graman
05-12-10, 04:38 PM
I have converted my curvy S model to an excellent long distance commuter/ tourer and I am detailing these mods. The final version of the bike has improvements made to comfort, aerodynamics and economy. The looks may have suffered but this is because I have put practicality first and this has allowed me to use the bike for my 70 mile commute all the year round and is the best bike I have ever ridden in cold and wet conditions.
Handlebars
My first change of handle bars were from my old Honda 650 hawk which are similar to the SV ones but about 30mm taller. These gave a good improvement but I still wanted a slightly higher raise.
There are 4 types of raised bar conversions:-
Raised clip ons.
These are a fairly easy mod to carry out and keep the stock cables. Slight disadvantage is that the bar centreline is in front of the fork centre, so that with the raised position, the clearances to the fairing are reduced. There is more clearance to the pointy fairing however. My first change handle bars were from my old Honda 650 hawk which are similar to the SV ones but about 50mm taller. These gave a good improvement but I still wanted a slightly higher raise. You can also buy special adjustable bars such as Helibars.
8262
Top - SV Standard S clip ons 11mm raise (bar centre to top of clamp.
Lower - HondaHawk clip on, 65mm raise.
Raised clip ons available:- http://www.banditmaniashop.co.uk/sv650-riser-clip-ons-1641-p.asp
Top Yoke Fixed Mounting (Comfort Kit)
This is the standard type used with the unfaired SV. Advantages are that a variety of handlebars can be used, but the brake hose &throttle cables will need to be extended, clutch and choke cables may need extending.
Top yoke comfort kit is available at Matts-Yokes on this site.
Modified Top Yoke to take bar mounts
This modification can be carried out by purchasing a set of bar clamps and drilling the top yoke for the bolt. This is an easy method of conversion but drill the hole close to the central portion of the yoke and away from any internal ribs on the underside of the yoke. DO NOT DRILLTHE HOLES CLOSE TO THE EDGE OF THE YOKE . This creates an increased stress close to the highest stressed location. Holes close to the centreline are close to the neutral axis and will have a negligible effect. (Primary loading of top yoke is in bending with a small torsional load). Note that some after market billet yokes have lightening holes in this central area. Use a large washer or spacer under the nut.
Modified fork nut spacer
I used this method for my bike but it is the method which has the most disadvantages to make but is adjustable. Once modified you need a new set of fork top nuts to change back. It requires aluminium bar to be machined. I used bar and turned it down to 41mm dia x 70 long, tapped it M12 x 40 at one end and then drilled a 22mm hole in the top at right angles to the bar CL. The forknuts need to be drilled through and tapped M12. An M12 bolt is then screwed in up side down so the thread protrudes from the top. The spacer is then screwed down onto the bolt and tightened up securely. A 22mm tube is located into the top hole and the angle of bar adjusted. The forks can also be moved up or down to get vertical adjustment. Finally, across brace is required to span between the two mounts to stop the mounting from detaching if the bike is dropped. I unfortunately had to test mine by falling off at 35mph and did no damage to the handlebars. (Shame about the fairing).
8263
Handlebars and deflectors
Footrests
I found the footrests were also uncomfortable and tried to find some unfaired footrest brackets on Ebay which give a lower position by about 25mm. They also are further forwards. I could not find any at the time and made my own from some 8mm thick alum plate (grade 6082 T6)which is the strongest commercial grade. This readily available from aluminium stockholders. This can be cut out with a hack saw and drilled. The tricky bit is that the footrest has two lugs on the mounting interface to stop rotation. These need small holes drilled to a depth of around 5mm as shown in sketch below. It also needs a shorter gear change rod from the naked model.
8264
L H footrest
8265
RH footrest with modified brake cylinder attachment
The rh footrest bracket needs a mounting for the rear brake cylinder. Pointy models have a different mounting bracket. Note that 03 & 04 models have a higher footrest mounting than later models.
