ducatipaso.org
http://forums.ducatipaso.org/

HELP! 17 inch wheel conversion. All AOK Except Speedo won't
http://forums.ducatipaso.org/viewtopic.php?f=13&t=7854
Page 1 of 2

Author:  1989750Sport [ Fri Jan 12, 2018 9:15 pm ]
Post subject:  HELP! 17 inch wheel conversion. All AOK Except Speedo won't

Rear wheel went on without a hitch. We used a 1992 750 ss rear wheel and a 1996 Ducati 600 SS brake hanger and rear brake. Later rear brakes were thicker and would not work. All that needed to be machined was a small spacer.

Front came togheter perfectly with one exception. Sourced 280mm brake disc adapters from Duc_Only. He advertises parts regularly on the Paso.Org site and provided some wonderful kit.

Only problem is the speedo drive for the 750 Ss is too wide. Approx 6mm so. The 750 sport drive won't work. Does anyone know of a skinnier speedo drove or another technical solution?

Ducati Paso.org ... you are my only hope

Author:  Mc tool [ Fri Jan 12, 2018 11:24 pm ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

Dunno about the sport but the Paso ( M1r forks ) needs to loose 4mm on the left side to get the wheel in the centre , and that entails machining the inside of the fork leg . The only other way would be to get some electronic or GPS based speedo , ditch the speedo drive and make a spacer . I looked at a few ways to sort it but one way or another 4mm had to go . Same deal at the back , I had to move the wheel 4mm to the left . Just because both wheels line up with a straight edge isn't the end of it , that wheel centre line must be in line with the chassis centre line . There are at least 2 speedo drives for the 17" wheel as they are diff where they meet up with the wheel . I don't think there is any diff in the overall thickness of the different 17" drives

Author:  1989750Sport [ Fri Jan 12, 2018 11:53 pm ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

Thanks so much for the quick response. Ma try to have forks machines as a last resort. The brembo wheel was used on a bunch of Yamahas, so I may check that avenue as well.

Author:  Mc tool [ Sat Jan 13, 2018 5:34 am ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

Im pickin that if the yip uses the same wheels it probly has the same drive , possibly with a different ratio , but a quick yak to the right wreaker would probly put you straight .. If you do go for the machined fork leg you may consider getting the machinist to also make a spacer to " undo" the machine work so there wont be any drama if you want to go original again later.

Author:  ducinthebay [ Sat Jan 13, 2018 11:21 pm ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

yeah, the speedo is the issue in that conversion. You can use the original Sport speedo drive and add some shims to fill the space. I used some 5/8" washers to fill the void. Not pretty, but it will work. The speedo drive for that newer wheel won't work unless you machine the left fork leg as mentioned. That's what I ended up doing. Alignment of the fork leg in the mill is of course a good trick, and critical to keep the front forks working well and not binding. No good way of trimming down the speedo drive that i could see.

If you do go with M1R forks, make sure you get 907 forks, or 851 forks that were made for the 17" wheel, or you are right back where you are now. Of course you will need triple clamps and clip ons for those 41.7mm fork legs. (stock Sport is 40mm)

Not sure what you had going on with the rear wheel. Newer rotor, caliper and hanger should all work together.

Cheers, Phil

Author:  1989750Sport [ Sun Jan 14, 2018 11:12 am ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

Hi Phil,
Couldn't get the old speedo to work with the new wheel. Looking into speedo for smaller nikes to see if I can find a slimmer unit. TZr 125 uses a brembo wheel and looks to be 5mm slimmer. Fingers crossed!

Author:  paso750 [ Sun Jan 14, 2018 11:20 am ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

a while back I was looking into speedometer drives and checked for similar narrow ones. I only looked for parts used on Ducatis and other italian bikes. Noone had the same ratio.

Attachments:
Unbenannt.jpg
Unbenannt.jpg [ 183.71 KiB | Viewed 834 times ]

Author:  1989750Sport [ Sun Jan 14, 2018 1:04 pm ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

Thanks! This is really helpful

Author:  paso750 [ Sun Jan 14, 2018 3:26 pm ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

according to an online tire size calculator if you go from a 130/60-16 front tire to a 120/70-17 the instrument will indicate -6% in speed and with a 130/70-17 it's -8% so at 100km/h it would show 92km/h. Here in Germany that wouldn't be legal. An instrument is allowed to show 7-10% more but zero less than actual speed. Don't know how rules are in the UK.

Author:  ducinthebay [ Mon Jan 15, 2018 4:26 am ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

1989750Sport wrote:
Hi Phil,
Couldn't get the old speedo to work with the new wheel. Looking into speedo for smaller nikes to see if I can find a slimmer unit. TZr 125 uses a brembo wheel and looks to be 5mm slimmer. Fingers crossed!

Yeah, it doesn't fit right up. I had to re-bend the tab on drive, and modify the plate on the wheel a bit. Like I said, it ain't pretty, but it is functional.

Phil

Author:  Derek [ Mon Jan 15, 2018 9:53 am ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

paso750 wrote:
according to an online tire size calculator if you go from a 130/60-16 front tire to a 120/70-17 the instrument will indicate -6% in speed and with a 130/70-17 it's -8% so at 100km/h it would show 92km/h. Here in Germany that wouldn't be legal. An instrument is allowed to show 7-10% more but zero less than actual speed. Don't know how rules are in the UK.

In the UK they can read up to 10% fast but 0% slow. Most speedos read around 5 - 10% fast. -6% on my 907 would bring it almost down to reading the correct speed. :D

Author:  ducinthebay [ Mon Jan 15, 2018 10:04 pm ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

In the U.S.A., there is no speedo check. So running without a functioning one is almost feasible. If there is a speedo on the dash, then you are good, basically. i have never heard of anyone ever being checked that they have a functioning, much less accurate speedo.

Get any speedo drive that will work, then find one of those digital speed radars on the edge of town and ride past it till you know where some key speeds are, and put a sticky on the glass.

Phil

Author:  Derek [ Tue Jan 16, 2018 9:19 am ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

For information. In the UK a speedometer, working or not, is not part of the annual MoT test. So like the in USA, they are never checked.

Author:  Mc tool [ Tue Jan 16, 2018 8:15 pm ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

In NZ it seems that as long as the needle moves ..... and aint obviously wrong no one give one. Somewhere in the rule book it sez that you must have a working speedo and more important a working odometer . In NZ diesel vehicles pay a separate road user charge based on distance travelled so you can see why the enforcers want an accurate odo . Electric speedos are a boon here as it so simple to interrupt the signal from the drive unit .More than one peep I know does this . One has it wired so that it only works when the air con is on

Author:  900streetfighter [ Thu Jan 25, 2018 9:24 pm ]
Post subject:  Re: HELP! 17 inch wheel conversion. All AOK Except Speedo w

I put showa’s on my 907 with a later 3spoke wheel w 25mm spindle. I took 2mm off the outside edge of the new type speedo drive to centre the wheel w no problems. Also the gearing was +50% reading fast. I put a mechanical km converter at the drive that almost corrects it.

Page 1 of 2 All times are UTC
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/