alan bechard Posted July 18, 2004 Report Share Posted July 18, 2004 (edited) I am about to start juggling suspension setting's etc. on my sons new Sherco 80. I will probably end up making more changes at once than I should, and have to retrace my steps to get back to a reasonable point along the way, but heck, it is all for fun anyway. So, thinking aloud,, If I raise (have more fork sticking out the top towards the handlebar) the forks in the triple trees, this will make it steer tighter, and the front end feel heavier and less likely to wheelie. It will also lower seat height and skid pan height. Roll the bars back, it turns slower, is more stable, maybe a bit easier to wheelie??? Roll the bars forward, quicker steering more weight on the front. Shorten swingarm, changes leverage on the rear shock, makes wheelbase shorter, turns tighter, easier to wheelie, effective ground clearance increases???? Thoughts corrections and comments welcomed. Edited July 18, 2004 by Alan Bechard Quote Link to comment Share on other sites More sharing options...
charliechitlins Posted July 18, 2004 Report Share Posted July 18, 2004 My only suggestion would be to measure up an 18" wheel and make sure your swingarm mods leave room for it, in case you decide to use larger wheels. Quote Link to comment Share on other sites More sharing options...
jtt Posted July 18, 2004 Report Share Posted July 18, 2004 (edited) Sounds like you've thought it out pretty well Alan. Remember shortening the swingarm will also effectively place more weight on the rear wheel too. Don't forget about sag settings too, as these can also play a significant roll in overall handling. Although not trials specific, HERE is a website of a guy that understands motorcycle geometry better than most. Edited July 18, 2004 by JTT Quote Link to comment Share on other sites More sharing options...
alan bechard Posted July 18, 2004 Author Report Share Posted July 18, 2004 I have a damaged swingarm that I am modifying, that way, I have not destroyed any expensive pieces in my fiddling. Or is that Feddleing? I am going to try not to do any mod's that are "irreversible" or quickly undone, should I blow it somewhere along the way. Dean comes home tonight, probably see it tomorrow. I am out to the shop to cut some aluminum and fire up the TIG. Try and get Doug to mod my spring. It is currently set up to zero preload. I heard a buzzing as I reved it up and realized it was the spring / washer assembly vibrating around. Quote Link to comment Share on other sites More sharing options...
charliechitlins Posted July 18, 2004 Report Share Posted July 18, 2004 TIG!! And i'm still welding cast aluminum with a torch. You are a fancy man. I should send YOU my broken levers! Quote Link to comment Share on other sites More sharing options...
kevin j Posted July 19, 2004 Report Share Posted July 19, 2004 shortening it up will effectivelymake the rear suspension stiffer proportionally all across the range too. I will be interested to hear how it works out. To think how even the 'stock' kid bikes now compare to the old TY80's. . . . The modern kid bikes are just what I think we need to get kids really to the highest levels again. k Quote Link to comment Share on other sites More sharing options...
bullfrog Posted July 20, 2004 Report Share Posted July 20, 2004 . . . and don't forget that the footpeg location along the wheelbase has a LARGE effect on weight distribution while riding. Shorten the swingarm and the footpegs are closer to the rear axle. Changing the footpeg/handlebar relationship can have very large effects on rider comfort, steering, lofting the front end, etc. Changes in this relationship MAY be easier to accomplish than some of the things you have in mind and MAY provide many of the same effects. Quote Link to comment Share on other sites More sharing options...
alan bechard Posted July 20, 2004 Author Report Share Posted July 20, 2004 Bullfrog, Do you have some specifics???? I know you have done a bunch on the Hodaka's, I am sure many of the mods would be the same. What worked the best, most effectively for you guys? I rolled his bars back to basicly vertical. I believe they are stock Domino's. Cut 1" off the end of each side last night to put me at 28 or 29 (I forget which) He has stock pegs on it at this point, Could try some of the back set J-pegs next week I think. Other thoughts? Thanks for the input. Quote Link to comment Share on other sites More sharing options...
