Suspension again!

[slartybartfarst]

No the same M10s work no need to swap.

We are reasoning the reason the front end feels hard on the standard bike is the spring is not preloaded enough so the forks sag onto the air gap immediately, the bike is supported on the compressed air which is a harsh rapid rising rate spring. So now with limited travel and and the air already compressed heavily every little bump thumps through, the springs do not get a chance to do their job.

In addition it seems the damping is to harsh with the standard weight oils, so the 5 weight sorts this.

My bike is nearly as smooth as my GSXR 1000 K6 which has amazingly compliant springing, the damping is not up to the GSXR but i did not expect that seeing the primitive set up inside the Raps forks and as the damper system is pretty sophisticated in the GSXR forks, however with this mod its really not bad and well up to the task for a nice planted feel on the Rap front end plus no more bumps thumping through!


I hope some one else tries this mod it would be nice to get feedback Im shure it will be positive.

[kev]

sounds like a good mod to me i tryed similar things with mine but ended up chucking them in the bin you either get the compresion damping right and then the rebound goes all to cock in the end fitted ri forks and then on to ohlins not a cheap option but its like riding on a cusion of air i would say that the roadholder forks on my triton work better than the standard rap forks

[snapdragon]

..............
i would say that the roadholder forks on my triton work better than the standard rap forks

Having only ever been 'ballast' on a Triton (and can't recall what sorta forks) I wouldn't know, mine have had the nylon stalk inner skimmed for smooth travel of the spring and 10wt oil (after the forks bottomed out in a pothole and rattled my bones) but no major changes.

[Bfef]

Hi slartybartfarst, I wonder if you could explain your fork mod a bit clearer for me (being a little mech. challenged!).

[slartybartfarst]

I used to be a "Suspension Luddite" LOL! I run an old Honda CB750 (1970) but I must say the front end is better than the Rap........however once Id ridden a modern sports bike that was it......it shifted my frame of reference.......still sceptical of such exotic items as Ohlins I rode an Ohlins equipped Aprillia factory...........Unreal! I totally agree if you want the best you gota pay the experts.

Im used to 70s bikes boinging around but the Rap was actually dangerous! Im happy when the suspension gives me the feedback to get a bike to the tyre edges.......I feel the suspension is at that level with these mods.

The other option is to do away with forks all together! I used to think this was the answer and I still regularly use a funny front end bike........ a Yam GTS 1000.

http://www.carolenash.com/insidebikes/b ... a/gts1000/

Its stable a very controlled for a big bike but gets walked all over buy an Ohlins set-up or just a modern sports bike......... looks like we have the engineering oddity of telescopic forks for another few years yet just got to get them sorted!

[Demansia]

Nice timing Slarty, i'm not far away from tackling a front end rebuild with some progressive springs & will give your fix a go.
Any chance you have some pics of the spacers you used so i can try & match some up for the job?

I am also waiting on a Falco rear shock to arrive in the next few weeks, so i think i will do one first to gauge the difference & then implement the other to get a true feel for how each end has changed the overall handling.

This all gives me some motivation to go spend some cold nights out in the shed tinkering (we got down to 1 degree this week)

Chad

[slartybartfarst]

I think i need to draw this set up give me a couple of days and ill post here, no pics im afraid as my mate modded mine when i was out on his bike comparing.

[Bfef]

Looking forward to it......... If nowt else can you say what diameter the alu "polos" were inside dia and outside dia?
Thanks..............

[Ballacraine]

I used to be a "Suspension Luddite" LOL! I run an old Honda CB750 (1970) but I must say the front end is better than the Rap........however once Id ridden a modern sports bike that was it......it shifted my frame of reference.......still sceptical of such exotic items as Ohlins I rode an Ohlins equipped Aprillia factory...........Unreal! I totally agree if you want the best you gota pay the experts.

Im used to 70s bikes boinging around but the Rap was actually dangerous! Im happy when the suspension gives me the feedback to get a bike to the tyre edges.......I feel the suspension is at that level with these mods.

The other option is to do away with forks all together! I used to think this was the answer and I still regularly use a funny front end bike........ a Yam GTS 1000.

http://www.carolenash.com/insidebikes/b ... a/gts1000/

Its stable a very controlled for a big bike but gets walked all over buy an Ohlins set-up or just a modern sports bike......... looks like we have the engineering oddity of telescopic forks for another few years yet just got to get them sorted!

The fundamental problem is each equation of bike & rider is unique.
It is really not much use folk posting their settings as even with similar weight & build of rider, preferences & riding styles differ.

That said, I have had a mid spec. Ohlins equipped bike & it was very impressive.
Even this though, does need setting up to the individual rider's parameters.

I do find the standard set up on my low mileage V Raptor pretty good.
Not perfect, but far from being troublesome.

Nige.

[slartybartfarst]

Nige
Is yours the blue raptor V ive seen about in IOM??

I agree suspension set ups is a personal preference. What we have is 2 identical Raptors 25K miles with 12 to 13 stone riders having a walloping 40mm of suspension sag front and back before they are even sat on!

They stood near upright on the side stands ......overall ride height was too low.......as the side stand aint grown we suspected the boingy bits are at fault!.....I bet there are a few more bike out there like this.

What we are trying to do is to get the bikes to some kind of baseline, we then stand a chance of working from that to tweak the suspension for personal preference....we stand no chance if once sat on 50% of the suspension travel is used up before we start and the bike is hitting the deck on every corner!

We are not making harder suspension here quite the contrary it is supple by comparison to where they were.

