Re: Tjt treatland steel hobbit rumpus plate

But a gila makes a ton of power.

Huge power = strong spring needed

Re: Tjt treatland steel hobbit rumpus plate

Dirty30 Dillon /

> JBOT Admin Wrote:

> -------------------------------------------------------

> But a gila makes a ton of power.

>

> Huge power = strong spring needed

True, too light of a spring could cause an un-controlled, fast variation.

Maybe time to start looking at the Amish Gold spring, or maybe some scooter stuff.

Re: Tjt treatland steel hobbit rumpus plate

I read through that entire progressive rate contra spring thread. I think that's what I wanna try next. Was also thinking about trying the stock contra with like 7 or 8 g weights and seeing what happens. But I do feel like the contra spring needs to be strong enough to stretch out that variation, and if I'm having it variate too quick with red spring idk if that would cut it.

I blew up another fuckin unobtainium clutch yesterday so it's all kind of on hold for a minute. The next thought is getting a 105mm scooter clutch and bolting that to the old clutch hub after lathing it down.

So in my logic, a clutch for a 107mm bell has actual diameter 104-105mm. So I bet one for a 105mm bell has diameter 102-103. If I can get it centered on point and the bell spins freely, then there would just be less throwout distance for the shoes to engage the bell? In my head that means less fatigue on springs n shirt but the other concern is the shoes potentially dragging.

Re: Tjt treatland steel hobbit rumpus plate

DONT DO A SCOOTER CLUTCH

won't work. Tried it.

It's not meant for crank mount. Will engage at low Rpms even with super strong springs. It's meant to spin and engage at 1/3 the crank speed.

Just cut a new taper in the pa1 clutch to fit the derbi crank. I've never destroyed a hobbit clutch and I run em at 8k all the time

Re: Tjt treatland steel hobbit rumpus plate

if you use a hobbit clutch,

Remove the rubber nubby guys.

You can use some Air or fuel tubing over the metal nubs if you want.

Those stock rubber pieces cause the arms to bow out horribly with strong springs. It destroys clutches.

As well, add 2 or 3 sipes in each shoe, really helps with nice engagement

Re: Tjt treatland steel hobbit rumpus plate

Truth, I didn't think about rear shaft vs crankshaft rpm reductions. I 'should' get a start v but that's another expensive rabbit hole to go down.

You do a good sell on the Hobbit clutches...

but the many puch clutches I've bent posts on kinda make me want a brace if I'm doing some stupid shit. I've been looking at that Malossi Delta clutch. Some scooter forum said the shoes on that are 110g each, i bet if I could get that down to the 70-80g range that'd play nicer. I needa weigh the derbi shoes and see what those are at and if that would get me in the ballpark. Other than that, spring rate is spring rate. The same thickness and coil count would need the same amount of force to move it, right? The same mass of shoe would exert a similar amount of force against that spring rate.

If the derbi shoes are wayyy lighter then yea it sounds like hobbit clutch is what's up

But I did measure a vino clutch the other day, that was 102mm and fit in derbi bell fine

Re: Tjt treatland steel hobbit rumpus plate

Dirty30 Dillon /

I have the Polini Evolution 3G scooter clutch for my Sacre motor build and it's lightened/high sprung but I still think that spinning on a crank will create super early engagement.

Re: Tjt treatland steel hobbit rumpus plate

Abdiel Gonzalez /

Red Contra+15grams+Rumpus plate= less acceleration

TJT plate+Red+15g = hold on tight. But I can't stay in the power band with this new kit with either. I experience RPM drop. Like going from 2nd gear to 4rth in a car.

Going to experiment with the yellow and stock spring. 2.75 rear tire and MLM subframe is preventing me from pushing in the tire to give the belt some slack could be one issue. (might need a tad of slip?)

Re: Tjt treatland steel hobbit rumpus plate

Red + rumpus is too much.

Yellow or stock + rumpus = niccce

Re: Tjt treatland steel hobbit rumpus plate

Abdiel Gonzalez /

> JBOT Admin Wrote:

> -------------------------------------------------------

> Red + rumpus is too much.

>

> Yellow or stock + rumpus = niccce

Ok done testing. I put in the stock spring and went to a drive. I can report that I lost acceleration vs Stock TJT ramp.

Red or Stock spring either way TJT ramp out performed.

13.5 grams

TJT > TreATS

Re: Tjt treatland steel hobbit rumpus plate

You have to adjust weights after you swap springs. Did you try going lighter, cuz you gotta

Re: Tjt treatland steel hobbit rumpus plate

I've had bikes where the tjt stock plate worked better, usually lower power bikes, 50cc way ported hobbit, 50cc ported derbi.

The rumpus plate shines with race gears, very powerful kits, and mostly stops overvariation.

It's a great piece of work

Re: Tjt treatland steel hobbit rumpus plate

Abdiel Gonzalez /

I tried with race gears also (I have 2 transmissions..1 with Race/TrickMetric and 1 with stock gears)

I got rid of most of the RPM drop now with TJT ramp+13.5g (down from 15g)+Red Contra and a older stretched stock belt. Still breaking her in.

One lightly used Rumpus plate soon for sale :)(edited)

Re: Tjt treatland steel hobbit rumpus plate

This shits rowdy.

