need help reading piston burn pattern

[bladefrost]

I see your bike has an ECU. did the engine originally come with fuel injection ? I see by your posts that you can alter the ignition timing via a computer ?

sorry to but into your subject, but are you able to give details of the CDI unit you have, and info I can look at on line, web site etc. Ta

Here's the link http://www.bintangracingteam.com/produc ... 08&lang=en

[bladefrost]

Tested today with 8 degrees total cam advance, bike is generally slower. The low mid and topend power is lower than with just 4 degrees of advance. I wonder why the cranking compression is also lower with 8 degrees advance than with just 4 degrees. On paper it should be higher. I can feel it when i kick start the motor its softer.

[Dan Timberlake]

Hi bladefrost,

tested today with the cam advanced and the lash loosened. the engine likes it a lot. now it has power on the topend. the engine now recovers when i give it full throttle from mid rpm. not like before it would just stall and die. its still would stall when you give it full throttle when running at low rpm but this is better than before. gonna try to advance more another 4 degrees.

Was the timing change and the lash loosening done at the same time. How much was lash changed, and where is it now compared to the cam maker's specs?


I'm thinking a 4 degree cam timing change from an honest and true "straight up" could change the power some, but noticeably, at top end and/or mid range, possibly even taking a little away from one and adding it to the other.
I would not expect it to make a power/no power or run/not run change.

Your reported results would mostly make me suspicious of the initial lash adjustment.
Have you checked the lash at different points on the base circle?
Do you use go-no/go feeler gages?

[bladefrost]

Hi bladefrost,

tested today with the cam advanced and the lash loosened. the engine likes it a lot. now it has power on the topend. the engine now recovers when i give it full throttle from mid rpm. not like before it would just stall and die. its still would stall when you give it full throttle when running at low rpm but this is better than before. gonna try to advance more another 4 degrees.

Was the timing change and the lash loosening done at the same time. How much was lash changed, and where is it now compared to the cam maker's specs?


I'm thinking a 4 degree cam timing change from an honest and true "straight up" could change the power some, but noticeably, at top end and/or mid range, possibly even taking a little away from one and adding it to the other.
I would not expect it to make a power/no power or run/not run change.

Your reported results would mostly make me suspicious of the initial lash adjustment.
Have you checked the lash at different points on the base circle?
Do you use go-no/go feeler gages?

Cam was initally installed straight up from the cam grinders recommendation. @ 1mm valve lift it reads 33 deg intake opening and 60 deg intake closing. 273 deg total.

Lash wash changed from 0.15mm to 0.10mm at the same time cam was advanced 4 degrees and it run best but after i added another 4 degrees to a total 8 degrees advanced it runs poor. The low mid and top end power was lost. I use IC EO method when adjusting the lash. I tried it at tdc but the lash was different from the iceo method. I use go no go also.