Breaking up at high RPM's!! PLEASE HELP!! By rockfish (Read 604 times)

[rockfish]

So long story short, I had a sputtering issue at low speeds when I gave my Bajaj 50 gas about a week ago. I decided to upgrade my cylinder from a 50 to a 72cc which went in great and fairly smooth. Also I went from the standard 18mm carb that I bought with the bike to a 20mm big bore carb.

Now I have a MUCH bigger problem! I need some help DESPERATELY so if some one can help I'd even be willing to pay!! That's how crazy this is making me!!

It will start and idle fairly well, but when you try to rev it to accelerate it will break up and is losing power. It seems to be getting gas but I'm going to replace the petcock just in case. Also, the carb is adjusted pretty well so I don't think it's a fuel/air issue. The plug seems pretty fouled but I don't think it's doing all that....ignition coil???

What the hell is going on? Please anyone!! I'd be forever in your debt! Thanks!!

[Bashan]

You're correct, it's probably the coil. It's a good idea to keep a coil, CDI, and plug around for diagnostic purposes. They're fairly inexpensive and they fail on occaision. Here's an article on testing standard and performance coils with a multimeter. Swap out your plug too and check the plug cap and wire. This is a complete ignition diagnostic including stator. No need to pay us but if this works we always appreciate donations to keep those nasty Google ads away. Rich