[Red Liner]

Since the gearless scooter thread was closed, and we've been asked to create brand specific threads for the scooters we own, here goes.

I have a year old TVS Jupiter. At about 2k on the odo, the scooter started gasping for life beyond 25-30 KMPH on the Odo. I was not around so my brother took it to the ASC to get it sorted. Reason give were that the plugs had fouled.

Now, with the scooter having 4.5k on the odo, the issue seems to have returned. Rev the scooter beyond 25 kmph and the scooter wants to shut down.

What could be the issue? I don't have the workshop manual with me, just the owners manual.

I got this scooter because I really thought this scooter being so many years in production would be spot on. Getting a bit annoyed. My used Honda Dio with more than 40k on the clock never skipped a beat.

[ashwinprakas]

Originally Posted by Red Liner

Since the gearless scooter thread was closed, and we've been asked to create brand specific threads for the scooters we own, here goes.

I have a year old TVS Jupiter. At about 2k on the odo, the scooter started gasping for life beyond 25-30 KMPH on the Odo. I was not around so my brother took it to the ASC to get it sorted. Reason give were that the plugs had fouled.

Now, with the scooter having 4.5k on the odo, the issue seems to have returned. Rev the scooter beyond 25 kmph and the scooter wants to shut down.

You did not go wrong in selecting the TVS over the Honda, because quality, cost, maintenance, reliability and performance wise the TVS is the better option.

Now coming to the issue at hand, Why are the plugs fouling?

1. Improper AFR, i.e you're running crazy rich, run your pinky round the inner exhaust tip, you'll know what you're looking for. There would also be visible smoke when revving the machine.

Running rich is not recommended as it not only fouls the plugs but also results in premature cylinder wear due to petrol being abrasive and resulting in 'bore-wash'.

Causes for running rich can be due to a blocked air filter, improper AFR tuning etc.

2. Improper SP, if you're using hotter than recommended plugs they can foul prematurely.

As we're done with the obvious lets move on to the more far-fetched theories;

3. The TVS 110's come with a state of the art CDI that shifts map based on both throttle input and load, so it would be best to look out for any co-relation between throttle position, map selection and stalling.

4. The pesky pulser coil, if faulty motorcycle would idle fine but crap out and start misfiring when the revs go up, plugs would foul and there would be visible smoke and soot residue.

5. Last but not the least do inspect the vacuum operated fuel valve.

Do have a good look and update on findings.

The quality of TVS A.S.S is nothing but pathetic, I have first hand experience with the Wego, hence the DIY route is recommended.

Cheers,
A.P.

[The Great]

Originally Posted by Red Liner

I have a year old TVS Jupiter. At about 2k on the odo, the scooter started gasping for life beyond 25-30 KMPH on the Odo. Rev the scooter beyond 25 kmph and the scooter wants to shut down.

I have been using the Jupiter since 2015. 4 years and no issues at all. Infact I have never even kick started it since the time I bought it. I love owning it very much.

This peculiar issue what you are facing, I had come across the same in my Yam Rx 135. After trying a lot of things the problem was actually very minor.

The fuel tank had gathered dirt and water inside and the opening towards the carb was narrowed. Cleaned the tank, used the IOC Addon (petrol additive) and my problem was solved.

No harm in trying this though.

All the best

[Red Liner]

Thanks ashwin and the great. I dont like taking a bike or scooter apart without a service manual in my hand. Will need to go to my mechanic and get him to trouble shoot things in my presence one by one until we get to the bottom of this!

Once i see him working on it, it will give me a mental picture of what to do next by myself.

[swissknife]

I have faced such issue in various 2 wheelers. Every time, it has been caused due to the air intake being choked for one reason or the other. You may want to eliminate this before looking any further. Plugs may be another reason, but 2 in 4.k is too many.

[samaspire]

I faced the exact same problem in my 2003 TVS Scooty last week. I suspected foreign particles in the fuel. The mechanic replaced the air filter (which was blocked) and the air filter pipe. Cost me 400 rs. (Including a new petrol pipe which had cracked + labour) and all is fine now.

PS: I do not know anything about 2-wheelers.

[pkulkarni.2106]

This is exactly what I faced a couple of years ago, when I gave my 1st gen Pulsar 150 for service.
Specifically, this happened after the regular service.
The bike would run just fine below ~2500 RPM (in any gear). As soon as the engine was revv'd, it would gasp for life.

Initially the mechanics suspected the spark plugs, then the ignition coil.
Later, when I realized Bajaj A.S.S.'s incompetence, I gave the bike to independant mechanic. I was shocked to see that Bajaj mechanics had cut one of the wire of brand new wiring harness.
Upon fixing that, the bike ran just fine.

I feel your problem has something to do with either the ignition coil, or some problem in the cabling.

[abhinav.s]

Our 2013 TVS Wego had a similar issue. Starts fine and rides for a short distance when not being revved and the moment you try to cross 20kmph it gasps and shuts down as well. Independent mechanic who was servicing the scooter for nearly 2-3 years diagnosed the issue to the carburetor valve getting stuck and not moving freely. First thing you check along with the air filter for any blockages should be your carb and the carb tuning.

[Crankpin]

I have the 2017 new access 125. From my experience, brown caramelised deposits from fuel start building up as early as 4-5k kms in the inlet port and inside the combustion chamber. I had the plug changed too as early as 6k kms. That could be the reason. Besides, after completing 12k kms, the deposits had appeared again and this time I got the inlet valve and the port cleaned. the scooter now has done about 16k kms and I keep cleaning the inlet port after every 5-6 k kms post which the scooter runs fine. I change the plug too as these deposits find their way onto the plug as well.
I’ve also been using fuel additives just about recently. So I’ll be looking out for any deposits in the port after using additives.

