Triumphrat

Tona94 · 10-19-2009, 10:04 AM

Hi, am rebuilding the forks of my 94 Daytona 1200. I live in southern Portugal and am asking for feed back re using SAE 10 rather than the SAE 5 recommended for use in the UK. It stays warm here with temps in the summer getting up to 30c/35c, with averages like southern California/northern Mexico. What are your thoughts.

Nobeard · 10-19-2009, 11:28 AM

Best reply I can give you is that the w number doesn't have much to do with temp range for suspension oils. Go to this link http://www.peterverdonedesigns.com/lowspeed.htm for much more in depth info - very mathematical in places but some good explanations too

Tona94 · 10-19-2009, 02:51 PM

Nobeard, thanx for that link, most informative (uni physics does come in handy from time to time).

Most of the brands that Peter mentions are not available locally and no Triumph dealer within 200 miles

Will go with the best grade 5 that I can find. Tx again

JohnD · 10-24-2009, 04:09 PM

Didn't see this thread at first as I usually stay over in "Daytona Deliberations" section.

That was an interesting site that Nobeard posted. My brain is still recovering.

Short answer from me is that you will do better with a slightly heavier oil like 10W as the stock D12 suspension is overly soft (IMO). However, that still is not like putting in progressive springs.

Longer answer is that since you are rebuilding, why not do yourself a favor and put in Racetech springs with Gold Valves (with Racetech oil) for the front, and a Hagon shock for the rear. I did this about three years ago and it really makes for a big improvement in control with NO loss in compliance. Here is a post of mine from about that time:

I have a 1999 Daytona 1200. I was unhappy with the OEM suspension and was looking for improvements in dive, squat and feedback. The 1200 weighs 495 lbs. so this is part of the problem, but maybe what I did will assist you in your search for improved handling for your 955i.

I replaced the front forks with Race Tech forks and Gold Valves. See www.racetech.com The rear stock shock I replaced with a Hagon unit. See www.DaveQuinnMotorcycles.com who is the importer for Hagon (from Britain)

Results were excellent for the 1200. Less dive, squat, better feedback. Makes a big bike handle well. Total cost parts, labor and tax was $1,203.79. Work was done Dec. 1, 2006

Following is a link to a thread about D12 suspension improvements. DaytonaCharlie made the same changes as I did, but later he replaced the Hagon rear shock with a multi-adjustable Penski unit, which he loves.

http://www.triumphrat.net/daytona-de...on-advice.html

These changes are certainly not cheap, but if you are doing your own work, the cost is considerably less. If you can do only one of the two, do the front end first.

Racetech is located in California, but have a center in Valencia, Spain (see the Racetech internet site):
http://www.racetech.com/page.aspx?id=19&menuid=82

Hagon is made in England and have several European distributers:
http://www.hagon-shocks.co.uk/wdeurope.htm

Penski in also in England (U.K.):
http://www.penskeshocks.co.uk/motorc...oadracedamper/

I know this is quite a bit more than just changing fork oil, but this gives you a more comprehensive list of choices regarding upgrading the D12 suspension. Good luck.

faffi · 10-24-2009, 05:05 PM

In my opinion, the stock Daytona fork - I presume the 900 share the fork with the 1200 - has too much damping and pretty good springs. It was more than firm enough when used on the Daytona, and now that I have fitted it to my Thunderbird/Daytona hybrid I have tried to soften it further and find it still too stiff.

I currently use 2.5W oil and have backed off both rebound and compression to their minimum settings. Spring preload is also set to minimum. I have also dropped the oil level from the stock 132mm to 150mm measured from the top. Dive during braking feels well controlled. Static sag with the bike only and with me are pretty close to ideal (I'm 210 lb in my undies). The fork has never bottomed, even when braking hard over rough surfaces.

I'd like less compression damping still for more compliance. Rebound feels borderline, but for control it probably shouldn't be softened more.

When CW tested the 1995 model (which I believe has a slightly different fork from my 1993???) they said the fork had a bit too much rebound damping even at the minium settings.