Screen
I have looked around on the web for a touring screen and not found one. I decided to have a go at making my own. I went to see the manager of a local plastics factory to see if he could help and told me that the cost would be prohibitive due to manufacturing moulds. He did however give me some plastic and some advice on making my own. You will need to make a wood jig so you can form it to a suitable radius. I used thin plywood (3mm) and had to gradually work it to form the shape. It then needs to be rigidly connected to a base. Cut out the plastic sheet to the required shape using a jig saw, place in your home oven and heat up till it starts to become workable. You need to experiment with an offcut first and heat to say 120 degrees centigrade. Increase in temperature by 5 degrees at a time, then remove with suitable gloves and see if it can bend. If not put it back in and increase temp. again. At the correct temp, you will find it will start to bend. When the screen has soaked at this temp, take it out the oven and place on the jig and push the sides down. You need to keep it pushed onto the jig until it cools enough to allow the material to set. I found it only needed about 5 minutes for this. You need good gloves (I used an old pair of welders gloves), or use two pieces of plywood to push onto to sandwich the screen.
This sounds like a lot of effort, it is it look me 3 attempts to get it right. I then found that although the screen worked well and funnelled the air away from my body and head, there was still turbulence from the air moving downwards at the top due to the negative air pressure behind the screen. I ended up making an extension smaller screen which I bolted to the main screen. Success, a screen which completely keeps me out the airflow, and is quiet as well. The base plastic sheet needs to be tough and not brittle. Perspex is too brittle, I used polyethylene for the main screen and polycarbonate for the upper screen requiring temperatures of around 120 & 160 degrees centigrade to soften them.
8266
Curvy with screens
Handle bar wind deflectors
I have used similar methods to make these wind deflectors and used polycarbonate and a hest gun to just heat a localised area in the middle of the deflector and bent it around a tube. Care is needed to not overheat the material , because it bubbles released CO2. These are fairly easy to make and reduce wind draught and rain on the hands. They work well in the winter and have not needed to fit my heated grips. These are shown in photo. 2.
Lower fairing deflector
I have also made these deflectors from polycarbonate which keep my boots from getting wet. I have not painted these as the undulations produced from forming would be more visible. These are also shown in photo. 2.
Summary
These mods have allowed me to use the SV through rain and winter on a 70 mile return commute. It now has the protection of a full tourer without the weight and still keeps the sporty feel of the SV. I also have a NTV 650 with a touring fairing but far prefer the SV. The finishing touch was to change the gearing to reduce the engine revs. I first tried a 15t front sprocket instead of the standard 14t, but now have found that a 16t sprocket will fit. This gives 16mph per 1000 rpm compared to the standard 13.2mph per 1000 rpm. It pulls this on the flat easily but is more sluggish running against strong winds. I would only recommend this gearing if you only run on dual carriage ways/motorways.
Handlebars
My first change of handle bars were from my old Honda 650 hawk which are similar to the SV ones but about 30mm taller. These gave a good improvement but I still wanted a slightly higher raise.
There are 4 types of raised bar conversions:-
Raised clip ons.
These are a fairly easy mod to carry out and keep the stock cables. Slight disadvantage is that the bar centreline is in front of the fork centre, so that with the raised position, the clearances to the fairing are reduced. There is more clearance to the pointy fairing however. My first change handle bars were from my old Honda 650 hawk which are similar to the SV ones but about 50mm taller. These gave a good improvement but I still wanted a slightly higher raise. You can also buy special adjustable bars such as Helibars.
8262
Top - SV Standard S clip ons 11mm raise (bar centre to top of clamp.
Lower - HondaHawk clip on, 65mm raise.
Raised clip ons available:- http://www.banditmaniashop.co.uk/sv650-riser-clip-ons-1641-p.asp
Top Yoke Fixed Mounting (Comfort Kit)
This is the standard type used with the unfaired SV. Advantages are that a variety of handlebars can be used, but the brake hose &throttle cables will need to be extended, clutch and choke cables may need extending.
Top yoke comfort kit is available at Matts-Yokes on this site.
Modified Top Yoke to take bar mounts
This modification can be carried out by purchasing a set of bar clamps and drilling the top yoke for the bolt. This is an easy method of conversion but drill the hole close to the central portion of the yoke and away from any internal ribs on the underside of the yoke. DO NOT DRILLTHE HOLES CLOSE TO THE EDGE OF THE YOKE . This creates an increased stress close to the highest stressed location. Holes close to the centreline are close to the neutral axis and will have a negligible effect. (Primary loading of top yoke is in bending with a small torsional load). Note that some after market billet yokes have lightening holes in this central area. Use a large washer or spacer under the nut.
