Forks / swing arm and stuff

[colnz]

Got a few questions

1) USD forks, whats the consensus on best ones to use. YZF750 , R6, R1 ?? which are the easiest to fit if I take a complete front end, how do the lock stops line up
anyone got first hand experience of making the swap??

2) I've seen one or two with braced YZF swing arms, I presume to facilitate a wider rear wheel, again what alterations are necessary to fit and are there any real
benefits to be had in stepping up from 160 to 180 section,

3) Rear jack up kits, does it serve a purpose or is it easier to get the same effect by sliding the forks through the yolks a litlle ??

4) recommended gearing for round town without losing to much on the open road

Thanks chaps

[trixynut]

First off, welcome to the forum!

Its useful to include your location in your info as we are all over the world here.

Also, the search facility is your friend

1) YZF is easiest. Just needs the stem from the TRX pressing out and into the bottom yoke from the YZF. Even has same speedo drive. Lock stops line up. You'll need YZF clip-ons too.

2) YZF swinger is same as TRX one but with bracing welded on. The bracing isn't needed on a TRX as it hasn't got the power. TRX swinger will take the wider YZF rim. Needs new wheel spacers. Again, search for dimensions etc... 180 has a higher profile so raises the back up, but can make the bikes turn-in on corners a bit slower. personal preference. Looks cool.

3) Jack up the back or lower the forks, same effect. Improves steering sharpness and response. I would lower the front first as its free and easy, and see how you like the feel before going for shorter dog bones to jack the back.

4) lots of opinions. personally I think one tooth off the front is easy to do without needing a longer chain and is the best.

[Tarwetijger]

1) USD forks, whats the consensus on best ones to use. YZF750 , R6, R1 ?? which are the easiest to fit if I take a complete front end, how do the lock stops line up
anyone got first hand experience of making the swap??
YZF750 is easiest, as the speedo-drive can be used. R1 forks don't have that so you need something else to know how fast you are going. Lock stops are not an issue.

2) I've seen one or two with braced YZF swing arms, I presume to facilitate a wider rear wheel, again what alterations are necessary to fit and are there any real
benefits to be had in stepping up from 160 to 180 section,
Most do it for a wider rear wheel, yes. Necessary alterations are none. Although line-up of the chain might be an issue.
Any real benefits -> No.

3) Rear jack up kits, does it serve a purpose or is it easier to get the same effect by sliding the forks through the yolks a litlle ??
Why not both?

4) recommended gearing for round town without losing to much on the open road
You mean different sprockets? It 's a matter of trial and error, I suppose.

Edit: you were faster Trixy.

[Ingy850]

Hi, as I understand it the YZF forks aren't that good, I'm in the middle of fitting R1 4xv forks into mine (they are the longest of the R1 forks so closest length to the standard ones but still shorter so will drop the front anyway), I have used later yokes to keep the offset the same but had to weld extra to the lock stops and the stem hole needs machining out to take a sleeve to fit the TRX stem (it is .033 mm too small for the R1 yoke). I'm also going to use the TRX wheel to retain the speedo drive, this requires some machined sleeves pressing into the fork bottoms and also 5.75 mm machined off the inside of the left hand fork bottom to centre up the wheel and new wheel spacer making for the right hand side. Quite a lot of work and probably quite expensive if you can't do it yourself, is it worth it? don't know yet, oh yes the calipers will need spacing to fit as well. Hope this helps, regards Ivan.

[cobbadiggabuddyblooo]

Lower front or raising back don't quite do the same.
Lowering the front effects more so your turn in to the corner by shortening your trail and lower rake angle.
Raising the rear changes effects more so your exiting corners by changing swing arm angle to give you more anti squatt out of corners to help prevent running wide out of corners.
You'll have a minimal influence by raising the rear with 10mm shorter dogbones on the front take/trail.

If your running a 70 profile front tyre you need to remember you've added an extra 10% ( 12mm height ) so you need to compensate by lowering the front end.

