Triumphrat

trick420

Hi Everyone,

So I see a ton of posts about fixing handling issues, getting more performance, etc., but I think my question is a little different...

I ride a 2004 Thruxton almost daily to commute. 9800 miles on the clock, maybe 1200 on the Roadrider tires. It's got some mods - AI delete, D&D slipons, retuned carb... It's fast enough and fun - hit's 100 easily.

It handles fine, I have no complaints other than some mid-speed wobble on the front end (I think I'll handle that with a damper - not sure if it's the Roadriders or the Dynabeads...)

Well, my gripe with the suspension is that I think it's kinda harsh. It feels solid in the twisties, and I don't get any floating that I have read about, but it seems like bumps at speed - instantaneous activation of the suspension (front or rear), feel harsh. Stuff that I feel like ought to be smoothly handles transmit a ton of shock right through the frame to me. Perhaps I'm, generally speaking, over-dampened?

So, I'm 5'11" tall, 210 lbs. The bike, as far as I know, is bone stock on the suspension, and Ive never done a thing to it. The guy I bought it from was an ex-racer and runs a vintage race bike shop - I would guess that he set it up stiff for himself, but he was also about 40# lighter than me.

I'd like to make the suspension feel more refined, without dropping a ton of cash on the bike, and hopefully without messing up the ride such that it wallows or floats in corners or at high speed.

Is this as simple as, say, changing the fork oil? Or am I SOL until I'm willing to change out fork internals and rear shocks?

Thanks for any opinions.

Jeff

Sheepdog

More likely an excessive spring preload issue instead of too much dampening. Reduce spring preload front and rear until your weight sags the suspension 10% of available travel (about 5/8" with the bike off of the stand...you will need a helper). This should get you the best balance of suspension compliance and wheel control.

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2003 Bonneville T100 and 2007 Moto Guzzi California Vintage

trick420

That's quick and easy for an experiment anyway. The Rear is definitely set good as it is. I'll piddle with the front end tonight and see what happens...

Stock front end only has preload adjustment, correct?

Gary_spain

You could be too stiff or too soft and bottoming out, you need to set the static sag. Stock front & rear only allow for preload adjustment.

Here's one (of many videos) which show you how to adjust the preload to get the right amount of static sag.

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07 Thruxton: TEC 2 into 1, K&N, TTP Breathe Bellmouth, 135 mains, 40 pilots, std. needles, 1 shim (0.65mm). All baffles removed. Bitubo Fork Cartridges. Bitubo Rear Shocks. TEC Steering Damper. 3 Pot Nissin (Honda) brake caliper.