Hello all, has anyone here tried to tune the carburettor of their Unicorn? I was having problems with the fuel efficiency dropping and hiccups while accelerating(especially between the 3K-4K mark). So today I decided to tune my carb.

Did some research on the internet, found two articles, one on tuning carbs in general and other specifically for the Unicorn. This article even has a video where tune-up process been demonstrated, albeit on an Apache RTR. The only difference we have to keep in mind that in our Unicorns, the fuel screw is accessed from the left and not the right.

So I just tuned my own motorcyle! This was my first time and I feel I have gotten it right as the bike feels smoother while accelerating now. Feels really good.

Now my question, is there a way to determine is the setting is right? I mean, it feels good when dricing, but are there any diagnostics or something that I can run to determine if the tune up has been done right?

Another question, how exactly does the tune up get screwed up in the first place? I mean, this whole fuel efficiency dropping and jerky acceleration thing started happening all of a sudden. I did not take my bike to a mechanic or anything, didn't touch the carb. How did it happen? All of a sudden the efficiency dropped from 45+ to below 40?

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The unicorn does not have a DC light, so it is normal for the light intensity to fluctuate along with the engine RPM. When he brakes, the engine RPM goes down which also causes the light to go dim.

Try to pull in the clutch and twist the throttle very slightly to keep the RPM at 2000 while braking. This should help. Not the best braking technique, but there nothing else you can do unless you're willing to get new parts and replace your stock lights.

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I have this exact problem on my 2013 unicorn. When the engine is cold, the bike stalls as soon as I try to accelerate. I think this problem is a "feature" of Honda Unicorn bikes. Nothing we can do about it. It gets worse during winters.

I usually warm up my motorcycle by running it on choke for ~2 minutes every morning, and then let it idle for another minute before I ride.

Another trick that I have discovered is, when you accelerate, and the bike began to lose power(hawa khana), let go of the accelerator a little. It will cause the engine to rev back up normally. Do this multiple times until the engine warms up sufficiently. Or you could just twist the throttle all the way and cause it rev up to max. Either way works fine for me.

Hi,
I have been using my dazzler for the last 5 years and for the last 1 year I am having trouble in starting up my bike after long idle(mostly in the morning and late evening when leaving from office)...

Hello, I own a Unicorn and I have the exact same issue. You can try tuning the carburettor and setting up a rich mix, but your fuel efficiency will decrease. Does your problem worsen during winters?

BTW, how many kmpl does your Unicorn give right now?

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My cold and hot RPM is 1-1.2 and 1.8 respectively.

BTW, I have deliberately tuned my carb to give better fuel economy. This issue has gotten worse as winters have set in. I want an FE of more than 40. During summers I run on a lean mix and this behaviour doesn't happen, at the same i get an FE of 45kmpl+

Is there a way to fix this without compromising too much on the fuel economy?

And btw, i warm up the engine by running on choke for 3-4 minutes every morning, but this issue still persists.

How many kmpl does your Unicorn give you?

hey RohIIT:

I read this post of yours. Now, I own a CB Unicorn(not Dazzler) and I have tuned my carb according to a ********** article i found on the internet. I first started the engine and set the idle to 3.5 K. Then I closed the fuel screw to its maximum permitted limit, The RPM of the dropped. After this i started opening the screw and the RPM rose.

I the article I read, it was written that one should keep an eye on the tachometer and when the RPM becomes constant and does not fluctuate with the engine running, that it correct AFR setting. So i turned the fuel screw around 1+1/8 turn out. At this point the RPM became almost constant and the fluctuation was minor(0.1RPM)

I have left it at that. Now I'll ride to college tomorrow and only then i'll be able to tell whether the issue of cold starts and engine shutting off in traffic have been fixed or not.

Did I do it right?

Thats good, But did you block the grey pipe going to inlet manifold ? I wrote a note there to do that , so meanwhile ride and see if jerking issue is gone , if not then Block grey pipe and try again. 1.25 turns seems little less to me as i have set to almost 2 turns for perfect working .

No I did not do that. I'm not very knowledgeable about this, so I'm kinda scared of messing things up. I just went and took a look at the carb and i saw a golden pipe coming from behind and merging into the intake between the carb and the cylinder. I saw no grey pipe.

Although the jerking appears to be gone, i feel a proper evaluation would be possible only when starting off from a cold engine. I'll ride to college tomorrow morning and then update this thread. If it still doesn't work, I'll try unplugging the pipe(btw is it grey or golden?) and closing it with my thumb, and then tune the carb.

BTW is this grey pipe you speak of, accessible from the left side(from where you access the fuel screw), or the right side of the bike(from where you access the idling screw)?

Okay so, here are two pictures that I took. I have labelled the golden pipe for you. Can you tell me what that metallic box is, where the golden pipe originates from?

Sorry for the poor image quality, I took them after sunset at an outdoor area with little lighting.

Yes this one , Remove the rubber pipe and block the metal lower pipe which is fixed to intake manifold and try again .

Thanks, can you tell me what that metal box is where the pipe originates from?