I am no expert but just thought of sharing a few ideas..

Main jet mostly makes a difference post 2/3rd throttle to wide open throttle. Fuel screw, idling and needle setting comes into play for first 2/3rd throttle.

In your previous post, you said there was popping while decelerating, which is a clear sign of running lean. You also mentioned with 15 size pilot jet, it always starts at first crank then it should be the correct size (Better not to use 17.5) Also you say there is a great improvement in performance with 117.5 main jet, so then that should be the correct size.

I dont know what can explain this behaviour! Seems very weird.

One thing would be to try out 15 pilot and 117.5 main jet again and get the fuel screw setting perfect. I guess you are familiar with setting fuel screw?? Just ensure the tacho doesnt fluctuate when you idle. I am sure you should be able to solve the issue with this.

Also what does the spark plug reading say? Is it too black or too white? Get a new plug if the current one is quite old.

Fuelling is dicey issue if you don't have related experience with carb systems tuning. its not as simple as swapping jets or adjusting the needle one or two notches. There is a very real possibility that you can make too many changes and really get lost along the way when you get conflicting readings. You will feel frustrated and wonder where you are going wrong. Unless you know a good tuner around who can do it for you based on experience and knowledge of your bike, you have no option but to follow the read - adjust - read process in step by step methodical manner.

The first thing to do is to form a good baseline. This can be done by going back to stock settings and taking readings at increments of 500/ 1000 rpm in each gear and record the results of the readings. Once you have the readings you can identify the range in which the lean or rich peaks are. You will then need to make changes in increments and take readings across the range. Depending on the readings you may need to make changes to the needle, idle jet, main jet and or the air screw. It's a long drawn process the first few times but will get easier once the baseline gets refined.

As you're in Pune, you can try either of the following combo's, change your spark plug to a higher number (i.e if it's a 6, put a 7) of the same size, just a normal one (around Rs50) and either fill with speed 97 or retard your timing by 4 degree's, then report back, also be careful where you fill fuel, if you're outside city limits you may get a lower octane, if you're inside then only fill at a trusted place, adulteration is common and wide spread, i've had a few bad experiences filling diesel in Pune.

I must say I'm mighty impressed with the RC Big Bore Camshaft and Racing Clutch spring to say the least.
The cams noise can be annoying to some but I'm living with it.
Regarding the TPS you can lock the TPS like how MadMik has done so that there wont be any engine check light showing up

There no need to keep the idle at 1600-1800 rpm.
I'm on RC cam and my rpm is in stock position.
You need to get the carb tuned ASAP.
Btw I'm on 117.5 main jet and the pilot jet and needle position is at stock position itself.

Ok. So tomorrow I will myself revert to the stock carburettor settings. The spark plug color is light tan i think.
The bike is idling fine without any hiccups.
@abhimanyu- can you please suggest me how to identify the lean and rich peaks in your experience. I am only asking to be sure of what i am
doing and to do it correct the first time itself.

Will get a new spark plug tomorrow and put in some high octane fuel. Lets see what do we get.

Could you tell what did you do to the TPS like MadMik.

cheers...

I haven't removed the TPS as I'm On stock Carb fro the time being but will do that once that 33mm semiflat carb is in place.
I think MadMik should show his presence here to help N-O-V-I-C-E

What's the name of the thread.?

Noticed something strange today.

The bike rides normally in traffic and once on the highway upon hard acceleration the bike tends to choke and come back
to life again automatically.

What i am trying to convey is I am cruising at speeds above 75-80 km/hr and suddenly the bike comes to reserve.
But behold I still have 5 litres of fuel in my tank. Then i turn the petcock to reserve and back to ON.
Then all is hunky dory until it happens again next day or the day after.

Then why is the bike choking with that much fuel in tank and runs normal again after fiddling with the petcock.
This is baffling and immensely confusing. Please any advice would be very helpful.

cheers...

Did it happen only once or does it happen everytime? Can you just inbox me about what happened. I had the same scenario but I will share it to you only personally.

N-o-v-i-c-e and i had a chat regarding the issue and seems my man accidentally had installed the pilot jet from the stock BS 26 carb instead of the 17.5 which was causing the choking and engine shutting off. We both have narrowed down the issues to the carburetor and nothing else.

I am super pissed with the hectic work schedule which is keeping me off my little project and believe me not a single day goes by when i come back home; look at all the RC kits and replacement parts, cursing myself over not getting done and over with the build. Regardless, the wait seems to be endless now..



Cheers,

I was getting tired of the Yamaha as well as other mechanics cursing me for frequently asking them to fiddle with my carburetor to get the perfect tune.
So I thought it was time to take matter into my own hands and i did. Also i can't travel frequently to these guys coz of my bad health.

So from last time I myself started to work on the carburetor. So the following is what I did last time.

I had installed the pilot jet of size 15 and main jet of size 115.
Because the bike earlier with the 17.5 pilot jet and main jet 117.5 was shutting down at traffic signals after a ride of more than 10km.
Turned out that the 17.5 pilot jet is supplying more than required fuel. So the engine used to die down due to excessive fuel flow.

After installing the pilot jet of 15 and main jet of 115 the bike wasn't stalling anymore. Even after a continuous ride of 40km the engine used to idle good.
But now the bike was seriously underpowered. And man the popping now was horrible. Lots of it. So it was certain that pilot 15 was lean.
It used to start at first crank just like with the 17.5 jet but would take a long time to warm up and stall in between.

So I had no choice but to install the whole P180 jet kit. i.e. pilot jet 17.5, needle jet, main jet 117.5.
Now the bike is warming up normally and wouldn't stall in the process. Bike is running better than before but still nowhere to what a fully souped
up FZ with RC parts should run like.

Now after some tuning with the P180 kit the bike runs without stalling for what short rides i have done.
But noticed that the after I shut the bike after a 10km ride, then it doesn't start easily. It takes some 5-10 cranks.
This was not the issue with the pilot 15, main 115 setup. Bike started under any condition.

Also now flat spot between 4k - 6k rpm. So i thought of trying to change the needle position a notch below.
To my horror i was shocked to see the needle has no adjusting grooves. It has a single position. It was supplied such with the BS29 i bought from Joel.
Even my stock BS 26 carb needle has 3 positions. So now I am unable to do anything about the mid-range at present.

So I am still trying to fine tune the carburetor and extract the power expected of the RC kit.

cheers...

That is really surprising! It is supposed to have 3 positions.

But you can try out one thing. if you have a small washer which can fit into the needle properly then you can use it to move the clip up/down depending on your needs. Since you want to make it richer, place the washer where the clip is now and place the clip below it which will be same as shifting the clip to the lower position.

Hope this helps.

Thats exactly what i planned to do today. So i was gonna go out to buy those small washers.

They are found only in specific shops some distance away from my home.

But couldnt go out because todayi felt too much out of sorts. I would go out tmororow if feel a little better.

cheers...