SP loud knocking sound @ 4k to 5.5k rpm

[LouisChen]

Hi everyone.

 

I just did a full servicing on my SP and had to change the piston.

 

I noticed that there is a distinctive knocking sound which comes in at about

4k rpm and lasts till 5.5k rpm. This knocking sound ends when the valve opens.

 

Does anyone have any related experience?

 

p.s. I also opened the air box with 1 nut. (could it be this?)

 

Thanks,

Louis

[Mageswaran_g]

Your connecting rod bearings may be in the state of giving way.

 

Did your mechanic tell you anything about the connecting rod loosening out?

 

One way to test it would be to ride your bike till you reach the fifth gear and shift it to the sixth.If there is a drastic drop in RPM,it would suggest what I think it is.

 

The sure most way would be to open up to see! These are just finding out based on symptoms.

[LouisChen]

hmm.. don't think it should be any bearings..

 

i last changed like 5 diff sets of bearings 3 weeks ago.. can't really remember what they were though.. some front and rear wheel bearings, pro arm bearings and something else ..

 

As for the drastic drop in rpm, nothing unusual based on these couple days of riding, just the knocking sound which only happens at this rpm band..

 

thanks for the reply, any other comments/opinions are welcome

[schwein.bissen]

Get the valve motor and cable checked. If it's moving violently instead of smoothly (components, wiring or CDI problem), knocking can result. Overly stiff reeds can also cause the problem.

[kwanheng]

Hi everyone.

 

I just did a full servicing on my SP and had to change the piston.

 

I noticed that there is a distinctive knocking sound which comes in at about

4k rpm and lasts till 5.5k rpm. This knocking sound ends when the valve opens.

 

Does anyone have any related experience?

 

p.s. I also opened the air box with 1 nut. (could it be this?)

 

Thanks,

Louis

 

valve timming? wrong?

[FS 349 Z]

i intro u go malaysia ah gua lane de "kok ping" go there take a look.. he sure can solve ur problem.. if cannot u come find me..

[ryanryanryan]

i tot sp standard will have this knocking sound b4 valve open?

[pyro13]

really meh?? like indicatot valve wanna open ar?

[homl]

i tot so too..my sp runs smooth until 4k, den from 4k onwards got some stress noise until valve open at 5k den its smooth again

[Iori Yamagi]

i tot so too..my sp runs smooth until 4k, den from 4k onwards got some stress noise until valve open at 5k den its smooth again

 

Yup agree... open till 5k is smooth and going kinda fast

[guwakzai]

sp wat valve open? got vtec? haha...

 

the jerky feeling is normal for sp . .

 

if idling got the knocking sound then is the cluth housing loose..need repair or change new 1..

[Team_Commander]

could it be the bogging zone>???

[queirtus]

i think its ur conrod loose,gotta get it changed

[Iori Yamagi]

i think its ur conrod loose,gotta get it changed

 

Sorry bro wat is conrod?haha i noob paisay