YZF750 front end conversion...

[Thom]

I must have asked Kayla about 40 questions related to this and ive spet half an hour in search but alas i am at an end with no clue...

I have bought myself what appear to be a good set of yzf750 forks (possibly with maxton springs in) for £150, is this a fair price? I thoguht so?

Anyway, i am now wanting to get the rest of the parts to convert my trx to a usd front end but although ive asked countless quetsions and been given as many answers i am a little confused as i didnt buy a whole yzf750 front end as is best.

What i do have is a whole TRX with blue spot calipers, so which parts can i transfer and what would i need to buy?

As i understand it i need yzf750 yokes, stem and bearings, however my clip ons, ignition barrel should fit?

Furthermore i have no idea about my trx axle, wheel, mudguard or brace, are these items transferable?

If anyone can give me a clear and concise breakdown i would be very happy?

[Kayla]

I must have asked Kayla about 40 questions related to this and ive spet half an hour in search but alas i am at an end with no clue...

I have bought myself what appear to be a good set of yzf750 forks (possibly with maxton springs in) for £150, is this a fair price? I thoguht so?

Anyway, i am now wanting to get the rest of the parts to convert my trx to a usd front end but although ive asked countless quetsions and been given as many answers i am a little confused as i didnt buy a whole yzf750 front end as is best.

What i do have is a whole TRX with blue spot calipers, so which parts can i transfer and what would i need to buy?

As i understand it i need yzf750 yokes, stem and bearings, however my clip ons, ignition barrel should fit?

Furthermore i have no idea about my trx axle, wheel, mudguard or brace, are these items transferable?

If anyone can give me a clear and concise breakdown i would be very happy?

Hi Thom,

If the forks are the later gold (fully adjustable) ones and they're in good nick with no pitting then I think that's a fair price

The YZF750 front end is loads easier than the R1 because the stems are a straight swap. You can use your blue spots but you need to relieve the caliper brackets on the forks a little.

You can't use the TRX wheel easily (although it is possible with work- the hubs are different widths and there's no alternative bearings available that go up to 22mm.) You need 320mm discs (TRX are 298/300mm)

You need the YZF mudguard (I think the FZR600R 4JH part is the same)

The TRX stem needs to be pressed into the YZF yoke.

The TRX clip-ons (41mm) won't fit the YZF forks (50mm)

I don't know about the ignition barrel, but it can't be a million miles away (a TRX barrel fits a Thunderace yoke for example)

To be honest, ideally you need the complete YZF front end minus calipers and stem. If you can get your bike and the bits down here we could probably sort it in a day or so.

[Thom]

ah buggar. that was a balls up on my behalf then!

building up a whole front end will be costly unless i find one whole!

Cheers Kayla, at least this will prove useful for others!

[trixynut]

The igintion barrel from a TRX will fit the YZF and any brake calipers that fit the TRX will fit the YZF and vicey versa. The TRX speedo cable will fit into the YZF speed drive too, but thats about it for interchangeable bits between the two front ends without getting into machining stuff.

If you get a whole YZF front end (forks, bars, yokes, wheel etc etc) you ONLY need to press out the TRX and YZF stems and swap them over.

[Thom]

Cheers guys, i'm keeping my eyes out for an entire front end or cheap bike.

Do we know of any other USD setups that are this simple?

I've seen Kwak ZXR usd's going cheap and wondered how much work would be involved.

[Mincehead]

If you get an entire front end it`s simply a matter of stem swaps, although you really want to keep the fork lengths `similar` to that of the TRX and remember if the folks on here haven`t done it there`s little knowledge available to guide you.
Ducati, Aprillia, all kinds of Yamaha and some Suzuki forks have all been used in members bikes but I don`t remember any Kawasaki forks being used, YET.
I don`t see any huge issues personally but after relieving any Kawasaki yokes of their stem you may find the Yamaha stem will drop in like a dick in a top hat, and may require building up with weld and re-machining.
Oh and don`t forget, if you want to keep a cable driven speedo you`ll need a front end using one, or it`s go down the digital speedo route with a magnetic pick-up.
Then there`s the gearing of the speedo drive to consider too, ALL Yamaha speedo drives are geared the same, I cannot say I know for sure that a Kawasaki one will be the same though.

[Thom]

You intrigue me.

So theoretically other than a speedo drive, front end length (surely similar if theyre sports orientated bikes?) and stem size... anything should fit with relative ease?

I guess theres one way to find out...

[Mincehead]

There is something else that may require modifying and that is the steering stops cast on the bottom yoke. But, they can be ground off and steel pegs turned up with threads in so that you can drill the bottom yoke to accept them where they will be required.
Most things can be modified / made to fit, but there could be a great deal of work involved too.
There`s plenty of R1 forks and yokes around, Suzuki SRAD forks or GSXR1000 USD`s too.
I`m not sure but I think YZF750 fork leg diameters are the same as R1, 50mm at the top yoke and 54 mm through the bottom.
I`ve a nice mirror polished set of R1 yokes I`ll not be using on my build as I`ve had a custom billet bottom yoke made up and am using a Lucas billet R1 top yoke.
The R1 stem once pressed out of the yokes can then have the TRX stem fitted, there may be a need to build up the diameter with weld and re-machine it to be a machine press fit though.
Personally I would recommend searching for a complete R1 or 6 front end, if you find a Suzuki or Kawasaki front end you`ll need to take some careful measurements to ascertain what work is involved.

[Thom]

I've got my eye on something at the moment, hopefully it'll come out in my favour.

Watch this space.

[NWS870R]

Suzuki front ends are no more difficult to fit just the usual stem swap & altering lock stops, etc. Gearing of speedo drive is also the same

[Mincehead]

Ahaaa, that`s good to know, cheers NWS.

[Kayla]

The igintion barrel from a TRX will fit the YZF and any brake calipers that fit the TRX will fit the YZF and vicey versa.

Yes, but no. The YZF 6 pots will fit the TRX forks but blue spots won't fit the YZF forks without relieving the caliper mounts.

[Thom]

thanks for this guys, its brilliant, i think i've found a whole r1 front end on ebay which is perfect, just need to win the auction now...

[Thom]

P.s reckon i could get an r1 speedo to work on a trx?

[Wombat]

If you get an entire front end it`s simply a matter of stem swaps, although you really want to keep the fork lengths `similar` to that of the TRX and remember if the folks on here haven`t done it there`s little knowledge available to guide you.
Ducati, Aprillia, all kinds of Yamaha and some Suzuki forks have all been used in members bikes but I don`t remember any Kawasaki forks being used, YET.
I don`t see any huge issues personally but after relieving any Kawasaki yokes of their stem you may find the Yamaha stem will drop in like a dick in a top hat, and may require building up with weld and re-machining.
Oh and don`t forget, if you want to keep a cable driven speedo you`ll need a front end using one, or it`s go down the digital speedo route with a magnetic pick-up.
Then there`s the gearing of the speedo drive to consider too, ALL Yamaha speedo drives are geared the same, I cannot say I know for sure that a Kawasaki one will be the same though.

I have seen pictures of a TRX with either a ZXR750 or ZXR400 front end. I think it was in PB many many years ago. Apparently CBR600 USDownies fit too.

Bob