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Paioli RSU front forks info

 
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who



Joined: 10 Nov 2010
Posts: 318
Location: Melbourne Australia

PostPosted: Thu Aug 31, 2017 4:58 am    Post subject: Paioli RSU front forks info Reply with quote

Whilst I've been researching bimota forks I came across this article regarding Paioli 'right side up' (RSU) front forks. The article provides some interesting info on the Paioli range of forks, and references the YB11 at the end.

If you want to keep it, if you highlight the text, copy and paste to ms word, you will end up with a decent hard copy.

http://kvenna.net/Doc/PaioliRSU.html
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2bims



Joined: 03 Apr 2010
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PostPosted: Thu Aug 31, 2017 6:27 am    Post subject: Reply with quote

That's certainly a good find, well done....with free downloads of the manuals being a bonus (have now downloaded and squirreled away the DB2 and Vdue Fork manuals...):-

 
Paioli RSU front forks, as used on Bimotas in the nineties.
Here we have a collection of scanned manuals for the different types of Paioli RSU font forks. In addtions, we have some drawings of the tools used to maintain these forks. The tools can be made your favourite machinist.
 
 
The manuals:
 

 
RSU41: used on Bimota db2 (Note! 12.9 mb)

http://kvenna.net/Doc/PaioliRSU41.pdf

RSU43: used on bb1, Mantra, db4 and  yb9 (not yet available).
RSU46: used on SB6, SB6R, SB7, Vdue (4.1 mb)

http://kvenna.net/Doc/PaioliRSU46.pdf

RSU51: used on YB11. (soon to appear here) 
 
The tools:
The tool in the image is the tool used to loosen the cartridge from the fork leg on an RSU46. The RSU41 and RSU43 tools look similar in appearence (according to the books, I have never seen them in the flesh), but the dimensions are most likely different. In Paioli's toolkit, there were also other tools, but I think this is the most important one. For seating bushings and seals, the  Motion Pro Fork Seal Driver  of correct dimension could be a suitable replacement for the original, I presume(?) I have never tried the MP tool on the Paiolis, but I use them on other brands of forks.
 

RSU41: (no measurements or drawings available).
RSU43: (no measurements or drawings available).
RSU46: as measured by Peter Nisgaard Brink of the Bimota mailing list.
RSU51:  (no measurements or drawings available).
 
 
Comments on the RSU family of forks:
The Paioli RSU forks has been used on the nineties era Bimotas, and other italian bikes of the same era. The manuals shown above are for the Bimota variants. These forks are a result of Kayaba's cooperation and ownership in Paioli Meccanica.
 
The former norwegian Bimota importer Jon Oftedahl writes the following abouth these forks, and the spares situation today:
 
Paioli made 4* different RSU style forks for Bimota between 1993 and 2000, namely the RSU 41, 43 ,46 and 51. The numbers indicate the dimension of the innertube. These forks shares a basic design, but as there are some slight differences in the assembly as well as diffent volumes of fluid and part numbers Paioli and Bimota came up with a separate workshop manual for each version. You can use any of these manuals as a guidance when working on your forks once you
know the differences. It is the RSU 41 that differs most as this fork has compression and rebound in separate legs. Also the cartridges (damping assembly) are fixed by an allen bolt from the outside while the others have internal
treads.

Paioli made specific tool kits for each of these forks. The tools used for removal of the cartridges and installing the upper bushings and oil seals are specific for each fork. As the cartridges are of a KYB/Kayaba design most shops dealing in Japanese brands should be able to help. You do not have to undo the cartridge to replace oil seals and bushings, but removing
the cartridge simplifies working on the forks. Also the cartridges should be periodically removed from the forks for a good cleaning. Just pumping oil through them while still fitted in the forks is not sufficient. The internals of any forks will wear. Also oil will age and water, teflon and metal particles will form a sludge over time and affect performance. We are not talking about old style damping rod forks here, but advanced cartridge forks with shims, tiny orifices and adjustable valves.

I believe that the RSU forks are quite good. Bimota have won several championships with these forks and what is good enough for racers like Risitano, Malatesta and Gallaso is good enough for you and me. These Paioli RSU forks were not cheap to manufacture. The modular design with a lower leg machined from billet, a separate (cast alloy) axle clamp, an aluminum
cartridge and the oil seals carried in a "floating" cup shows that little expence has been spared. But these forks will not perform if neglected. I firmly believe they are up to the job, especially when taking into account that they were designed almost 15 years ago. They may not be in the same league as an modern Öhlins unit. There also have been some batches (early 46 and 51 units) with production tolerances a bit on the large side, but a well maintained and correctly set up Paioli RSU fork will carry you safely both on road and track. It really upsets me when owners neglect regular maintenance (nor  know how to set them up to suit their riding style) and than moan and groan about the forks.

