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Front forks (again)


bobk100

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Hi All

 

Sorry if this is repitition but I haven't the time to trawl  any more posts.

 

My bike has 100mm of travel before it bottoms out and 40mm sag when I take it of the stand.

 

To get 25mm sag I have to load the tube with so many spacers it's hard to get the screw tops again it's a challenge to get'm done up again and it restricts the total travel as I presume the springs are jammed up.

 

Sound about right?

 

Anyone ever machined the bottom of the forks to accept brake bleeders? Is there enough 'meat' to do the mod.

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skorpion
Defender
14 hours ago, bobk100 said:

Hi All

 

Sorry if this is repitition but I haven't the time to trawl  any more posts.

 

My bike has 100mm of travel before it bottoms out and 40mm sag when I take it of the stand.

 

To get 25mm sag I have to load the tube with so many spacers it's hard to get the screw tops again it's a challenge to get'm done up again and it restricts the total travel as I presume the springs are jammed up.

 

Sound about right?

 

Anyone ever machined the bottom of the forks to accept brake bleeders? Is there enough 'meat' to do the mod.

That's a very good question, the forks are, pun intended, truly shocking, especially after a few years of use!

I think that they're not very well controlled at all, I have much better forks on my mountain bikes, with full adjustability too.

Trisaki (Mark), on this forum is well versed in improving the operation of the forks and suspension as a whole.

From what I can remember the fork oil level isn't correctly given for the early bikes, which once corrected makes a big difference along with a good quality fork oil.

The rear shock isn't exactly a stellar item either, there are lots of alternatives to the horrible Honda offering. 

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So - the plot thickens!

 

I took the springs out and the total travel is 125mm. Springs in = 100mm

 

https://www.motorcyclespecs.co.za/model/Honda/honda_nc700X_12.html quotes  153mm

 

So I'm not sure what I've got going on.

 

I'm guessing my next step is to take the lot apart again, undo the damper rod and see what's on the end of that and post a picture to see if resembles the OE.

 

Getting a bit tired of burning the midnight oil on this. Can't help thinking I'm missing something completely obvious but for the life of me I can't think what.

 

  • Confused 2
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skorpion

Had my forks internals out many times though never measured total travel with the springs out,  how did you bottom out the forks with the springs in?

my forks don't bottom out at any time on the road, ether hitting a pothole or emergency braking.

 

The only fault I found with the forks is that they are far too stiff on high speed compression, this can be cured (though expensive) or the edge taken off cheaply.

Edited by skorpion
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  • 2 weeks later...
Urbanfireblade

Surely your compressing the front fork spring to its maximum when fitted, hence only 100mm travel, whereas the fork tubes without springs fitted have a total of 125mm.

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fred_jb
On 07/07/2020 at 21:47, bobk100 said:

Hi All

 

Sorry if this is repitition but I haven't the time to trawl  any more posts.

 

My bike has 100mm of travel before it bottoms out and 40mm sag when I take it of the stand.

 

To get 25mm sag I have to load the tube with so many spacers it's hard to get the screw tops again it's a challenge to get'm done up again and it restricts the total travel as I presume the springs are jammed up.

 

Sound about right?

 

Anyone ever machined the bottom of the forks to accept brake bleeders? Is there enough 'meat' to do the 

 

 

For a road bike I would be looking for a loaded sag, i.e. with you in normal gear sitting on the bike with feet off the ground, and an assistant holding the bike vertical, of about one third or 33% of the manufacturer's stated suspension travel. I would work off the manufacturer's figure as it is very difficult to accurately measure this.

 

However, in my experience the front suspension sag varies relatively little between loaded and unloaded as rider, pillion and luggage weight has a much bigger effect on the rear suspension, so that is what I would concentrate on first.

 

 

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skorpion
5 hours ago, fred_jb said:

 

 

For a road bike I would be looking for a loaded sag, i.e. with you in normal gear sitting on the bike with feet off the ground, and an assistant holding the bike vertical, of about one third or 33% of the manufacturer's stated suspension travel. I would work off the manufacturer's figure as it is very difficult to accurately measure this.

 

However, in my experience the front suspension sag varies relatively little between loaded and unloaded as rider, pillion and luggage weight has a much bigger effect on the rear suspension, so that is what I would concentrate on first.

 

 

 

I think you are quite right about getting the rear correct for your weight first before looking at the front forks, I found that for my weight 16st adding more preload to the forks made them less supple so I have gone back to the standard fork caps, with none standard 140mm  oil level, 7.5 weight fork oil. 2017 NC750X

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Trumpet

The front forks have progressive springs. The sag you are quoting is for a linear spring.

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