Updated forks revisited

[Bitza]

Hi All, Just thought I'd drop a thread to update on some mods I've completed and to thank those (Gazza was one) that offered some advice.

The bike was originally a 1994 M900 now with an injection engine, a 750 rear wheel with 160/60 Bridgestone Battleaxe 061's with a 120/60 front, Ohlins rear shock and 2000 M900 Sie forks. I knew I had problems with the bike's handling but wasn't sure what the cause was, it was very reluctant to turn into corners although exited quite well, the suspension was very harsh over bumps particularly rumble strips. Attempts to date to cure the problem up to that point had been via suspension adjustments which improved matters but certainly didn't cure anything.

Most recent mods have been to extend the rear suspension hoop by 20mm (with some nice stainless rose joints), and fitting a pair of Michelin Pilot Power 2ct's 160/60 rear & 120/70 front. The results are fantastic, its transformed the bike happy times! It now falls into corners and is so light and the suspension is behaving itself too although probably could be improved. Another bonus is that the comparative light weight of the Michelin tyres gives you the type of advantages you get with lighter wheels i.e. better acceleration/braking and quicker in changing direction.

Thanks again for the help and moral support, Bitza.

[Flip]

Good to hear you have got the handling on it's way to being sorted, can you please tell me what forks you have fitted and how many millimetres they are pulled through the yokes?

I ask as I have set my bike up exactly as I had it with Pirelli Dragon Evo's fitted but since fitting Michelin Pilot 3's they have slowed the steering down horribly making it feel like the front in underinflated, especially at low speed like when filtering through traffic- not a nice feeling!

[Nickj]

Raising the rear has effectively reduced the steering angle, remember some of the old 748's and others had adjustable head stocks so you could steepen the angle for track use.
Dropping the forks on the yokes does a similar thing.

Tyres.. don't you either love or hate them ! Some of us will remember the days when Avon SkidMasters ruled the earth, wasn't it a revelation when you switched out to TT100 or 110's. Suddenly the adrenaline burst in fast corners wasn't about the tyres wandering all over the place :eek:
Now tyres are actually uniformly good but as always some are better than others, but they still remain a bit of a personal feel thing... so may varients in compound and carcass flex.
I think the monster frame is fairly flexy so I like a soft silica rich compound and a bit of sidewall flex to give a 'soft' ride feel.

[Mr Gazza]

Really pleased that you have things sorted now and I'm glad you think I helped in some way, but I am far from an expert when it comes to Motorcycle Dynamics.

On the last ride out that I had, I wondered if there was something wrong with my bike.
I seemed to be having trouble turning it in and then holding the line I wanted...Not great for my confidence.

Absolutely nothing has changed on the bike ..I even checked the tyre pressures before the ride.

Now it was rather a chilly ride and quite a long one too. I have been hosting a horrid background cold and also suffering from aches and pains from all sorts of little muscle pulls and general end of Winter knackeredness.!! ( Oh yes my Doctor has got me on some extra strong placebos for my hyperchondria..:chuckle:)

When I feel like that, the cold makes me tense up and muscles go into spasm much easier...My body just doesn't work as it should. it all leads to misinterpreting feedback from the bike and making the wrong responses. Anxiety goes up and riding becomes worse.!

It's only natural to blame the bike for bad handling. But on a warm day with a full belly and maybe a half a pint of fine ale inside.The reverse is true, perhaps that might even instill over confidence?

I think that a very high percentage of how your bike feels is perceptual and not measurable?

You mentioned new tyres...Now you can't beat that new tyres feel can you....Placebo effect I wonder??

It would be interesting to see if a rider would report better handling on his bike if it were to be taken into a tyre depot for new tyres, but only had the old tyres cleaned.?

I reckon it's all in the mind....We have ways and means of making you think....:chuckle:

[Flip]

Raising the rear has effectively reduced the steering angle, remember some of the old 748's and others had adjustable head stocks so you could steepen the angle for track use.
Dropping the forks on the yokes does a similar thing.

