It was the bikes maiden voyage on track this weekend, 1000 bikes festival at Mallory park (UK)
It all went OK, no bits fell off.
But as I picked up speed throughout the day I find after heavy brakeing I get a shudder on the front that seems to set up
a fore and aft patter as its tiped in to the corner that continues untill i exit on to the straight or slow right down for the next corner.
, but only on the longer fast corner like Gerrards for those who know the circuit.
Its allmost like both wheels are out of ballance fine on the straights ?
First thought it was the track but its the same on outher fast corners, the M1Rs on the front seem stiff I have 10w oil in them, rear is a Nitron shock set to my weight and the bikes, Is it posible its front too hard against a softer rear ?
Must say never ridden anything that take the hairpins like this ! I hate them now I can actualy pass bikes in the realy tight stuff.
Any sugestions from any one, ?
Havent had a chance yet to check the bike over but sure its ok and nothing loose.

Hi Auburn,
So waiting to get my bike on the track too!
Could it be your brake discs that are warped? Also, are your rims painted behind the discs? That can have an effect on the discs. Any suspension issues would present itself along a straight as well as corners.
Are your rotors solid? I should have asked this first!
Good luck.
Cheers,
Steve

Hi New discs, and pads, EBC floaters, rims newly painted but nothing behind the discs,
will check for any run out when it goes back on the lift,

Start with checking your steering head bearing adjustment. If the bike was just assembled and new races/painted frame/new bearings etc. it can take some actual use before everything settles in. There is also a tendency to leave the initial preload a bit light and that is shudder inducing clearance. Its hard to explain but I adjust the bearings so the steering feels sort of like stirring thickish paint. Smooth and fluid, should just fall to one side or the other with a nudge but not clank on the steering stop.
Also check if the forks are binding. Loosen the axle, hold the brakes on and bounce the front end a few times to center it and snug it up with the brakes still on. Loosen the fender mounts too, I've had the legs bind because it was assembled and tightened before the wheel was installed.

I've had tires cause a chatter [mostly on slicks] from too much compression damping, too much air pressure, and not going fast enough. Next time on track see if rolling on the throttle reduces or eliminates the shudder. Sometimes it can come from the other end of the bike too so you will need to play with thing next time out.

i'd put 5 weight in the rh leg. have they been sprung to suit?

They still have the paso springs in, maybe to firm ?

find out what the rate is.

just droped the fork oil out there was still pressure behind it when i took out the drain plug,
will refill with 5 w
cant find anything else amiss , the bike on level ground allways looks a little front end up ?

As mentioned by others, check the bearings etc as they do make a difference, but really you would notice them in the paddock as you ride it around/ take it to scrutineering.

First thing about ANY bike is set the sag. This gives the bike its balance so to speak as its only the springs holding it and you up in corners, if its too soft at one end then this is how the bike will sit...but there are other things that can affect it too.

You say your bike is set high in the front? What should it sit like? Is everyone elses bike right? His looks different to mine? Questions that haunt more than one racer! I use this method to get a base setting....especially on a bike that you may have no experience with or is a new build.

For setting the front stance, see how much travel you have on full fork extension (take the springs out and let it down) and set it so it is about 10 or 15mm from hitting the underside of the yoke.
For the rear, imagine a straight line from the rear wheel spindle, through the swingarm spindle and follow it up to the front. This wants to just come up to the top of the front tyre or just below it, a piece of straight bar will do for this - just make sure its not bent!
How do I know this is right? I dont, but you have to start somewhere and the swingarm angle if you do that is about right (11-12 degree or so). From here on in, this is your Ref ride height.

Im not at the workshop so this is from memory, but here are my sag levels for my F1. I weight 78kg.
Total fork travel = 115mm
Front (9.25 springs)
Static 20mm
Rider 30mm- 35mm
Rear
Static 0mm
Rider 25mm
I work with +-3mm on the rear, and use +- 5mm on the front end, I can tell a difference if I wind on more or less preload outside these figures but in genaral I dont touch the rear and only change the front for different circuits.

If you have to wind on more than 15mm preload on the rear spring from free lenght (measure the spring lenght when its off the shock) to achieve the ride sag, then it is too soft so get a harder spring...similarly if you have only 5mm preload and achieve them the spring will be too hard. 10mm is the normal preload.
I have no idea on the M1R forks, Ive never even seen a pair but I would guess the springs (if standard) would be too soft. Even an R6 only has 8.5 springs in and most older bikes much less than that. I could be wrong though, they could be way too stiff but I doubt they will be.

Now for the damping...this is where it gets interesting.

Front
Too much compression: This will keep the front high mid corner, taking much needed weight off the front. Remember, we can only adjust low speed compression (if adjustment is available) unless you have ultra-high end forks or are prepared to change the shim stacks (if any). Brilliant under hard braking or if you are a hard braker in general but the rest of the bike must be set accordingly.

Too little compression: Will tend to dive on the brakes, but will load up the front better mid corner. Because it dives so much, you get large weight transfer on the front and you may run wide on the way in to turns as it pushes. You may also get some speed wobbles down fast straights and the bike will pitch too much through chicanes.

Too much rebound: Will put weight on the front as it packs itself down mid corner, you will also be in danger of running out of travel trail-braking. Front will feel skittish as the tyre cannot follow the bumps on the road, but in general will not cause pattering.

Too little rebound: The bike will sit high mid corner as there is no damping control to stop the spring extending the fork. It will also cause the tyre to return too quickly to the road after a bump and the G Force of you and teh bike pressing down as well will cause a pattering as the tyre slips and slides, loads and unloads.

Rear
Too much compression: Not a cause of pattering, but will tend to push the front. You will also lose a bit of traction on hard power exits. If you are ripping tyres up with big bands, then look at this.

Too little compression: Will cause the rear to sit down mid corner, taking weight off the front and push the bike wide. Running wide on exits is also a result of the bike squating too much.

Too much rebound: Again, will make the bike sit down on the rear pushing the front and taking weight off. Mid corner, it can pack down the rear especially on long corners making the problem worse. Runs wide on exits, and makes the front feel light changing direction.

Too little rebound: Like too little in the front, the tyre cannot follow the bumps and can cause pattering as the rear loads and unloads. May also push the front as the bike will tend to sit higher in the rear as the shock is allowed to extend a bit more mid corner. If you get pattering with too little rebound, sometimes it will stop as you get back on the power.

High Speed Compression (shim stacks) wont cause pattering but you can notice it over bumps mid corner.

Now Gerrards is a smooth corner these days, but is a perfect corner to see if the bike is set right. It sounds to me like either your bike is too high in the front, too low in the rear, or too much rear rebound or too little front rebound..or a combination of all four which result in sever pattering at a much lower pace.

What was it like through the right hander after Edwinas? This is a corner that requires hard acceleration as you are pretty much on the stop and you are compressing the bike through the first RH turn..if it is too soft in the rear you will run wide here but also the front will feel very light. Similarly, on the exit of the Bus Stop, did you have to wait for it to settle before you got on the power through Devils Elbow?

Wow thanks for this info, I will check everything i can and will book a track day ASAP,
we did the old mallory with no edwinas no bus stop.
Did seem to run wide at devils elbow , hairpin excelent, patter going in to gerrards seem to be started by heavy braking ?
at the final session as I was picking up a bit started to get the same feeling brakeing hard for the esses but it shows up more on gerrards. It dose feel light on the front exiting the hairpin heading for the elbow.
I will gothrough everything hope to get it sorted for Donnington on the 11 Aug.
much apreciated information Thanks,