[adrian]

Originally Posted by ashwinprakas

So to put it simply, the possibility of the TPS resulting in this condition simply going by logic doesn't make sense, but then again I'm no expert on FI systems hence why my arguments are suggestive so far.
Cheers,
A.P.

Got curious after reading the following excerpt from the manual. For the record, I find myself very much in ease with carburetor motorcycles

[ArizonaJim]

Originally Posted by adrian

What is the chance of the TPS being a culprit in the scenario ?

The Throttle Position Sensor is high on my list of suspect parts that could be causing the engine to run rich.

As was mentioned above, it does have an influence on the spark timing but its main job is to tell the ECU how much fuel needs to be injected into the engine inlet. If it thinks the throttle is half way open when in fact it is only one quarter of the way open, the ECU will inject enough fuel to meet the demands of a half open throttle. Needless to say, that would be much more fuel than is needed.

The TPS is just a variable rheostat. A mechanical device that changes the amount of electricity it allows to pass thru it depending on its position.
If something goes wrong with it and it allows too little or too much power to pass thru it, whatever is using that power will not operate correctly.

After checking the electrical connections as I mentioned above, if the problem is not solved, replacing the TPS and setting it to the correct position could fix the rich fuel condition.

[Malhi]

Originally Posted by ArizonaJim

The throttle position sensor must also be set to indicate the correct voltage when the throttle is closed. This voltage should be 0.6 +/- 0.2 volts. If it is incorrect, the ECU could cause excess fuel to be injected into the cylinder.
The manifold air pressure sensor is also a likely item that could cause the engine to run in a rich condition.
Although this didn't show up as a fault code, the computer just looks at whether it is working. Not if the information it is feeding to the ECU is correct.



In any case, the throttle body should not need to be replaced.

I did a Tps voltage check at home.

In the first scenario the positive was connected to the top wire of the sensor and the negative to earth. This is what I got.

Throttle closed:

The reading was .76

Throttle fully open:

The reading was 3.91

To test the operating voltage I connected the positive to the middle wire of the sensor and the negative to the bottom most.

The result was 4.94

As suggested I also checked for consistency in the sparks. Although I was wasn’t sure quite sure how to go about it and it was very difficult to keep my hand stable but I did not notice any irregularities in the beats until the cap was taken as high as the last two threads of the plug.

Regarding the crank sensor and ignition censor I noticed two wires taped with yellow and green tapes (visible in the photo) one of which was coming out of the rhs cover. Could it be that I was actually scammed in replacing the fuel pump and the real problem lay in the connections of these wires which was fixed and the bike returned to me? And the error codes are stored since then?

[Malhi]

Hi everyone.

Recently completed a small mod to the motorcycle which I’d like to call “the real blackout edition.”

Few photos.

[Malhi]

Here is a question guys, and sorry for being a little vague. In the posts above I mentioned that I messed up with the sensor screw and the voltage it gave was around .75. I rode it at this setting for a few days till I got time to replace the screw. But here’s the thing, the bike ran butter smooth! The pick up increased and the engine was so much relaxed. I was easily doing 80 in stretches where I earlier would barely touch 70, I was flicking the bike around with much more ease and confidence.

The only downside I noticed was that a familiar Tak-Tak became more prominent I.e. on the slightest of revs while idling (it goes away on higher revs). The noise is more audible from the left side of the engine- the right side is mostly cam and tappet clatter.

But being on the safer side I reduced the voltage today to the standard .6V and also replaced the screw. The problem now is that when I give a sharp twist to the accelerator the engine just starts to die down as if not getting enough fuel. On not so sharp acceleration it works fine. The good part is that the tak-tak seems to have faded.

My question is- if the bike does not throttle well on the ideal .6V setting (means something is wrong with it) then can I go back to the .75V where everything seems to be perfect and exciting as well? (Given the fact that RE says that the voltage can be anywhere in between .6 (+-2).)

Regards,
Malhi.

[Malhi]

Hello everyone. Although it seems that I am the only participant in this part of the thread but for the benefit of others who might someday want to go the TPS voltage route I felt a moral responsibility to lay everything on the table.

Therefore, in conclusion I’d say that .6v setting is working just fine, the initial acceleration problem was probably because I’d not given the new setting enough time set in properly. Although, I feel that .65v would be perfect.

In the future, and I don’t know when that’s going to be, I think I would like to get better spark plugs, a free flow exhaust, a less restricted air filter and adjust the tps to match the richer air flow. I am pretty sure it’ll do a much better job that any of the piggyback ECUs.

That’s all for now.

Over and out.
Malhi.

[Randhawa]

Stick to around .6 to .62v, works best for single and twins also. I was quite happy with .62v setting on my Bonnveille.

I suggest you check the condition of the throttle cable also. When was the TB cleaned and did you ever changed the fuel line? Need a free flow down pipe then come around, it's OEM.

[srini1785]

Originally Posted by Malhi

Hello everyone. Although it seems that I am the only participant in this part of the thread but for the benefit of others who might someday want to go the TPS voltage route I felt a moral responsibility to lay everything on the table.

