what drag racing does to a clutch

tmpowdercoating

tmpowdercoating

Donating Member
Registered
had some problems at the track last weekend. the clutch kept locking up on me and i couldnt get it to slide like normal. tore into it this morning and this is what i found. looks like it got a little hot. anyone know of any mods to the baskets or pressure plate to get more oil on them. i have a few extra baskets and pressure plates laying around. think im gonna drill some holes in them and do some experimenting.

clutch 001.jpg

clutch 002.jpg

clutch 001.jpg


clutch 002.jpg
 
If you drill more holes into the basket the oil will escape from the cltuch assmebly quicker. The oil flows into the assembly through the shaft. Give yourself more time in between runs to let the clutch cool.
 
Commuta_Busa said:
If you drill more holes into the basket the oil will escape from the cltuch assmebly quicker. The oil flows into the assembly through the shaft. Give yourself more time in between runs to let the clutch cool.
Click to expand...

sometimes when you are bracket racing and go a few rounds you might only have a couple minutes in between passes. i remember some of the old school racers use to drill holes to get more oil. is the shaft the only place it gets oil. i noticed the inner basket has holes in it. not sure if its to drain or get oil.
 
ive found out that the factory OEM clutches get the most life when drag racing ive tried many different kinds and OEM works best IMO
 
When you spin the oil pump I've only seen the oil coming out from the shaft. So for the inner hub it makes sense to enlarge or add a few more holes so the oil gets to the clutch pack but the outer basket already drains oil very fast. On a stock inner hub I have I did this but it didn't show any measurable change to the clutch pack temp. The oil temp didn't increase so I can't say it had any effect on cooling the clutch. The clutch pack always had a higher temp. As far as preventing the clutch from getting fried there are so many variables that I don't know how you would measure any kind of improvement.

Get a big ol' fan to blow on the assembly between the short rounds.
tmpowdercoating said:
sometimes when you are bracket racing and go a few rounds you might only have a couple minutes in between passes. i remember some of the old school racers use to drill holes to get more oil. is the shaft the only place it gets oil. i noticed the inner basket has holes in it. not sure if its to drain or get oil.
Click to expand...
 
few things ive been thinking about are a big old fan, removing the oil fill cap between rounds, and leaning the bike way over to the right before starting to soak the clutches.
 
I think Draco has some technic to cool the clutch too. You might want to check with him...

Get yourself a big ol' bottle of co2, drop a short line in through the oil fil and shot some gas on it between rounds. Just keep the flow low so it doesn't form ice crystals in the air.:laugh:
 
i dont know if i would drill holes in the basket, they are pretty week to begin with....seems like there would be a better way than that...

we used to use fans to cool the things down between rounds, it kinda helps
 
Last edited:
In between runs find something to hold the clutch lever down this helps alot with overheating and its simple to do :thumbsup:
 
qrychefanus said:
i dont know if i would drill holes in the basket, they are pretty week to begin with....seems like there would be a better way than that...

we used to use fans to cool the things down between rounds, it kinda helps
Click to expand...


Yeah if the basket came apart and blew through cover. Could be deadly.
 
Mine used to break the innermost two or three clutch fibers when I was running 6 of the heavy duty Brocks Clutch springs. Now I run Brocks 3 heavy and 3 medium and have not had anymore broken clutch fibers.

The bike is drag raced heavily and has 242 hp.
 
damn. have you thought about nabbing a hayes? seems like you've got it dialed pretty well tho. damn, 1.3 short times huh? must be a wild ride
 
ogre said:
damn. have you thought about nabbing a hayes? seems like you've got it dialed pretty well tho. damn, 1.3 short times huh? must be a wild ride
Click to expand...

Actually I talked to tim about the hays a couple days ago. It's just I'm in the middle of the season and don't want to have to deal with all the setup and tuning. I will have a slider for next season.
 
call frank from power house cycles I know him and he has some wild bikes and might have a idea or 2
 
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