Handling & Suspension 2004-2008

I reckon angle somewhere between 26 and 30 degrees, 30 for me 26 for you

even with 50mm extension its front heavy, the engines weight is well forward in the cases

depends what you're doing though weight on the front be good for this stuff there is a berg in there

flat ground and nice hard wet sand

[youtube:w7a6c9hf]http://www.youtube.com/watch?v=54UNvp4VEU0&feature=related[/youtube:w7a6c9hf]

[youtube:w7a6c9hf]http://www.youtube.com/watch?v=ySH_Lj2U4-g[/youtube:w7a6c9hf]

when there are no whoops or soft stuff the stock chassis is quite good like you say sooo much front grip. thing is though its gained by weighting the front with the chassis layout rather than trail which must work great sometimes but in loose dirt all it is is dead weight masking the real issue being that trail is lacking for sand and you can't lift the front easily to get the trail back or stop the front digging in because of the weight.

I could keep the angle I have and make zero offset tripples but I like the feel of a raked out bike becasue generally they don't blow through the stroke as bad when it counts and with a 30 deg rake I need the stock tripples to get 150-160mm trail.

the steeper the forks though the less the trail is reduced when they dive

complicated stuff and more interesting than shims for sure

Man that looks like fun, Bushie!
I used to ride my own little makeshift oval here back in the '80s (when you were still allowed to ride on the beach) on my '82 XR500R. Just pick a spot where nobody was, and start riding in circles. lol. Used to ride wheelies up and down the hard pack forever on that thing. Pick it up in 1st or 2nd, go through the gears and ride the rear wheel until the wind coming off the Pacific blew me sideways or I ran out of power.
Thanks for bringing back some good memories...

Can you have to much weight on the front?

I have my forks sticking 7mm from the triples a big tank and I'm a heavy rider 115 KG and i shred every front Tyre i use.
I'm now using Metzeler MC5 intermediate and the side knobs are starting to tear off.
The only time I'm confident with the front is on tarmac and there it turns well but off road its not so good unless
there is a berm or a rut to use.
Next time i go riding i will try the forks on the first line.

0.49kg front springs and in the rear Racetech SRSP 6326 P30
static sag about 32mm haven't been able to measure rider sag due to no helpers but should be around 100 mm

Regards
Hilmar

Hilmar it might be that the seat tank layout is nicer with the front lower and yes more weight on the front but the at the same time trail is reduced

those offset adjustments you're going to play with should help find out. problem is though reducing the offset to increase trail also moves the front wheel back and it gets even more weight so it may not be ideal.

you could try dropping the rear raising the front and taping a plank of foam to the seat to increase trail and still have a nice seat setup its only small changes though you need to lower the rear about 200mm to change the rake by a degree.

I don't think that there is too much weight on the front for every situation .. just for mine

for that kind of flat beach racing you could run a 100mm longer swingarm on the stock 08 chassis and still not have too much weight on the front and then you could easy do with a 19 paddle rear and about 160 HP. if they put in another section in the softer sand and some jumps/ whoops you would be better off with a 100mm steeriing head extension.

you could go too far though there are a few roadbikes in there if you follow the links on the side of youtube, short bikes with high front wheel loading, very steep forks small diam wheels and not much trail, they look very hard to ride even on that nice surface

Brucifier the vids above are AFAIK of Australias only currently running beach race near Mackay in QLD. Mick Hansen has won it for the last umpteen years on a methanol CR500, lightweight rider on a light weight bike with around 90 HP. There used to be a beach race here but it got abandoned for being too hard to organise with insurance etc.

The Aust safari finishes on the beach here this year so we get to see some Bergs at WOT in the sand. its a great sight, there used to be 2 here mine and another but the other was allways broken or on fire :twisted:

I'm currently out at Sea on fishing vessel as 2nd Engineer wont be back on dry land until 26 of September.
Then the E axle should be here and then i will experiment with fork height and the offset.

It also could be wrong Tyre selection on my part the terrain is so variable that i ride on.
Hard, sand, rocks, gravel, soft. but its mostly hard, rocks and gravel.
The gravel can be fluffy volcano rocks and sand with rocks of all sizes inn it.
I will test pirelli MT16 next.

just to throw into the equation bushie:

it's a 400 which is lighter and lower than your lump. grip "appears" to have increased considerably with the forks raised in the 18mm TCs.

it's also made the forks bottom out too easily IMHO and I'm working hard to stop this.

I have fought for 3 years with 22s and I'm not going back now. the factory boys ran them. that or 17s i guess.

my problem is whether half this has been based around one fork spring too hard? 48s and i'm 95KG. the 48s could be the reason i'm in this muck or the reason It's going well.

you need to go back to the 2000 to 2004 chassis mate?

regards

Taffy

Taffy said:

just to throw into the equation bushie:

it's a 400 which is lighter and lower than your lump. grip "appears" to have increased considerably with the forks raised in the 18mm TCs.

it's also made the forks bottom out too easily IMHO and I'm working hard to stop this.