Therefore, in conclusion I’d say that .6v setting is working just fine,

You are not the only participant in this thread.

The 0.6 or 0.72V question, IMHO, does not arise when the bike is accelerating. As you are probably aware, TPS is a potentiometer , the readings (0.6 or 0.72V) taken at throttle closed position indicates a situation that carb users so fondly call as the idle screw setting. In a carb its a physical screw that you set at say 2 turns out and is used only during idling of the engine. During the running , its the main jet that takes over as the throttle cable is connected to the plunger above the main jet.

So engine running smooth or rough based on TPS sensor reading at closed position is not a correct conclusion.

[Malhi]

Originally Posted by srini1785

So engine running smooth or rough based on TPS sensor reading at closed position is not a correct conclusion.

No doubt I could be wrong but i did some research on https://forum.classicmotorworks.com/...?topic=12481.0 forum and found that the effect is not just confined to idling. Moreover, we have the brass screw for that. But again I could be wrong.

@Randhawa: The throttle body had been thoroughly cleaned and the fuel pipe, spark plugs, air duct, air filter are new.

[Malhi]

Hi again everyone.

It's the engine knock that's been bothering me lately. I've tried to ignore it for the past many months thinking I was just getting too obsessed with finding faults in the machine. However, off recently the noise has just gotten too obvious to ignore.

I am attaching audio clips for anyone who could help me pinpoint the issue. I just hope it's not the con rod.

https://drive.google.com/folderview?...kDRYi5FkV-t0yk

[ashwinprakas]

Originally Posted by Malhi

Hi again everyone.

It's the engine knock that's been bothering me lately.

Sounds more like the hydraulic tappets have gone for a toss.

If I recall right you'd have to take the cylinder off to get them replaced. In which case you could simply inspect the conrod for play.

A distinct characteristic of piston slap is that in the beginning it only shows up at idle and goes away under load. This doesn't sound like it.

Regards,
A.P.

[Malhi]

Originally Posted by ashwinprakas

Sounds more like the hydraulic tappets have gone for a toss.

A distinct characteristic of piston slap is that in the beginning it only shows up at idle and goes away under load. This doesn't sound like it.

Tappets sure are loud but I am concerned about the 'wooden' knock which comes when the engine is revved up and goes away on releasing the throttle. As far as I know tappet noise will not be effected by gearing and acceleration but this knock vanishes on higher revs in shorter gears.

Adding a bit more information- the "knock" does not occur on high cruising speeds, I.e. 80 and above, but as soon as I hit a flyover in 5th gear the sound stays until the descending starts.

Although the pick up, top speed, beats are perfect but I am a little bothered because I have started to feel the "knock" through the handlebars into my hands.

Ripping the engine into two is not something I would want to start with and that's why i am trying to reach to the exact problem myself before handing over my beloved to those disappointing mechs.

Here is another audio.

https://drive.google.com/file/d/10h-...w?usp=drivesdk

[Randhawa]

To change the tappets, crankcase needs to be opened. Usually it's the cams or RHS crank bearing making a bit of noise if abused. Cams can be adjusted or replaced easily. There is a common noise from all UCE engines(piston slap). Very common for people who have done running in by the book and ride not too hard. No adverse effect of the noise, no issues with performance or FE. A decade ago the piston barrel kit was around 8k, takes half an hr to change it. Check compression if you are too worried.

[ashwinprakas]

Originally Posted by Malhi

Here is another audio.

https://drive.google.com/file/d/10h-...w?usp=drivesdk

Personally for me a Pulsar owner it sounds as though the normal knock you get when you crack open then throttle in neutral, on Pulsars this can be avoided by tensioning the Scissor Gear a tooth tighter(3 teeth) than the factory recommended setting(2 teeth). This on my motorcycle is not a knock that usually occurs when gradually increasing throttle I.e only when rapidly cracking open the throttle.

But then, another reason that can cause a knock is running way off than the ideal state of tune. Again I simply cannot be certain going by an audio clip, all I can provide is generic cause and effect cases.

Originally Posted by Randhawa

There is a common noise from all UCE engines(piston slap).

Sir, a piston slap is by no means normal on any motorcycle, it is the result of excess clearance in the Conrod bearings.

State of tune that results in knocking is a different thing.

Regards,
A.P.

[Malhi]

Originally Posted by ashwinprakas

Personally for me a Pulsar owner it sounds as though the normal knock you get when you crack open then throttle in neutral, on Pulsars this can be avoided by tensioning the Scissor Gear a tooth tighter(3 teeth) than the factory recommended setting(2 teeth). This on my motorcycle is not a knock that usually occurs when gradually increasing throttle I.e only when rapidly cracking open the throttle.

I've heard that sound on my Avenger so I know what you are referring to (Seems like I am jinxed ). Yes it is very similar to it.

This YouTube mech-vlogger by the name of NCR motorcycles has put up a couple of videos of bullets with a very similar sound problem. According to him the Con rod pin and the bearing are the culprits. Here are the links:

https://youtu.be/Ird6qUESW0w

https://youtu.be/rXrUrdj8TBg

https://youtu.be/SGYUsf-pwpQ