Handling & Suspension 2004-2008

well i don't ride that really fluffy sand much.

I have loaded the front wheel by increasing the trail and reducing the offset by4mm this loaded the front nicely and lead to the ability to drop nicely into corners so everything you say is true but it also allowed me to change the gearing I've had for 8 years for the first time and still hit those berms. so 51 x 15 became 50 x 15 and quite frankly I may even go one more because hitting those berms was killing me while corner exit grip could have almost done with me cogging it up. so I'm looking at 49 x 15 maybe soon and the 8mm that the wheel went back could become a further 8mm.

now that means the front wheel has come back 4mm and the rear wheel has gone back 8mm and could be 16mm. I'll deal with each thing as it comes in order of priority but clearly the forks are dipping nicely on the corners, grip is the best ever but I'm bottoming out heavily in a straight line due to the full travel now becoming full travel and a whallop....

I'm happy with the steering head angle at present and the trail and rake etc. that doesn't mean the balance of weight is right though does it!

so onwards and upwards.

thing is when you do these things: was it the trail or the balance of weight changing that helped?

regards

Taffy

dropping the rear moves weight back and increases trail. so for sand a ++

reducing offset increases trail and put more weight on the front. so for hardpack again a ++

not bike specific but staying on top of the soft stuff looks important at 45 - 50 seconds

[youtube:1pcss88x]http://www.youtube.com/watch?v=KDp4AwW6gaw&feature=related[/youtube:1pcss88x]

A you found a video of Icelandic Formula off road.
Fun sport especially if you are a Power Freak :rock:

Maybe my problem with the bike setup I'm setting it to much for Harpack when i should sett it more in between Hard and soft.
its about 50:50 soft hard that i ride, sometimes more or less.

Regards

Damon

why don't you put a 5mm spacer in the rear shock? that would kick out the front end off leaps and stuff I guess and stood still! change all your ride height numbers too I guess.....

regards

Taffy

great idea ! post event 8O

ill just get json to send me a flux capacitor from his bigwheel so i can time travel to last week

as part of the stuff i'm doing I have been looking up wheelbase lengths and I'm / you're in for a surprise bushie!

I read TBM fore this month and they have a Reiju (wr450 engine) on test and they mention wheelbase lengths and this is what they have:

Reiju 450 = 1485mm
yam wr450 = 1500
rmx450 = 1480
ktm 450 = 1485

my husaberg = 1460

that's 40mm less than the yam!

I haven't got balance factors for these bikes but at a guess mine is now very front heavy and I can now see why the factory went to a forward extended headstock.

my next muddled question would be: so what happens if you extend the headstock forwards 15mm or if it were 20mm forwards at the front and the rear wheel can go back 10mm?

do I get all my steering problems back?

regards

Taffy

98 yz400 1520mm wheelbase, 295mm ground clearence, output shaft and swingarm pivot 45mm higher than the crank centre!

the interesting bit is when you measure from the front wheel axle to the crank centre, then you need 50mm extension at the head.

not sure how all the weight distribution works out in practice, in theory yes move the front wheel forward then move the rear back, you should get the same net result as not doing anything.

its never that simple though

Taffy said:

as part of the stuff i'm doing I have been looking up wheelbase lengths and I'm / you're in for a surprise bushie!

I read TBM fore this month and they have a Reiju (wr450 engine) on test and they mention wheelbase lengths and this is what they have:

Reiju 450 = 1485mm
yam wr450 = 1500
rmx450 = 1480
ktm 450 = 1485

my husaberg = 1460

that's 40mm less than the yam!

I haven't got balance factors for these bikes but at a guess mine is now very front heavy and I can now see why the factory went to a forward extended headstock.

my next muddled question would be: so what happens if you extend the headstock forwards 15mm or if it were 20mm forwards at the front and the rear wheel can go back 10mm?

do I get all my steering problems back?

regards

Taffy

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A little bit off topic, but indulge me, I'm an old fart now. Taffy's effort here reminds me of the fun I had in the late 1970s up to about 1981, 30 odd years ago. Researched all the specs I could from magazines and came up with some numbers and a bit like Bushie is doing, cut up my stock frame and built a new one around the motor. It was a bit of a rehab project for me having smashed myself up road racing in 1976.

I dug around and found a page in the photo album, all I've got.

From memory, the forks are Ceriani and the front brake is a Suzuki. The headlight is a Cibie Biode, it has 2 100w QI bulbs for roo spotting. The pipes were cut up Dunstalls, the oil cooler a Hayden, the rear shocks were S&W and the swingarm was cut up and the bushes replaced with tapered bearings. The frame cradle was removed and the engine just hangs. The tank is aluminum pop riveted to the built up frame and sealed with KREEM. This means that to do the valves meant the engine had to be dropped, which actually wasn't too hard. So a monococque frame, built by me, in my first shed.

