Feedback Score: 4 reviews
Join Date: Aug 2003
Location: Conroe, TX
Common Mechanical Problems of the BF750i/650i
Thought it might be helpful to make a list of the most COMMON mechanical problems/weaknesses that occur on the BF750i and BF650i. (NOT including the BF650sra b/c that is a separate list). This list could be helpful for new BF 750i and BF650i owners and/or someone interested in buying one.
I'll start the list (in no particular order)...please post below with any suggestions you have to add to this list.
BRUTE FORCE COMMON MECHANICAL PROBLEMS:
1) Stock oil seals on engine and front/rear diff tend to leak; Fix: Keep an eye on them and replace as needed (no aftermarket seals available at this time)
2) Stock front and rear shocks are too soft for fast-paced riding; Fix: replace with aftermarket shocks
3) Stock CDI is very restricted on carb'd models; Fix: replace with aftermarket CDI to eliminate low speed and top speed retarded ignition timing and to increase maximum ignition timing
4) Stock radiator tends to plug up with dirt/mud and cause engine overheating; Fix: Thoroughly clean the radiator fins with a water hose on a frequent basis (don't use a pressure washer), especially needed after a muddy or dusty ride. Some folks install a fan switch and operate the fan continuously during rides.
5) Stock bushings on front and rear a-arms wear out fast/have no grease zerks; Fix: Replace with aftermarket bushings
6) Stock actuators for the KEBC and 2wd/4wd tend to fail within a few years; Fix: Some folks remove the KEBC actuator and fork and live without the KEBC function. A few folks have also removed the 2wd/4wd actuator and modified it to function manually via a choke cable set-up. If you don't want to make those changes, you can occasionally disassemble the stock actuators to clean, lubricate and reseal with silicone/gasket maker.
7) Stock radiator fan breaker tends to malfunction; Fix: Replace with inline fuse.
8) Pre-2007 BF750i stock front a-arms cause hard steering; Fix: reduce castor angle or replace the upper and lower the stock a-arms with later model BF750i a-arms.
9) Stock front diff may break/lock-up, especially if jumping while in 4wd or if one of the oil seals leaks; Fix: Avoid jumping while in 4wd, change the front diff oil as recommended, and keep an eye on the oil seals.
10) 2007-10 BF750i rear differential ring and pinion locking nut sometimes comes loose; Fix: Apply red loctite to the nut and torq to spec
11) Stock Airbox intake snorkel needs better splash protection to prevent water from entering the airbox during shallow water crossings; Fix: Install EHS Mudder Lid or install full snorkels.
12) 2005 & 2006 BF750i had buss connectors that would sometimes cause odd electrical problems; Fix: Cut the wires and solder all the white wire together and all of the black wires together.
13) Stock tie rods bend too easily; Fix: Replace with stronger aftermarket tie rods.
14) ANYTHING ELSE ???
2007 KFX 730 (sold)
2004 Twin Peaks 800 (sold)
2003 Prairie 650 (parted out)
2002 Prairie 650 (parted out)
Last edited by Mikeyboy_esq; 09-25-2012 at 07:54 PM.