Upjetting

[rob-jones]

Hello!

Basically, I have a Gilera DNA 50cc rev and go.

Before selling it, I thought I might as well renew the MOT for a sweeter sale. It failed on the exhaust as it had a few rust holes in it, and said that it would cost around £300+ for a new, standard one.

Now this is where my lack of knowledge and research truly shines!

So I bought one off eBay for £80 (Viper) which came with a new set of rollers.

I then got a garage to fit my exhaust and rollers, although from what I can gather, they didn't upjet the bike, which as I've read, is a must if you're going to be adding a sports exhaust?

The bike hasn't got much power at all and barely tops 20mph, whereas it used to do 45mph+, although I have only ridden it twice in this state for about 2 minutes at a time, so hopefully won't have done much damage.

Now, is it likely that this is happening because of it not being upjetted and it can't hack the new power?

Any information would be very appreciated! Thanks!
____________________
Currently own a Honda NSR 125.

[Nope.]

1) This post should be in the workshop, not General Bike Chat

2) Yes, it does sound like it hasn't been correctly up-jetted and you should be thankful that it hasn't yet seized. You need too take you current jet (a 56 in these I think) and add 10%. This gives you 5.6 so a 62 jet. Check your carb is the delorto carb and then either buy a jet box or just buy a single jet and fit it. Either way, stop riding it until you've up-jetted.

3) Whatever garage you went too sound like retards. Was it a bike garage? I would complain if I was you. If you asked them too fit the exhaust and all ancillaries and they didnt up-jet then I would put a complaint in.

Corrections in bold.
____________________
Former: Derbi GP1 50, Sachs XTC 125, Suzuki GSXR 400 GK73A, Kawasaki ZX7R, Suzuki DR250, Yamaha RD350
Current: 2011 Yamaha XT660Z Ténéré, 2003 Yamaha YZR-R1 5PW (In Build), 2009 Kawasaki ZZR1400

[rob-jones]

Oh yeah, I've reposted in the workshop now! My bad!

Thanks for the advice, I've literally done about 4 minutes of riding on it so hopefully won't have done any damage *fingers crossed!*

Well the thing is, I asked the garage I went to, to fit the exhaust and MOT it. They passed it on the MOT, fitted my exhaust and rollers and delivered it back to me.

They gave me an invoice of around £100 in December, I called them up just days after trying out the bike and noticing the problem and the woman said "Okay then, I'll speak to the lad that fixed your bike then I'll call you back!"

Unless they're just really slow, I don't think they're going to call back.

So I have a fitted exhaust, rollers and an MOT for nothing, but still this problem of upjetting!
____________________
Currently own a Honda NSR 125.

[sickpup]

[Nope.]

[TimNorwich]

Do you know if it has a powerband? Might be worth having it checked out if so...
____________________
Speedshite 50cc > Honda XR125L > Kawasaki GPZ 500 S > 02 Honda Hornet > 05 Honda CG125 winter hack > 04 Kawasaki ER-5 > 99 Honda Hornet 600 > Kawasaki GPZ 500 S > 99 Honda Hornet 600 > 05 Honda CBR600F > 01 Honda Hornet