Pro Circuit Suspension Mod for YZ250FX

What it is

• Revalved and resprung suspension for our YZ250FX.

Pro Circuit may be one of the most well-known aftermarket companies in the motocross world. With the success of their Supercross/Motocross race team and their proven products and modifications, everyone knows the brand. With their own in-house suspension department, we sent our Yamaha YZ250FX suspension there to be revalved, resprung, and serviced after we felt it needed to be modified for our riding and racing. They can do anything from simple oil changes to modified parts and even works suspension if that is in the budget.

How it works

• Plush initial stroke.
• Holds up well in the rough braking bumps and whoops.
• More balanced.

After competing in a couple races and riding in a few different types of terrain, we felt the need to modify the suspension on our 2017 YZ250FX. As it was stock, it was too soft for all of our testers in the common West coast terrain including local grand prix style races and motocross tracks that we typically ride. Similarly, going up to 50 hours on stock suspension oil or any oil for that matter is a bad idea. It breaks down rather quickly and will only make the suspension feel worse in most cases. That is where Pro Circuit comes into the picture.

We enlisted them to help solve this issue where they then went all out in replacing all the wear items including seals and oil along with changing both the fork springs and shock spring, internal valving, a bladder cap kit for the shock, and installing their National Spring Tubes in the forks. The spring rates utilized were .48 fork springs and a 5.4 Kg shock spring which is what was needed for a 157lb off-road expert rider. The National Spring Tubes allow the oil in the forks to flow more freely than it does with the stock spring seats. This is claimed to allow for a plusher ride without being too soft.

In our initial testing following the service, it provided a much different feel from stock. Both the forks and shock were much stiffer which is what we were looking for. The first couple rides were spent riding in a variety of conditions from fast and sandy tracks to hard pack square edge terrain. With our main focus being to setup the suspension to work for the 1.5 hour AMA Big6 races, finding something that’s comforting and doesn’t wear you out while still working at the high speeds over the ultra rough terrain is difficult.

We ran the sag at 105mm which is right in line with their suggested 102-105mm sag. After multiple days of riding and racing, we were having difficulty in setting up the rear shock. The rear end liked to kick up a lot over just about everything from braking bumps to sand whoops and we had to slow the rebound down quite a bit to help fix this. Eventually, we ran out of adjustment slowing the rebound down so Pro Circuit ended up making a setting change. After receiving the shock again, we were able to find a much better setting with minimal amounts of adjusting the clickers. The bike settles down a lot more through braking bumps without any packing and it is much more confidence inspiring than before. Similarly, when hitting whoops or square edges, the bike stays planted to the ground and has a progressive feel through the stroke.  

After getting our shock to work properly, we were able to really focus on the fork. In the initial setting, the fork was very supple and responded very well to smaller braking bumps. On smoother tracks or in tighter terrain, the forks shined. However, once up to race speed on much rougher terrain, we still had some issues with the fork being a little too soft. They would dive a lot in the bigger braking bumps and kept the bike from feeling balanced. Pro Circuit was able to make a change to the fork settings as well to try to fix this problem. And they did. With the newer setting in place, the forks were still plush enough in the initial stroke that it would work good in tight terrain along with rocky terrain and it didn’t deflect off the rocks at all. Similarly, once in the bigger braking bumps and whoops, the forks stayed up in the stroke and we didn’t feel any harsh spots. Very rarely did we bottom out the forks and the only time we ever had a problem with that was on some hard landings off of big jumps. It was a manageable hit that didn’t phase us at all and was expected for being setup for off-road racing and riding.

With Pro Circuit being such a large company that has become world renowned for their services and products, one downside can be wait time. Depending on the time of year and plain luck, they could be swamped with work or they can be relatively empty handed and ready to take on anything at that moment. Our wait time varied anywhere from just a couple days to a little over a week with this suspension which could have been much worse. Also, they were willing to work with us and make some changes when asked too which is crucial when getting your suspension worked on. Finding the perfect setting on the first try isn’t usually the case, especially with a new customer, so being able to make changes is an important aspect when working on suspension.

At the recent Prairie Dogs/Desert MC Night Team Scrambles at Glen Helen, myself and Chance Fullerton were able to win the race overall with these settings and Chance himself felt the suspension was night and day better than what he had ridden on at the 24 hour race last year. Additionally, I was able to get a couple top 5’s in the Pro 2 class at some of the AMA Big6 WCGP races earlier in the year.

In conclusion, our YZ250FX suspension needed some work to fully satisfy our wants for west coast racing. The stock settings were a little too soft for our testers in just about every condition we ride and race in. Likewise, stock suspension oil is only good for so many hours which amplified the problems we were having. Pro Circuit; however, was able to fix this problem. With the proper spring rates and revalved settings, we were able to get the bike working much better with stiffer settings and a balanced feel. The bike handled everything from slower rocky canyons to endless braking bumps and whoops and most motocross tracks. Their services aren’t cheap with our total coming in at $1,490.00. Yet you have to factor in the parts which were $52 for the seals and $260 for both the fork springs and shock spring and those aren’t always necessary when getting suspension work done. And having a suspension tech that dials you in for $360 is a deal considering how much better the bike worked for us. They helped find solutions with the suspension beyond what it could do stock.