Promecha modded forks- which oil

[s man]

Emmit, front valving is very inherent, If you are bottoming the forks, screw more spring into it! Forget the sags for now.
The spring is what holds the bike up, & from what you are saying that is not happering. Its bottoming out the front. I cant imagine why, You have plenty of spring left so use it.I have never bottomed the front of mine, even under extreem braking fully loaded. So there is IMO not enough spring preload.
Do that first.
Next the chattering over small corragations,is fine if the bike still behaves, which mine does. I must say it is
a bit unnerving, but as long as it still behaves thats all that matters. We are talking a 250kg roadbike. There are gonna be compramises everywere. Some guys think these thing handle well. I think they handle like a hinge. Peter has made mine 100% better, but it is IMO still a pretty poor handler. I am use to pin sharp race bikes though.So I have lernt not to expect to much out of the big tank. The high speed damoing is a known issue that cant be fixed without a lot of money. Peter makes it a lot better, but its still not in a sports bike class.The low speed damping is pretty good IMO
I pushed the forks up through the tripples about 5mm & screwed more spring in, which really worked well. But didnt stop the chatter. I dont think you will.

Now the rear, 4 comp, 4 rebound & middle spring. Give that a try & see how it feels. Those two things together will push
a little more weight forward which could help.
If your still having trouble I'll meet you somewere & we can go over what we have & see whats going on.

[Angry Emmet]

Thanks Sman, will try as you suggest, although might be a couple weeks, haveing too much fun on the z900 for the moment, its now 1075cc,ported head,cr29 carbs, cams etc, sorting jetting and a chassis vibe, similar accell to the Rex but not in the handling dept.

Agree totally re the BIG GIRL handling on the Rex, you might just be 100% correct with the chatter on small bumps.

cheers.
A.E.

[Angry Emmet]

Hello Gentlemen,
quick update on the ZRX Promecha modded front forks i was having issues with. Sorry for the extended time delay, i have been having some issues with work and other bike stuff which took precedence.
Now, my issues were bottoming on big bumps, too much high speed rebound, stiction etc. Pulled apart last week, one cartridge not square to out tube= stiction, oil level 30mm, yes30mm lower than recommended= BOTTOMING, And when comparing fork oil weight with my pissy test method (large syringe,no plunger,fill and time known volume to dribble from syringe, good for comparison only men!), oil in forks was THE DIRTIEST oil i have seen in any forks in thirty years of working on bikes having only done 6k, oil was thinner than my 15wt, thinner than my 10 weight BUT thicker than my 5 weight (only just though)....SO, i went to 2.5wt Motorex, 120mm from top of tube fully collapsed springs out, I also refitted the cartridge so was square to tube (this happens quite easily when tightening cart.mount bolt at bottom, you just need to be a little careful, i assemble all, no spring, put fork cap on,compress tuber to half travel so all is square/supported,then tension with tension wrench), GUESS WHAT? bottoming GONE, stiction much improved, chatter a lot better, comp now 5 out from full hard, rebound 7 out from full hard, NOT BAD NOW! I guess either it got the wrong oil and height when revalved, no big problem, it can happen, or Motorex 2.5 is a lot thinner than what oil Promecha use which is more than possible, as for the oil height the older 1100 has an oil volume and oil height that is equal to what mine had before the latest oil change.....
Anyways, thanks to all for your input and love to Strika! Oh, and shocks next when $$$ and saturday work permit! Would i used Promecha again? Hell yes, you pay for their knowledge, you hope for good workmanship every time, I am a mechanic of some 34 years, anyone can make mistakes AND i am tayloring MY Rexxy to ME! Peter is a good guy, forgotten more about suspension than most will ever know!
A.E.

[s man]

Hmm how strange ant? I wonder if mine has the right amount of fluid?? But then again I wasnt having the issues you were, so I gather its pretty close. Either way It tranformed my bike, & I am pretty happy with it.
Like I said before, if I wanted sports bike handling I wouldnt by a ZRX, probably a Z1000 or ZX10 would have been better. But the ZRX fills my needs perfectly. But its good to see you got to the bottom of your problems. I would be calling Pater up & telling him what you found, see what his reply is. Should be interesting..

[Angry Emmet]

Hmm how strange ant? I wonder if mine has the right amount of fluid?? But then again I wasnt having the issues you were, so I gather its pretty close. Either way It tranformed my bike, & I am pretty happy with it.
Like I said before, if I wanted sports bike handling I wouldnt by a ZRX, probably a Z1000 or ZX10 would have been better. But the ZRX fills my needs perfectly. But its good to see you got to the bottom of your problems. I would be calling Pater up & telling him what you found, see what his reply is. Should be interesting..

Thanks Sman, might drop him an email, bit hard to get him to the phone. Its an easy mistake to make and it was maybe/probably one of his workers. Anyways is working well now, still choppy when cranked over at silly speeds, small bumps but lots of them, the rear is now worse than the front, but as you say a GOOD improve over stock...although my shocks have now run out (mostly) of compression adjustment,fell like they are stuck on pos.1 for comp, i guess the gas is leaking out, so shocks next....and on it goes!

I fully understand what you mean about sports bikes or a Z thou etc but these are just beautiful to look at and nice to ride,the others are just too easy, my contention these days is to pick someing i love the look of and then modify a bit to suit. I have a Z900 with a bit of work, you should see the looks on blokes faces when they pull into Colo Heights and realize they have just been terrorized by a old bloke on a very stock looking 35 year old bike!!! The zrx is just an extension of that i guess! I might add i prefer how the skinny tyres steer to these later fat ones, the old Z is just like a pushbike in corners!
Cheers,
A.E.

[oldman]

No, not oil levels or weights just sounds like the valving is too little on the low speed circuit while too much on the high speed circuit. Revalve being the solution.

thanks mate, yep, sounds like valving might be it. But i wondered if it not inherent etc.

Revalving is a great idea. You might as well check to see what the stock spring rate is. My Z1000 had a spring rate set for a 135 pound person. I went to a .95 and it made all the difference as well as a revalve. Cheers!

[Phil]

pick someing i love the look of and then modify a bit to suit.

Yes, thats my motto too

[Angry Emmet]

pick someing i love the look of and then modify a bit to suit.

Yes, thats my motto too

Yeah mate, buy what you are passionate about and modify to your own taste, besides anyone on any sports bike of the last ten years can get along quicly, there's not really much in that is there? I prefer something that makes me work for it, which probably also explains why i have my missus!

A.E.