Roller weight

matttttt · Borekit Bruiser Joined: 24 Dec 2004 Karma :

Ok so I've just had my new ZX fitted and I was wondering... because my moped (speedfight 2) goes quick off the mark but then settles at 40 could I increase or decrease the weight of the rollers to make it go any faster? Thanks in advance Very Happy

Chr!S · Nitrous Nuisance Joined: 17 May 2005 Karma :

matttttt · Borekit Bruiser Joined: 24 Dec 2004 Karma :

so how do I check what weight rollers I have at the moment?.. or is that best left to a mechanic?

graeme · Renault 5 Driver Joined: 02 Jan 2005 Karma :

by weighing them on a set of scales
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Kye · Scooby Slapper Joined: 13 Sep 2004 Karma :

matttttt · Borekit Bruiser Joined: 24 Dec 2004 Karma :

I see, so what set up would make my bike go 50-60 mph Kye? Would it mean just keeping the same rollers and getting the clutch springs uprated?

Chr!S · Nitrous Nuisance Joined: 17 May 2005 Karma :

So after the marathon explanation you more or less just said what i did?

Muppet. Rolling Eyes

He wanted to know the simple answer, i told him, lighter rollers, it spins up faster, heavier rollers it doesnt.

Rolling Eyes

mchaggis · World Chat Champion Joined: 10 May 2004 Karma :

Heavier rollers won't do anything with the top speed though. The ways to get a higher top speed are with more power outright, or with a different overall drive ratio. If you can adjust the torque characteristics of the engine enough that it will run to higher rpm, that is simply increasing the power, so long as it is producing the same amount of torque.

Automatic transmissions are something I hate with a passion, not because I'm irrational, but because they always seem unnecessarily complicated, inefficient and take control away from the operator. Oh, and they're the reason I didn't do nearly as well in the Powertrains exam as I could have done.
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Discovering the delights of Hammerite and a 3/4" brush. Very Happy

Simonbt · Nitrous Nuisance Joined: 10 Mar 2005 Karma :

Simonbt · Nitrous Nuisance Joined: 10 Mar 2005 Karma :

Kye · Scooby Slapper Joined: 13 Sep 2004 Karma :

Basically the higher the bike produces power, the more top speed you can get to, since it can pull the gearing further than what it could before, since its revving higher.

If you want more top speed, then I suggest getting a 70cc kit and a gear up kit.

Is it an AC or LC speedfight? I've tuned both before and the AC one refused to get to a half decent top speed, it just won't do it.

The AC was running a DR70cc kit and LeoVince ZX with a 17.5mm Dellorto PHVA carb and would do about 50-53 tops.

The LC was running a 70cc Polni Cast Iron kit, not particulary a revvy kit either, I'm sure it'd be similar with a DR kit, and a LeoVince ZX and that would do 60 on the speedo all day long.

Automatic transmissions are easy once you get your head round how they work. I now do it for a living on an apprentiship so it comes naturally, yet ask me to rebuild a gearbox and I'll be fucked because I've never been inside one before.

If you want some half decent speed out of a 50 I suggest getting an LC Piaggio engined bike, they tend to be the quickest stock and tuned.
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Ducati 600SS
Vespa PX125

Biker-Kev · Brolly Dolly Joined: 01 Jun 2005 Karma :

Dont forget to re-jet your carb becausr the new exhaust will cause damage if you dont.
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Theory: Passed 8/11/2005 Practical: Passed 13/12/2005 Proud holder of A2 license

matttttt · Borekit Bruiser Joined: 24 Dec 2004 Karma :

I was told at the shop it didn't need rejetting......

Kye · Scooby Slapper Joined: 13 Sep 2004 Karma :

If it was a newer version with a catalytic converter in the exhuast then you will need to rejet about 4 sizes up (i.e 56 - 60 on the Piaggios for instance), if its an older one then I doubt you will have too.
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Ducati 600SS
Vespa PX125

matttttt · Borekit Bruiser Joined: 24 Dec 2004 Karma :

so what de-restrictions do you suggest I don't do to my bike for fear of blowing something?

Kye · Scooby Slapper Joined: 13 Sep 2004 Karma :

The more you tune it the more you have to look after it, i.e changing rings more often on a big bore kit.

Leave it standard derestriction and a sports exhuast, because getting that extra 5mph after that starts to cost hundreds. Especially on an AC speedfight.
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Ducati 600SS
Vespa PX125

matttttt · Borekit Bruiser Joined: 24 Dec 2004 Karma :

so if I just do the clutch springs and take the plate out of the variator is this too much?

matttttt · Borekit Bruiser Joined: 24 Dec 2004 Karma :

bump

Biker-Kev · Brolly Dolly Joined: 01 Jun 2005 Karma :

Dont know about the clutch springs but the easiest de-restriction for you to do is take the plate out the variator, get a sports exhaust which will have variator rollers in it to match the exhaust.

Possibly change the C.D.I but i dont know if this will do anything with the changes already mentioned.
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Theory: Passed 8/11/2005 Practical: Passed 13/12/2005 Proud holder of A2 license

Kye · Scooby Slapper Joined: 13 Sep 2004 Karma :

CDI doesn't need changing on the Speedfights, and if they're the immobilised models you can't get aftermarket ones anyway, different fitments.

Exhuast with rollers, and a cast iron 70cc kit is a good combination, reliable and torquey and this is one of the most popular tunes I do to 50cc's in the workshop.

I recently helped setup a Malugati F12 Phatom AC. Hebo alloy 70cc kit, pipe and variator. This thing literally flys off the mark, its a very revvy kit and is running 3.7g rollers but the owner was getting it to wheelie with both feet still forward in the footwell. Once again with AC motors they only tend to top out at 45-50mph without gearup's etc, which kinda spoils the fun of mopeds in my opinion.
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Ducati 600SS
Vespa PX125

georgeyboi · L Plate Warrior Joined: 11 Apr 2009 Karma :

i have a sym city hopper, that has all the revs i need, it gets to its top speed (38) no trouble at all, but when it tops out, it feels like i could be putting the power to more use, so should i get some heavier rollers, just to bring the ratio back to even or what?
what about a new clutch spring, as i have a flat point at about 28-31.
w/b

The Artist · Super Spammer Joined: 06 Jan 2008 Karma :

Fuckin hell, could you dig any deeper?

clancy · World Chat Champion Joined: 11 Apr 2009 Karma :

so changing the roller weight isnt hugely nesacery unless you change the exhaust ? and if you do the correct rollers generally come with the exhaust?

or have i got the wrong end of the stick here?

leigh.
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georgeyboi · L Plate Warrior Joined: 11 Apr 2009 Karma :

well, i had a custom exhaust built so i still have the stock rollers, the acceleration is fine, no problems, but not much top speed, so, what will give me more top end basically?
w/b

azzerj94 · Derestricted Danger Joined: 19 May 2010 Karma :

hi all. i have a cpi aragon gp 50 and it is fitted with a leo vince TT exhaust but ive been told that this exhaust still has restrictors, is this true ?? Could anyone suggest ways to make this bike go faster than the 38mph it's running at at the moment.
thanks