Tuning

[Marcquinn]

Hi can any one help me, I've got a sym jet 50 and it was only doing 30, so I purchased a performance exhaust and a 65cc big bore but now the problem is its only hitting 35 and once it's at that it's making a vibrating noise and won't go over 35 ... Please help
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M.quinn

[Snop Doog]

[RhynoCZ]

Put it back as it was, wait till you're old enough to buy something bigger.

Anyway, make it stock again, to see if the problem goes away.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Marcquinn]

I'll have yous know I am old enough its just to get to work
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M.quinn

[Wonko The Sane]

You've bought a vehicle designed to do 30mph and no more

you've done some modifications to adjust power without completing the process, the amount of fuel going into the engine needs to be adjusted now that you've altered the flow of exhaust and the engine size.

either the carb needs setting up and the correct jet fitting or, if electronic ignition it needs mapping.

you'd be better off putting it to stock, selling and getting a 125cc if you want to do more than 30mph
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[Rogerborg]

Didn't like the answers that you got last time?

https://www.bikechatforums.com/viewtopic.php?p=4233711

We have a Workshop section where you'll be told to put it back to stock again in a much[*] more polite fashion.

[*] in the same sense that putting your Stage Eleventy Big Bore Head Power Valve Band kit on has made your ped "much" faster.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[talkToTheHat]

Usually EADGBE, with a hardtail guitar at DADGBE, as a teenager CGCFAD. A=440hz

Werckmeister I if im playing J S Bach on the hard-synths, or anything exclusively synthesiser based and written whilst the kit was set up to play bach.

If using the analog synths some attempt at tuning is usually made. It's embarassing having to use auto tune on a synth.
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Bandit. does. everything.

[Snop Doog]

[arry]

[Marcquinn]

30mph I do 15 miles of Juelcarrage way
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M.quinn

[Silver_Fox]

And the word is "you", p̶e̶a̶s̶a̶n̶t̶ my good sir

[P.addy]

[Rogerborg]

Remedial arithmetic: 125 is more than 65.

You're trying to turn a moped into something that it's not. Even if you do magically get something like 50mph out of it after spending many hundreds of pounds and putting in countless hours of careful tuning, it'll still have 28mph brakes and suspension.

Stop pouring money into it, sell it on to a 16 year old, buy yourself an unmeddled-with 125 that will do a real 65, and don't meddle with it.

With hindsight you'll realise that this is sound and well intentioned advice, not a challenge to your throbbing masculinity.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[andyscooter]

As said get somthing more suitable

15 miles on a duel carriage way no thanks
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gilera runner vxr200 (chavped)
if its spelt wrong its my fat fingers and daft auto correct on my tablet

[Teflon-Mike]

[Silver_Fox]

"Dual" carriageway. As in 2


Unless you were being comedic with the jousting metaphor, in which case, I'll er get me coat

[Wonko The Sane]

[Nobby the Bastard]

15 miles of dual carriageway?
On a moped?

That's a special grade of stupid you caught....
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Marclev]

[almostthere]

You're doing the right thing with the exhaust and big bore kit, you need to fit a stage six or seven carb kit for a bit of extra oomph, get some mag wheels to reduce unsprung weight and upgrade to ohlins suspension to transform the handling, you'll soon be able to give Marquez a run for his money with a bit of practice.
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Beer, It's the reason I get up every afternoon
www.mfairco.uk

[andys675]

you're a tit that's why, there are usually 2 "restrictions" with peds

one is the engine speed, usually the exhaust has a restriction in it that lowers the rpm of the engine, bypass this successfully and the engine can rev higher

another is the wheel speed, in the transmission (usually the variator) there is something that lowers the speed the back wheel can turn at

you have got the engine revving higher, but the back wheel can't spin any faster because you've only de-restricted the engine so far

your ped engine is now revving flat out at 35mph, not surprised it is vibrating

then you need to sort out the fuelling
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