The engine had 750 carbs, Yoshi Daytona cam and (dual?) valve springs, the head was ported by Ross Hannan, it had Yosh duraluminium rods, cut up 750 pistons for about 600cc, a close ratio Yosh gear box, and a special one off kick start idler gear because the electric start wouldn't crank it over, and was too heavy anyway.

I bought any oxy set and stick welder and taught myself to weld for this project. It ended up painted blue and was very effective, but by then it was time to move on. Marriage, a GPZ1100B2, a car, more study, building a house....... memories.

The one lesson I did learn was that to have your only mode of transport and your project one and the same doesn't really work.

Good luck with the cutting and shutting.

Steve

those pictures are gold Steve :cheers: :cheers: :cheers:

great story I love the bike, shed, piles of stuff and special mention to the street sign

And I neglected to mention to Taffy and Bushie, Keep up the great work, test, experiment, 2 steps forward, 1/2 sideways, sometimes backwards and eventually forwards again. One of my philosophies is that you don't always (never?) know its a dead end until you actually get there, and even then, maybe there's a secret exit, so gotta go there to find out anyway.

Onwards to......the future :mrgreen:

bushmechanic said:

special mention to the street sign

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The things that used to amuse adolescent minds!

Steve

:cheers: x - o - lent! :cheers:

and agree 100% about the transport and test bed not making good buddies as well!

I used to steal rode signs: I had the head of norfolk constabulary's car parking box, and his deputies, I wiped out a 'P' sign once when I fell asleep at the wheel (so that became a souvineer), beware of the bull.

the one i always wanted to steal was one in the middle of Thrapston before it was bypassed. there used to be a fork lift factory on both sides of the road and the sign out the front read: danger fork lifts crossing. :twisted:

i always had visions of a mummy fork lift and a baby fork lift trying to cross the road..... man I wanted to steal that sign and then get a comic caption made of 'mum' and 'son' waiting to cross a busy street! :idea:

regards

Taffy

well not so much handling today but I was at this MX track with hardpack and the bike seems to turn on a sixpence even on the fluff but I'm struggling to nail a berm? I turn up , lay into it and just can't quite get the bike to follow the rut? grip is great, suspension - best ever, go up to a hairpin and turn but my rut riding is tits!

I seem to wander and can ride out or fall in? is that a sign of too much steering offset?

had 22 and have 18? guess what!

regards

Taffy

try 16 or 14 then you'l know

I broke my odomiter cable today.

F+ said:

I broke my odomiter cable today.

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I am interested in your line of thought? You thinking if your rake was back at 14 Degrees it would have given you the clearance to miss the object that busted you odometer cable? :? Or have you been drinking and posted in the wrong section? :lol:

Davo said:

F+ said:

I broke my odomiter cable today.

Click to expand...

I am interested in your line of thought? You thinking if your rake was back at 14 Degrees it would have given you the clearance to miss the object that busted you odometer cable? :? Or have you been drinking and posted in the wrong section? :lol:

Click to expand...

I just had to say it somewhere, no reason.

It happened under water yesterday and I just finished it off today on my track.

Not drinking tonight because it's going to rain, and I still have some tire left.

I think it had to do with not softening up the front end for the trail, I had it cranked for the track.

bushmechanic said:

try 16 or 14 then you'l know

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Nope - well not as my next test at least. I have 10mm of forks showing over the yokes so will try kicking out the rake a little.

surprised you came up with that bushie?

regards

Taffy

surprised?

I like to verify by going too far, if you haven't got a set to test though thats fair enough

i have actually!

the 18s turn around into 16s and as you may recall i still have the 14s here from the old frame.

however, I can change the rake by adjusting the forks back down into the yokes. this will change the rake, a little more trail (so the same thing) and take weight off the front all in one go - i hope.

let you know.

regards

Taffy

F+ said:

Davo said:

[quote="F+":32aylm4f]I broke my odomiter cable today.

Click to expand...

I am interested in your line of thought? You thinking if your rake was back at 14 Degrees it would have given you the clearance to miss the object that busted you odometer cable? :? Or have you been drinking and posted in the wrong section? :lol:

Click to expand...

I just had to say it somewhere, no reason.

It happened under water yesterday and I just finished it off today on my track.

Not drinking tonight because it's going to rain, and I still have some tire left.

I think it had to do with not softening up the front end for the trail, I had it cranked for the track.[/quote:32aylm4f]
That wore through, not inpact related.

Maybe I'll take a pic.