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J Slam Modification

Discussion in 'Cruisers' at netrider.net.au started by tonner, Jun 28, 2011.

  1. Anyone done this mod? http://www.stargis.net/webslinger/Docs/slam.pdf looks sweet as :cool: as but Im a bit worried about ground clearance on gutters and speedbumps afterwards.
    Not cool getting stuck on a speedbump:censored:


     
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  2. Ah... I don't think you have a lot of clearance to begin with...right?

    Depends on how fast you want to go around corners I guess...

    Edit: It also looks like you drill holes in your frame to move the suspension linkage, if that's the case, I would steer clear.
     
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  3. It's hard to see exactly from the photo, but it looks like that new section of gusset you are now loading is narrower than the bossed section of the original mount.

    I wouldn't be doing it. At best it will flog out, at worst you could start a crack and have an in service failure.

    Pretty bloody bodgy.
     
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  4. Much easier to get a new spring made

    Evolution yamaha play with these things in Melbourne give them a call
     
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  5. Seems there isnt a V Star 650 running around in the USA that hasnt had this mod done ?? I was figuring on only going about 15mm as opposed to the 1" the yanks recommend just so it did end up too low.
    I will ask some more questions and strip down my bike a bit to have a look at the frame.

    Thinking out loud: If the bolt is tight with no movement how can it flog out the hole??

    I guess a new spring might do the job but being shorter will need to be stiffer and I dont really want the ride any stiffer.
     
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  6. bear in mind, a change in rear ride height changes more about the way the bike rides than you would think.

    not that on a cruiser you would ever notice.
     
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  7. If half of what I have read on the yamaha forum is correct the handling improves, especially at low speed which is where cruisers struggle a little.

    More research I guess
     
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  8. I'm obviously not on a yamaha, but for what it's worth:
    My Beast is lowered 3 inches. It really does change the riding characteristics and you better be sure that you can handle how the bike behaves (and the seriously reduced clearance)
    Otherwise, that mod in the OP is SAWEEEET! ;) ImageUploadedByTapatalk1309358621.099551.
     
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  9. The smaller area means higher bearing stress.
     
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  10. Thanks for the input, I gotta ask what sort of new handling behaviours did you come across?
    Agree it does look so badass
     
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  11. Smaller area and higher bearing stress? I dont understand what you meen, can you clarify this a bit.
     
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  12. When the mounting point was designed, it was designed to a maximum stress level to prevent failure. The bit that is drilled in this case looks narrower in the photos. So the bearing area is just the bolt diameter x width (x two sides). Stress = force/area. So the force is going to be roughly the same, but if you halve area, you double the stress.

    If the stress gets too high, the steel in the plate will yield and the hole will flog out.
     
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  13. Now I got ya, the load bearing and stress on the mounting bracket.

    I dont think this would be an issue in this case, seems to me most of the load will be along the length of the shock which is as per normal with little stresses applied to the bottom or top sides of the bracket. The collar on the shock also acutally sits against the end of the bracket and will lessen the load on the bolt and mounting hole.

    I reckon it should be ok.....I have asked the question though on the Yank forum if abnone has had failures or issues relation to stress in this area.
     
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  14. Ummm NO. NO. NO. NO. NO.

    The shoulder of the shock is not designed to take the load. The eye is. If the shoulder really is loaded then it will break. It is not designed for that.

    and ANY load that is seen in the shock WILL be seen at the eyelets at either end. The load doesn't magically disappear in the shock.

    And take anything you read in a Yank forum with a major bucket of salt. These guys chop the shit out of their bikes, with little thought to engineering consequences. They only ride a few ks a year and most get away with it. I stalk the Jockey Journal a bit and some of the stuff that gets done is scary bad engineering.

    There might be enough width in the brackets, it's hard to tell from the photos, but what you posted above is wrong.
     
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  15. The bike will 'flop in' or 'dive' into the corner when leaned, so you'll either have to keep the speed up or maintain a firm grip on the bars to keep your chosen line in turns or bends, otherwise your @$$ will be on the ground.
     
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  16. I guess I will no all about tomorrow
     
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  17. Just did a 30km test ride, if anything it seems to handle better. Definitley none of the issues mentioned above with diving into the corners. It did bottom out on 1 bad bump but I will adjust the preload a bit and see how that goes.
     
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  18. Went for a 200km ride yesterday after bumping up the preload to 7 on my shock, no more bottoming issues and bike handles a treat. love how my bike looks sitting nice and low, being rather short in the legs it is easier to back up and to handle at low speeds. I even had 4 individuals come up to me and say what a top looking bike I had.

    Overall very happy with the mod.
     
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  19. B4 & After pics please? :)
     
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