GGman KYB conversion

[gasgasman]

My previous bike had the 50mm 'zokes on it. (now enjoyed by Jay)
I really liked the lack of flex on them. My Current 45mm 'zokes just seemed to wallow in the ruts and deep sand.
I usually stay off the ground, last couple rides I've hit the dirt like 3 times. The front end would just loose traction and down I went.

So, decided to try the KYB conversion.
Thanks to EdVentura, GMP and Danj56 for their valuable input.
It was a LOT of work and well worth it. I rode today and the stock YZ valving seemed spot on. Front tire stuck like velcro. My confidence was very high. I did not get arm pump and my arms are not sore at all.

Here's my build. I found some brand new 2012 YZ 125 KYB forks on e-bay.
Parts used;
2012 YZ KYB SSS forks and guards.
2010 YZF 250 3x clamps.
2009 YZ 250 Front wheel w/ axle and spacers.
2010 YZ450 front caliper.
Replaced GG upper steering stem bearing with same one as the bottom.
Two door stops from HomeDepot.

I wanted to use the OEM GG fender and headlight. The YZF bottom clamp has two vertical pins that aren't used. So I cut threads on the pins to mount a bracket to hold the GG fender.

Bracket shown here. I drilled two new holes aft of the GG OEM rear holes.

For the fork stops, I installed some PopNuts in the frame to hold the door stops I bought from HomeDepot.

Door stops mounted. I have since shortened them to regain some steering angle.

 

[gasgasman]

Fork stop in action.

Top clamp install. I used the GG top bearing seal. The GG damper mounted up perfectly.

Headlight mounted up. Little far out on the bottom. Not bad though.

 

[gasgasman]

Side view. Front wheel did not hit the fender at all.

 

[gasgasman]

The fork compression is set at 11 clicks and the rebound is 6 clicks.
Now I have to get the shock to match the front forks.

 

[jhendr3702]

The fork compression is set at 11 clicks and the rebound is 6 clicks.
Now I have to get the shock to match the front forks.

looks like alot of work... glad it works great...

(and yes.. those 50's are sweet )

jay

 

[pscook]

What did you do about the stem? Is the YZ stem close enough that you only replaced the upper bearing? Stem length is fine? If you don't mind, can you post up your total cost on parts?

 

[gasgasman]

The stem is the YZF part.
The GG stem is smaller at the top and requires a smaller bearing.
The YZF stem is the same diameter for the entire length.

I'll add up the parts and let you know.
The brand new forks were $800 from e-bay. I bought new because I did not want someone's hack job.
e-bay seller has a crap load of new parts.
http://stores.ebay.com/328-Power-Sports/Yamaha-YZ-YZF-/_i.html?_fsub=404612719

 

[Rick]

What spring rate? OEM ? Do you plan swapping springs?

 

[twowheels]

Very sweet. Nice job.

 

[phoenix]

Very nice. Thank you for sharing. I love seeing people's ingenuity.

 

[Anders]

Thanks a lot. I have a similar fork coming my way now. I also found an unused one on ebay. However, I presume I will send them by the local suspension guru while I'm at it. I plan to use my oem wheels if its not too much truble, perhaps by cutting a suitable, smaller brake disk or fabricating a suitable caliper bracket.
Btw, the brake disk I use now is also a home brew.

Sent from my OMNIA7 using Board Express

 

[rgranger]

So, are you available for hire I remember someone telling me that I should not work on my bikes anymore.....

 

[gasgasman]

Anything for you Rob.

 

[Fred1956]

Anything for you Rob.

Not to hijack, but are you guys from the Houston area??? or maybe Amarillo?? I'm trying to find out what type of terrain to expect for the upcoming Nat Enduro

 

[rgranger]

I think Girard would welcome any excuse to avoid helping me work on the the bike We are in houston, Girad has ridden everywhere around here so he would be the best to answer - where is it being held? I have been so buried in work, I have only been able to keep one bike broken...

Not to hijack, but are you guys from the Houston area??? or maybe Amarillo?? I'm trying to find out what type of terrain to expect for the upcoming Nat Enduro

 

[jhendr3702]

Not to hijack, but are you guys from the Houston area??? or maybe Amarillo?? I'm trying to find out what type of terrain to expect for the upcoming Nat Enduro

which enduro.. i am in amarillo.........

 

[Fred1956]

which enduro.. i am in amarillo.........

The Concho, it's being held in Blackwell, Tx.

 

[jhendr3702]

The Concho, it's being held in Blackwell, Tx.

have never rode there... but i think it will be alot of clay and rocks..

pretty rough terrain.

 

[gasgasman]

So, I have a couple months of rides with the KYB conversion.

About 2 rides ago I installed some billet free pistons in the forks. Saw a lot of broken OEM free pistons on several forums.
http://www.youtube.com/watch?v=D1tu98GQD3Y
Flushed the fluid and bled the cartridges. I put 350cc of 5W fluid in the outer forks. That was too much. The initial fork travel was very plush, but harsh on the mid stroke. There were a lot of sharp spikes to my wrists.

I called up SMART Performance and ordered their SPI 3 special fork fluid.
http://smartperformanceinc.com/215VM2K5.html
I added 300cc of the SPI 3 fluid to outer fork per their recommendation.
The forks are very plush now. Even with the stock YZ125 fork valving/spring, the forks work really well.
I don't think I have ever had this much confidence to go fast on the bike as I do now. We have a loop that we ride on, my average speed on the loop has been a steady 19mph. Today I hit 21.9mph.
Helmet cam to come.

 

[jhendr3702]

So, I have a couple months of rides with the KYB conversion.

About 2 rides ago I installed some billet free pistons in the forks. Saw a lot of broken OEM free pistons on several forums.
http://www.youtube.com/watch?v=D1tu98GQD3Y
Flushed the fluid and bled the cartridges. I put 350cc of 5W fluid in the outer forks. That was too much. The initial fork travel was very plush, but harsh on the mid stroke. There were a lot of sharp spikes to my wrists.

I called up SMART Performance and ordered their SPI 3 special fork fluid.
http://smartperformanceinc.com/215VM2K5.html
I added 300cc of the SPI 3 fluid to outer fork per their recommendation.
The forks are very plush now. Even with the stock YZ125 fork valving/spring, the forks work really well.
I don't think I have ever had this much confidence to go fast on the bike as I do now. We have a loop that we ride on, my average speed on the loop has been a steady 19mph. Today I hit 21.9mph.
Helmet cam to come.

i had smart performance do the forks and shocks on that wr i had.. huge improvement ..