A forum for owners of Yamaha TTR250 trail and enduro bikes!

petenz · Super Guru

05 YZF250 USD front end meets TTR...

TTRfan · Super Guru

Excellent post Pete - thanks for documenting and sharing biggrin

Brian

Kaos · Senior Member

Top job. Much easier than my WP swap. I had to get bearings milled down.
How are the forks for length compared to the old ones. I have some bar raisers and managed to pull the fork legs up through the clamps a fair bit to get ride height right.
Gonna get them revalved??

ttr steve · Super Guru

Nice work smile

devon_rich · Senior Member

Good work. Let us know how it rides compared to stock

mossproof · Super Guru

Good work Pete. Love it when a plan comes together!
Could you weigh the ttr bits before you dispose of them please. (Sorry, I really should get out more!)
I forsee a yzf bidding war on ebay...

petenz · Super Guru

The YZF forks are 10mm longer.... top to axle centre.
Axle offset is 5mm less than the TTR so slightly more trail...

should make the bike track straighter & be more stable in a straight line...

I thought the YZF front end was going to be heavier than the TTR but the bike now has 2.5/3kgs less front weight..

even the TTR mudguard bolted straight on...

this has to be the easiest USD swap yer could find..

looking at bearing sizes the YZF & WR forks from 2001 to 2006

or forks that use 28/52/16 or 30/52/16 size bearing will fit..

or any bearing with a 52mm OD to fit the steering head...

and a stem of around 240mm from top of the bottom clamp to the top of the stem.....

petenz · Super Guru

Kaos wrote:
Great Job.
Now we are waiting for the ride report.

rained all last week end.... so done nothing on it...

sheds to small or could be two meany bikes in it .

Didn't want to put any in the rain to make working room..

but I got the front caliper rebuilt... seals & new pistons..

So its put it on , bleed it then the longer cables , change

the tyre....

.

mossproof · Super Guru

Excuses excuses. Get a bigger shed! (Or wheel it into the kitchen!)

petenz · Super Guru

HaHa... One bikes already inside...

The Montesa 125 H6 lives in the lounge...

(think I need to stop working on bikes & get the lounge finished)

TTRfan · Super Guru

biggrin biggrin biggrin biggrin

No smell of petrol in the lounge? confuse confuse confuse

ttr steve · Super Guru

See what you have done Simon, you will be in trouble with Pete's other half wink wink wink

mossproof · Super Guru

At least they can share the sofa and both have something good to watch when the tv programme's not to Pete's taste! Just trying to think if I've seen that film with Jeremy Renner and Kevin Bacon working in a tyre bay??

petenz · Super Guru

ttr steve wrote:
See what you have done Simon, you will be in trouble with Pete's other half

no other half now...

thats how I get away with it...

...

TTRfan · Super Guru

I found this photo showing dimensions of the TTR's bottom yoke. Might be useful for someone.

TTR yoke post dimensions.jpg

ttr steve · Super Guru

petenz wrote:
ttr steve wrote:
See what you have done Simon, you will be in trouble with Pete's other half
no other half now...
thats how I get away with it...

...

Ooops

Sorry Pete

If I put my size 11 in it again

petenz · Super Guru

ttr steve wrote:
petenz wrote:
ttr steve wrote:
See what you have done Simon, you will be in trouble with Pete's other half
no other half now...
thats how I get away with it...

...

Ooops
Sorry Pete
If I put my size 11 in it again

lol.... don't be sorry....

i'm shaw as hell arn't....

..

mossproof · Super Guru

How different are the hubs Pete? Would a YZ wheel fit a TTR or vice versa with the correct bearings and spacers, or is the brake rotor in totally the wrong place/wrong size?

petenz · Super Guru

i would have to look... will on the week end when i change the tire...

..

mossproof · Super Guru

No rush, just while the opportunity is there to compare them it would be interesting.
I'm keeping my eyes on ebay

petenz · Super Guru

little bit more info on the front end..
just changed the oil ...YZF front end takes 662cc of oil or the oil level is 125mm...

put both the rebound & compression damping clickers to there middle setting for a start point..

Still waiting on the brake hose , It needs a 1600mm to route it where Yamaha intended...

brake calipers rebuilt new seals & pistons..cost $70NZ...

Havn't riden it in anger yet... Have a ride this sunday....

.

-- Edited by petenz on Tuesday 2nd of May 2017 12:53:10 AM

bwaldo · Member

I have done the same upgrade on my bike, super easy. The hardest part is sourcing the forks!

FBRConcepts · Veteran Member

Man, thats an awesome project! any updates since last post on the bikes new characteristics? now you have me scouring ebay for forks instead of rebuilding the TTR units... lol also any picture updates with the bikes completely put together with the new front end, I bet it looks BOSS!

Chris

petenz · Super Guru

I had the first real ride on it last week end...

The front ends needs a bit of work...

way over sprung for my weight... they come standard with

.43kg/mm springs that suit a 75-85kg rider i'm about 77kgs

so they should have been about right for me.... so i think

they have been replaced with stiffer ones or have pre-load spacers..

i will move the forks up though the clamps as it turns quite slow

to much rake at the moment....

at the moment the TTR front end was better....but that will change...

TerryK · Super Guru

G Ballard used to love the TTR forks & he would put TTR forks on WR's, well that's what I heard.

I don't mind the TTR forks but I guess I don't ride it that hard, not on the limit with jumps etc.

Terry

petenz · Super Guru

bit of a update on how it goes...
the first ride i got with it was dalethorpe.. 40km loops all in the trees..
I had more trouble this year than any other... got tossed off 4 times
The front end just dosn't work on tree roots/rocks etc.. the TTR front end was far better...

but a week after that I took it for a ride where there was single track forest trails & open
fast flatish trails... n the trees it was a fight...TTR forks were far better... but get it out
on the teraine it is sprung & valved for what a diffrents... that front end is so planted but it was
still turning slow so I went back to the car & droped it though the clamps 25mm...( reduced the rake &
shortened the trail )... went out for another ride... Still not great in the trees but did turn better...
out on the flater more open trails... the bike went were ever the wheel was pointed ...
keep your weight above the bikes centre line & push it down in the corner the front wheel stayed put
when the back steped out...

It is a YZF front end so was never set up for rocks / roots / ruts etc... but once on the type of terain
it was designed for it works at a level the TTR front end can't come close to...
but as I don't ride that type of terain often i will have to have it re-sprung & valved more towards enduro specs..

if i was useing the bike as a duel sport I think I would leave it as it is... as on the 4 k gravel road section back to the car
it was pretty dam fast around the corners & held its line in lose gravel very well...

..

Kaos · Senior Member

To be expected I suppose. A MX spec fork is never going to be plush enough in slower sections with tree roots and rocks, they are designed for fast big hits and big jumps etc.,
Softer springs and a revalve and it will a completely different animal.

I am very happy with my WP fork swap. I had previously had my TTR forks revalved with new springs and thought they were pretty good. The WP USD are better everywhere. I did have to pull them up through the triple clamps heaps though, but now they steer better too.