jtt Posted July 20, 2004 Report Share Posted July 20, 2004 So Alan, what exactly are you trying to accomplish with these mods? Is there something that he doesn't like about the bike? ...or is this just pure experimentation on an unwitting guinea pig Quote Link to comment Share on other sites More sharing options...
alan bechard Posted July 21, 2004 Author Report Share Posted July 21, 2004 The Sherco 80 is a bit long for my taste. It utilizes the standard frame and swingarm from Sherco. It utilizes the 17 / 19 tire combination. It utilizes different forks, which give it 1" less OAL. (overall length) Because you have smaller wheels, the skidpan is closer to the ground, but your OAL is the same, so that ratio between them is changed. This makes it more likely to skidpan and hang on objects. Because the rear axle is where it is on my bike, and my son is comparitively small, he cannot get his butt back over the rear axle like you or I to transfer weight. Because his weight is now, essentially 1" forward of the centerline of where he would be on my bike (forks 1" in, rear the same) he is essentially always in a "weight forward" riding position. (not sure if that makes sense) So,,,,, my goal, place him with a centered or rear biased weight position and change the ratio of skid pan height to wheelbase length more in line with what a "standard" bike is. This should allow him to clear obstacles better and allow for better wheelies with his limited weight input. Quote Link to comment Share on other sites More sharing options...
jtt Posted July 21, 2004 Report Share Posted July 21, 2004 Actually Alan, that made perfect sense...I must be tired Now all your planning is making more sense. Basically you almost need to scale the bike down to the wheel size. So if the steering head geometry is the same as the bigger bike, the smaller front wheel will effectively give less "trail" as well? Do you think you'll need a longer fork to offset the raised rear (as result of the shortened swingarm)? This might help with the skidplate clearance, but will also raise his overall height as well, which may or may not be a good thing...just thinking out loud. I don't know a whole lot about this subject, but do find it interesting. I'd like to hear more as the project progresses. Quote Link to comment Share on other sites More sharing options...
wardo Posted July 22, 2004 Report Share Posted July 22, 2004 First, I don't want to hijack the discussion, but it has raised some questions on my own bikes setup. Although I know how to setup an MX or Enduro bike I am somewhat clueless about where to begin on my Sherco 2.9. I spoke to Ryan Young and he said he doesn't mess with sag, etc. At 170lbs, the stock springs seem to be close, what about sag? What other things should I consider? Are there baseline settings that those in the know use? Thanks in advance for any help. Regards, Wardo Quote Link to comment Share on other sites More sharing options...
charliechitlins Posted July 22, 2004 Report Share Posted July 22, 2004 If I remember correctly, Jon Stoodley has a good description of setting race sag on the Gas Gas website. Although...at 170lbs, Ryan is probably right. I don't think he would tell you the bike was right in the interest of trying to make you thing a Sherco is perfect and needs no adjustment. Also...your front forks are not adjustable, and balance between the front and rear is important. I added preload to the rear (I'm a tad heftier than you), but I also added some to the front. I think I went with about 2.5" of sag on both ends. Quote Link to comment Share on other sites More sharing options...
wardo Posted July 22, 2004 Report Share Posted July 22, 2004 Charlie, Thanks for the direction, here is a link to the exact page: http://www.gasgas.com/Pages/Technical/tria...nsion-tips.html . I didn't mean to imply that I didn't trust Ryan's input, but rather I was looking for alternatives that I could consider. Ryan's experience and success speaks for itself, I just like to try different things out and want guidance in which way my testing should go. Thanks, Wardo Quote Link to comment Share on other sites More sharing options...
charliechitlins Posted July 22, 2004 Report Share Posted July 22, 2004 Welcome to the board. There are lots of good folks here. And enjoy your Sherco. It's a great bike. Quote Link to comment Share on other sites More sharing options...
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