Front End Forks Swap YZ

[Rickyme]

Shawn that bar riser looks pretty tall, how high do you think Id need to go - as in would 30mm bar risers get the bars out of the way of the fork caps?

 

[Shawn Johnson]

Here is a picture of a cable guide. It's not the actual one I used. I had the modify the mounting holes for it to fit.

 

[Shawn Johnson]

Shawn that bar riser looks pretty tall, how high do you think Id need to go - as in would 30mm bar risers get the bars out of the way of the fork caps?

The caps are 1 3/4" plus 1/2" for the adjuster nut (for a total of 2") above the triple clamp.

 

[Shawn Johnson]

Here is a picture

 

[Shawn Johnson]

Shawn that bar riser looks pretty tall, how high do you think Id need to go - as in would 30mm bar risers get the bars out of the way of the fork caps?

I used the Powermadd 2" riser.

 

[Glengemen]

Shawn,
How are the new forks when you hit a good rut or rock?
I hate the lack of front suspension travel on the stock forks and will eventually have to do something with them. Replacement with a 12" fork seems like a good option. I find mine has not enough compression resistance for me and the rear has too much. I've only bottomed the rear a couple of times and the front is hundreds per off road ride. The roads out here are pretty jacked up in places.

 

[Shawn Johnson]

Shawn, they are not my parts, they are made by Aquatic, the original swap was worked out by in the US and the first batches of parts made in the US

The YZ brake you are using is not up to the needs of the Terra or the 650GS in repeated use situations, that was one of the concerns of the originator of the swap

Actually the YZ Nissan brake has the same or even a little better than the stock Brembo setup.

 

[Shawn Johnson]

Shawn,
How are the new forks when you hit a good rut or rock?
I hate the lack of front suspension travel on the stock forks and will eventually have to do something with them. Replacement with a 12" fork seems like a good option. I find mine has not enough compression resistance for me and the rear has too much. I've only bottomed the rear a couple of times and the front is hundreds per off road ride. The roads out here are pretty jacked up in places.

Night and day difference. The stock fork really holds back the "fun factor" of the bike. With the new forks you are in more control and have a way smother ride as long as you have the correct fork springs in for your weight. Now every time I take the bike out I have way more fun going over bigger obstacles since the new forks can handle it, and are very plush.

 

[Rickyme]

Thanks heaps for all that info Shawn
about the original forks, Ive had mine re valved but they are still just rubbish if you want to go anywhere more serious than a gravel road.
Hopefully I can wait a little bit before I need to address the back suspension

 

[Rickyme]

Shawn, they are not my parts, they are made by Aquatic, the original swap was worked out by in the US and the first batches of parts made in the US

The YZ brake you are using is not up to the needs of the Terra or the 650GS in repeated use situations, that was one of the concerns of the originator of the swap[/quote
I reckon itll be ok, Im only about half way through the adv thread for the BMW yammy conversion but there dont seem to be any problems so far.Theres a 320 ml rotor and adapter available which Im sure will eat the Brembo setup for lunch

 

[Shawn Johnson]

I have put 2500 miles on the conversion and the YZ front brake stopping power is on par with the stock Brembo brake.
Actually the YZ brake is better becuase it's quieter and doesn't "howl" like the Brembo does/did.

 

[Rickyme]

Yep am getting a braided line made , now I might get it made in red after seeing that photo.

and using YZ wheel with an extra spacer that I will cut down - to centre in the forks

Had a conversation with a suspension guru about my ideas, he basically told me the racetech internals would give me a better result as the YZ open chamber fork is ...well rubbish, not really worth discussing - just a bad place to start.

However we went on to discuss some spring options and shortening the travel to 270mm and he seemed more interested and hopeful of a good result.
Ive heard the racetech solution is about the same as my investment in the yammie front end but I still end up with not much travel and no way to adjust it - And ill probably be able to sell the original terra front end

Now I know these guys deal with top level motoX dudes and deliver a very good result but ..

Ive bought the YZ stuff (although I can send it back if it doesnt work) cause I want to a bit more travel and some adjustability.

Ive got KYB open chamber forks on my WR300 2013 and they are magic, in fact my whole WR300 is magic now that Ive put a rekluse on and a lectron carb, done some valving and lowered it 40mm

OK so I like changing my quirky Italian bikes around and also.....

The terra is never going to see a table top or a set of triples

it was a mongrel to begin with

 

[Shawn Johnson]

I just remembered that you will need an extra spacer (cut down) for the front axle since the stock triple clamps are a bit wider. When I bought the front wheel off Ebay the axle and spacers were included. I had to buy another spacer kit off Ebay for $15.00. The kit is two spacers, you only need one it's the one on the left in the picture. I have attach a picture.