Most Bimota owners don't ride their bikes much. You can not expect oil seals and scrapers to be up to their job after 10 years even if the odometer shows only 10000 kilometers. Most owners will forget about the forks untill they start leaking, but that is to late. When they fail to impress it is cause people think to believe that forks does not wear nor require any particular maintenance. In fact they are very wrong. If you have ever seen the internals of a fork after 20-30 thousand kilometers you'll be amazed by the wear and tear. Most forks will require a total rebuild if you want original performace retained, a fact that fork tuners know only to well about. Ask any specialist and he will tell you that forks should be maintained on a regular basis. If you are using your bike on a track or pushing it hard on the road the forks may require a rebuilt every 10000 kilometers. Bimota did
not take lightly on fork maintenance. That is why they made those overhaul kits. It is a shame that many owners and dealers did not pay attention.

Regarding oil seals for the RSU 51 (YB11) fork there are no alternatives except the original (51/10/63) ones made by Kayaba/KYB. Freudenberg/Simrit (the largest manufacturer in the world of industrial oil seals) even checked with their competitors. I do not consider quality problems with the OE oil seals to be the reason for premature oik leakages, but rather a combination of a batch of RSU 51 forks being manufactured with large internal tolerances and little use of these bikes. Silicon grease like DOW 111 works wonders on these seals and help them not leak first thing in the spring. For those of you that are looking for alternativ oil seals and think that those for the Marzocchi 50 forks can be used (they are 50/63/10) my advice is not to bother. They will leak after a few miles. Also there are no alternatives except original parts for other wear parts like DU bushings and scrapers.
For the RSU 41, 43 and 46 forks parts for the 4 Japanese brands, KTM, MuZ, Triumph etc can be used. However, the cartridges are spesific for Bimota. 

* Paioli made 3 versions of the RSU 46 forks (the last one being a hybrid design made for the final version of the Vdue) and 2 versions of the RSU 51 not counting identical forks except for the spring rate, lenght of the innertube or colour of the fork legs for Bimota.

           Regards
              Jon
(former Bimota Norway)
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who



Joined: 10 Nov 2010
Posts: 318
Location: Melbourne Australia

PostPosted: Thu Aug 31, 2017 8:12 am    Post subject: Reply with quote

Nice work 2B's.

I've also read that new buyers of bimota received suspension manuals as well. So where are they?

We need to get all the information we can onto a drive for prosperity sake.

Bank it onto a few hard drives, and then put it up into the cloud?

Google isn't going anywhere, and they offer 15 gig for free and if you go over like nothing really.

If we are shut down by the despots, we can move somewhere else, as long as the information remains in circulation and in more than one place-channel.

I've got all the Yamaha (YB4-11) series engine manuals on disc, including helpful YEC kit manuals for the OW and YZF,
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Evilchicken0



Joined: 12 May 2010
Posts: 2696
Location: London

PostPosted: Thu Aug 31, 2017 2:44 pm    Post subject: Reply with quote

I've got an Ohlins manual for generally setting up suspension somewhere
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vort28



Joined: 22 Mar 2010
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PostPosted: Thu Aug 31, 2017 4:59 pm    Post subject: Reply with quote

Think I have a few of thee RSU 46 manuals somewhere, even have a set of service tools in the Bimota locker I think.
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who



Joined: 10 Nov 2010
Posts: 318
Location: Melbourne Australia

PostPosted: Fri Sep 01, 2017 10:18 am    Post subject: Reply with quote

I've got all the yamaha YB series service manuals which you need for engine elect etc. , also TL1000 for the SB8. Kit manuals for the OW01 YZF750 (useful info if you are going racing)
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brian



Joined: 22 Aug 2011
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PostPosted: Tue Sep 05, 2017 12:33 am    Post subject: Reply with quote

Yeah I got the original Paioli manual with the 16 year old SB6 that I bought. I am at least the 3rd owner. I was happy to see that it had been owned by some nerds like me that 'keep' stuff. I also got the original stand, owners manual, spare keys, key fob and complete service history Laughing
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Current rides - '99 Bimota DB4, '96 Bimota SB6, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250,
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brian



Joined: 22 Aug 2011
Posts: 2408
Location: QLD, Australia

PostPosted: Tue Sep 05, 2017 12:35 am    Post subject: Reply with quote

brian wrote:
Yeah I got the original Paioli manual with the 16 year old SB6 that I bought. I am at least the 3rd owner. I was happy to see that it had been owned by some nerds like me that 'keep' stuff. I also got the original stand, owners manual, spare keys, key fob and complete service history Laughing


And the bonus was that it was in great condition and only 4200 klms
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Current rides - '99 Bimota DB4, '96 Bimota SB6, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250,
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