When setting sag on your early R1 forks ( 98-99 ) you need to factor in the increase in travel from 120mm to 135mm.

You can do an axle mod to accomidate the TRX 17mm front axle and front wheel.
I've detailed this mod in my rebuild thread with 1 sleeve inserted into the fork and the other welded on a longer 17mm axle. ( from memory a DT yamaha swing arm pivot pin )

You can run a 170 profile tyre on a std TRX 5" rear rim if you want a little more contact patch but a 180 will deform the tyre and begin to compromise things.

YZF 750 swing arm and 5.5" rim is just unwarranted extra weight. If you choose to run a 5.5" rim you can mod a YZF 750 or later model R6 lighter wheel to fit the Std TRX swingarm.
To obtain chain alignment you have a couple of options.
Some choose to modify and offset the front sprocket or as I chose to machine 6mm from the rear sprocket carrier which allows you to run the original chain and sprockets. You can see the raised edge the rear sprocket sits on so a simple job.
Steepen the swing arm angle further to compensate for the wider rear tyre pushing wide exiting corners. So if you have 10mm shorter already go to 12mm.
Bracing is not really needed until you start to push over 100Hp and close to 70ft/lb torque.

[cobbadiggabuddyblooo]

As for brake caliper alignment a simple washer fitted between caliper and mount sorts this out for you.
I chose to not use the TRX speedo drive and plenty of good speedo, taco combo digital dashes at reasonable prices or run the Std taco with a digital speedo inserted in original dash. Udaysen has this set up on his TRX with digital speedo in the TRX dash.
Wiring is simple too and also listed how to and colour coding of wires on my rebuild.
This way finding a replacement fork leg or upgrading to later model R1/ 298mm disc forks is no problem.
As for fork length, the early 2000's R1 forks are a only a tad shorter but only have 120mm travel so the compressed length under brakes and turn in is no different so really not an issue.
The reason the went with longer travel forks on 98/99 R1 was to try and keep the front wheel on the ground when exiting under power. Further frame / geometry changes where made in 2000 to deal with this and hence the shorter fork and travel.
Early R1 forks are still a little primal but a little better and YZF750 / early R1 forks can be reworked to perform with better sensitivity.
No weight difference between the R1 forks either because the early 98/99 R1 forks use a thinner walled tube so the extra length negates any weight difference with the later shorter forks.

[dulaeng]

Hi & welcome I don't post much but I felt I should on this. Mine has Marzocchi Multistada forks which were a friggin nightmare to fit but got there in the end + Aprilia Millie 1000RR swinging arm again I almost gave up but in the finish it looks great & well chuffed

[Veronica]

Just got hold of YZF 750 rear wheel to fit to TRX swing arm noted spindle size on YZF wheel is 28m. Can this be sorted by FITTING TRX WHEEL BEARINGS TO YZF WHEEL SO TRX WHEEL SPINDLE CAN BE USED? Thanks for any info

[cobbadiggabuddyblooo]

To get sprocket alignment you you have to remove the studs on the sprocket carrier and machine the 6mm raised section where the spocket sits so it's flush.
Bearing size to get to a 20mm axle will mean the bearing itself will be 1mm wider so you need to make a 20mm new crush tube between the bearings in the wheel hub. 1mm needs to be removed from the inside of the sprocket carrier. Make a new spacer and top hat spacer too.
Another option is possible making a long 28mm to 20mm hard chromed sleeve to fit in the wheel hub from bearing to bearing. Then you just need to machine up spacers for the ends.

[trixynut]

"To get sprocket alignment you have to remove the studs on the sprocket carrier and machine the 6mm raised section where the spocket sits so it's flush"

This is not strictly right. if you have a rear sprocket like the original one I.e. dished/inset on one side, simply flipping it over so the dished/inset side is inside closest to the wheel will align the sprockets. Sure that's what I did.

All the info is on here if you search, including dimensions for the new top hat spacer needed.

[Veronica]

Thanks for the info lads, much apriciated will persevere.i