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**The Monk** · 08-27-2016, 12:15 PM

Re: Pulsar 135LS engine jerks/misfires/vibrates a lot at high speeds?

Query Approved

If you used to fiddle with the carb a lot, then chances are high that that is where the problem lies. See if you can swap it out with some other motorcycle's carb to ensure that is where the fault lies.

**bobisbacktorock** · 08-29-2016, 12:53 PM

Re: Pulsar 135LS engine jerks/misfires/vibrates a lot at high speeds?

As Suggested by [MENTION=38752]monk[/MENTION], swapping the carb with another pulsar 135 will help you isolate the issue atleast. If issue persists after the swap, carb isn't the culprit, else you know whats wrong.

**dnewguy** · 08-29-2016, 04:41 PM

Re: Pulsar 135LS engine jerks/misfires/vibrates a lot at high speeds?

Originally posted by KartikJ4001 View Post

Some Info about my bike:
KMs done: 10.5K
Fully stock
Engine oil changed to Motul 7100 20W50
Spark Plugs new
Air Filter Clean as a whistle
Recently serviced
Fuel cap/tap replaced to some other one as previous one was broken
New pipe connecting fuel tank to carburettor
I have opened Carburettor 3-4 times before due to some problems

So here's the deal. My Pulsar 135LS jerks/misfires and vibrates a lot after 80kph... It goes back and forth at such speeds like it's running out of petrol... It hesitates like it's misfiring or something.. There's some loss in top end though I can reach 120kph on a good road after a lot of struggle. There's loss in mileage as well. I remember my bike used to resonate/vibrate at 60-75 kph and after that it used to be smooth but now it's kinda smooth till 87kph(7k RPM) and after that it vibrates a hell lot I'm guessing this is because of this jerkiness at those speeds.
Like I mentioned above.. Spark plugs are new. Air filter is clean. Fuel tap is new ( though of other brand ). New fuel pipe. As I mentioned I used to fiddle a lot with my carburettor earlier.

I researched about this on the web and this is what I'm suspecting:

Carb Slide/Diapraghm problem
Spark Plug wires/Ignition coil problem: I watched a video on youtube of a Cbz guys saying his bike was doing things like mine at such speeds and he said his spark plug wires were faulty
Water in fuel tank: Water has gotten into my time previous times as well.
Throttle position sensor problem?: I disconnected it but still it was the same.
Stuck auto choke?: Some guy told me about this. I have an auto choke and yes it's faulty. It doesn't work correctly. I disconnected it a long time back. Simple.
Choked Jets?

What do you guys think? What could be the problem? SVC guys here in Nagpur are very dumb. If I tell them what the problem is they'll test ride it and say it's fine.

Hi Kartik

I also own a P135 and use Motul 5100.
I'm told that the 7100 increases the vibes i.e the engine feels more aggressive. This might be one of the reason.
I have had the issue of water in the fuel tank too last year which resolved after thorough cleaning of the tank. Monsoon is still active in delhi so this too can be the culprit.

Finally, i will say that although the bike revs happily to 90 - 100 kph but it feels too strained doing those numbers and vibrates a lot. It gives zero confidence at those speeds and the brake - tyre combo is awful. I no longer push my bike to triple digits. I will strongly advice to keep an eye on the engine oil level if you regularly ride at 80+ speeds.( I seized my engine due to this very reason).
I don't think the bike is meant to take all that abuse. Its only 135cc and feels at home at city speeds of 50 - 70kph.

Do report back your findings.

Cheers.

**KartikJ4001** · 08-29-2016, 10:44 PM

Re: Pulsar 135LS engine jerks/misfires/vibrates a lot at high speeds?

Originally posted by dnewguy View Post

Hi Kartik

I also own a P135 and use Motul 5100.
I'm told that the 7100 increases the vibes i.e the engine feels more aggressive. This might be one of the reason.
I have had the issue of water in the fuel tank too last year which resolved after thorough cleaning of the tank. Monsoon is still active in delhi so this too can be the culprit.

Finally, i will say that although the bike revs happily to 90 - 100 kph but it feels too strained doing those numbers and vibrates a lot. It gives zero confidence at those speeds and the brake - tyre combo is awful. I no longer push my bike to triple digits. I will strongly advice to keep an eye on the engine oil level if you regularly ride at 80+ speeds.( I seized my engine due to this very reason).
I don't think the bike is meant to take all that abuse. Its only 135cc and feels at home at city speeds of 50 - 70kph.

Do report back your findings.

Cheers.

OK buddy so I finally solved my problem after much testing. I'm writing it at the end of this thread. Well I can happily ride at around 87kph @7000 RPM on the highways no problem. I have MRF tyres and I keep my brakes maintained. And why do you want me to look at my engine oil level at such speeds? I regularly ride at around 90kph and I never faced such issues. My engine oil level is always correct no matter how I ride it. It's a very capable machine no doubt. Duke 200 does 100kph at around 7000rpm... This machine does 87kph at 7000rpm

I'll be modifying this machine later. I'll add a 6th gear if possible or I'll play with sprockets so that I can cruise at lower rpms and I'll also rebore it. Thanks for the answer! Cheers!

