slipping clutches and dynos

[woollymoof]

Has anyone ever had trouble with the clutches in their engines slipping on the dyno?

If so, what did you do to prevent it?

[woollymoof]

Has anyone ever had trouble with the clutches in their engines slipping on the dyno?

If so, what did you do to prevent it?

[B Lewis @ PE Engine Management]

We have never had any problems with small engines and slipping. Sounds like it may be time for a rebuild.

[Wilso]

Our clutch began to slip while in the car on the night before we left for Detroit. And by slip I mean leave nice chunks of friction material and bits of aluminum in the oil pan. Luckily we had another engine that we could steal the plates from. I did some research on the web and found that the wet clutches found in most motorcycle engines are not prone to wearing out. Because it was probably the second time our car had been driven, we knew we did not burn it up. My guess is some novice bought a high powered bike, didn't know how to ride, burned up the clutch, wrecked it and then parted it out on Ebay. To answer your question, our clutches have never slipped while on the dyno. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Denny Trimble]

The only time our clutch slipped last year (unintentionally) was the day after we did 80 accel runs. I'm still puzzled...

The car sounded like a CVT with an intermittent cutout... the engine stayed at the same RPM no matter what the driver did with the shifter http://fsae.com/groupee_common/emoticons/icon_smile.gif

[MotoDave]

Oil can have an effect on the clutches in MC engines, if you're having problems try using the full synthetic MC specific stuff. I had a similar problem with a streetbike, and switching to the good oil cured it.

[powered by wattard]

Kirk, much experience in this area. Let me guess, are you using penrite oil, not sure if you guys are running a dry sump. Have you pulled the clutch plates out yet, what do they look like, are the frictions just glazed or are the metals blue, also check the spring tension on the springs that hold the pressure plate.

Replace any parts that look suspect and use Shell VSX4 motorbike oil, if the engine is stock(ie no turbo) you wont have another problem. If I can help any further, email me at will@murmotorsports.com

Regards

Will Attard

[andrewd]

the standard cbr600 f4 clutch slips at about 80 Nm

so unless your getting more than that, there shouldnt be a problem http://fsae.com/groupee_common/emoticons/icon_wink.gif

[woollymoof]

Thanks guys,

We did a clutch a couple of months ago with maybe 10 hours of dyno work, the engine was from a wrecked bike. I didn't realise what was happening straight away so when we took the clutch out it looked like we'd pulled it out of a fire, not a bike.

This latest clutch is from the other engine that we're running and has done less time on the dyno. I haven't pulled it out of the engine yet.

It is frustrating esp since we were meant to be sending the cams to be ground today.

Will, we are using Penrite, they're a sponsor. Are you against all penrite oils in bike engines or just a specific one?

[sg]

I can vouch for the standard clutch slipping at 80Nm also. The carbon fibre clutches from Barnett can hold approx 95Nm but only after the clutch is warm this is also with small packers under the springs to stiffen it up a bit also. This is on a CBR600 engine running R4 superbike oil from castrol.

[powered by wattard]

Kirk, we lost a few clutches with Penrite oil, as you guys have. I will never use it again in an engine that has a wet clucth. Do not use this oil, even if for free. You shouldn't have problems with stock components but you have lost 2 clutch packs. If spring pressures are Ok, then just put VSX4 in it and try it. It will cost you $40.

We tried Barrnett clutches, the friction material is no better than OEM, the reason they hold more torque is the spring pressures are increased.

Use different oil

Will

[andrewd]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by sg:
I can vouch for the standard clutch slipping at 80Nm also. The carbon fibre clutches from Barnett can hold approx 95Nm but only after the clutch is warm this is also with small packers under the springs to stiffen it up a bit also. This is on a CBR600 engine running R4 superbike oil from castrol. <HR></BLOCKQUOTE>

hello shane
hows it going?

[woollymoof]

Still got problems.

Would you have to replace the clutch disks when replacing the oil, even if they look ok, because they'd been soaked in the dodgy oil?

[sg]

The barnett clutch springs are identical to the original springs for the CBR600. I measured them when we got our clutch. I also tried to get heavier springs and were told the reason they can't be any heavier is that the spring is already right on its maximum stress range for the availiable space. We also ran a back to back comparison with a brand new clutch and the barnet clutch and found the torque holding capabilities were increased by 15Nm. The barnett clutch must be warm before it delivers maximum performance though.