I got a stage6 minarelli horizontal clutch to work, kind of a pain in the ass for the performance. Bolted it to the cut down old clutch hub, lathed out the bell, lightened the shoes to 75g from 99g, cranked down malossi mhr black springs. Doesn't engage super high but it doesn't drag at idle. The clutch is for a 107mm bell and mine is at like 105.8, I don't wanna go any further for fear of the bell wall being too thin, but that's where I could pick up more stall. I have my rear pulley lathed down to close fully so that gear ratio is so low that early clutch engagement isn't a problem, probably helps it be more streetable.

Fresh red contra, 7.5g weight, rumpus plate. Variates at like 10.5k ish and pops wheelies. Haven't gpsed it for a minute but was getting low 60s before.

My rear pulley bushing started to push itself out, preventing the pulley from closing fully. Found a flanged bushing at ace I was able to make work.

Re: Tjt treatland steel hobbit rumpus plate

im playing around with the polini variator right now. she's just slipping with the red spring at 12g, put the stock spring back in and she rips pretty well.

jumped up to 18g and she's doing much better but only topping out low 50's - whereas with the tjt / treats plate at 6g (i think? maybe 12... but i think im at 6g) and stock springs she RIPS and hits 60. I feel like i can crack the red spring (running treats endurnce belt btw, stock hobbit springs and the straight cut trans gears) with increasing the weights in the polini variator... might jump up to 22g in the polini or so and see what happens w/red spring

i like the polini variator better but it's a lot harder to tune. it's smaller then the tjt and with my tjt on the crank it has some wobble...which will cause issues down the road, where-as the polini spins straight :)

will report back

Re: Tjt treatland steel hobbit rumpus plate

Variator stats

Stock: 254g 89mm

Camino: 214g 83mm

Polini: 275g 95mm

TJT: 388g 102mm

Fixed side: 95mm

D35E606D-93F6-4DAF-B6AB-A146B83BD755.jpeg

Re: Tjt treatland steel hobbit rumpus plate

^ fuck yeah, wiki this

Re: Tjt treatland steel hobbit rumpus plate

> Mike Boyd Wrote:

> -------------------------------------------------------

> ^ fuck yeah, wiki this

Not sure now to do that

Re: Tjt treatland steel hobbit rumpus plate

Ride today w the polini. 5gr rollers, stock contra and stock belt. Very smooth across the entire range. The notched variator resulted in two hits, one at mid range and one top end. Shift point is around 6000 rpm. Probably going to drop roller weight a few grams and get the shift closer to 8000 rpm.(edited)

Re: Tjt treatland steel hobbit rumpus plate

Emil Kniemel /

> JBOT Admin Wrote:

> -------------------------------------------------------

> I've had bikes where the tjt stock plate worked better, usually lower

> power bikes, 50cc way ported hobbit, 50cc ported derbi.

>

> The rumpus plate shines with race gears, very powerful kits, and mostly

> stops overvariation.

>

> It's a great piece of work

I know this thread is for hobbits and I definitely swear by the rumpus plate for my 70cc hobbit.

However I assume the quote above applies to derbis (not just derbi kits on hobbits) as well? I was stoked on the rumpus plate for my hobbit so when i began building my flat reed derbi i got one too. i am using the STOCK derbi 6-roller w/ aftermarket plate.

my derbi is the 50cc gila kit and i wasn't getting anywhere. switched to the DOS plate and it seems to be much better. i also have the TJT plate to try that i pulled from my hobbit which now has the hobbit rumpus plate.

i bought the bike as an unfinished project and so i dont know what the rear contra is. it looks white. feels stiffer than the stock hobbit spring.

current weights are 3 black and 3 blue. 16x38 gearing. i can hit 39mph in my neighborhood but havent tried in longer stretch yet. of course its gonna rain all week in socal. bizarre. right now is ok tho. also my pipe is the repop big muff.

Re: Tjt treatland steel hobbit rumpus plate

50cc likes really weak springs.

I'm running my very ported pp to cyl reed stock cyl with the stock spring and it's great.

But I'm using the stock tjt plate.

I think hobbits have a bigger prob with overvariation than derbi.

I also noticed my 50cc derbs is very sensitive to gearing. Can't speak to your bike cuz I have 16s which is kinda weird(edited)

Re: Tjt treatland steel hobbit rumpus plate

my rumpus plate escaped

IMG_20191006_152338103.jpg

Re: Tjt treatland steel hobbit rumpus plate

Clutch bell carnage!!!!

Re: Tjt treatland steel hobbit rumpus plate

Wow. That is impressive.

Re: Tjt treatland steel hobbit rumpus plate

Emil Kniemel /

No locking nut thing on the variator? I havent been running one cause im still tuning but now im scared.

Re: Tjt treatland steel hobbit rumpus plate

Brandon Weiss (Detective brandon to you) /

How do you think that failed? Did a nut loosen up and things collided? Or maybe the bell was weak and had metal fatigue? I wouldn't think that any setup would be able to destroy a bell with just power

Re: Tjt treatland steel hobbit rumpus plate

Holy shit that's crazy. Wouldn't want my foot anywhere near that.

Re: Tjt treatland steel hobbit rumpus plate

congrats! you win sick ripper carnage of the week!! sucks those bells are kinda hard to get, but rad to see a sick fail like that! rebuild and rip!

Re: Tjt treatland steel hobbit rumpus plate

His case has a hole in in. This Derbi is ded.

Re: Tjt treatland steel hobbit rumpus plate

Brandon Weiss (Detective brandon to you) /

> Daniel '' Wrote:

> -------------------------------------------------------

> His case has a hole in in. This Derbi is ded.

It looks like it's in the transmission, not the crankcase....cpuld probably be saved with JB weld or alumiweld if he had no other options

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