Friday, June 17, 2011

Progressive Springs

 I felt that the Suzuki C50 was a diving to much in the front under braking so I changed the front springs out to Progressives.  I used Progressive part number 11-1126. Since Progressive doesn't make spring specifically for the C50 I had to use the next best. These springs are about 5 inches to short so I had to cut some PVC pipe to fit.  The combined length of the spring and spacer is 21.73", the length of the original spring.  You should also measure the original spring and see if is still in spec.  If it's less then 21.29" then it need to be replaced anyway.

If you have risers then this might be an easier install because the springs might just be able to lifted out past the handlebars, but with the stock risers you will need to move the handlebars out of the way.


With the bars out of the way it's time to open the fork tube caps.  You have to loosed the upper pinch bolt on the side of the triple tree first.  Then comes the tube cap.  Caution, the cap is under spring tension.  You must have the bike on a lift and the wheel just off the ground to open this cap.  Even with the wheel off the ground the cap is still under tension, just not as much.  We came up with a method of removing these caps.  We used a ratcheting box wrench and a dowel that fits inside it to counter the spring.




Since then we learned that we didn't need the dowel because we became accustomed to the amount tension that is under that cap.  There is a lot of threads on that cap, so when you get to the end just keep a rag over the cap and place you other hand over the rag, pressing down, to catch the cap when it POPS off.  If you don't cover it, it will shoot up to the top of the garage or it can hurt someone, please take precautions here.

When I first opened the riser tubes I noticed that the fork oil level was way low, they should be 6.96" measured from the top of the tube to the oil without the springs in and the forks collapsed. Also, the capacity of each fork tube is 412ml or 13.9oz, so if you were to remove each tube and turn the tube over to drain out the oil, then you can just add that amount back. I think that most of us should at least check the oil level because low fork oil level would definitely add to the front end diving under braking.

Remember to torque the top cap and the pinch bolt to the right setting when you reinstall.  Cap bolt should be 25.5 lb-ft  and the pinch bolt should be 16.5 lb-ft

Now I have the Progressives in, and the oil level set to the proper level. I can say that there is a remarkable difference in the ride. Handling and braking feels great.

If you folks take anything away from this write-up then it should be to check the oil level. If you siphon out the old oil and replace with new oil set to the proper level you should see a big difference in your ride.

This is a link to the oil level adjusting tool I used. Something else for the motorcycle tool box.


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