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Offline Newbs1ok

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Re: Crossrunner Fork Oil Weight
Reply #10 on: November 13, 2019, 09:37:07 PM
Skids
Your being benevolent describing the Scopion OEs as awful
Current Bikes
VFR 800 X 2015 and BMW R850GS 1999
Previous bikes
Too many to mention in 46 wonderful years of riding on the road ,  everyone of them have given my stacks of fun and satisfaction

Online Skids

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Re: Crossrunner Fork Oil Weight
Reply #11 on: November 14, 2019, 06:20:39 AM
*Originally Posted by Newbs1ok [+]
Skids
Your being benevolent describing the Scopion OEs as awful

 :008: :031:
1 VFR simply isnt enough! Crossrunner for commuting, VFR1200F for summer fun.

Offline Kiwi49

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Re: Crossrunner Fork Oil Weight
Reply #12 on: March 19, 2020, 07:35:03 AM
Finally made the change for front fork oil (standard to 12.5wt) and new tyres - Pilot Road 5 - at 36F/42R psi.
Initial 'feel' (after doing a Dave Moss set up seminar), is that the suspension feels much firmer front and rear, but much more controlled.
Confidence in the bike's capability has lifted - even though I pushed it very hard before the changes, and enjoyed those thrashes immensely.
Now to bed in the tyres and give the bike some 'brisk' exercise  :046:
Body is old but the skills are still fresh

Offline Scimitar

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Re: Crossrunner Fork Oil Weight
Reply #13 on: March 19, 2020, 03:08:52 PM
Hmm. Interesting. But I suspect that your confidence might be more due to the PR5's than the 12.5wt fork oil. You will certainly experience a firmer ride with the heavier oil and this might give the impression of a racier suspension but I think it could be for the wrong reasons.

In my experience, for what its worth, most Jap bikes including the CR, are under-sprung and over-damped. So I fear that you might have compensated for the soft springs by making the damping even more stodgy. What is your rider weight?

Stronger springs, dependant on your rider weight, are better able to fight through the damping forces and keep the tyre touching the tarmac. We need the suspension to be able to move up and down quickly but without packing down or overshooting, following the road in response to irregularities. Heavier damping will make this speed of response slower. Just my ten-pennoth.  :006:
Who in their right mind would design a vehicle that falls over when it stops?

Offline Kiwi49

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Re: Crossrunner Fork Oil Weight
Reply #14 on: March 19, 2020, 10:31:24 PM
Thanks for the reply.
The improvement just on the OE tyres was big.
Body is old but the skills are still fresh

Offline apscurrah

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Re: Crossrunner Fork Oil Weight
Reply #15 on: May 23, 2020, 12:28:51 AM
Hi All
I found a big improvement in the forks by swapping the oil to 5W and increasing the pre-load to max. As mentioned earlier most Jap bikes are under-sprung and over-damped, Crossrunner being a classic example. This helps to alleviate both, giving a much less jarring ride.
I believe(?) that the OEM springs are linear and I feel that fitting aftermarket progressive units would help, especially with excessive dive under braking. That’s next on my list when the budget allows.
JMHO  :001:

PS. I will take it to a suspension guru for the spring change so re-valving may be part of it too. 
Last Edit: May 23, 2020, 12:30:46 AM by apscurrah

Offline Scimitar

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Re: Crossrunner Fork Oil Weight
Reply #16 on: May 23, 2020, 08:46:09 AM
I think you are on the right track. The limitation, as we know, will be the unsophisticated valving and shim stack.
Still, the lighter oil will enable the forks to move more rapidly and follow the ground better.
I noticed that the springs that PDQ removed from my CR were progressive, so I guess that’s what factory had originally fitted.
My RaceTech Gold valve conversion has transformed the front end, together with non-progressive RaceTech springs.
Get advice from suspension experts but I think you’ll find that many of the serious tuners do not opt for progressive springs.
Who in their right mind would design a vehicle that falls over when it stops?

Offline Kiwi49

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Re: Crossrunner Fork Oil Weight
Reply #17 on: May 24, 2020, 10:15:26 PM
Finally got Michelin Pilot Road 5's brand new. 36F/42R pressure, reset rear spring preload and rebound, front forks flushed and 12.5 wt fork oil (a witch's brew concoction) added. What a difference that has made to the bike. I know - new tyres will be a huge improvement, but the confidence to push hard through corners, the ride quality and being able to use the rev range made me feel like a 71 year old Marquez.
Body is old but the skills are still fresh

Online Skids

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Re: Crossrunner Fork Oil Weight
Reply #18 on: May 25, 2020, 07:24:23 AM
*Originally Posted by Kiwi49 [+]
Finally got Michelin Pilot Road 5's brand new. 36F/42R pressure, reset rear spring preload and rebound, front forks flushed and 12.5 wt fork oil (a witch's brew concoction) added. What a difference that has made to the bike. I know - new tyres will be a huge improvement, but the confidence to push hard through corners, the ride quality and being able to use the rev range made me feel like a 71 year old Marquez.

Nice one!  :028: :031:
1 VFR simply isnt enough! Crossrunner for commuting, VFR1200F for summer fun.