----consecutive posts auto-merged-----

So I finally solved my problem. I'm writing this for helping people like me who might face this situation sometime in the future. So the problem was in the Carb Slide/Diaphragm. I went with my friend to my favourite spot where I do tons of things to my bike. I opened my carb, cleaned it thoroughly and found that the carb slide/diaphragm was not smooth. It was getting a bit stuck in motion. So I opened it and cleaned it thoroughly and put it back again and ensured that it wasn't getting stuck. It was moving freely after I put it back again. So I packed things up and then went for a spin.. And Voila! Problem solved! I must mention that I found some water droplets in the petrol I flushed from the carburettor so I cleaned my tank after all this just to be sure. Now the bike is great at high speeds but still the vibration part is bugging me

I'm looking for ways to solve it. I would appreciate it if someone would help. Thanks!

----consecutive posts auto-merged-----

Originally posted by The Monk View Post

Query Approved

If you used to fiddle with the carb a lot, then chances are high that that is where the problem lies. See if you can swap it out with some other motorcycle's carb to ensure that is where the fault lies.

Thanks brother I solved it!

----consecutive posts auto-merged-----

Originally posted by bobisbacktorock View Post

As Suggested by @monk, swapping the carb with another pulsar 135 will help you isolate the issue atleast. If issue persists after the swap, carb isn't the culprit, else you know whats wrong.

The problem was with the carburettor! I solved it. Thanks!

**dnewguy** · 08-30-2016, 11:38 AM

Re: Pulsar 135LS engine jerks/misfires/vibrates a lot at high speeds?

Originally posted by KartikJ4001 View Post

OK buddy so I finally solved my problem after much testing. I'm writing it at the end of this thread. Well I can happily ride at around 87kph @7000 RPM on the highways no problem. I have MRF tyres and I keep my brakes maintained. And why do you want me to look at my engine oil level at such speeds? I regularly ride at around 90kph and I never faced such issues. My engine oil level is always correct no matter how I ride it.

Good to know.
The synthetic oil tends to leak with old seals. And as their replacement interval is 2-3 times longer than the conventional oils, it is wise to keep the oil level in check. I had a seized engine due to low engine oil level that's why.

Cheers.

**bobisbacktorock** · 08-30-2016, 12:40 PM

Re: Pulsar 135LS engine jerks/misfires/vibrates a lot at high speeds?

Bottom line is any air cooled engine will consume some amount of oil over time (no matter how well its maintained).

The oil is consumed either due to slight oil seal leakage and rest goes out through crankcase breather. Some of the oil vapor again mixes into the fresh air coming inside the engine through the air filter and gets combusted. Some residue is found in the bottom of the filter box and collector pipe.

This phenomenon is observed more on air-cooled engines because the clearances cannot be as tight as liquid-cooled ones as air-cooled engine operate on a wide variation of temperatures unlike liquid cooled where the temp remains pretty constant. Thanks to radiator and temperature sensing cooling fans.

If air cooled engines are made with clearances similar to liquid cooled counterparts, the chances of seizure increases.

Our job is to maintain the oil level at all time. Because sufficient oil is must for engines to work properly be in Synthetic or Mineral.

And please consider watching : https://youtu.be/tYkg0oDUXs8

**KartikJ4001** · 08-30-2016, 08:00 PM

Re: Pulsar 135LS engine jerks/misfires/vibrates a lot at high speeds?

Originally posted by bobisbacktorock View Post

Bottom line is any air cooled engine will consume some amount of oil over time (no matter how well its maintained).

The oil is consumed either due to slight oil seal leakage and rest goes out through crankcase breather. Some of the oil vapor again mixes into the fresh air coming inside the engine through the air filter and gets combusted. Some residue is found in the bottom of the filter box and collector pipe.

This phenomenon is observed more on air-cooled engines because the clearances cannot be as tight as liquid-cooled ones as air-cooled engine operate on a wide variation of temperatures unlike liquid cooled where the temp remains pretty constant. Thanks to radiator and temperature sensing cooling fans.

If air cooled engines are made with clearances similar to liquid cooled counterparts, the chances of seizure increases.

Our job is to maintain the oil level at all time. Because sufficient oil is must for engines to work properly be in Synthetic or Mineral.

And please consider watching : https://youtu.be/tYkg0oDUXs8

Thanks for the information buddy. I will check the oil level regularly now! Thanks!

----consecutive posts auto-merged-----

Originally posted by dnewguy View Post

Good to know.
The synthetic oil tends to leak with old seals. And as their replacement interval is 2-3 times longer than the conventional oils, it is wise to keep the oil level in check. I had a seized engine due to low engine oil level that's why.

Cheers.

Thanks for the help man! Cheers! Bike pulls great at high speeds even though there are vibrations.

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