Note: The spacer is cut down to 3/8" inch not 1/2" like I stated before.

 

[WayneC]

Actually the YZ Nissan brake has the same or even a little better than the stock Brembo setup.

Shawn, no it does not, you are trying to compare a 28mm piston caliper with a 30/32mm caliper, they are very different beasts under sustained usage

As for needing the riders, you only need the riser if you do not shorten the forks as per the 650GS and others using YZ forks, details are in the YZ thread at Advrider,the changes in valving to suit the heavier machine like the Terra or 650GS is minimal and you will find the details in the YZ notes pdf under the "typical" valving in the pdf.

The 320 mm disk from EBC is competition only and if you check the fine print the floaters need maintenance, not all that good for a dual sport machine

 

[Shawn Johnson]

Shawn, no it does not, you are trying to compare a 28mm piston caliper with a 30/32mm caliper, they are very different beasts under sustained usage

As for needing the riders, you only need the riser if you do not shorten the forks as per the 650GS and others using YZ forks, details are in the YZ thread at Advrider,the changes in valving to suit the heavier machine like the Terra or 650GS is minimal and you will find the details in the YZ notes pdf under the "typical" valving in the pdf.

The 320 mm disk from EBC is competition only and if you check the fine print the floaters need maintenance, not all that good for a dual sport machine

I'm just going off my personal experience. I understand the law of physics. For me the YZ brakes work just as good as the larger stock Brembo brake setup. After 2500 miles of use (I'm hard on brakes) I don't see any wear and they work excellent for stopping my 220lbs frame. The great thing about using the YZ parts is when they wear out there will be no problem getting replacement parts for cheap.

 

[Shawn Johnson]

Forgot to specify...which rear spring did you go with? I'm looking to swap mine for an RT...

Thanks!

I was wrong, it's not a Race Tech spring, it's a Eibach rear shock spring, part number SESP802250750. Sorry I don't know the rate of the spring.
Also needed was the shock collar for the shock, Eibach part number SPSCF567606

 

[WayneC]

Information for all

The stock yoke fork tube diameters are Upper 54mm Lower 57mm, this is the same as the WP4357MXMA forks and they are what the G650X riders are fitting to retain the existing yokes, bars, ignition mounts etc. The G650X guys have also worked out the caliper mounts are the same as for the WP so the caliper hanger can be re used with the WP forks but that the wheel offset is different so some spacing is needed, UKGSer forum has more info on the hanger aspect

The YZ forks are Upper diameter 53.9mm, Lower 58.4 mm so if you force the YZ into the stock lower yoke it stresses the yoke and so there is a risk of it breaking, this is why the G650X and F800GS BM owners do not do it

Marzocchi Shivers can be fitted but there are variations in the lower yoke dimension, some are 57mm others are 58mm

The info and experience on what is possible with forks for the Terra is well researched with the G650X owners and one location for info is the G650X Suspension thread at Advrider, as always there is a fair bit of banter in the thread, there is no need to reinvent the wheel

http://advrider.com/index.php?threads/bmw-g650xchallenge-front-suspension.277533/page-12

 

[Rickyme]

I'm just going off my personal experience. I understand the law of physics. For me the YZ brakes work just as good as the larger stock Brembo brake setup. After 2500 miles of use (I'm hard on brakes) I don't see any wear and they work excellent for stopping my 220lbs frame. The great thing about using the YZ parts is when they wear out there will be no problem getting replacement parts for cheap.

Im with you mate, this argument was quite heated on adv rider between various individuals so no need to repeat here I reckon.
Im going to use of house of horsepower prepared forks as the correct spring rate is a bit hard to get here in Aus. They will be an inch shorter with a progressive spring 045 - 048 i think and they will be serviced with seals, valving etc.
I took the terra away for a couple of days fully loaded on pretty rugged fire trails. the rear isnt actually too bad it just doesnt react very quickly.

 

[Rickyme]

Any ideas on the Terra head tube bearing set up to be able to use the yamaha triples? The GS conversion works with just a bearing change on the lower race I believe.

 

[WayneC]

The Husky bearings it seems are 29 x 48 x 17.5 mm at the top and bottom but I have not seen an SKF/NTN/Koyo bearing number for them so working out an alternative outer or whether the Husky outer is compatible with the YZ inner is not possible. (outer and inners are interchangeable only within a series)