Motorcycle Safety & Driveability: engine dosent rev quickly, capacitive discharge ignition, digital cdi

Question
hi Anil

what is "ignition curve"  , how is it obtained?

what does it show of engine.

what is digital CDI . Does ignition curve has anything to do with CDI. Can it be changed for better porformance

I have a Pulsar  150cc bike.It used to pull quite well untill the odometer showed 10,000. Now it is 19000.It pulls with a lot of dificullty.the engine revs like it is on a great friction.The revs do not shoot up as it used to in the beginning as soon as throttle is twisted.

My gut feeling is that it is losing compression.What to do? I dont think clutch plates are at fault . Does anything needs to be cleaned.

bye


Answer
Hi Chandan,
Ignition curve refers to how your bikes sparking behaviour changes as you rev. Since the spark takes some finite time to travel between the electrods of the plug, and the flame has it's own propogation time, we need to spark a little before the piston reaches TDC. As the bike revs higher, this time difference needs to change too.

CDI, or capacitive discharge ignition, uses a small capacitor discharge to maintin timing of the spark. The new wanve is digital ignition, and is very precise. You don't need to change the ignition on your bike - relax!

Perhaps it's just time for a routine service? Modern bikes don't lose compression at 19,000 kms - have you ever opened your engine up? Tell me about your riding style - perhaps it may have something to do with it. Also, does the ewngine sound clean? No mistimed sparks and al that? Why don't you get you clean your air filter, carb, and get the plug cleaned (or even replaced, if you've never done it before). And please replace with the correct specified plug.

Regards,
Anil