[surajspai]

I had one particular issue with my activa 125-the spark plug boot was not fixed properly and a loose connection between it and the spark plug had caused the connecting part to burn due to arcing. At low speeds, it would run fine but the moment I twisted the throttle, it would gasp and sometimes shut off too.
Replacing the boot solved the issue for me.

[sajo]

I had a similar issue on my Jupiter, after I tried to start it after a year of lying idle. I initially thought it could be because it hadnt run for a while, got the battery changed, but it would simply die on me.
Finally an FNG where it had died without any hope of reviving it diagnosed it as what he called as "Rust" in the carb, with impurities having settled in it for close to a year and were blocking the jet. He had shown it to me, it looked like fine white dust. Got it cleaned, and is running okay since.

[IndigoXLGrandDi]

We have TVS Jupiter 110 ZX SmartXConnect bought on 07-12-2022. It has run 4700+ Kms.

I am facing problem with the vehicle as below-
It shuts down on its own at low idle rpm. While traveling if I closed the accelerator at slow speed, the engine shuts down. There is sufficient fuel in the tank. This (shutdown of engine) does not happen everyday or everytime.

I tried to troubleshoot by checking the below part randomly. I found traces of water (I think its water. Correct me if I am wrong). I have removed water (or whatever the liquid) 3 times at the interval of 1000-1200 kms till date. When I removed the liquid, the vehicle runs fine.

The Water quantity may be a half to 1 teaspoonful.

What does this part do? What is/are its function(s)?







Some Rust (?) is seen inside this part. The Red Rectangles are marked to show the same.



This is inside the Yellow Colour Metal Cover shown in 1st and 2nd Photos. What does this flap do?



This is the view after the Plastic-Steel-Rubber Part shown in 4th Photo is removed.


How does the water finds way here? Or is it the ethanol?

[adrift@life]

Originally Posted by IndigoXLGrandDi

We have TVS Jupiter 110 ZX SmartXConnect bought on 07-12-2022. It has run 4700+ Kms.

I am facing problem with the vehicle as below-
It shuts down on its own at low idle rpm. While traveling if I closed the accelerator at slow speed, the engine shuts down.

What does this part do? What is/are its function(s)?

I believe that's the air suction valve and its filter, the secondary air injection system.
the plate you have removed is a reed valve or nonreturn valve that allows air from the air filter to the exhaust side and prevents exhaust backflow.
The vacuum on the exhaust side opens the reed valve when you decelerate.
I am technically vague here as to how this works.
I need to brush up.
But you're scooter wheezing because it's not getting enough air. The water is due to the condensation because of the valve not opening I guess.

More aware members can correct me.

[SS338]

Originally Posted by IndigoXLGrandDi

We have TVS Jupiter 110 ZX SmartXConnect bought on 07-12-2022. It has run 4700+ Kms.

We have the exact same issue with our TVS Jupiter bought in 2021, which has run close to 10K kms. It is a ZX smartconnect Disc model.
The issue is very similar as in the issue is not repeatable at will, and sometimes does not even show its ugly head even for 1-2 months. However, when it shows up, we have to just give the scooter some rest for a few mins and then it starts normally. It can not be associated to heating or anything as it mostly happens within city confines after just around 4-5 kms and other times it runs fine when when taken out for 15-20 kms nonstop.

We have tried below things with the help of service center but to no avail:-
1. Cleaned the fuel injector
2. Replaced the fuel pump
3. Thoroughly cleaned the throttle body and air intake manifold
4. Changed the petrol station thinking it may be some fuel contamination issue

To add: We had this issue within 1 month of the purchase of the new vehicle and that time, the ECU was replaced FoC by the service centre folks and the vehicle was fine for close to 2 yrs, until this issue came back on its own.
The part that you are showing is I believe a Evap system to prevent fuel vapour leaking from the petrol tank. I have also noticed a large buildup of petrol vapours inside the fuel tank everytime when I open it, which is way more compared to what I'm seeing on my other vehicles.
My belief is either the issue is related to 1\Incorrect fuel delivery map of ECU at some edge case 2\Faulty design of fuel tank cap or fuel Evap system

Will be closely following this thread now.

[IndigoXLGrandDi]

Originally Posted by SS338

We have the exact same issue with our TVS Jupiter bought in 2021, which has run close to 10K kms. It is a ZX smartconnect Disc model.
The issue is very similar as in the issue is not repeatable at will, and sometimes does not even show its ugly head even for 1-2 months.
To add: We had this issue within 1 month of the purchase of the new vehicle and that time, the ECU was replaced FoC by the service centre folks and the vehicle was fine for close to 2 yrs, until this issue came back on its own.
The part that you are showing is I believe a Evap system to prevent fuel vapour leaking from the petrol tank.

Sorry for updating late..

I had replaced this part myself in July but forgot to update here. Its name is SAI Cleaner and costs Rs. 72/- at TVS Service Centre. Sorry I took the photo yesterday. Hence the Sticker on it looks faded/torn.


After replacing it, the Jupiter was running fine.


Again for past few days, similar problem resurfaced. So removed water from the same and the vehicle is running fine.

I guess the water needs to be removed every 1000 kms or so. I had replaced this part previously when the ODO was 43XX Kms. Now the ODO is 56XX Kms.

Hope this helps.

As mentioned by bhpian adrift@life, it might be Air Suction Valve and its filter, the secondary air injection system since there is an open end which might be used to suck air from environment. Please feel free to correct me if I am wrong.