Handling & Suspension 2004-2008

bushmechanic said:

ahm how can lack of squat make the bike climb out the top of the rut?

a bike with too soft HSC on the comp will climb out the top of the rut becasue the back squats too much.... dial in the HSC on the shock to combat squatting and it tracks perfectly

BTW IF what you want is less anti squat whats to stop you lowering the engine 10mm at the front and shortening the shock to flatten the sarm

Click to expand...

oh dear here we go again. i phuqing hate this... :roll: :roll:
ahm? short for what?

how can lack of squat make the bike climb out the top of the rut?
if a bike squats at the rear as you open the throttle leaving a corner while cranked over this is what happens: the rear sits and the bike is now aiming on a smaller radius curve than say if it had none. so without squat on the rear it goes into a longer radius curve.

a bike with too soft HSC on the comp will climb out the top of the rut becasue the back squats too much.... dial in the HSC on the shock to combat squatting and it tracks perfectly

HSC has nowt to do with coming out of a corner. this is LSC country. my HSC has been on maximum for 3 years.

BTW IF what you want is less anti squat whats to stop you lowering the engine 10mm at the front and shortening the shock to flatten the sarm

I have said in the shock section that; the FC shock was shorter (so it lowered the swingarm) and i did say that i wished I'd had the OEM engine plates with me to go with the FC shock (so I could drop it back down the 7mm at the front again) that way I would have had MORE anti squat. i didn't even have neutral i had pro-squat!

i don't enjoy eating rope.

IMO if you lower the swingarm with a shorter shock and then lower the front of the engine you get your ANTI-SQUAT back and not 'less' of it but more. the important rule is the 'three axis rule'.

thank goodness its easy to go between each set up

regards

Taffy

your right, we disagree. mine is based on what I have felt and noted as i tested.

for instance, literally falling into the inside rope was so pro-squat that it had to be seen. again backing what i say and disagreeing with your paperwork.

and I can dial in and out squat on the rear using the LSC screw. again, this has been written here over the last few weeks. after all, squat isn't a HS movement so i think all you, your mates and your books are all wrong.

as said, the sprocket makes hardly any difference at all. none. the rotation force around the raer wheel is defined by the overall gearing which given that you are not changing the overall gearing means by dint of this that you've done nothing.

if i ran 15x40 or 13x40 i'd expect to apply more force and anti-squat with the 13t. but thats a completely different gearing set up. if it's 15x60 or 14x56 or 13x52 i will have no difference. its me that has written on UHE MANY TIMES that a larger front sprocket will give slightly more torque. but as said it is negligable.

regards

Taffy

just so you can see what the factory say what they did.

let us say for arguments sake that they went for an enduro shock and they have reduced like me the anti squat from crazy levels, they could then raise the engine at the back to lower the anti squat. however, as the previous photo has shown the factory has raised the front of the engine as well so that the belly of the engine is parallel to the bottom frame rails. so i make it:

rear of engine raised while swingarm and frame remain the same which lowers the anti squat - lets say the engine went up 2mm at the back. this is about 1.6mm at the gearbox and so to alleviate this they then raised the front of the engine by 7mm which is 1.6mm at the gearbox again.
they have jacked the gearbox sprocket to get rid of anti-squat?
i make that nearly 3.2mm at the GBS axis.

so DID the swing-arm pivot move up as well? I have looked very closely and they appear to be using a standard factory swing arm pin and it looks like the same frame hole, the swing-arm hasn't moved and only the engine could be moved.

but in order to get some anti-squat back after what I've said above it looks as though they MUST, they HAD to have lifted the swing-arm as well because this would create a helluva lot of anti- squat and if so, all the factory achieved was
raised the swing-arm pivot - (how - not sure?)
raised the engine - eccentric spindle holes....real easy
front of engine raised to negate this change in GB axis point.

this leaves you with an angled swing arm
some anti squat as if they'd never done it (by raising the front of the engine)
makes the shock lay over more and therefore work harder and faster.

the problem is that it needs a fast shock so you need to put the shock as far away from the pivot as possible so that max travel is still being used.

I would have thought that therefore the bottom of the shock should have been nearer to the rear tyre with shock angled over ala Katoom!

people talk of the upright husaberg shock being mathmatically better but the whole shock needs to be working - fast and hard! that is often more important.

regards

Taffy

cheers Mud (don't know your name)

well thats always good but there are factory bikes and and 'tickled up' factory bikes I suppose aren't there!

in their last year (or was it two) they extended the frame by between 15mm for Bjorn Carlsson and 25mm for Joakin Lundgrun. so do you perhaps have the welding around the headstock?

the only other area they would have changed would be the shock mount holes or the swing-arm pivot? the engine might have had eccentric (off-centre) shoulders in the back of the cases? the swing arm spindle might look off-centre? the head of the SA pin is shaped like a running track (T & F) and that should sit central to a rim around the edge?

these are the areas I figure the factory played with. thanks. photos are always good. go into the owners doc and you'll see photos of TM-enduro's factory bike with an extended frame.


from TM-enduro to me in August this year:
Taff
I'll reply best I can from memory. I still have the 496. A few things in life have kept me from getting much bike time lately.