I have fought for 3 years with 22s and I'm not going back now. the factory boys ran them. that or 17s i guess.

my problem is whether half this has been based around one fork spring too hard? 48s and i'm 95KG. the 48s could be the reason i'm in this muck or the reason It's going well.

you need to go back to the 2000 to 2004 chassis mate?

regards

Taffy

Click to expand...

hey its 2010 Im making my own

the 2000 -2004 should be an improvement for what I want but with the same wheelbase its still going to have a high front wheel loading and the engine still 60mm higher up than is possible.

Weeds lowered his and loves it

Re your 400 Taffy hey if it works for you thats what counts. the beauty of playing around with this stuff is to get to understand chassis design to a point where you can ride one and then cut it up and tailor it to your liking

yeh well I chopped ddown my subframe 6 years ago, did some birdshit welding and splodged red oxide all over it....not impressed - even with myself

It's becoming clearer everyday why they stretched the frame....

only been back on the scene a month and up to my eyes in it. with this eccentric eye for the rear maybe I can lower the rear of the bike? I should also mention that I have 1" bar risers on mine taking more weight off the front.

trouble is that everytime i've taken weight off the front I've lost grip in the past....

regards

Taffy

Whats the 400 engine weigh Taffy?

only a coupla kilos less than yours but all that extra weight is in the crank and rod and in the meantime the head and piston carb etc are over an inch higher.

regards

Taffy

yes its a weird concept having all the different engine sizes with the same chassis and even the same suspension springs and valving

heres more beach stuff, Wanted to post a link to this this earlier but couldn't find it

the commentary is gold :cheers: :cheers:

Hansens corner speed is shocking in this clip he was riding injured. didn't matter, won anyway hes hitting 200km/hr on the straights.

[youtube4tz3sb2]http://www.youtube.com/watch?v=4mwh3TaDYRg&feature=related[/youtube4tz3sb2]

Yeah, nice commentary. lol.
Was that a 'berg in second?
The guy on the inline four's pretty nuts.

yes its a berg in second.

orrite new frame is jigged up I think its right to weld it 8O

30 degrees rake, trail is hard to measure but somewhere between 145 and 155mm, wheelbase 1570mm so I've got enough room to reduce the front wheel offset by 10mm and ground clearence about 315mm instead of 380mm stock.

bushmechanic said:

yes its a berg in second.

Click to expand...

Was it you riding Bushie?

bushmechanic said:

orrite new frame is jigged up I think its right to weld it 8O

Click to expand...

Will you post a photo or two?
Regards,
Davo

Nah that berg is all shiny and stuff definately not me

pics when I get the camera working it looks a bit like the pic in my gallery suziberg geometry wise and like a murder scene aesthetically

frame taking place slowly, not enough spare time but need to ride

to get more trail the easy way I put a 5mm lowering spacer in the shock (15mm lower back end) and plumbed a T line into the fork bleeders, minimum oil level and 5psi pressure.

front end works good, its better but still needs more trail and the flatter swingarm angle ive got now really really sucks for traction and brake jack ie its got none compared to before.

so the miniumum swingarm pivot point height for me is about 450mm, less than that and its too much like a flat tracker.

well I just measured mine at 460mm to the centre of the pin although the footrests get in the way. is that really the best way to tell? dropped forks and worn knobblies make a difference surely?

you need to raise the swing arm mount with eccentric crankcase spacers like the ones I had made. also, lower the front of the engine perhaps? option one is mechanically better.

regards

Taffy

sounds right Taffy about 460 is stock

my "new" frame has the engine tipped over so the swingarm is 450 off the ground and the ground clearance at the front is 315mm.


all kinds of ways to measure this stuff, wheels off the ground or under the bikes own weight. doesn't mater as long as its relative.

you'd think dropping the back and making the forks stiffer would make it harder to turn hey? Ive just been carving 2 foot inside the tightest lines I could hold yesterday... increase in trail

well I don't get that (reason)?

but then I discovered that the (your) turning can be better at medium high speeds and then turn up at a barrel and watch the front plough a furrow.

regards

Taffy

no barrels here, they blow away when the rums all drained out :twisted:

what gears a slow corner for you taffy ? I use 3rd minimum and thats with 16/40

yesterday i was comming into corners with near full lock on ploughing a furrow while today there was no need. she just tracks so nicely with more trail.

the other things to consider are the soft sand and forward weight transfer in 2-3ft whoops, you need more trail in these conditions becasue the front tyre digs in reducing trail and the bike is often taking all the weight on the front when you want to be on the throttle.

more trail means more grip and less slip angle on the front wheel required to turn. in the sand the less slip the less the wheel digs in so as long as you can stay on top of the sand you don't have to plough through it. less weight on the front, and anything to increase trail generally means sharper steering in soft sand. I know that sounds back to front 8O on a harder surface you can increase the front wheel loading and reduce trail and reduce the effort required to turn.

Im sure it works in your conditions but your bike would be a handful on my track.