Power Loss

[Dane123UK]

Hello,

i have a Yamaha Aerox 100cc, it was standard apart from upjetted, and a sports exhaust it went pretty much 60-65mph.

eventually it lost power and now hardley does 50mph.

i've tried swapping rollers see if that helps and does'nt, lighter rollers just make it vibrate but reaches 50 quicker.

current rollers, standard 9grams, older lighter 8grams.

could this be the piston rings?, belt? can anyone help me out?

[Wafer_Thin_Ham]

Have you done a compression check or checked the belt for wear?
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[hazza]

change the plug before you panic.
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3 Honda NC50's(Sold)-->'72 Puch Maxi S (Sold, want it back!)--> '90 Yamaha RXS 100 (Stolen)--> '87 Honda Cub 90(Sold) --> '95 Kawasaki Eliminator (Sold) --> '98 Bandit 600 (Sold) -->'07 SV650S (Current)

[Dane123UK]

[Vincent]

You need a compression guage like this:-

https://i77.photobucket.com/albums/j71/Drewskovitch/imagesqtbnANd9GcQyBNv3lLtoJ_IAXkKXf.jpg

take the spark plug out, screw the guage in, kick the bike over and check the compression. If the rings are worn badly, you get "blow by" and the compression will drop causing the bike to lose power.
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[Dane123UK]

[hazza]

id buy a new plug before you buy the comp tester. I had the same symptom years back on my old rxs 100. Performance diminishes on 2 strokes when the plug wears out, which happens a lot faster than it does on a 4 stroke. If money isnt an object, id get the comp tester too. It will always be a handy tool to have if you decide to continue having bikes.
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3 Honda NC50's(Sold)-->'72 Puch Maxi S (Sold, want it back!)--> '90 Yamaha RXS 100 (Stolen)--> '87 Honda Cub 90(Sold) --> '95 Kawasaki Eliminator (Sold) --> '98 Bandit 600 (Sold) -->'07 SV650S (Current)

[Vincent]

Might be time for a de-coke Compression testers are handy things to have and not very expensive.
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[Noxious89123]

My gf's 2 stroke used to bloody EAT plugs! Always keep a spare.
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