Drilling Extra Oil holes in Inner Clutch Basket

[TR]

I have read that drilling extra holes in the inner clutch basket improves oil flow to the clutch plates. Why would one want to do this ? Using an XR400 as a example I read on TT that their specialist recommend doubling the number of holes.

Has anybody tried this and would like to share his or her experience ?

Sincerely,
TR

 

[Gary B.]

I do it on all my bikes. Haven't smoked a clutch yet!

 

[Rcannon]

Gary, have you noticed this mod doing anything? I did it to my YZ 250 while I added a Hinson clutch basket to replace the well notched stocker.

My clutch is very smooth and nice. No complaints. I wonder if any of this good performance may be due to the extra holes I drilled?

 

[nikki]

Why would you do it - to keep your clutch better oiled and cooler. When things get too hot in your clutch is when you have problems. Hinson inner hubs already come with pre-drilled oiling holes but most stocker inner hubs don't. Some do though - like stock 426 inner baskets I think. We have drilled holes in the stock hubs on my 125's... usually something like every other insert and something like 2 holes, skip, 1 hole, skip, 2 holes, skip, 1 hole, skip...

 

[Kawierider]

Would the best way to do this be with a drill press, then use a small file to round off any burs? WHat size holes did you all you?

 

[jmics19067]

I believed I use a 3/16 drill bit but I can't remember what ever it was it was smaller than the valley at the bottom of the spline. I used a regular hand drill and a brand new bit so I wouldn't have problems with the drill walking. I did deburr mine with a small needle file then wrapped a piece of 400 grit wetordry sand paper around a paint stick and lots of light oil <wd40> and semi polished the splines smooth . For shirts and goggles even deburred the splines on the metal clutch plates but still stacked them in the order of the rounded edge inwards. Had a new clutch cable and new good style lever and perch and it was super silly smooth and easy for awhile

 

[Kawierider]

Thanks

 

[DEANSFASTWAY]

Ive seen some tuners drill angled holes in the pressure plate in the angle of clutch rotation to help introduce oil into the clutch assy .

 

[Camstyn]

So what's the tradeoff? How come they aren't already littered full of holes?

 

[DEANSFASTWAY]

Some do have some holes stock .

 

[Ty]

DEANSFASTWAY,
do you think this would alleviate the crf 450's tendency to swell up. (even with a restrained clutch hand, my lever is on my fingers in minutes)

 

[DEANSFASTWAY]

might help .

 

[flynbryan]

Originally posted by Ty
DEANSFASTWAY,
do you think this would alleviate the crf 450's tendency to swell up. (even with a restrained clutch hand, my lever is on my fingers in minutes)

Ty this is something I've been curious about for a while now :think: I'm apparently pretty clutch happy from what my bike has been telling me and was wondering if this mod would help our bike.

 

[rickyd]

This sounds like a good mod, safe too drill a 3/16 hole??

 

[DEANSFASTWAY]

Alot of folks out here are also running more oil like a whole quart in the trans .

 

[Studboy]

I run almost a full quart in my KX. The manual says to go only half way up the sightglass but I go all the way up. My clutch/tranny work awesome but I don't shift with the power on and always use the clutch to shift so I guess my case isn't that extreme.

 

[DEANSFASTWAY]

I meant on the CR450fs Stud boy your 265 probably makes so much grunt you dont have to hurt that clutch much .YA?

 

[flynbryan]

Originally posted by DEANSFASTWAY
I meant on the CR450fs Stud boy your 265 probably makes so much grunt you dont have to hurt that clutch much .YA?

Deansfastway I've been running between 590-600cc in my Crf. Can't running too high an oil capacity cause stress/pressure on the seals causing leaks? I've heard of other people running high oil levels as well, Just a question.

 

[Studboy]

My KX does have pretty good bottom/mid so I usually don't feather the clutch unless it is not an easy time to downshift. :)
I couldn't call myself a clutch or gear abuser by any means.

 

[DEANSFASTWAY]

FlyinBryan youre right about over filling the oil causing leaks etc. But thats usually by grossly overfilling the oil. There are some reasons why you dont want too much oil like the oil could aerate and foam up also more oil puts more drag on gears rotating things in 4 strokes except 450F crank and stuff . That the main reason behind Dry sump motors , To combat windage of the oil . I know of a few local pros out here that race 450F that are using the full quart . We also have put these 450F motors in Quads and are now working on a larger clutch (extra plates ) and a spacer plate for the clutch cover to hold more oil and maybe let the clutch circulate or put a swail or scoop in the cover to try to channel oil into the center of the clutch . On Quads you turn 2 10 inch wide tires and more weight and drag from both front tires so you need a really stout clutch .

 

[flynbryan]

My friend is a die hard ATV fanatic Dean(I'm guessing thats your name?) and he's been hounding me to sell my motor to him when I get another bike. I thought it was awsome when they were putting the YZ400F motors in Lauger(spelling?) rolling chassis. It's one of the few times I have truely admired something in an ATV package:) Good luck w/ your mods and let us know of any 2wheeled benifitical information you find :thumb: