tko 600 slipping

[mavgarb302]

So in my new backdraft w 427r been pretty mellow breaking everything in maybe a slight goose every now and then. About 630mi on it and about to bring it to radical roadsters for its first service/inspection/alignment etc. Anyways I have still yet to load it hard at wot maybe 3/4 really no reason to be honest. Well today around 60 in 4th on a straight I got into it a bit and at around 4500 the RPMs raised faster than they should have, no the tires werent spinning and there is no oil leak from rear main. To make sure I repeated it and sure enough I am getting slippage around 4k hitting the gas.. cant tell in 1st or 2nd but for sure in 3rd, 4th and 5th.(unless there's somekinda of slip in diff I dont know about, doubtful) After my testing different gears I went back to just putting it around as I had. the car was very jerky when taking off being new that was expected, that has wanned and not sure if it was slipping when I first bought it or if it just started. Anyways why would a brand new clutch (bought with 80mi) be slipping? sorry TKX

[saki302]

First and easiest thing to check is that your clutch is fully engaging and the slave isn't putting excess pressure on it.

[mavgarb302]

Originally Posted by saki302

First and easiest thing to check is that your clutch is fully engaging and the slave isn't putting excess pressure on it.

the pedal all feels correct. about an inch push on the pedal and clutch disengages. I assume that is what you mean. I am not new to motorcycle clutches but am new to auto clutches. Basically the same between them except wet vs dry, if this was happening on my bike I'd say worn clutch or weak springs but it is brand new, unless they put a crap weak clutch in it. When it is engaged/engaging it feels good, feels right it isnt until a load is put on it that it starts slipping. The VMAXs old and new are nortorious for this even with new clutches so theres a thing called the double D mod where you stacks clutch springs, unfortunately on this I cannot. But it is exactly the same, just letting loose once engine is over 4k where the 427r really starts pulling.

[Tommy]

I've had clutches in two different cars act that way. The first had a hydraulic throw out bearing that was leaking fluid onto the clutch after it over extended due to an improperly adjusted clutch pedal stop. The second was a hydraulic throw out bearing that was improperly adjusted at installation and was depressing the pressure plate fingers even when the pedal was not depressed. In both cases it was necessary to remove the transmission and clutch to inspect, diagnose and fix the problem.

[mavgarb302]

Originally Posted by Tommy

I've had clutches in two different cars act that way. The first had a hydraulic throw out bearing that was leaking fluid onto the clutch after it over extended due to an improperly adjusted clutch pedal stop. The second was a hydraulic throw out bearing that was improperly adjusted at installation and was depressing the pressure plate fingers even when the pedal was not depressed. In both cases it was necessary to remove the transmission and clutch to inspect, diagnose and fix the problem.

Between the paint issue and this..I am almost thinking C8 had been the way to go...lol (hearsay) There hasnt been any leaking underneath but it may be just minor enough to wet the clutch..IDK I hope you are not right.. Even under warranty I have to pay labor, had I known that....sigh

[spdbrake]

Originally Posted by mavgarb302

the pedal all feels correct. about an inch push on the pedal and clutch disengages. I assume that is what you mean. I am not new to motorcycle clutches but am new to auto clutches. Basically the same between them except wet vs dry, if this was happening on my bike I'd say worn clutch or weak springs but it is brand new, unless they put a crap weak clutch in it. When it is engaged/engaging it feels good, feels right it isnt until a load is put on it that it starts slipping. The VMAXs old and new are nortorious for this even with new clutches so theres a thing called the double D mod where you stacks clutch springs, unfortunately on this I cannot. But it is exactly the same, just letting loose once engine is over 4k where the 427r really starts pulling.

You should have approx 1/4" freeplay at the clutch pedal before you feel the resistance. Depending on the master cylinder bore dia. After depressing the pedal 2-4" later the clutch should be fully disengaged.
It sounds like your master is mis-rigged and the clutch is 1/2 way depressed at all times, thus the slippage in higher gears.
If yours is a dual disc clutch the 1" pedal travel and full disengage you described still points to a mis-rig.

[mavgarb302]

Originally Posted by spdbrake

You should have approx 1/4" freeplay at the clutch pedal before you feel the resistance. Depending on the master cylinder bore dia. After depressing the pedal 2-4" later the clutch should be fully disengaged.
It sounds like your master is mis-rigged and the clutch is 1/2 way depressed at all times, thus the slippage in higher gears.
If yours is a dual disc clutch the 1" pedal travel and full disengage you described still points to a mis-rig.

Just went out to check. You may be on to something hard to tell.. With the wife lightly pushing on gearshift towards 1st (wont go until clutch is pressed), I put a measuring tape on clutch peddle to measure it with engine dead of course. Theres about 3/4" of total free play before resistance and roughly 3 1/2" more to disengage clutch before goes into gear. Not ever coming into this issue before I assume there is not much difference running/not running. the clutch pedal feels fine, feels like it engages great, when it slips theres no vibrations as if misaligned etc.. Best way to describe is that it just seems like weak diaphragm spring or oil on clutch. I tend to not think it is oil though and being new I cannot see the spring being weak.

[Gaz64]

I don't see any mention of how the clutch was run-in.

Clutches are like brakes, they work better as they are run-in.

Sounds like your clutch is slipping from insufficient grip.

Who makes your clutch?

Details of the engine please, how much power etc?

[patrickt]

Originally Posted by mavgarb302

Just went out to check. You may be on to something hard to tell...

Do you have a HTOB or a traditional external fork and slave? And from a slow roll if you hit the throttle can you easily spin your tires without smelling your clutch disk?

