Top 5 ways to make the Suzuki RM85 a Top Performance Motocross Bike | Moto-House MX

Posted by Frank Milazzo on

How do you make the Suzuki RM85 a contender against the other great 85cc motocross bikes out there? You can do It all yourself for under $900. The Suzuki has always been known as an excellent handling dirt bike, now let's get more power out from the motor.  Moto-House MX has simple bolt-on parts that can make the Suzuki RM85 a contender!
The Suzuki RM85 has not seen changes for years, but that is not necessarily a bad thing. Even though the RM85 has not had any performance updates, the bike can be very competitive with just a few bolt-on modifications and upgrades.
 
I always like to look at building an 85cc bike on a budget, but yet have the performance to hang with the new bikes that cost over $5,000. First, we need to find a good low hour Suzuki RM85 There are also alot of used ones out there between $1,000 to $1,500. The Suzuki RM85 motor’s power output is focused on low to midrange and with a little work you can change this bike into a competitive racer. 

1. Carburetor Kehin PWK 28mm Keihin PWK 28mm Carburetor Suzuki RM85 | Moto-House MX

First tihs I would update is the old school carburetor on the RM85. The stock Carburetor is the old style Keihin PE 28mm round side and I would recommend to replace it with a Keihin PWK 28mm carburetor. The Keihin carburetor will give the RM85 a stronger acceleration right off the bottom end and put a stop to any bogging off the bottom. This carburetor is standard on all of the other 85cc bikes, which must tell you something if all the others use the same carb.

2. Vforce 3 Reed SystemVForce3 Reed Valve Suzuki RM85 | Moto-House MX

The next thing we added to the intake system is a Vforce3 reed cage. The biggest advantage of the Vforce3 reed cage is it will increase air flow. When you can increase the airflow to the engine, it means more horsepower. Since the VForce3 offers double the reed surface area, this reduces reed pedal travel, increase in power through the entire power range, improved bottom end, stronger mid-range and longer top-end over-rev. The double reed tip design also reduces wear on the reed petals for greater longevity. That’s a win all the way around.

3. K&N Air Filters & Air BoxK&N Air Filter Suzuki RM85 | Moto-House MXTwin Air Filter Suzuki RM85 | Moto-House MX

Last but not least, using a high-quality air filter will top off the intake system. On days with good weather, I have found the best results when using a K&N filter. The K&N will flow more air compared to a foam filter, but when the weather is bad, or track is very wet, I will opt for a Twin Air filter which is always a good solid choice. The reason why I don't use the K&N in wet weather or really muddy conditions is when you add a pre-charger over the K&N filter, it is a little too restrictive. I also recommend using a PC Racing Pro Seal to help with a positive seal around the air filter to the air box. Keeping dirt out is always very important.

4. FMF Factory Fatty Exhaust System FMF Factory Fatty Exhaust Pipe Suzuki RM85 | Moto-House MX

Last but not least, using a high-quality air filter will top off the intake system. On days with good weather, I have found the best results when using a K&N filter. The K&N will flow more air compared to a foam filter, but when the weather is bad, or track is very wet, I will opt for a Twin Air filter which is always a good solid choice. The reason why I don't use the K&N in wet weather or really muddy conditions is when you add a pre-charger over the K&N filter, it is a little too restrictive. I also recommend using a PC Racing Pro Seal to help with a positive seal around the air filter to the air box. Keeping dirt out is always very important.

5. FMF powercore2 Shorty Silencer                       FMF Powercore 2 Shorty Suzuki RM85 | Moto-Houose MX

When you combine the Factory Fatty with the Powercore 2 Shorty, you have a winning combination. The FMF Shorty silence enhances the bottom to mid range power.  When racing on larger tracks and looking for more over-rev from the engine, the best choice I like is the FMF TI-2 Silencer for a real factory-level performance. The FMF Titanium 2 Silencer is also the lightest silencer FMF has ever made which also adds to the performance.

  Engine Performance                             Racers Gasket kit Suzuki RM85 | Moto-House MX

One of the most important and the first thing to remember is your engine is only as good as the condition of your crankshaft, piston, and rings. Piston and rings should be replaced at least every 15 hours, and crankshaft should be inspected. You have to think of your piston, rings, and crank as the heart of your engine and keeping them strong is just like keeping your heart strong.  I like to use a thinner than stock base gasket to lower the cylinder height. This will raise the compression and help with power all through the entire powerband.
The Suzuki RM 85 has always handled great, and the suspension is excellent as long as the bike’s spring rates are set up correctly for your rider. You should keep the fork and shock fluids fresh and clean. The last thing I liked to do is to swap out the rear link and change it to the PR2 rear link. 
Overall, the Suzuki RM85 is a great little bike that has unlimited potential to make it how you want and a very reasonable price. If you have more questions contact us at Moto-House MX 407-558-0282 

 

 


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  • Keihin doesn’t make a PWK 28 for the RM85. Any suggestions?

    keith kingsfield on

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