Hi All....I have an 05 BF750 w/ about 750 miles on it. I rode about 70 miles over the weekend and noticed oil leaking out of the rear end where the right axle meets the differential. It seemed as though the seal pushed out. The oil was black and the differential very very hot. It seemed to leak more after riding at higher speeds. Anyt ideas on wht this could be? I found some posts that mention the internal break but not sure that is the problem.

Also, my 2wd/4wd light flashes back and forth. When I shut the bike off and turn it back on it stops for a while. Not sure if that could be related.

Thanks for your help!

 

Flip,I don`t own one of these,but some things that come to mind:
1.Were you using the rear brake a lot?
2.Make sure your rear case breather hose is still on&open.Should be visble coming off top of rear axle case.
3.Is it possible that the rear brake is adj. too tight?Jack up the rear end&turn rear axle to see if it`s loose.

After you find the cause of your problem,you`r gonna need a new seal.I would advise a Clymer repair manual on your machine.Also,with the rear brake assy in the rearend,I would change the rear gear lube every year or so.After you get it going again,every now&then feel your rear axle&see if it`s getting hot again,to see how much you can use the rear brake.You might have to slow down a little.
Dizz

 

I own one of those and let me point out something.

> BF750s don't have a rear differential. It is independengt rear suspension but L/F wheels turn at same rate.
> Rear gear case oil is a special oil that lubricates both gears and brake system which is wet brake like on farm tractors - multi friction plates.
> Some how you are creating lots of hit on the rear brakes and heated/expanded wet brake oil is spewing out.
> Are you riding with your foot on the right pedal brake?
> Are you riding with parking brake on?
> Maybe wet brake oil was over filled?
> Maybe like the other guy said, the rear brake cable is too tight and dragging?
> Don't fill hypoid gear oil in there. You must use wet brake oil from kawi or from any farm tractor store like Mobil 454.
> 2/4WD flashing has notthing to do with the wet brake oil spewing out. It has either something to do with 4wd engagement or engine brake sysgtem. Both if the controller (black box) is shot.
> Lastly and most importantly, do yourself a favor by getting a genuine Kawi service manual for your 750, nothing else - the BEST investment you would ever make on your quad. All the above info are in there - no guessing game when something goes wrong.

 

Hi Guys,

I picked up a factory service manual yesterday....A few questions:

Re. brakes...If any of the cables were too tight or stuck, would the bike be able to roll freely in neutral?

Also, I noticed when I took the fill screw out of the rear end, that it hissed indicating that there was a vaccum built up inside. Is there in fact a breather hose? If so, I have not seen it.

Thanks!

 

<div class="FTQUOTE"><begin quote>Originally posted by: flip1950
Re. brakes...If any of the cables were too tight or stuck, would the bike be able to roll freely in neutral?

Also, I noticed when I took the fill screw out of the rear end, that it hissed indicating that there was a vaccum built up inside. Is there in fact a breather hose? If so, I have not seen it.
</end quote></div>

&gt; If the brake cables are set too tight, you would NOT be able to push the quad in neutral freely. Best way to check is to raise the rear end, and try to rotate the wheels by hand.

&gt; You missed the vent hose? It is about an 3/8" OD black rubber hose attached at the top of the rear gear case a couple of inches behind the two rear brake cables bracket little toward to the left. Follow the rubber hose all the way to the handle bar. There might be a kink or restriction since your rear seal blew out instead of venting out the excess pressure built up inside the gear case. If you don't take care of this, your new seal may fail again later.