How does lock-up clutch work?

[Guest]

Hi Everyone,

Could someone please explain to me how a lock up clutch works. Does it just bolt to the end of the clutch basket and provide extra clamping force using weights that get thrown out and clamp the basket as the crankshaft increases speed?

Are there any negatives with adding a lock up clutch?

Do you need to put a deeper clutch cover on the bike to provide extra clearance for the system?

If someone could post pictures with a nice explanation I'd really appreciate it.

Thanks,
Nick

[dr_fosg8]

There are plenty of racers around that will be along to answer that one for sure. Most of the ones I have seen come with a spacer that will go in between the clutch cover and the case to increase clearance for the parts.

[rapidray]

Yes, you need a spacer to move the stock cover out or you need a specialty clutch cover like the RBD cover to move the pivot out away from the motor. They work great on the street, & I use them on my big motors to keep the clutch lever pressure livable. I have a complete lockup assembly for sale, with ALL the parts if you need one. I answered that to your ad over on Psychbike also. Ray.

[Big Jay]

The lock up clutch increases pressure on the pressure plate as rear wheel speed increases, not engine RPM. That would be a slider.

http://gszone.biz/clutches.html

[RacingJake]

Think of it like a two stage clutch,

1st stage is static spring pressure thats allows the clutch to slip at launch depending on how much spring pressure you run with.

2nd is the arms that you can add more weight if needed that prevents the clutch from slipping on the topend of the track due to the light static spring pressure.

Lockup's work best with a slick and wheelie bars and add a 2 step to fine tune your launch rpm and you be running 1.3's 60 footers at least.

For street use they reduce the clutch lever pull around 50% ???

Here's my 7 year old MRE lockup with 41 pound springs and bolts on the arms, been running it like that for years.

[trippivot]

,




notice how ape jay stated wheel speed compared to engine RPM?


the silver one is a single stage lock up, the arms clamp tighter when the wheel speed thru the transmission is faster( faster=tighter)

the red one is a slider clutch - it also has "lock up arms" but it is bolted to the clutch basket and it clamps down tighter as the engine rpm's go up. one is hooked to the basket


the lock up is cool for the street. A couple special parts are required to install . not complicated to operate , you won't even feel the difference - except no more slipping clutch on a 3rd gear roll on.

[rapidray]

Jake, I find it hard to believe you would need weight on all 6 arms. What's going on there? Ray.

[Nicholaschase29]

Thanks for the nice explanations and pictures. It's helping me understand how they work a lot more.

I still have a few questions:

Is a separate pressure plate required or just the part with the arms and weights and a spacer for your cover?

Do you need to put gaskets between the cases and spacer and spacer and cover?

If you try to pull your clutch in going 120 will you be able to easily? I would think if you had HD springs in that created the same amount of force as the lock up with stock springs at 120 - then you'd have to fight the lock up with the same amount of pressure as you'd have with the HD springs. Am I thinking wrong?

Thanks,
Nick

[rapidray]

Thanks for the nice explanations and pictures. It's helping me understand how they work a lot more.

I still have a few questions:

Is a separate pressure plate required or just the part with the arms and weights and a spacer for your cover?

Your pressure plate + the lockup parts.

Do you need to put gaskets between the cases and spacer and spacer and cover?

Yes.

If you try to pull your clutch in going 120 will you be able to easily? I would think if you had HD springs in that created the same amount of force as the lock up with stock springs at 120 - then you'd have to fight the lock up with the same amount of pressure as you'd have with the HD springs. Am I thinking wrong?

I pull the clutch in at the finish line at the end of every 145mph run I make, NO problems!

Thanks,
Nick

No problem, Ray.

[TG7060]

lock up

You also need harden buttons on the clutch hat. As you can see in the photo. There wear marks on the hat from the arms rotating on the hat. MTC will install them for you.

[blowerbike]

You also need harden buttons on the clutch hat. As you can see in the photo. There wear marks on the hat from the arms rotating on the hat. MTC will install them for you.

hardened buttons are nice but many never use them including myself.

[RacingJake]

Jake, I find it hard to believe you would need weight on all 6 arms. What's going on there? Ray.

It's my fat a$$

Years ago I was having just alittle clutch slippage before the 1/8 mark with 41 lb springs with just 3 bolts so I just installed 3 more and it's been like that for a long time and I just forgot about it. It locks up pretty fast, maybe before the 60ft mark and still get a 1.32 60ft. Best part is the clutch pack last for years if you know what I mean !

Maybe I could get more out of it with more tuning cause I have new fiber's that been soaking in oil for 4 years now.

Our local 1/8 track open's in April and there's a few ZX14's the Rat bike wants to play with

[rapidray]

I know what you mean, Jake, as I am a "2 cow leathers" guy! LOL!!! I know what you mean about making the clutches last also as I have the same ENTIRE clutch I first put in my motor when it was new in Jan, of 2004! I also don't have buttons on my pressure plate & have NO problems with it! Ray.

[blowerbike]

3 short bolts/one nut each.
6 lighter than 750 springs.
1260 turbo w/ small tire drag chassis.
1.28 60' 8.50's@ 158mph.
i'm 230 in shorts and flip flops.
w/ an RBD cover and short cable kit you could pull my clutch in w/ 2 fingers.
f in awesome!
same power plant/turbo in a kosman car tire chassis...
i ripped all the fiber from the plates in 2nd gear.
i went to 1100 springs w/ the same bolts and life was good.
8.32@ 158mph.
i'm fat and less was better on the small tire bike.

[Nicholaschase29]

What's the going rate for a used MRE spacer and MRE clutch weight plate?