Is my derbi senda running properly?

[ItsTommmm]

The spark plug looks a good colour. I'm wondering if what's happening is normal or if I need to adjust jetting a bit. I let bike warm up properly. It won't rev instantly like from idle to quarter turn but when I rev it a bit more I get better responce from from no throttle to a quarter. So its like if I get it going a bit it goes absolutely perfect but only when its been idling for a bit it doesn't pick up revs instantly.

Any advice appreciated.

Thanks.

[RhynoCZ]

Why would you change the jet? Is there a reason why you'd do that? If it's stock, then do not touch it. I'd start with checking the adjustment of the throttle cable/s. Then I'd check the idle adjustment. If everything is alright, then it's time to have a look at the airfilter. If that's alright, there could be a slight air leak in the intake manifold. You could also clean the carb, read the manual and put it back to its factory settings, if you've already fiddled with it.

Never fiddle with the jets, if it ran alright before. It's not going to fix a thing.
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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

[ItsTommmm]

[Just_James]

If you're having the problem since fitting the new exhaust then you may need to upjet but if you're mostly having the issue at low revs then you may be able to just adjust your air / mixture screw.

Fairly simple vid on how to here

https://youtu.be/YxpQjDQzX7g?t=3m1s
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Current Bikes / Projects: 1999 Rieju RS1 50
Previous bikes - 1986 DT125R (field bike), 1989 KX250, 1980 KX420 (with 500cc big bore), 1992 YZ250, 1988 KX500, 1989 XR250R, 1988 VFR400R NC24, 1999 Cagiva Mito 125, 2008 Rieju RS2 50 , 1993 Honda NSR 125

[ItsTommmm]

[RhynoCZ]

What James says, by the way Tom, always start with what you or your mates, previous owners have done, before you ask a question. It helps us to get you the right answer quicker.
____________________
'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

[ItsTommmm]

[..]

use these...Polini CP 19. manifold. Airbox adapter. 78 MJ. 36 PJ. needle clip on 2nd notch, air screw 1 full turn out from fully seated, runs better than any D50B0/B1 engined senda with crap Dellorto carb.
https://i556.photobucket.com/albums/ss4/anonymouse15/DSC_0036_zpsaqyppwuk.jpg
https://i556.photobucket.com/albums/ss4/anonymouse15/DSC_0034_zpsm0vtv4os.jpg
https://i556.photobucket.com/albums/ss4/anonymouse15/DSC_0004_zps9g4yu7yl.jpg

[ItsTommmm]

[..]