Help 08 balius 2 won't rev over 12k rpm

Hello everybody from around the world! I'm from Malaysia.
Just bought the bike in FEB22. It's my first bike in my 40th. It has 20k km on the meter. Got it a makeover with new paint and through rough cleaning except for the engine since the previous owner had just got the oil changed, carb cleaned and synced, rejetting with pilot jet #35(stock is #32), the main jet is still #98,#95,#95,#98. It has a stock air filter and exhaust system. The pilot screw is at 2.5 turns out now. It was 2 turns out(manual is 1 5/8) when I got the bike but after some readings, I add 0.5 coz I found out the idling keeps hanging a while at 2k then dropping back, seems it's lean. Idling is fine now, start-up easy(without needing to blip the throttle, just press ON).
The ride is good throughout 12k rpm(maybe it's my first bike experience on my 40th), but it has some hesitation to reach 14k when I pulled from 1st to 4th gear. When I change to 5th gear, it won't rev past 12k. When I shifted to 6th, the speed went up to like 130km/h-135km/h and stuck there when the engine reached 12k.
I made some markings at the throttle, I notice the last 1/4 of the throttle has no power when I was at 12k rpm at gears 5th & 6th. It's like a cutoff, I did feel something when I full throttle it, the power is like come and go some kind of feel.

So, I would like to seek help & guidance from my fellow members here. Appreciated!!

 

The rubber that hold the carb onto the head? I will take a look after this. It does not have fuel filter. Plug colour is more like darker tone tan colouring but i haven't got a chance to make a pull and inspect it immediately.

 

I do have a video. I have uploaded to my yt.

 

While I was checking the air leaks, I found out the airbox does not close properly on both L & R sides. The bottom cover does not fit into the groove at the top cover and it has been like this for quite a time. I heated the areas with a heat gun and pushed them back to fit into the groove. So I went for some ridings in the evening and try to tune the air jet screw a little. Since I have the #35 pilot jet, everything is stock standard. I found out the mixture screw is very responsive at 1.0 turn out. But still can't make up to top speed on the highway. Stuck at 12k rpm again on gear 6. The last 1/4 of throttle has no response, bogged. I tried to pull the choke, bog also.

When I reached home, I noticed the headlight is not working, so I changed a new bulk, not working either. I asked around my friends to diagnose the issues. Found out the relay was not giving out power to the headlamp switch at the handlebar. (The headlamp will only work when the bike starts up, no ON/OFF button. The Balius in Malaysia has special handlebar switches L & R because it was used as a police motorcycle back in the day. The local distributor does not bring in this model for the local folks but yes to 1998 zxr250. Although it's a 2008 model but the switches are like the 90s'. You have to pull back the signal to the centre after use.)


I bought a used junction box to test and it works. So fixed the headlight issue. I could have sliced into the other hot wire and fused to fix it but I wanted to know what is the real problem.
While I was tidying up the wires and checking on the extra unused wires for the switches. I found out the voltage is rather high (the voltage was good when we are doing the diagnosis earlier). As high as 15.++v at all of the hot wires. I check the battery, it's 16v without starting up the bike! I removed the battery quickly and the acid poured out from the caps when I took it out. I took down the rectifier and it was fried at the socket(where can I buy this socket?).



I took out the old battery which came with the bike when I bought it on 14th FEB'22. It's a no.9 size battery which has been relocated to the tray under the seat. I changed it to a stock no.7 size battery while the bike was dismantled for an exterior makeover at the end of FEB. I didn't use it since that. And guess what? It's still sitting at 16v!


While waiting for the new KAWASAKI rectifier to arrive. I will buy a new battery to test the voltage with the bike started up.

So can I say that my rectifier is gone? Will a poor/malfunctioning rectifier effects the bike performance? Is that causing me couldn't rev through 12k rpm on 5th and 6th gear?

 

Yes. I will perform this test when I got my new battery.

 

Hello forks! It's been 2 months since my last post. lol!
I've got the bike fixed actually. It's riding good, at least to me now. I'll post up what has been done below.

I've got the regulator replaced with a new one from KAWASAKI and also, replaced the cooked socket. The high voltage on my earlier post was actually due to the low battery from the multimeter LOL! But nvm now.


I bought a new OEM air filter as well to replace the wet paper filter. It didn't make any difference on the bike from the old one actually. So I decided to do some DIY at the old filter with some fish tank biochemical cotton filter. It's helping with some tuning at the pilot jet screw. It rev up to 15k rpm.



The KEYSTER jetting kit arrived from JAPAN last month. It has a list of guides on how you can jet your carb to get suit your desire mod. There are 2 different sets for the outer piston and inner piston.


Thinking of the stock muffler on my bike, I replaced the 1&4 main jet with #101(from #98) and 2&3 with #98(from #95). Changed the slide needle to the one slightly rich with 1x R on it. The pilot jet is #35. The pilot screw at 2 turns out. It rev up to the red line easily at 3rd gear with full throttle. I didn't check the plug yet till now, lol! It's very dangerous to cut the engine midway to stop the bike and perform the checking on the sideway.


I didn't replace the pilot screw on the first attempt at jetting the carb. I faced the issue earlier(before servicing and jetting the carb) where the idle get unstable when the bike get hot, it would die out while waiting at the traffic light. Follow by a hard start-up. It still happened even after I cleaned the carb! I then proceed to replace the whole set of pilot screws from KEYSTER. It solved the issue after that.


Below is a video of some pulls...

 

Yes sir! I enjoy it so much!