Without having another bike nearby to compare it to, or taking the time to get a good photo and measuring the bike using CAD, I don't have exact info for you. I recall that it had a 25mm headstock extension and likely was steepened. The pegs were in the stock location I recall. The SA pivot was moved up 3mm or so. This was done by relocating the mounts on the frame. The engine remained in the stock location (I think), so location where the SA bolt goes thru the motor was plugged with alu and rebored in a new location. The net result is the bike really hooks up, but doesn't squat much under acceleration.

A taller seat was used. I need to go check, but I recall the TCs were 17m offset.

The bike can be best described as nuetral, meaning it handles about the same throttle on or throttle of, unhill or downhill, and it really works well when it gets slick, but to me i(T')s too responsive when things are dry and tacky.

and then:
taffy
on THE downside to the raised SA pivot is that you cannot run the preferred 14-48 gearing w/o wearing out the SA slide very quickly, since the chain pulls directly over the slide. I have been running the 15-50 combo instead and having longer SA slide life.

I will get pics of the SA pivot. I need to look around, I may have taken all these photos before. Wow, that was along time ago! (4 yrs).

so from this it is clear as mud! it sounds like the swing arm was raised in the frame, the engine was lowered the same amount (or more, or less?) back to sit in its original spot at the back.

if you lower the engine 3mm you lower the gearbox sprocket about 2.1mm and have massive front SA chain slider problems. so the engine was lowered at the rear and will explain why it looks parallel to the frame in the works photo.

this does now affect the shock. but more as a ratio of movement.

with the frame dipping at the front and jacked at the rear it left a little subframe adjustment to finish the job off!

regards

Taffy

here is another photo of the factory bike. infact it's the top half of the same page.... as the photo below it of the bike!





you just can't see the swing arm as having moved up here? the shock angle looks exactly the same but we're talking mm's here so....

so with the swing-arm pivot up 3mm that means the rear wheel spindle is down over 5-6mm and it was so steep it was daft - I felt so anyway. so 6mm more and it'll be awful.

they just HAVE to be using a shorter MX shock. there is no way the enduro shock at 400mm long is in there. anyway, a factory WP unit won't be coming as an enduro shock....

that would then explain exactly what i felt on sunday in my description of the FC shock on mine. the trouble is, my bike rode so low at the back. read this extraction , written just yesterday and before i'd put 2 + 2 together here today (yeh! I know TM had written to me but with yesterdays ride it all makes sense now!) so here it is:

Taffy said:

the first test was on the FC shock and i transferred over the spring but unwound it at the preload by one whole turn, immediately though something wasn't right????? the preload collar at the the ring clip end wouldn't fit and I knew straight away that the FC must be a shorter shock. I fitted it and did a session like this and it so over steered that i once came out of a corner hard and it shot clean into the inside ropes. this is a low point i can tell thee.....

so over the next three rides I lowered the clamps at the front and by the third session she was behaving again......... worse was to come as I started to understand WTF it was doing to my bike. with the taller front to the engine (see handling) the SA was nearly in a squat position, the harder i had been opening the throttle the more it had been squating and driving me into the inside rope. so to run this shock again will need the engine plates back 'as per normal OEM'. that way i'll get a little anti-squat to help the situation.

regards

Taffy

Click to expand...

so what is it?:
a raised SA pivot by 3mm and eccentric 3mm bushes (perhaps ) in the engine to take it back down to original position. this could all have been done by just lowering the engine anyway with the same bushes?

so they must have done it to raise the swing arm pivot in relation to the top shock mount. use a shorter shock, use it over it's full travel making it work faster, and harder and the faster and harder a shock works the better the damping. it also had the effect of changing the angle of the shock towards a KTM. so all that bull about the husey shock angle and ratios being better has been turned on its head.

this should also mean the FC shock doesn't travel as far before bottoming out. not a bad thing but does again mean an MX shock that 'stops when it stops' is required.

This is when you wish the SA pivot was 4" further ahead and the shock had been in the same point and angle as now. I'm very surprised the factory weren't the first to go for far longer swing-arms and break the mold there as well.

regards

Taffy

mud400 said:

Hey Taffy,
My name is Doug, by the way.
OK, my bike has the same mods as TM's but I have the 25mm headstock move.
Just in the frame I have a lowered subframe. extended headtube (not changed, just extended), and they moved the swingarm pivot 3mm.

The way the SA pivot was moved on my is they actually welded the mounts in a different position, they are not modified, just moved. They then bored the back of the motor out 3mm up to compensate for the moved frame mount. It is a major pain to remount the motor after you take it out.

