The Woods Ripper That YOU Can Build – We Build It Part III – The Chassis

suspension_studio_fullClick on any of the photos for larger versions

If you read Part II of this series you will have seen the effort we put into the YZ/ Athena motor. Our efforts paid off, it turned out much better than we anticipated. If you haven’t seen it, it’s worth a look, check the link above. With such a beautiful motor in hand it seemed a shame to put it back into such a mundane rolling chassis. Bearing this in mind, we thought it only appropriate to make a few enhancing modifications to the rolling chassis of our Woods Ripper project.

In stock form the YZ suspension is dated by modern standards. However, with a bit of effort, it could be modified to work very well for our purposes. Since we were building a woods bike that would not be subjected to the huge forces imposed by jump landings we felt we could get away with this. If we were building the bike to be used for MX we would have looked into replacing the fork and shock with more current units. As we approached the changes we would be making we felt it important to consider rider positioning, we wanted to keep this position as neutral as possible. We started by chucking the stock upper and lower triple clamps for something that would offer more rigidity, allow us to use a Renthal Fatbar, and provide better front end feedback. We chose a Factory Triple Clamp Set from APPLIED Racing that not only met our needs but also featured reversible bar mounts providing even more control over rider position. We added a Renthal bar with the KX bend because we wanted to keep the bar as low as possible to keep the weight bias and riding position as far forward as possible.

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Upper and Lower Triple clamp by Applied Racing

Once we had the triple clamps/ bar combo sorted out we turned our attention to the stock suspension which was in need of some help. Our YZ desperately needed new oil seals and a serious service on the fork. OEM spring rates were far too soft for our average rider weight and the stock valving was miles too harsh for woods riding. We wanted a suspension that was not only supple enough to soak up high speed bumps, small roots, rocks, etc. but one that was resistant to bottoming when landing from reasonable jumps as well. For this type of set up we could have easily sent out our suspenders to one of the many suspension tuners out there. But the idea behind this feature is that it’s a bike you can build. We are hoping to encourage you to do the work yourself so you can better understand how your bike works.

We chose to rebuild the YZ suspension with Race Tech products, installing Gold Valves and springs front and rear. We have installed Gold Valve kits on several different bikes and have been pleased with results each time. The Race Tech system breaks down compression and rebound valving shim by shim, enabling the user to really fine tune the valving to his or her liking without having to take the time to send parts out to a tuner. We have said it a million times… If you want to go faster, get your suspension working for you. All the power in the world is no good if you are riding a bucking bronco.

Re-valving the YZ would require complete dismantling of  the fork and shock. While we had it apart we sent the fork tubes and shock shaft to Extremeion for their Diamond Like Coating (DLC) treatment. DLC makes suspension feel much smoother by reducing stiction and as an added  bonus, it makes the seals last longer. It’s not cheap but it makes a difference and we feel it’s worth the investment.

The Race Tech Gold Valve to the left of the OEM unit.

The Race Tech Gold Valve to the left of the OEM unit.

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The Race Tech shim high speed and low speed stacks ready to be installed.

While we had the suspension apart we sent the fork tubes and shock shaft out for DLC by Extremeion.

While we had the suspension apart we sent the fork tubes and shock shaft out for DLC by Extremeion.

Lug removal is required for DLC and is a complete nightmare!

Lug removal is required for DLC and is a complete nightmare!

For some reason 2 t’s tend to feel lighter on the front end when compared to 4t’s, making them feel almost twitchy up front – It could be the extra lbs. In an effort to reduce this feeling on our Woods Ripper, we opted to install a steering damper hoping to alleviate this issue. In 2010 we did a comparison between the SCOTTS unit and the model from Ohlins. The stability provided by these dampers is unparalleled. If you have never tried one see if you can find someone who has one who will let you ride their bike. The difference between having one and not is like night and day. We were most impressed by the Ohlins unit. One of the key features we really liked about it was that it had such a low profile, it didn’t require taller bar mounts (see rider position), and it was so compact. It was the appropriate choice.

Ohlins steering damper, compact and out of the way.

Ohlins steering damper, compact and out of the way.

Talon's rear shock spring adjuster is a beautiful piece of work.

Talon’s rear shock spring adjuster is a beautiful piece of work.

Completing the series of suspension mods we made on the rear shock was a Talon spring adjustment collar. Adjustment collars that generally come as OEM are nasty stamped steel (KTM is not included in this group). Our YZ was no exception and the years of abuse from flat blade screw drivers had taken their toll. Ours looked more like a piece of circular barbed wire that something that would be found on a motorcycle. The unit from Talon on the other hand,  is a work of art. Machined from billet aluminum, it provides extreme fine tuning adjustment and much more appropriate for a project like this.

Having the suspension in the bag we turned our attention to the swing arm linkage and wheels. Our stock wheels were in surprisingly good condition considering their age and much to our surprise so were the swing arm/ linkage bearings. We did have to replace the bearings on the front hub with a fresh set from ALL BALLS Racing. But a good cleaning and repacking was all that was required for the rest. The main issue we faced was the years of accumulated muck and grim that was never properly cleaned. Nothing we did to clean it off worked. The spokes looked really rough, plus the scratched, dull, silver OE rims were going to look out of place on such a clean chassis. Sounds like an opportunity… We called our friends at Warp 9 for a fresh set of hoops in black. While we had the wheels apart, waiting for the rims to arrive, we ran the hubs through the bead blasting booth and brought them back to life.

 

Each spoke and nipple was individually hand polished

Each spoke and nipple was individually hand polished

 

We also spent some time, a lot of time, at the polishing wheel and brought the spokes and aluminum nipples back to life. It’s pretty amazing what a bit of elbow grease will do! We fitted a set of MotOz Terrapactor tires front and rear. We have ridden on MotOz tires for over 2 years now on our test bikes and they have proven to provide excellent grip and durability.

With the wheels assembled and suspension reworked we had a few modifications we felt appropriate for the braking system starting with the front.

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The shorter routing makes for a firmer feel at the lever.

Ride Engineering has a far better routing for the front brake line.

Ride Engineering has a far better routing for the front brake line.

The OEM routing for the front brake brought the brake line underneath the fork lug adding an additional 10 inches to the brake line. Ride Engineering offers a simple solution for this with a shorter line that utilizes a cable stop which mounts to the fork guard allowing the line to route above the hub, between the fork and spokes. It makes for a more “sano” look and is steel braided for a more consistent feel at the lever.

For the rear brake we kept the OEM brake line but added a brake clevis and brake pedal spring from FAAST Racing. The pedal spring increases the amount of effort required to activate the brake and makes “brake feel” far superior to a stock set up. The Clevis eliminates any play in the system and is a no brainer upgrade as far as we are concerned. We mounted a set of FastWay F3 foot pegs for added grip and comfort on longer rides. New Renthal brake pads front and rear finished off our brake system mods.

This brake clevis from FAAST Racing combined with the brake pedal spring make for an amazing rear brake.

This brake clevis from FAAST Racing combined with the brake pedal spring make for an amazing rear brake.

Next up… We mount new plastic, install graphics and a few other parts and take our Fresh YZ/ Athena 144 for a test ride. Be sure to come along, it’s going to be tons of fun!