[mavgarb302]

Originally Posted by Gaz64

I don't see any mention of how the clutch was run-in.

Clutches are like brakes, they work better as they are run-in.

Sounds like your clutch is slipping from insufficient grip.

Who makes your clutch?

Details of the engine please, how much power etc?

I bought this thing 80mi new. The backdraft manual doesnt say which clutch was used. trans is a TKX, lakewood bellhousing, 566/544 dynoed 427r but zero mention of clutch.. Yes it is slipping ONLY under mid to heavy load, shifts fine, comes out of gear fine, clutch disengages high on the pedal etc.. I guess I could call Speed Fanatix inc which installed the engine.

[mavgarb302]

Originally Posted by patrickt

Do you have a HTOB or a traditional external fork and slave? And from a slow roll if you hit the throttle can you easily spin your tires without smelling your clutch disk?

no idea on the fork.. and yes will spins 1st and 2nd..3rd 4th and even fifth will slip.

[patrickt]

Originally Posted by mavgarb302

no idea on the fork...

Get under the car and look for a hole in the side of your bell housing, that will be in front of your transmission, and will look like this. This is what my clutch fork looks like. If you can't find something that looks like this then you probably have a HTOB (hydraulic throw out bearing). An external fork like this is very easy to check for too little play.

[mavgarb302]

it is a hydraulic throw out bearing..Theres a small hole in the bell housing which the hoses go into. I reached in there and there is some sort of oil/lubricant, not enough to gather on your finger or shine but enough that it the red clutch is slick. Slightly slick...I dont know if it was from greasy hands when it was installed or if there is some sort of leak..it is very minor from the little i can touch but I know dry clutches do not like any petros..lol

[patrickt]

That's progress. If you can angle your phone's camera in to get a pic or two, that would help. Brake/clutch fluid is usually amber. In the old days you could get blue, not anymore. Transmission fluid can be red. Grease can also be red. Peeking through a tiny hole to try and figure out why your clutch is slipping is a tough way to diagnose the problem. Pulling the transmission on a Cobra is not the end of the world; it's really an afternoon's work. Unless somebody comes up with a brilliant observation, that's probably what you're looking at.

[mavgarb302]

Originally Posted by patrickt

That's progress. If you can angle your phone's camera in to get a pic or two, that would help. Brake/clutch fluid is usually amber. In the old days you could get blue, not anymore. Transmission fluid can be red. Grease can also be red. Peeking through a tiny hole to try and figure out why your clutch is slipping is a tough way to diagnose the problem. Pulling the transmission on a Cobra is not the end of the world; it's really an afternoon's work. Unless somebody comes up with a brilliant observation, that's probably what you're looking at.

I did take some pics...lol but as I said it just isnt enough to show, I can only feel it on my fingers that it is greasy, not wet but greasy...so I am kinda figuring I have a leak or the slave cylinder has too many shims, ever so slightly still pressing on spring...think I am going to grab an inspection camera tomorrow and get a good view..lol
no the actual pressure plate is painted red-ish...and hell naw this thing is still under warranty, I just bought it Jan 7 2022

[mavgarb302]

another post very simular problem except I only have like 620 miles on my car... Just the intial first post by aurthor..Clutch Slipping in High Gears

[cycleguy55]

Originally Posted by mavgarb302

I did take some pics...lol but as I said it just isnt enough to show, I can only feel it on my fingers that it is greasy, not wet but greasy...so I am kinda figuring I have a leak or the slave cylinder has too many shims, ever so slightly still pressing on spring...think I am going to grab an inspection camera tomorrow and get a good view..lol
no the actual pressure plate is painted red-ish...and hell naw this thing is still under warranty, I just bought it Jan 7 2022

You've found the problem, but not necessarily the root cause. Were the clutch disc, pressure and flywheel properly cleaned before installation? Do you have a leaking main seal or HTOB? is your clutch fluid level going down or staying full?

The transmission will obviously have to come out for a proper diagnosis and repair.

[Tommy]

IMHO, your problem is likely the result of incorrect installation of one or more components. If that is the case, I see no way I'd be willing to pay for labor for them to fix their error. It's not like you broke it by driving it too hard.

[mavgarb302]

Originally Posted by Tommy

IMHO, your problem is likely the result of incorrect installation of one or more components. If that is the case, I see no way I'd be willing to pay for labor for them to fix their error. It's not like you broke it by driving it too hard.

From what I gather Backdraft only covers parts under their warranty not the labor. Didnt think to ask because I have never heard of such a thing. There is a slick feel to the back of pressure plate, not wet just slick so theres that..no way the clutch is worn out in 600 miles so it was either shimmed incorrectly or there is a leak from rear main or hyd thowout, either way ti is kinda BS that it isnt covered. yeah Ive pretty much babied it running it easy with ocassional harder acceleration to mate everything correctly, so this slippage might have even been there since day one, IDK.. James w Radical Roadsters says he can look thru bellhousing to see if HTOB is fully disengaging and thats probably correct. My 2011 Roush phase 3 when I sold it had 97,000 miles on it and I know you could see it removing the rubber boot because ever so often I'd take air to it. im putting pics i took last night or clutch, in my album, while you cant tell much maybe one of you pros can see something (make of clutch/HTOB)

[spdbrake]

It does sound like it could be the HTOB leaking.
Wedging the clutch pedal at full deflection with a 2x4 against the seat overnight should reveal a pretty good leak point if it or the lines are leaking.

If you don't have one, a Bluetooth Endoscope is invaluable for troubleshooting, retrieving part numbers, etc...
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1