My 94 300Bayou 4x4(bought used in May of this year) seems to be developing some gear whine which becomes most noticeable in 3rd
gear and does not seem to become louder or fainter as the load on the drivetrain increases(acceleration or ascending hill). In 4th gear and 5th gear I do not think the noise is as predominant however. I also cannot pinpoint noise source as front or rear differential or transmission. I probably have 30hrs or so ride time since I bought it and would classify the riding as very easy since I am a new rider. I changed differential gear grease(limited slip oil on front diff,std on back to manufacturer's recommendations) and mtr oil(again used recommended oil) when I purchased. Oil levels in front/back differential and mtr are fine,no visible leaks. It is possible that there is more vibration sensed in the handlebars too, but this is something tough to quantify and am not even sure I am not imagining it.

Also, finding neutral has progressively become more difficult. When I bought it and after oil changed transmission shifted to neutral easy, not requiring any rocking. Now, occasionally I need to rock to slip into neutral.

I do not ride the old girl hard since I bought it used earlier this year and am just wondering what kind of drivetrain noise you Bayou 4x4 owners experience. It is one of those things that it is not broke and would prefer not to try to fix it unless it is a precursor to something serious(and expensive) condition later on.

I will change all the fluids to see if new lube makes any impact.

Should I check the circumference between the front pair of 26in and rear 26in tires(Blackwater tires)? While all my riding is on the dirt there would still seem to be some load on the drivetrain that occurs because the front wheels travel a different distance(even slight) per revolution than the rears.

Do these drivetrains exhibit harmonics? I do not think it is a harmonic situation because it is not totally dependent on mtr rpm and tire rpm.

Sorry for long winded note. I know this is probably impossible to diagnose on a forum but I was hoping to obtain some of your experience in this area. Thanks

 

Based on the clues you've provided, the culprits are most likely the 26-inch tires.

The extra weight of the Blackwaters combined with their larger diameter, which effectively gives every gear a higher ratio, has placed extra stress on the drivetrain sufficient to cause premature wear.

The most likely wear points are the CV-joints and/or the universal joints. Only examination by a competent mechanic is likely to pinpoint the exact cause of trouble. The diagnostic effort required to troubleshoot problems of this nature can be considerably expensive.

I have a '91 Bayou 300 4x4 that I bought used in July '98. My daughter and I rode on the nearly worn out OEM Dunlop KT962A tires (24x8x11 fronts & 24x10x11 rears) for about 8 months. Then just prior to the big Cochranton Poker Run in April '99 I put on a set of Goodyear Mudrunners (25x8x11 fronts & 25x10x11 rears), which were somewhat heavier than the Dunlops they replaced. But despite their nominal 25-inch diameter, they were by actual measurement the same size as the 24-inch Dunlops, so my effective gear ratios did not change. Also, I intentionally did not go to a wider than stock tire so as not to increase driveline stress any more than necessary, or increase steering effort any more than necessary.

After 18 months with the Mudrunners installed, during which time my Bayou 300 4x4 has gone to Cochranton, Quads-On-The-Rocks I & II, and has been used to work around the house pulling a Sears 14 CF garden cart (usually filled with mulched up leaves), I have not experienced any drivetrain problems.

You have several options available to you, none of which are optimum. Since the source of the gear whine is difficult to pinpoint, you can: (1) pay a mechanic to locate and fix it - but this does nothing to prevent the problem from recurring; (2) you can replace the 26-inch Blackwaters with a set of 24-inch tires of your choosing; (3) you can perform both operation # 1 and operation # 2 - but it will be expensive; or (4) you can continue to drive it until something breaks, and then fix it - which also could be expensive.

You didn't say how wide the Blackwaters were. But if they were part of a 12-inch wide "Bigfoot" kit, then the 50% increase in front tire width, and 20% increase in rear tire width, have probably overstressed your CV-joints. If they are the 12-inch wide tires, I'd say your best bet, especially in light of the casual trail riding you claim mostly to do, is to replace the wider tires with ones of stock width as soon as possible. This won't fix the problem, but it will keep it from getting much worse.

Army Man

 

thanks army man. I posted several months ago asking question about 26inx12in blackwaters putting excessive strain on wheel bearings. I ended up replacing all 4 wheel bearings. I know the big tires will increase wheel bearing loads and make overall gearatio taller but since I am not riding hard I did not think I would be adding significant stress to drivetrain otherwise(hard to say what the previous owner did though)

I might raise it up on blocks and use the old long handled screwdriver trick or stethoscope on the differentials and transmission. I know it probably won't work but may help identify the source.

After replacing the wheel bearings I had decided on going to a smaller/narrower tires next year.

 

I have a 98 300 4x4.I ride it hard,and I use it to work around the house. It works great ,no noises or anything to speak of.Sounds like the previous owner of your atv rode in 3rd gear alot. With the larger more aggresive tires he would have run in the lower gears alot.The 300 is not a power house and 3rd would be a good trail gear.My 300 still has good factory tires on it , and it will go anywhere you want it to go.I also shift between Hi & Low range so not to stay in the same gears all the time.

 

Was riding over the weekend, I think you might be on to something about spending a disproportionate amount of time in 3rd gear. I did notice the 3rd gear whine was intermittent, some shifts it made the noise, some shifts the noise was not there. Makes me suspect shift forks, something in the shifting mechanism that allows the gears to mesh in slightly different positions. Just a hunch.

 

My dad has a 95 300 4x4 and it was making a slight noise intermittenly. Kind of a whirring noise. We tracked it down to the universal joint right behind the cover behind the shifter. It is on the driveshaft going to the front differential. The universal joint was dry of grease and basically worn out. Only place we could find a replacement was from Kawasaki at a cost of $47. There are four circlips that are not included in this price, but if all yours are still there you can reuse them. Circlips are $2 a piece.

It is hard to check this part but the way to do it is jack up the bike so that all four wheels are off the ground and put the transmission in neutral. Then spin the rear wheels (sort of rock wheel back an forth) by hand to see if there is any play in the front driveshaft.

Also while the wheels are NOT turning and the bike is off the ground, grab the front driveshaft and try shaking it. If there is any play, this may very well be the noise you are hearing. The front joint is the same part number, but it is covered by a rubber boot that keeps the dirt out of it.
You can go to www.buykawasaki.com and they have very good pictures of the parts I am referring to.
Oh yea, I call it a universal joint and Kawasaki calls it a "spider".

(It is important to check this with the wheels off the ground so that the drivetrain is not bound up.)

Hope this helps.

Jason

 

Thanks Jason, I can confirm the front driveshaft does not have any side to side movement when I push and pull on it so I think the carrier bearings are ok,but I did not think of checking the universal joints. I will have a look.

 

Forgot to mention in last post that my dad has 25x12x11 blackwaters on the rear and 25x9x11 blackwaters on the front. Never any problems with bearings while using these tires. They actually ride fairly smooth but we never really ride on "hard pack" ground. Mostly grassy fields, muddy areas, and backwoods so the ground is generally soft.