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Rokon Modifications
Neat stuff to do to your Trail-Breaker
Got a performance improving idea? Send it in!
Stainless steel airbox for riding through deep water.
Drive that Rokon underwater with a Deep Water Kit from John Bohmer. This kit will allow you to ride in water 30 inches deep (or at least until the bike starts to float on those hollow wheels). A great item to have if you ride in swampland or where you have a lot of stream crossings, this thing will get you through wet areas that would drown the stock aircleaner. Deep water has always been the Rokon's weakness...no longer! This is a beautifully built and well tested stainless-steel airbox. Unlike other contraptions people have used to hit the deep water, this one has no throttle hesitation and no power loss. Contact John before ordering or if you want more details. This thing works GREAT!
Check out these pictures I captured from video while testing out my air-box.
The pictures are poor quality, but you get the idea. I was able to take my Rokon places I had never been able to go before. This airbox works fantastic and is a "must have" item if you want the ultimate in off-road performance and need to tackle deep water.
For more info, or if you are in South Florida and are looking for a new Rokon, contact:
John Bohmer
Affordable Equipment Inc.
388 South Military Trail #1
West Palm Beach, FL 33415
(561) 478-4407
FAX (561) 478-3998
These stainless steel air-boxes are custom built by John (he also offers hot-rod Rokon carbs) and I can tell you first-hand that the air-boxes are top quality and come with everything you need to complete the installation...takes about two hours to install if you work slow like me.
There is much more to these units than meets the eye. It is more than running a big tube to your carb, two-stroke engines are very touchy when it comes to airflow and much testing and design work went into these boxes. Rokon Inc tried it in the '80s and dorked it up because they didn't do their homework....these boxes here are built right, look good, and most importantly, they work. Getting it to work with no power loss was the tricky part and took much research and testing.
Johnny and his Rokon dealership are listed on the DEALERS page also. For more info on these units, contact John in West Palm Beach, Florida at:
561-642-4355
Here is another deep water kit, this one built by RED136 is made from an electrical junction box. Red, "For the air intake assembly, I used an old electrical junction box. I cut the front out, put in the mesh assembly to keep the large stuff out and installed a K&N filter out of a Ford Escort. The Y going into the carburetor is made out of 3/4" (left and right ventricle) merging into a 2-1/2" pipe. All joints were TIG welded on this assembly and the final touches on the inside where the joints were smoothed out with bondo. The original Bohmer velocity stack was retained. To couple the carburetor to the air intake I used two 3/4" x 23" pieces of universal radiator hose."
More awesome creative thinking from the Rokon gang!
Big carbs.
Got a worn out carburetor you need to replace, or just looking for a performance increase. Try one of these carburetors from John Bohmer in Florida. Price is $133.00. Also available is a K&N style filter with nicely machined aluminum velocity stack and with an "Outerwear" pre-filter all for $42.00. Or get the whole mess, carb and filter kit, for $175.00.
Unsolicited appraisal from New Hampshire's Rokon Syco: "One word--AWESOME"
Find more on big carbs here.
For more on the deep water kit and also information on replacing your bushing type steering head with a late model bearing type, try here.
A lot of people have asked about polishing the aluminum Rokon wheels. Polished up, they look great, but they will show EVERY scratch. As good as they look, if you plan on riding the bike hard it is probably not worth the effort. Here is a 69 Trail-Breaker with polished wheels. Also note the modified sweat-on sprockets. These are early style sweat-on sprockets modified for use as a bolt-on sprocket. They were used only for a short time in 1969 when Rokon made the transition from the old style wheel to the newer style.
Need to haul a bit more junk into the wilderness with you, try a trailer.
A sidecar can be used to haul material or passengers. They attach to the bike in about 30 seconds with one bolt. Price from Rokon is around $1000. Here are a couple sidecars, one with a nicely modified tray and the other an ultra-rare "lefty" model. Also check out the Rokon "Freaks" page for a sidecar rig with a driven sidecar wheel.
Another way to carry more of your junk...er, treasures into the wilderness is on the front and rear racks. The stock racks leave much to be desired. Here is an improvement on the rear rack, and an even better rear rack can be seen here. This front rack was made by combining two of Rokon's BBQ racks into a front basket.
A good modification for the older bikes is to drill holes in the frame to oil the over-ride spring. Later model Rokons have these holes drilled from the factory. It is an easy job best done with the rear miterbox removed. Just drill a couple holes in the frame to line up with the over-ride spring's normal placement. It is also a good idea to drill a hole below the spring to allow water to drain out from the frame when you wash the bike. Without a drain hole, water will fill up the frame and the over-ride spring will corrode, rust and break.
Here are some good ideas. Aluminum handguards and folding footpegs.
How about this modified engine mount to strengthen the mount and to make engine swaps easier. With the original mount, you need to remove the transmission to get access to the rear motor-mount bolts. This altered engine mount allows easier access, uses larger mounting bolts (5/16-18 in place of the wimpy 1/4-20 strockers) and also does away with the requirement to remove the crankcase access bolts which, on the pre-74 bikes, are used to mount the engine.
Here is a modified exhaust and altered kickstand mount so that it doesn't catch on rocks and logs as you slide the bike over them. Make the bottom of the bike as smooth as possible and it passes easily over obstacles on its custom full length skid-plate. The shock mounted seat makes for a more comfortable ride.
Here are a couple trick ideas from Bryan in Colorado. First up, a gas cap vent hose to keep the gas off your leg. And here is one for all of you riding older bikes, grease zerks for your steering head king-pin bushings. Here are some notes from Bryan on performing this modification:
"The shoulder bolts were drilled with a 3/32 bit to near where the
shoulder and threads intersect. On the top bolts I drilled the side hole
about 2/3s down the shoulder, on the bottom bolts I drilled the cross hole
just past 3/4s of the way down to get more grease on the bottom
bushing flange. This is the part that has the greatest stress. A #3 drill
was used to allow a 1/4-28 tap just into the head for the zerk. Straight
zerks were used on the top bolt, 90 degree zerks for the bottom bolt.
Zerks are common in the 1/4-28 style. The bolts have to be greased
often (each ride of consequence) for the zerk to make a substantial
difference in wear."
Thanks Bryan!
How about this slick modification from Frank M. to replace the driveline over-ride spring. It uses the bendix assembly from a starter motor. Been in use for over 20 years with no problems.
Here's a neat modification from Rich.
"After you've drilled the two
holes to lubricate the driveshaft over-ride spring, the
older Aquila seat has to be removed, at least partially, to
get oil in. I took a couple of short lengths of 5/16" OD
rubber vacuum tubing (auto supply), inserted one end of
each in the oil holes, and brought the loose ends up so
they're held between the seat front and the fuel tank. The
open ends can be plugged with a small screw or dowel."
Here is a slick trick for owners of RT140, MK3 Automatics and MK4 Automatics. The special bearing (Rokon p/n 100482) used in the jackshaft can be replaced with a standard bearing when modified like the jackshaft shown here.
Chain keeps jumping off? Might have an alignment problem. Here is some info on shimming the wheel to bring the wheel sprocket into alignment with the miterbox sprocket, thanks to 2wheeling Glenn.
Many of you have made similar modifications to your bikes. Share the successes (and failures) of your engineering work. Send in pictures of your modifications and improvements and I'll post them here.