Yes I get all that, I raised the rear of the bike years ago to overcome it's horrendous understeer wanting to push wide and have the forks through four lines showing which is the standard setting for the Marzocchis on a '97 bike.

The other things since swapping the tyre have been getting the rear Nitron shock serviced and having the forks converted by Maxton- both which have made a fantastic improvement over how it was but the Michelins have made slow speed manoeuvrability feel sluggish and somewhat vague- like as I said, that it is underinflated all the time.

[DrD]

Out yesterday bedding in new Rosso Diablo II
Amazing difference going to 170/60 from 180/55 on the rear has made.

[Flip]

Yes I can agree that the standard 170 section rear works a lot better than a 180- or at least the two 900's I have ridden with 180's fitted both felt horrible compared to my 170 shod bike.

[Bitza]

Thanks for the comments all.

Flip, the forks are off a M900 Sie, i.e. Showa fully adjustable with 65mm caliper bolts, I've got them set 15mm through the top yolk, however you obviously need to bear in mind the 20mm extension of the suspension hoop and the fact that I use the narrow rear wheel with a 160/60 rear tyre (by my understanding a 180/60 tyre gives a height of 108, 180/55=99, 170/60=102 & 160/60=96).

I'm sure the greatest benefit from my recent mods has been getting rid of the 120/60 front and reverting to a 120/70. I know that I should only change one thing at a time so I know what effect it has had but somehow it never works out that way and is of course how I ended with the original problem in the first place!

Lastly if you like a 170 rear over a 180 (and have say less than 90bhp to harness) then I would certainly recommend trying a narrower rear wheel and a 160/60.

Have a great summer's riding all, Bitza.

[Flip]

Thanks for the comments all.

Flip, the forks are off a M900 Sie, i.e. Showa fully adjustable with 65mm caliper bolts, I've got them set 15mm through the top yolk, however you obviously need to bear in mind the 20mm extension of the suspension hoop and the fact that I use the narrow rear wheel with a 160/60 rear tyre (by my understanding a 180/60 tyre gives a height of 108, 180/55=99, 170/60=102 & 160/60=96).

I'm sure the greatest benefit from my recent mods has been getting rid of the 120/60 front and reverting to a 120/70. I know that I should only change one thing at a time so I know what effect it has had but somehow it never works out that way and is of course how I ended with the original problem in the first place!

Lastly if you like a 170 rear over a 180 (and have say less than 90bhp to harness) then I would certainly recommend trying a narrower rear wheel and a 160/60.

Have a great summer's riding all, Bitza.

I know what you mean about changing more than one thing at a time- I was in a similar situation last year when I did a bit of a re-fresh on my 900. I had the forks reworked by Maxton along with a service on the rear Nitron but due to me running out of time before a whizz round Europe I had to put new tyres on too and after some deliberation plumped for the Michelins as everyone was raving about them.

I kept all my original settings the same i.e: forks through the same amount and rose joints turned out the rear hoop 32mm from the edge of the hoop to the centre of the joint.

Initially when I rode it for the first time I noticed how the Michelins gripped and felt very confidence inspiring but while on my trip away the first time I was filtering I had to pull over as the front just felt horrible and heavy making it really hard work. That feeling continued onto low speed mini round-a-bouts and the like.

I thought I would get used to it and put it down to the extra grip of the Michelins but after a couple of thousand miles the feelings continue to bug me and so I am now going to try raising the rear a little more.

A while back Rich at Louigi Moto sent me a couple of his risers which I have resisted fitting as they are quite extreme and the rose joint thread needs to be shorted for them to screw in but I will have a play and see where it goes.

If I still had my old Pirelli Dragon Evo's I would pop them back on just to try but I chucked them rather annoyingly.

I don't see swapping the rear wheel for the smaller bikes narrower rim as I was completely happy with the handling before the tyre swap- I may just have to bite the bullet and buy another pair of Pirelli's!!