I don't think my footpegs have been moved.

The story behind my bike is it was one of two "factory" 450 bikes that where brought into the US for the 07' season to show just what these bikes can do, they have factory modified production suspension, not the fancy factory stuff. It is REALLY good though. The engine mods are really neat, twin valve springs, Ti retainers, big valves, polished tranny, factory ignition, etc. I have since put a 380 kit in mine. With the factory mods it makes a really great 380.

It is funny TM mentions the chain sliders. Mine is a piece of urethane instead of the stock one. It ate through the stock one in a heartbeat.

Click to expand...

hello Doug

sounds like a great machine fella! although not wanting to run it as a 450...where's yer balls! :cheers: :cheers:

firstly I pretty much knew they wouldn't change the headstock angle unless it was done relative to the frame being kicked up at the rear so no i didn't expect that.

I guess if i was to ask for info I would say to either take a photo of the gap twixt the engine and the frame, to measure your engine plates which I expect to be different to standard and like mine and also I guess-when you get a chance I'd love to know the actual shock length?

i can guess weight ratios and transfers under riding conditions although I would love a ride on one....

I think that should I modify my frame to suit this I would drill the hole for the spindle some 6mm bigger and then put an off-centre-drilled shouldered-cap in the hole and weld.

I once lowered my sub-frame. I cut the top arms where they turn inwards to the main frame tube and let it pivot there while i took out about 8mm frome the diagonal struts and re-welded. what it did was to EXTEND the upper arms length and meant that the seat no longer hooked under those lugs on the frame.

I had to break the seat base and saw a gap 2/3rds of the way to the rear of the seat and pop-rivet an alloy plate across the gap.



I even had the tall foam put in and then added more to that! I'm only 5'9" tall....


if the bottom of this shock is kicked back and laid over it should have taken the reservoir further from the frame yet it is still very close? I now think that the top mount has gone forwards a few mm? the angle of the shock in the photo of my 2002 frame and this works machine don't seem to compare....

regards

Taffy

are you there Doug?

don't tell me that the Husaberg Heavy's have silenced you!or did we get too technical again!

regards

Taffy

after you've read this ladyberg I can see you with welder in hand turning yours into a factory rep!

I think your lattitude is a bit above ours in the UK. we are level with New York and its bloody cold here I can tell thee! last night minus 5c and moving to +3c by lunchtime. will call the track to see if they are going to be open soon.

back on subject though:
I have fitted the FC shock again and checked it out on the bench. it was shorter on the bench by 26mm which is like 10" at the rear wheel or something stupid! (remember yanks the Taff rule: mm up to an 1" and then inches, feet, yards and miles there on in)however it really only affects the static and rider sag and not the most important one: race sag.

It just means that whenever I'm in mid-air it takes longer to land and I don't catch double lips. I've had to fit 1" bar risers which is a bit more than I wanted and this will allow the clamps to go down the forks to the sweet spot.

as well as fitting the FC shock (with DCC from yet another shock I got in) I have gone back to the OEM front engine plates which should give me good anti-squat. one thing I should mention is that its not a balancing act with the FC shock, its like riding on 14" wheels and really flickable.

I just hope this is still an enduro bike and not an MX machine.

regards

Taffy

well I wrote the above on Sunday morning - 8.50am and the circuit and all others was closed so i decided to go to work all day on the bike.

this will give the bike more anti-squat. I looked at the old figures for 'my' shock and it was (i measure from on top of the spindle nut to a slit in the tail seat on the right) 650 - 614 - 548 while the 'FC' shock measures 625 - 580 - 522. so you can tell that the Top Out Spring is worth about 20mm at the rear wheel, well something is? the TOS is working when the bike is on its wheels and worth a whopping 34mm. quite why the TOS is working when my fat arse is on it - I'm not sure.....? clearly though the difference is 26mm race sag.

so, I've gone and fitted the eccentric crankcase dowels and the holes are nearer the top by 1.75mm. it leaves 1mm of wall in the dowel on one side which is about as close as you want to be -maybe we could have squeezed it to 2mm. I'm also going to try and jack the rear a little using this eccentric shock eye. it's 3mm offset so I should get about 9mm at the rear wheel. the difference then is 17 in race sag height. I'm back to the standard engine plates with the engine tilted down at the front.

I've sunk the TCs while in the workshop by 30mm which is daft but the figure you wanted is 445mm and you can add 10-13mm to that it I jack the rear and raise the clamps as a result.

I love this TOS even though all at K-talk hate it! they all talk about 2002 and 2003 as "bad" years. fact is though it changes the sags so badly that there is no way the husaberg could use them on anything but the MX'er? the rear swingarm looks very flat today. but the 9mm and then raising the clamps will make a big difference.

synergy talk of an eccentric bush for the rear shock so I'm going to talk further with them.

regards

Taffy