All that said, people differ in what they want from a fork. For instance, the old Kawasaki Z400 twin had entirely too much compression damping and too little rebound, yet many owners filled thick oil to control front end dive under braking and were happy with that. Myself, I drilled out the compression damping holes to 1/4in and used thicker oil than stock - this gave me more rebound and less compression than stock for a very comfortable, yet controlled front end.

To control dive, I upped the oil level 20 mm from stock for a much more progressive spring action.

In my opinion, springing is what should control dive, not damping. Especially on non-cartridge forks that lack the ability to separate between low and high speed damping. This is where the RaceTech valve comes in by simulating a cartridge fork.

JohnD - did you fit the RaceTech fork kit yourself? I'd be interested in how you reduced the compression damping (a vital part of the kit - the valve then controls low speed compression damping [like you have under braking] but 'blows off its seat' under high speed damping situation [when hitting a sharp bump] for compliance).

JohnD · 10-24-2009, 07:35 PM

faffi,

I can't recall my set-up and I am up north right now and won't be back in Florida (where my D12 is) until mid-December, so I can not take a look at the bike.

I had the work done three years ago by my local Triumph dealer (you see that I include labor charges in the cost) and the mechanic is, by chance, the same weight as me and almost as tall. I'm 6'4' (1.93m) and 185 lbs. (84 kg.) So since he is the expert, I let him make the adjustments and they seemed to be spot on for me. Without getting into the exact adjustments (since I can not remember them now), I can only offer my impressions.

In the stock set-up, I had a lot of dive on braking, a lot of rise on hard acceleration (in the lower gears it almost felt like the front end was coming up). In curves the bike felt a little uncertain, without a lot of feedback. Compliance was good. I discussed, with the dealer, making changes to the stock forks, including weight of the oil, spacers etc. The dealership felt that it could be improved, but that it would never approach the results that RaceTech could provide.

After the Racetech installation (springs and Gold Valves) the former dive under braking and rise on acceleration were very much reduced. Feedback and stability were enhanced. Now I felt in control, with the abillity to brake and accelerate without losing stability. My confidence rose.

Before the installation I had been worried that the result would be a hard feeling suspension - that compliance would be lost. The amazing thing is that the suspension is just as compliant - bumps in the road for example are absorbed as well, or better, than when stock. So I lost nothing and gained a lot.

I remind you that I changed the rear shock to a Hagon at the same time, so some of the improvement lies here too. The Penski shock would make things even better. I also used the Racetech oil which is ordered seperately, if you want that.

Maybe, I sound like an advertisment, but others who have made similar changes seem to be equally pleased with the improvements.

Sorry again that I can not give you my exact set-up at this time. I agree with you that springing is best for dive control and I think that progressive springs (as in Racetech) provide this.

Tona94 · 10-25-2009, 06:27 AM

JohnD and Faffi. Big thanx for your info. My 94 D12 has progressive springs, I put in 10W, but as Nobeard indicated, weight depends on the manufacture. Oil to 132mm. Wheels are out for a week to powder coat, so will fine tune at that time, Tx again

faffi · 10-25-2009, 08:15 AM

Thanks, JohnD. Yes, the benefit of RaceTech valving is just that; they can increase both comfort AND control. Stiffer springs nullifies the comfort gains from the damping improvements, but increase control.

Glad you are happy with your bike

JohnD · 10-25-2009, 09:14 AM

Tona94,

When you are finished with your rebuild, post some photos. I am curious as to how your wheels look after the powdercoat (rest of the bike as well). I suspect you don't have to ride far to find a few curves in Portugal.

Tona94 · 10-27-2009, 09:49 AM

JohnD, I moved from California to Portugal via the UK in 88. Lots has changed here, road wise. I live on the Algarve and am blessed with fine weather and lack of traffic all year round. The local culture re 2 wheels is still a bit stressed, so I ride as though I am invisible. Just had the SBK in Portimão (our new local track) and with the MotoGP in Estoril the awareness in changing. 3 hours into Spain and the Ronda to Marbella run. Thankx for your info, will post photos.