derbi and hobbit clutch springs

hey people! let's hear what springs you're running, what rpm the clutch engages at with them and what your setup is.

doppler blue springs

engage around 4k

hpi mini rotor

derbi flat reed 70cc metrakit

tm24

8 petal reeds

tjt variator modified

Re: derbi and hobbit clutch Springsteen

Ryan knows my setup, but for reference I'll put it up...

PA50

Doppler Blue Springs (when new engages around 3600)

Lightened clutch bell, lightened TJT, clutch brace

CDI

Ported Athena

Derbi metra head

4 petal reed, custom intake

OKO 24

Custom pipe

Re: derbi and hobbit clutch springs

weird my tach shows 3900k, guess I have some adjusting to do :)

Re: derbi and hobbit clutch springs

On my hobbit, I got some mhr red dudes, pretty tuff

Dr kit, 1977 crank boyesen reeds 21phbg mm destroyer

Engage at???? High! It seems like the bike starts to variate before they engage fully, I'm runnin 3.2g dr pulleys in a derbi 6 roller. Is that crazy? Does that mean the springs are too tuff? I think those weights are a little light for that pipe too

Re: derbi and hobbit clutch springs

1.5k dio springs on the stock cylinder, proma, boyseen reeds, tjt with custom weight. revs up nice, lifts the front tire on take off and excels right up to 45 and holds nicely.

Re: derbi and hobbit clutch springs

Honda 78 pa50 ii

dr

super stuffy crank

stock head

tjt 18 grams total

phbg 21-100 main jet

boysen carbon reeds

Motomatic destroyer

stock points

camino pulley

1.5kclutch springs off ebay

engages around 4k, feel some slipping off the line but in about 10 feet it starts to rip hard and get rowdy all the way up to 57mph.

hobbit gps.jpg

Re: derbi and hobbit clutch springs

before porting. i'd get another GPS reading after porting (it's considerably faster now) but my rear wheel has a gigantic flat spot on it and is fairly wobbly over 45mph.

i'm using polini springs now, some 4500k ones.

Re: derbi and hobbit clutch springs

Damn 63mph is pretty legit.

Re: derbi and hobbit clutch springs

Emil Kniemel /

1978 pa50ii with reeds, mlm peoples pipe, 80 jet, graham's oversized weights on a notched variator. was topping out around 41mph.

just put in new clutch springs yesterday. engagement is way later than before, dunno when cause i dont have a tach, but id say around 4k or something.

theres no way its gonna wheelie. feels like its dragging/slipping.

before clutch springs engagement was early, but take off would be fine and right away.

i have the green polini springs in:

https://www.treatland.tv/derbi-polini-clutch-springs-set-p/polini-springs-245.012.htm

thinking of going lighter, throwing in the black. input?

Re: derbi and hobbit clutch springs

campeona del mundo /

i really like these malossi ones

great if ya got an hpi that revs out nice n fast. i'm currently using the blue flavor and like them a lot with my athena build.

Re: derbi and hobbit clutch springs

Emil Kniemel /

people usually remove starter clutch when doing stronger clutch springs?

Re: derbi and hobbit clutch springs

yes

Re: derbi and hobbit clutch springs

but ... but then you cannot push start your hobbit. WHYYYY!

I got a spare cover for a pullstart mod, Ill do it sometime.

Re: derbi and hobbit clutch springs

drill start ftw

Re: derbi and hobbit clutch springs

Emil Kniemel /

Carry a drill with you everywhere?

Strange. Unless you're Drill Man?? (mega man)

Re: derbi and hobbit clutch springs

Emil Kniemel /

Emil Kniemel Wrote:

-------------------------------------------------------

> 1978 pa50ii with reeds, mlm peoples pipe, 80 jet,

> graham's oversized weights on a notched variator.

> was topping out around 41mph.

>

> just put in new clutch springs yesterday.

> engagement is way later than before, dunno when

> cause i dont have a tach, but id say around 4k or

> something.

>

> theres no way its gonna wheelie. feels like its

> dragging/slipping.

>

> before clutch springs engagement was early, but

> take off would be fine and right away.

>

> i have the green polini springs in:

>

> https://www.treatland.tv/derbi-polini-clutch-sprin

> gs-set-p/polini-springs-245.012.htm

>

> thinking of going lighter, throwing in the black.

> input?

put in the black, and swapped back the variator to stock with pa50ii weights. havent gps'd yet, but better than it was, not sure if better than stock clutch springs with lighter weights.

gonna try the 1977mopeds 15 x 1070 belt when it comes.

also, tips on using the clutch puller and not damaged the threads on the crankshaft?

Re: derbi and hobbit clutch springs

Re: derbi and hobbit clutch springs

Emil Kniemel /

drillium!

Re: derbi and hobbit clutch springs

Downhill Harvey (OFMC) /

Leave the nut on the end of the crank when pulling the clutch.

Re: derbi and hobbit clutch springs

Emil Kniemel /

hmm.. gonna have to buy an extra nut and grind down the sides as a hand twist on cap just to pull the clutch then. (home made clutch puller is very tight fit).

Re: derbi and hobbit clutch springs

Emil Kniemel /

Re: derbi and hobbit clutch springs

The red tjt derbi clutch springs are only 4lbs stronger then the stock clutch springs. Even with a 50cc stock cylinder and big pipe.. I needed more stall from the clutch to rip out of the hole and in the corners it would berp.. and whinnnn into the powerband. These should help a lot on stock and kitted bikes. Prototypes, as of right now..

Picture 059 (Medium).jpg

Re: derbi and hobbit clutch springs

derbeez ryderz /

i've been running MHR blacks in my derbi for 1.5+ years. with no issues. they have a nice hi stall speed, thats great for a mid range pipe. they are a serious task to get on but worth the bloody knuckles IMO. i put some in a friends variant sport and de-glazed the crusty pads. he was looking like doug domokos wheelie-ing around the block.

actually looking into removing weight from the shoes on mine, but theres not much there to take away on the derbi's shoes.

Re: derbi and hobbit clutch springs

I tried the gilardoni springs on treats, they were weak sauce. Prob like new stock strength. Then I tried some other doppler ones, they were weak too.

mhr is the way to go!! If you wanna hi-stall

Re: derbi and hobbit clutch springs

I snapped two sets of mhr black springs and my buddy snapped one set of mhr reds on his hobbit... trash if you ask me.

Re: derbi and hobbit clutch springs

1.5k DIO clutch springs

DR kit

Proma circuit

Slips better than stock, but want more.

I'll be converting to electric start soon and looking for better springs after I ditch my starter clutches.

Re: derbi and hobbit clutch springs

Got 1.5k dio springs on mine, gonna try drilling the shoes out like Max though.

Re: derbi and hobbit clutch springs

I used some "2000 rpm" red Chinese clutch springs for a yamaha jog.

I got em on eBay for like $5. Super stiff, but I could still benefit from drilling my clutch arms a bit. Been rocking them since I built the hobbit.

Re: derbi and hobbit clutch springs

derbeez ryderz /

I have seen friends stretch the springs installing the mhrs, but no broken ones. I don't know, they are super expensive and it takes a lot of work/are risky to install. But, theirs just no other way to get the hi stall on the flat reeds.

Re: derbi and hobbit clutch springs

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account