Modified fork nut spacer
I used this method for my bike but it is the method which has the most disadvantages to make but is adjustable. Once modified you need a new set of fork top nuts to change back. It requires aluminium bar to be machined. I used bar and turned it down to 41mm dia x 70 long, tapped it M12 x 40 at one end and then drilled a 22mm hole in the top at right angles to the bar CL. The forknuts need to be drilled through and tapped M12. An M12 bolt is then screwed in up side down so the thread protrudes from the top. The spacer is then screwed down onto the bolt and tightened up securely. A 22mm tube is located into the top hole and the angle of bar adjusted. The forks can also be moved up or down to get vertical adjustment. Finally, across brace is required to span between the two mounts to stop the mounting from detaching if the bike is dropped. I unfortunately had to test mine by falling off at 35mph and did no damage to the handlebars. (Shame about the fairing).
8263
Handlebars and deflectors
Footrests
I found the footrests were also uncomfortable and tried to find some unfaired footrest brackets on Ebay which give a lower position by about 25mm. They also are further forwards. I could not find any at the time and made my own from some 8mm thick alum plate (grade 6082 T6)which is the strongest commercial grade. This readily available from aluminium stockholders. This can be cut out with a hack saw and drilled. The tricky bit is that the footrest has two lugs on the mounting interface to stop rotation. These need small holes drilled to a depth of around 5mm as shown in sketch below. It also needs a shorter gear change rod from the naked model.
8264
L H footrest
8265
RH footrest with modified brake cylinder attachment
The rh footrest bracket needs a mounting for the rear brake cylinder. Pointy models have a different mounting bracket. Note that 03 & 04 models have a higher footrest mounting than later models.
Screen
I have looked around on the web for a touring screen and not found one. I decided to have a go at making my own. I went to see the manager of a local plastics factory to see if he could help and told me that the cost would be prohibitive due to manufacturing moulds. He did however give me some plastic and some advice on making my own. You will need to make a wood jig so you can form it to a suitable radius. I used thin plywood (3mm) and had to gradually work it to form the shape. It then needs to be rigidly connected to a base. Cut out the plastic sheet to the required shape using a jig saw, place in your home oven and heat up till it starts to become workable. You need to experiment with an offcut first and heat to say 120 degrees centigrade. Increase in temperature by 5 degrees at a time, then remove with suitable gloves and see if it can bend. If not put it back in and increase temp. again. At the correct temp, you will find it will start to bend. When the screen has soaked at this temp, take it out the oven and place on the jig and push the sides down. You need to keep it pushed onto the jig until it cools enough to allow the material to set. I found it only needed about 5 minutes for this. You need good gloves (I used an old pair of welders gloves), or use two pieces of plywood to push onto to sandwich the screen.
This sounds like a lot of effort, it is it look me 3 attempts to get it right. I then found that although the screen worked well and funnelled the air away from my body and head, there was still turbulence from the air moving downwards at the top due to the negative air pressure behind the screen. I ended up making an extension smaller screen which I bolted to the main screen. Success, a screen which completely keeps me out the airflow, and is quiet as well. The base plastic sheet needs to be tough and not brittle. Perspex is too brittle, I used polyethylene for the main screen and polycarbonate for the upper screen requiring temperatures of around 120 & 160 degrees centigrade to soften them.
8266
Curvy with screens
Handle bar wind deflectors
I have used similar methods to make these wind deflectors and used polycarbonate and a hest gun to just heat a localised area in the middle of the deflector and bent it around a tube. Care is needed to not overheat the material , because it bubbles released CO2. These are fairly easy to make and reduce wind draught and rain on the hands. They work well in the winter and have not needed to fit my heated grips. These are shown in photo. 2.
Lower fairing deflector
I have also made these deflectors from polycarbonate which keep my boots from getting wet. I have not painted these as the undulations produced from forming would be more visible. These are also shown in photo. 2.
Summary
These mods have allowed me to use the SV through rain and winter on a 70 mile return commute. It now has the protection of a full tourer without the weight and still keeps the sporty feel of the SV. I also have a NTV 650 with a touring fairing but far prefer the SV. The finishing touch was to change the gearing to reduce the engine revs. I first tried a 15t front sprocket instead of the standard 14t, but now have found that a 16t sprocket will fit. This gives 16mph per 1000 rpm compared to the standard 13.2mph per 1000 rpm. It pulls this on the flat easily but is more sluggish running against strong winds. I would only recommend this gearing if you only run on dual carriage ways/motorways.