As for an explanation why some bikes should be good I don't know all I know is our 2 were pretty hopeless (with the same problems) however.......the Manxton fork bike reacted like the fork was working way better and had a sensible sag.

May be Cagiva springs deteriorate at varying rates or owner pre load/weight settings take a lot out of the springs or even they fitted different springs intentionally/unintentionally over the production run or there was great variation between batches......we may never know.

Having replaced fork springs with Hagon progressives and rear shock (on my bike) with Hagon rear and ridden 2K miles still no major improvement was evident........ which is strange. I guess logicaly it leads to the the conclusion the Hagon springs are no stronger than the Raptors at 20K miles?

So rather than get caught up in a load of suspension spring rates that we can neither verify or measure we decided to apply a little common sense at little cost to what we got.

It seems that by hoiking up the front and back suspension around 25mm (triangles on the back spacers on the front) the bike returns to a usable stance. By using thinner oil in the forks the damping is more compliant. And by using a specific air gap in the front forks and the progressive springs bottoming out is sorted.

I suspect that the standard springs not Hagons will be fine but have not experimented with this yet and probably never will so I leave this up to others.

Ill post drawings of the bits/set-up tomorrow look forward to any feedback if anyone tries this mod.

[Ballacraine]

No, mines a fairly standard looking silver one.
It just has a Skidmarx screen & Titanium cans.

Yes, there is nothing worse than tired boingy bits. It can be downright dangerous if you run out of cornering clearance.

I can't pretend to be a suspension expert. It is really only a thing I look at if I am having serious problems.
At 10.5 stone I am a little lighter & my bike has 16,000miles on it, the first 15,000 of which look to have been fairly unsympathetic.
Being a shortarse I don't want to raise me little legs any further from terra firma, so I doubt I would go that route.
I do get the impression that the standard set up is not best quality though.
I have a Hagon to go on the rear when the time comes.
It is certainly puzzling that you didn't notice much in the way of improvement when fitting the Hagon bits though.

Nige.

[slartybartfarst]

Nige

I cant fault Hagon stuff or the service. I bought my bike with the Hagon fitted and during the swap of the triangles the shocker blew its guts out!!

Luckily Id just left it dangling from the top mount to get a brew seems like it was only the fact it was under compression in situe that was holding it together.

It must of gone with a hell of bang..... it dented my steel bike ramp!! Took me ages to find the other end other the far side on the garage.

Any thoughts of dissembling shockers myself to see how they work has been postponed indefinatly or at least till I want a quick way of putting the new skylight in the garage!!

A call to Hagons revealed a refurb at £90 needed. I explained I did not know the history of the bike and was fully expecting to pay but next day Hagons phoned me and said shock was done!! it appeared to be their problem and it would be in the post FOC!!

You just don't expect that nowadays. That's what I call good service, I promptly ordered a set of front springs to complete the package.

I have a Hagon on my Yam GTS as well with remote hydraulic adjuster I slipped that one into an old section of motorcycle inner tube to protect the seals before fitting as that bike is my 2 wheel pickup truck so dont get a lot of cleaning. I figured the that the rubber inner tube would not be so good on the rap as it would burn however my heat sheild works well so maybe in future ill cover up the shock.

See pics of the heat shield, its not very elegant just a big chuck of ally clamped to the rear exaust however it works real well, by luck its about the biggest size of flat you can wangle in. I was not sure if it would be effective as it does not sheild all the shocker but may be its also deflecting the hot air away, its certainly at the right place just on the bend of the exaust is hellishly hot after a a good thraiping...... whatever it works! I did not want to cook a new shocker.

In future i may make a more elegant version

Cool i can post pics at last! Ill get some drawings and pics of the suspension mods.

Oh yea you can see how high the preload is on the hagon, this gives about 5mm squat under no load.

[slartybartfarst]

Ah pictures.

Thanks to Rob at R&S Motorcycles in Leicester for the the triangles they don't just do tyres! I made my first set out of plain alloy 5mm and they were too soft so Mk 2 was stainless 5mm. Use Dural stainless or mild steel. You can simply use the origanals as a pattern and move the hole as shown. This jacks the rear end 25mm.

Drawings of the fork mod to follow

[slartybartfarst]

The drawings of the fork mod are attached. Sorry i don't have the full dimensions of the yellow spacer as I did not make them, I could get it if I stripped my forks but make them outside diameter of the plastic tubes and 2mm smaller than the internal diameter of the tubes on the inside.

I have simplified the mod in that there are now no "polos" on the top all the spacing is done by the bottom spacer now 20mm shown in yellow.

Again i cant remember the fork insides as my mod was done while i was away testing the other bike and it may be simpler to space down the top of the spring under the top damper rod nut or simply source sections of tube and replace the standard plastic spacers with 20mm longer items in, plastic, alloy, steel etc........but the ends have to be perpendicular so it would seem facing them off to length in a lathe would be the wise precaution.

The important thing is to get the spring compressed by the additional 20 mm and get the threads of the damper rod 13mm into the fork top nut.....I know the manual says 11mm but im just posting what we have done.....make your own decision on this one.....11mm would probably be advantageous but ive seen posts here saying theirs were in 17mm......this would limit fork travel.

And finally 5 weight oil filled to 100mm from the fork tube top with all spacers in place but no spring.

[Demansia]

Great drawings Slarty, now it all makes sense.

When i pull my forks apart i'll have a look at the plastic tubes, it could even be possible to replace these with aluminium tubes of equal diameters & add the 20mm length onto them instead. Will see when i get them apart, otherwise i have a mate that can machine me some spacers to your designs.

Will keep you posted, but at this stage it is going to be a few weeks before i get some spare time

Chad