Fork oil and exhaust stud questions. XJ9 Divvy.

[c_dug]

Hi All,

I need to order the last few bits to get my divvy back on the road, you'll probably have guessed that they are fork oil and something to do with exhaust studs. One thread beats two so excuse the multiple questions.

Fork Oil
I think standard for oil for the XJ9 Divvy is 5 weight, which might as well be water Last time I changed the oil I put some 10 in there, I honestly can't remember how much difference it made but I do know that with the blue spot callipers on the front the bike seriously dives when braking. The proper solution is more firm linear springs (It already has progressive Hagons) but I don't have £80 laying around at the moment! Am I likely to ruin what handling I do have if I put 20 weight oil in the forks? I get that in theory it slows everything up, what is that likely to do in practice? Will it actually mask the issue at all, or am I barking up the wrong tree?

Exhaust studs
Well, nuts actually. I wan't to buy some brass/bronze nuts for the studs, I have a vernier calliper at work but the bike is wheel-less at home and I'd like to buy the bits today if I can. So, can anybody confirm the size? I thought they were M6, but they look to be an 8 to eye now that I have the old nuts off. Don't really want to waste time and money sending bits back and forth.

Thanks
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[mgh0]

Nut is M6.

https://www.motorcyclespareparts.eu/yamaha-parts/motorcycles/xj900s-diversion-1996/exhaust-343171.aspx
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"Courage is not defined by those who fought and did not fall, it is defined by those who fell and rose to fight again." Adrienne Rich.

[sickpup]

Should have brass nuts here if you want to pick some up.

[c_dug]

I'm going to check at work tomorrow but I might take you up on that if we don't have any . I have a niggling suspicion I've seen some in a drawer somewhere.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[WD Forte]

If its any help, a common or garden pencil ( HB, whatever)
is about 8mm in dia
Also if you take the dust cap off a tyre valve, the threaded bit is 8mm too
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bikers smell of wee

[Stalk]

Studs are m8 and the nuts are round and driven by an 8mm Alan key. Well they are on both mine. Don't know if you will get nuts on the studs and be able to drive them with a socket, looks a bit tight. But I haven't tried.
Cheers

[evoboy]

The thicker fork oil wont stop it diving, it will just slow it down slightly. Thicker oil in damper rod forks ( like yours ) will normally make the most difference to the rebound damping, slowing it down giving less of a 'pogo' action.

The downside being is that it may make the ride more choppy as the suspension is slower to react to bumps.

I would go for 15w oil. The progressive springs make it difficult to do any form of setup so 15w would be a good compromise.
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Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

APT Motorcycles

[c_dug]

I've found some brass hex bar at work so I'll knock up a couple of nuts if I need them, thanks for the offer anyway sickpup

What stalk said has made me think though, it can be a struggle to get an Allen key to the nuts as it is. I'll have a go with some off the shelf stainless nuts to check fitting before spending any time making brass nuts. Thanks Stalk

As for the suspension, would I be better of knocking up some shims or something?

Edited because I can't read a username
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[evoboy]

[c_dug]

I believe the bottom yolk is too far up the leg for the forks to compress that far, but I did have a cable tie on the leg while the bike was still on the road and with hard braking I could get the forks to all but bottom out, judged by measuring with a ruler and comparing to the fork travel in the manual. I never felt what I'm lead to believe is the distinctively knock of them bottoming out though.

I was under the impression (and I'm happy to concede if I'm wrong) that shims would precompress the progressive forks to a more firm section of spring?
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Moo.]

Standard weight is 10w with standard springs. Hagon recommend 15w with their progressive ones. (I've also got the progressive springs in mine, use 15w oil, better then the 10 but still dives a bit )

Are yours the adjustable ones?
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A2 Passed 18/6/10

[c_dug]

Adjustable for preload only (I think, they have a cap on the head which compresses the spring, that's Preload, right?).

Interesting they recommend 15w, I'm pretty sure I've had 10 in it since I last changed the oil.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Vincent]

If they'll fit, these are brilliant for exhaust studs but I'm not sure what yours are like. I can't work out what a nut that can be removed by an allen key is

https://www.ebay.co.uk/itm/Honda-Yamaha-Kawasaki-Suzuki-M6-M-6-CHROME-EXHAUST-DOME-NUTS-set-of-2-/300846357261?pt=LH_DefaultDomain_3&hash=item460bd71b0d
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Space Is Deep

[evoboy]

[Raffles]

[Stalk]

https://www.yamahamotorcyclespares.co.uk/genuineparts/9537/12/yamaha%20xj900s%20diversion/exhaust?uID=0
Item no 19, bit expensive! Stud one end, Allen key in other.