Author Topic: RT Progressive springs okay on naked K75? And other suspension questions...  (Read 3947 times)

Offline herseyb

  • ^ Proficient Motobricker
  • Posts: 366
One of the first upgrades I did after swapping all the fluids on my new to me K75 was put in the progressive springs up front.

Seeing as this is my first full size bike, I'm not really sure what handling should be like, but man, it feels pretty dang stiff going over bumps!   The wheel tracks the ground well, and doesn't get all smooshy when breaking, but I feel a hell of a lot of the road.

Do y'all think the RT springs are overrated without the fairing? 

Also, I also messed up the pre-load length by 0.25" too short when doing the install.  I have the spacer that came with the kit so I could do it again, but I'm not sure how big of a deal that is in terms of tuning.  How much would y'all worry about that?

My rear shock (an aftermarket ohlins that came with it) is preset for two up + gear. 

Right now I'm actually mostly 1 up, so I could soften the spring there but it seems like most of the bumps are coming through the fork, and the kick in the pants from the rear is noticeable but not too bad.

Any input is welcome!
  • Brooklyn
  • '93 K1100RS

Offline johnny

  • TrailBrakingThrottleWhacker
  • ^ Quintessential Motobricker
  • Posts: 7652
  • Whacking...n...Chopping Sliding...n...High Siding
greetings herseyb...

id go with your spacer as is and see how it goes...

abouts the rear shock... this is were everything happens... id figger out what spring and valving you have... a shock for a 500 pound rider with 400 pounds of gear isnt ideal for a 120 pound rider with 100 pounds of gear...

after i figger out what i gotts then i would set the right height as high as allowed... then blast some twistys... set it down 1/4 inch and blast the same twistys... once i getts that dialed in i would move on the other adjustments and commence to blasting and dialing it in...

there is a sweet spot... you will know it when you find it because its liberating... a half an inch on the rear shock of a motobrick can transform an old geezer into valentino rossi...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline K75RT Keith

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  • Posts: 447
+1 on what Johnny said.  Rear shock that is too stiff makes a K an uncomfortable, disagreeable machine.  That said, what brand and weight fork oil did you use?  As there aren't industry specs for fork oil weight, that could be part of the problem.  My experience is that different brands of 10 wt are not created equal.  some are thinner and some thicker and that little difference make a big difference in 
You can't help someone who doesn't want to hear the answer.

1990 K75RT

Offline herseyb

  • ^ Proficient Motobricker
  • Posts: 366
Thanks Keith -  Not sure what brands...

I actually used a couple different types of oil cause we were down the end of a few bottles in the shop to get it done.  The right shock got some kind of gnarly looking oil in it, so I've been thinking about draining the oil again to satisfy my perfectionism.

Do you recommend I try a particular brand?

I dialed the rear 4 clicks softer on compression damping and that has made a big improvement.  I had sent the shock in to get refubed by Ohlins, as it was leaking oil when I got it.  They set it up for 50% 1 up riding with my weight, and 50% two up +60lbs of camping gear with my GFs weight included - so it makes sense it came back pretty stiff.

Both knobs were originally set at 19 clicks from fully closed, which is pretty close to the middle of their range.

I might try two more clicks to just to see how that treats me.  Adjustment makes way more sense after RTFM.  Thanks for the links johnny.
  • Brooklyn
  • '93 K1100RS

Offline herseyb

  • ^ Proficient Motobricker
  • Posts: 366
Stopped by a fellow bikers house last week.  He pointed out my front suspension had very little (practically no) travel, which got me back on the hunt for this....

Turned out:  Too much oil = no air to compress = limited range for travel.   

I drained some out and have fork dive again.  Once I get my hands on a flavor injector I'll try putting in 330 CCs, as opposed to the try and measure 5" from the top for air gap method. 

What does "right" feel like for k75 with prog springs? 
  • Brooklyn
  • '93 K1100RS

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