Re: Bizarre, Inexplicable Issues With My Pulsar 135LS Which Have Been Really Frustrating. Please Hel

Query Approved

Re: Bizarre, Inexplicable Issues With My Pulsar 135LS Which Have Been Really Frustrating. Please Hel

Ultimately, any gasoline engine needs three things to run: fuel, air, spark. The symptoms you describe seem to lean more towards the fuel/air side of things, but you have other things going on too. First, I'd make sure that the jets you replaced are properly set and are the correct units for the bike. The idle circuit jet is going to be different from the main, so I'd check to make sure you didn't accidentally reverse them, and that they are correct i.e. you didn't get two mains. Pull the carb apart again, and when you check the jets, make sure that you didn't get a scrap of gasket material caught in a fuel passage. Check the needle valve to make sure it isn't worn too far; if it's too worn it'll sit too low in the outlet and prevent enough fuel from getting to the motor at idle. I know you said you checked that, but it doesn't take much wear to significantly change the relationship between those parts due to their tiny size.

Second, make sure that the rubber boot that connects the carb to the motor is in good shape, as well as the various hoses and vacuum plugs. If anything's cracked, or if the carb isn't seated in it properly, or it isn't snug on the intake manifold, you'll have leaks. Don't just slather it in sealer; check and replace. If it's leaking, it might account for the problem you have starting the bike; you might be getting water into the motor. I don't think it's the diaphragm, since it seems to me that would also cause problems when the bike is on the road, and you seem to imply the bike runs ok on the highway.

Third, when you say the bike runs better at night, does it matter if the main headlight is on? With those little bikes, the electric system doesn't have a lot of reserve. Turning the headlight on at night might be changing the amount of electricity going to the spark plug. You might need to check the gap on the plug electrode to see if it's within spec. If there's a cracked wire or bad connection somewhere, getting the bike wet might prevent it from running due to a short.

Re: Bizarre, Inexplicable Issues With My Pulsar 135LS Which Have Been Really Frustrating. Please Hel


Woah man I almost gave up on expecting a reply. Thank you very much. Alright quick update for you guys for all my actions over the past two days.

Day 1)
Yesterday was my friend's birthday so bought a surprise cake for my friend and then we went to a far-off place free from any humans, cut the cake there, had some cold drink and then got to work. I disassembled my motorcycle completely there, then removed all the electrical connectors including the CDI box and cleaned them good with some petrol. Also I made sure to completely empty my fuel tank by running it dry in order to avoid any issues caused by water. Cleaned all the connectors and put them back, tightened battery connectors just to be safe. Then I got to the carb, opened the bottom, couldn't open the top because of screwed screws Didn't open the jets as they are brand new and don't wanna destroy them again but made sure to blow some air in them. The jets are fine and in spec. No issues there. Had a look at the float, the float is non-adjustable so can't do much there. Had a look at the float needle but there's very little I know of it. I couldn't open the top so couldn't have a look at the carb rubber slide but I ensured it was moving freely. I noticed one thing, the carb slide was quick to get down after moving it up, I saw some video on youtube where some dude was diagnosing bad rubber slides and he said the carb slide should come down nice and slow ( Opinions?). After this, I removed my AFR screw, blew some air in the hole and put it back in, cleaned TPS sensor with some petrol and assembled the carb back, installed the carb back, secured it nicely, also applied some fevicol on the rubber boots just in case to avoid any unwanted air leaks. I've replaced the rubber boot on the engine side but couldn't find the one on the air filter side, it isn't available separately and comes with the entire air filter box so I just applied a lot of fevicol on it to avoid air leaks. Then assembled the motorcycle back and then went for a test ride at night but nope, wasn't convinced. Still the same, only felt some minor improvements maybe or that feel-good feeling you get after doing some work. All in vain or maybe not?

Day 2)
Bought a new, original clutch cable and installed it(irrelevant to all this).
I wanted to go to some mechanics today to see if they can find something. I don't like going to them as most of them aren't that well informed with complex issues such as these and I was right. I went to 3-4 mechanics and all had some shit to say. Then I went to the showroom, spent few hours there convincing the service representative that I wanted to test a few things and didn't wanna leave my bike there for a day. Somehow got through but was only able to tune my carb. OK FINALLY some improvements, I noticed my motorcycle is now starting in just one click but the idle was still not that stable as I would like during the day. Was actually surprised to see my motorcycle starting in one click and also idling MUCH better but still there's a lot of room for improvement. Then got home, wanted to diagnose the issue further, shortlisted more items to check, wanted to check ignition coils and cable (set of 2), watched some videos to test ignition coils, borrowed a multi-meter from a friend and got to work. I couldn't find the official manufacturer readings for the resistance for my bike but here's what I found.
For the MAIN ignition coil and cable-
It was around 2.9-3 ohm for the primary resistance test and around 5-6k ohm for the secondary resistance test.
For the SECOND ignition coil and cable-
It was always a different value actually for the primary resistance test, it was flickering between 2.5 to 5 but was mostly between 2.5 to 4, for the secondary test it was the same as the first coil, that is around 6k.
So what are the official readings? I heard, for the secondary test, the reading should be around 10k but I don't know.
Also checked my battery. It read 13.28 volts when the engine was off and went to 14+ when the engine was running and rpms raised. So battery is superfine. Also cut my petrol pipe short for easy access of petrol to the carb.

Then at night, I observed the idle was much smoother and steadier again like it is always at night, went to the city to complete some tasks, couldn't really test my motorcycle properly so when I came back, I went to a far off place again and put the bike in neutral, revved the bike all the way upto 11k rpm for some time and noticed some interesting observations. After revving for some time, I let go of the throttle to see if the engine dies again, it ALMOST died, but then quickly recovered again, confirmed it again by repeating the actions. Also observed another IMPORTANT thing, exhaust was backfiring a lot when I was revving at 11k rpm which means it is running RICH at full throttle. Backfire on deceleration means a lean condition and backfire on acceleration means a rich condition. Can anyone confirm this?


Overall my motorcycle was much better today. But why is it running rich at full throttle? The jets are brand new. Could it be the main jet needle? Or could it be the carb rubber slide diaphragm which is retracting quite fast or is worn out or something? Or is the engine getting more fuel at full throttle from something else? Lots of advancements today but the issue still remains a mystery to me. What should I be doing next? I also want to check my TPS soon. Kindly help. I'll see what I can do with the carb.

Oh almost forgot about the auto choke, that thing never works right so I've always turned it off by removing it's wire. Could the choke line actually be leaking fuel? It's an auto choke so don't know but there definitely is a choke jet in the carburetor. Thoughts? Should I just seal that passage?

About the bike not starting after washing, I think it could be because of the water getting into the spark plug cables and also over the ignition coils. Thoughts?

Loving all this so far. Eventful day.