GuzziMoto Posted September 26, 2019 Posted September 26, 2019 As luhbo mentioned, you have to include everything in the final number when comparing different bikes. So, the trans ratios, the rear gear ration, and the diameter / circumference of the tire. Different size tires can make a pretty big difference. But if you have one bike and you change your rear gear to a shorter / higher ratio gear with all else being the same you will gain power and acceleration at the possible expense of top speed (assuming it was capable of pulling the previous gear to redline). And also obvious, it will turn more rpms at any given road speed / gear selected. Racers change gear ratios all the time. We would carry around with us a selection of rear sprockets, picking the right gear for each track. Fancier racebikes allow changing individual gear ratios in the transmission, our TZ250 allowed us to change 1st and 2nd gears while our Ducati's didn't allow that. Gearing is usually the cheapest way to make a motorized vehicle, two or four wheels, perform better. You want more power off line line? You want better acceleration? just give up a little on top and go to a shorter gear. The difference can be stunning. Sadly, it is not nearly as easy to re-gear a Guzzi as it is to re-gear most other sporting motorcycles. That is the biggest weakness of shaft drive.
vtwins4life Posted January 7, 2020 Author Posted January 7, 2020 So...my shop has agreed in theory to take this on over the winter. Now, I just need part #'s (or the make/model and year of the bike it came on) for the 7 and 8 tooth pinions. Can anyone assist with that ? Many thanks ! VT4L
Lucky Phil Posted January 7, 2020 Posted January 7, 2020 29 minutes ago, vtwins4life said: So...my shop has agreed in theory to take this on over the winter. Now, I just need part #'s (or the make/model and year of the bike it came on) for the 7 and 8 tooth pinions. Can anyone assist with that ? Many thanks ! VT4L I'm not that familiar with the EV model just what I can see in internet images,but Guzziology recommends to use a T5 7/33 ring and pinion set for 5 speed 1100's with the 8/33 ratio. It also says that that early California 1100's had the wrong speedo gearing fitted from the factory and they overed so the bike wasn't going near as fast as riders thought when they were waiting to shift into 5th. Ciao 1
vtwins4life Posted January 7, 2020 Author Posted January 7, 2020 Help a brotha out with a year make and model of a T5 (latest possible please) that would use the 7/33 gearing :-) VT4L
Lucky Phil Posted January 7, 2020 Posted January 7, 2020 19 minutes ago, vtwins4life said: Help a brotha out with a year make and model of a T5 (latest possible please) that would use the 7/33 gearing :-) VT4L No idea, Guzziology doesn't mention year models. They probably only built the T5 for a few years. Is your bike possibly one of the effected wrong speedo bikes? because if it is Guzziology says once you change it to the correct speedo ration it doesn't feel overgeared at all. Ciao
pete roper Posted January 7, 2020 Posted January 7, 2020 Any model from the T3 through to the T5, all the Tonti framed LeMans and the Cali II all used the 7/33 ratio final drive. If going down the route of seeking a complete bevelbox be aware the the earlier drum rear brake 850T not only uses a different ratio, (8/35 from memory?) but also has a thinner flange on the pinion carrier and uses different pinion bearings meaning if it is going to be used with a later swingarm it will need a spacer making up to fit it. Also fitting any of these bevelboxes to the EV will require the swapping of the axle spacer in the box, (From memory.). It is nowadays getting hard to find a decent 7/33 from an earlier bike. Most of them the pinion splines are munted through age and abuse and often the pinion teeth will be pitted. Caveat emptor. The alternative is to purchase a new 7/33 gear set and build a new box.€416 from TLM but you'll need shims, bearings etc. 3
Lucky Phil Posted January 8, 2020 Posted January 8, 2020 1 hour ago, pete roper said: Any model from the T3 through to the T5, all the Tonti framed LeMans and the Cali II all used the 7/33 ratio final drive. If going down the route of seeking a complete bevelbox be aware the the earlier drum rear brake 850T not only uses a different ratio, (8/35 from memory?) but also has a thinner flange on the pinion carrier and uses different pinion bearings meaning if it is going to be used with a later swingarm it will need a spacer making up to fit it. Also fitting any of these bevelboxes to the EV will require the swapping of the axle spacer in the box, (From memory.). It is nowadays getting hard to find a decent 7/33 from an earlier bike. Most of them the pinion splines are munted through age and abuse and often the pinion teeth will be pitted. Caveat emptor. The alternative is to purchase a new 7/33 gear set and build a new box.€416 from TLM but you'll need shims, bearings etc. Glad you chimed in Pete, I was out of my depth here. Ciao
vtwins4life Posted January 15, 2020 Author Posted January 15, 2020 The Shop called me today. They have never taken apart a Guzzi diff so they quoted me a range of 2-10 hours to do the work, and I'm on the hook for any wrong parts they order. Hard Pass....guess I'll just live with the tall gearing.... VT4L
Chuck Posted January 15, 2020 Posted January 15, 2020 3 hours ago, vtwins4life said: The Shop called me today. They have never taken apart a Guzzi diff so they quoted me a range of 2-10 hours to do the work, and I'm on the hook for any wrong parts they order. Hard Pass....guess I'll just live with the tall gearing.... VT4L Good choice. They would probably screw up the shimming and trash your new stuff to boot.
Lucky Phil Posted January 15, 2020 Posted January 15, 2020 3 hours ago, vtwins4life said: The Shop called me today. They have never taken apart a Guzzi diff so they quoted me a range of 2-10 hours to do the work, and I'm on the hook for any wrong parts they order. Hard Pass....guess I'll just live with the tall gearing.... VT4L Gee they sound like professionals that know their stuff..........Not You could always ask Pete Roper if he can source you a T5 bevel box and maybe check it over for you and ship it. I reccon shipping would be about $100us Ciao
vtwins4life Posted January 16, 2020 Author Posted January 16, 2020 It's the world we live in now - dealers don't want to get involved in far-fetched "will this work" kind of efforts like this apparently. Swap out factory part for factory part from same model/year bike ? No problem. Swap out something from an older bike onto a newer bike from 20-30 years ago ? They've never been asked to do it, and don't want to assume the risk if it doesn't work out. They are quite professional and have done excellent work for me in the past. VT4L
pete roper Posted January 16, 2020 Posted January 16, 2020 https://shop.tlm.nl/en/used-rear-drive-7-33-cal-3-us-17350250a-moto-guzzi (Shrug.) found this in two minutes.
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