Another final drive fluid change question.

[CMWingfield]

I've been reading for quite some time the various threads concerning changing the final drive fluid on hexhead bikes and I have a question for the board:

 

When I was a kid, I used to help my Dad work on different kinds of vehicles, and in the old days the practice with old trucks was to suction out the old fluid with the rear end under the truck using the filler hole, then replacing the fluids with new stuff via the same hole. I can't recall this being discussed as an option on the hexheads.

Are there reasons why this method isn't considered, rather than breaking down the final drive?

 

Thanks,

Mike

[IanW]

I've been reading for quite some time the various threads concerning changing the final drive fluid on hexhead bikes and I have a question for the board:

 

When I was a kid, I used to help my Dad work on different kinds of vehicles, and in the old days the practice with old trucks was to suction out the old fluid with the rear end under the truck using the filler hole, then replacing the fluids with new stuff via the same hole. I can't recall this being discussed as an option on the hexheads.

Are there reasons why this method isn't considered, rather than breaking down the final drive?

 

 

 

 

Thanks,

Mike

 

Mike,

The drain hole at the rear of the FD is lower than the level of the oil when filled, so you cannot fill through it.

Ian

[Tech1]

I wonder if the level is intended to be at the plug, just slightly overstated on the oil capacity. The oil capacity may be the amount on a "dry" fill and even then may be rounded up slightly. It may also be at the plug with the suspension compressed, rotating the plug higher.

[RFW]

I've been reading for quite some time the various threads concerning changing the final drive fluid on hexhead bikes and I have a question for the board:

 

When I was a kid, I used to help my Dad work on different kinds of vehicles, and in the old days the practice with old trucks was to suction out the old fluid with the rear end under the truck using the filler hole, then replacing the fluids with new stuff via the same hole. I can't recall this being discussed as an option on the hexheads.

Are there reasons why this method isn't considered, rather than breaking down the final drive?

It makes no sense to disassemble the rear drive just to get the oil out (when no drain bolt is present). At the very worst, remove the drive and turn it upside down and let the oil drain out of the filler hole.

 

But the method you suggest is perfectly valid ....provided you can get the hose all to way to the bottom, inside the drive. It is pretty cramped in there!

[Auto1]

Is it possible to make your own drain bolt on the bottom of the final drive by drilling a hole and tapping it ?

[Limecreek]

It may be possible. Please try it out first and let us know how it turned out.

 

Actually I was thinking about the same thing and decided the pivot and drain method is simple enough for this guy.

[lubie]

Why not pull the plug and do a few wheelies until it's empty??

[Jim VonBaden]

You lose about 1/3 of the FD oil if you simply pull the plug.

 

There is virtually no room next to the gears, and even filling it is a slow process. No way you can suck it out of the FD, no room to get a hose in there.

 

The amount of oil is .22 liters refill, and .25 liters fresh fill.

 

Jim

[RFW]

Is it possible to make your own drain bolt on the bottom of the final drive by drilling a hole and tapping it ?

Sure. Drilling and tapping are easy. The only trick is to spot face the hole so that the drain bolt has a flat surface to seat against.

 

Also considered good engineering practice not to use a bolt so long that it locks against the crown gear.

[IanW]

When I drained my FD I raised the bike to almost vertical (using a block and tackle attached to an "A" frame) and drained the oil, then lowered the bike, removed the muffler, the wheel and filled it through the speed sensor hole.

Ian

[Illini]

The amount of oil is .22 liters refill, and .25 liters fresh fill.

 

Jim

 

For us dumbasses that didn't pay attention to the metric system instructions in grade school, It's also 7.44 ounces.

[JR356]

When I drained my FD I raised the bike to almost vertical (using a block and tackle attached to an "A" frame) and drained the oil, then lowered the bike, removed the muffler, the wheel and filled it through the speed sensor hole.

Ian

 

 

Hi,

 

Seems that with the time and effort involved in lifting,it would be just as easy to do it the conventional way.

 

JR356

[RFW]

For us dumbasses that didn't pay attention to the metric system instructions in grade school, It's also 7.44 ounces.

You mean you have to WEIGH it???

[Firefight911]

For us dumbasses that didn't pay attention to the metric system instructions in grade school, It's also 7.44 ounces.

You mean you have to WEIGH it???

 

You say that as if it is a bad thing???

[gettysburg]

For us dumbasses that didn't pay attention to the metric system instructions in grade school, It's also 7.44 ounces.

You mean you have to WEIGH it???

 

If it's a fluid ounce, it's a measure of volume, not weight/mass.