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...because every day is MotoGP day when you own a CBR 125r...
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PostPosted: Thu Jul 03, 2014 5:15 am 
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Joined: Fri Apr 18, 2014 11:38 am
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Location: scotland
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Has anyone done anything suspension wise to their bike? Seems to me it makes sense if we are making them faster,make them handle better.
I'm thinking about hagen progressive springs on the front and a yss progressive shock on the rear.
Any experience/thoughts?

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 Post subject: Re: new springs
PostPosted: Thu Jul 03, 2014 10:42 am 
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Racing ECU (!!)
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Joined: Sun Mar 23, 2014 9:21 pm
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Location: Parksville, BC, Canada
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I've done quite a bit with suspension on the bike and it pays really huge dividends for very little money. In fact, after doing up the front suspension and putting tires on it I was readily able to clean the clock off a 2010 R6 and a 2008 CBR 600RR - among others. A small bike, that's well set up, will always outhandle larger bikes. So if you choose a stretch of road that has short straights with tight corners you can really embarrass the litre-bike crowd :laugh: :biggrin: :top:

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PostPosted: Sun Dec 27, 2015 6:39 pm 
what did you do to the suspension and what were the dividends you speak of?


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PostPosted: Sun Dec 27, 2015 7:09 pm 
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It starts with tires - if you don't have the proper tires it really doesn't matter what you do. So that's first. The very best tires I could find were Metzeler Interac M5's. Unfortunately, they are no longer available. I think I may have the last set of new M3's in existence :laugh:

They are a Z rated tire and they are 110's. All other tires are useless in comparison. The M5's are a real tire and the typical 125 replacement tires (Shinko/Michelin etc) are not even remotely in the same league.

After that you need to set the rider-aboard sag in the front suspension. You do this by sitting on the bike fully geared up and taking some before/after measurements. Once that's done you then install some inexpensive PVC pipe in the front shocks to change the preload. This can be done without buying tires as the first step.

After that, assuming you have new tires, you need to adjust the trail setting to get the bike to fall in the way you like. This is a critical setting and pays huge dividends because you're effectively adjusting the suspension to match your new tires. That step gets done by lowering the bike in the forks.

Once both steps are done the bike will handle exceptionally well. Ie, you can take some 40k corners at 100k. Literally. Armed with the right tires and right suspension tweaks the show's over when compared to most any other bike.

This was a video I shot earlier this year for a friend over in the UK showing how the bike as running. I was only riding at about 80% of maximum but you can see in a lot of the corners I'm doing typically double what the road signs recommend.

it's also worth noting that engine in that video was bagged, burning a lot of oil (usually half a litre between runs) and would not exceed 12,000 RPM due to a valvetrain issue. In short, the engine was under performing by a wide margin. It's since been replaced but the weather has been so bad that it's not worth going out and breaking it in :blink:

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PostPosted: Sun Dec 27, 2015 7:39 pm 
Marvin, what would you suggest for a tire currently in production? How would an dual sport tire like a Shinko 244 affect performance? I live in an area where there is a fair bit of gravel and want something that can perform primarily on the road (though I doubt I will trick my ride out into motoGP beast you have), but occasionally not slip and slide on fresh gravel if I go over 40km/hr. I am running stock tires on mine.


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PostPosted: Sun Dec 27, 2015 7:48 pm 
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I really couldn't say - all my riding is focused on maintaining the highest level of traction on pavement and keeping the shiny side up :smile:

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PostPosted: Sun Dec 27, 2015 8:05 pm 
Fair enough :)


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