Cdi, Rpm, Speed

[Chaoz]

got a question to ask.. does CDI affect your rpm to speedo relationship?

 

my ebay purchased de-restrictor CDI arrived today. And I installed it. Just now when I was on my way home on the expressway, i noticed my 100km/hr (highest gear) rpm became 7.2k rpm from the usual 6.2k rpm.

 

Is it caused by the CDI or my clutch plate suddenly spoil?

 

i only noticed it about 4-5 hrs after i change the cdi when i was cruising home.. was too busy wacking earlier on to notice..

[Guest chongzv08]

i am a spamming ccb

[Mageswaran_g]

yes.CDI spark affects the combustion timing the revolutions the crankshaft makes.

I think the CDI you just bought is suspected fraudulent.

7.2k RPM for 100km/h is too much for a 400cc.So that means,you may top out at slightly above 160km/h@1400RPM in sixth gear.

Your original CDI seems better.

It could top out slightly below 180km/h compared to the later.

[zyrofillica]

how does cdi cause the rpm to change at same speed without a new set of gearing in your gear box?

[hachi]

Agreed....Gearing are mechacnical....ie if you bike' spd 100kph at 6000rpm......At 200kph it will be 12000rpm.....Gear ratio are fixed.....Unless you change the final drive ( sprocket )

[hachi]

yes.CDI spark affects the combustion timing the revolutions the crankshaft makes.

I think the CDI you just bought is suspected fraudulent.

7.2k RPM for 100km/h is too much for a 400cc.So that means,you may top out at slightly above 160km/h@1400RPM in sixth gear.

Your original CDI seems better.

It could top out slightly below 180km/h compared to the later.

7200 rpm at 100kph so 14400 rpm 200kph.....Unless clutch slips.....

[Chaoz]

when i change back my old cdi, the rpm - speed returns to 6.2k rpm at 100kmh.. so confirm is the cdi's problem..

[Mageswaran_g]

CDI or ECU maps the revolutions your piston actually makes.Strong spark=more power at less revs

[Mageswaran_g]

I had CDI problems once upon a time.

I understand the technicality.

Gear ratio sprockets and tyre rim diameters are all other factors that determine bikes top end ultimately.Manipulating them is a way to change your bikes acceleration or top end profile.