5000 rpm, is that about right or not? Anyone any thoughts? I’m only looking for a reasonably easy capability of 70mph.
As I played a lot some 15 years ago with gearing, fitting low-rev diesel engine to one of my Guzzis, I think I can help. Standard V50 does 20kph to every 1000rpm, so 100kph, 62 mph, makes 5000 rpm. BUT - Monza was slightly longer primary ratio. You know, the two cogs hidden on the very front. Standard V50s have there 14/23 gearing, while Monza one is 15/22 and I believe this is the longest available ratio for small hole clutch, if you know what I mean. All the longer ones - you’d need to upgrade to slightly different clutch and gearbox of course. How to check what’s inside without separating the casings? Well, you’ll better have somebody to help, as you need to dismantle generator cover, put Allen key into the rotor just to make a needle of it, to count the engine revolutions. If you have standard V50 gearbox, on 1st gear, you’ll do over 17 engine turns to turn rear wheel once. If your gearbox is Monza one - you’ll do just 15 and half. Let us know what did you find. I presume(not knowing by prefix), your Monza is Mk I, not II - II would be 4-valve head I believe?
…I’ve not bought one yet, a tad worried that the V50s might not be mentioned much, but I should do really. Getting interesting though, is it all down to these two, the countershaft and the idle gear?
Yes, the actual five gears are often the same, you do the swap in the front and tadaaam, magic happens. Ever seen V50 NATO? Lower gearing for military use, actually that set of cogs taken from V35 - you use Vth, but the revs are like on IVth in normal V50. Here is the picture of primary cog from V50 NATO(L) with kickstart dogs, and “civil” V50II - count the teeth.
I had big wish to have my V50 kickstarted, then found the shaft in NATO one is 12-spline, my older V50II is 10-spline. Built up the box made up of two, so I believe my kickstared box with normal V50 primary gearing(fabricated in one set) is one of very few in the world:) Bit noisy - but what a satisfaction!
Okay Adamigo!, I’ve taken the plugs out, taken the alternator cover off, put the bike in first and stuck a bit of tape on the rim of the rear wheel. …I’m getting 17.5 turns of the engine for one turn of the wheel. I guess this makes mine an early gearbox and my V50 even more of a mongrel than I thought. No matter, I’ll finish reading what you sent me Don, thanks, and I expect I’ll try Gutsibits for another gearbox if I can’t get the individual parts. Thanks both for your help!
Interesting topic on gearing,I have a v65tt which I believe is low geared from factory,I would like to up the gearing so can I achieve the same resulfs,I have no intention of off roading anyway .
If you want to go really high, Nevada/Breva/Lario offer top of the range primary gearing. The models were popular, with some patience applied you’ll find such a gearbox sooner or later.
