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Originally Posted by TheRajput My six months old CL350 has completed 2600 kms and the stock exhaust has been replaced with a wild boar. This is the first rainy season with the bike and yesterday while riding in heavy rains the engine died thrice within 10 kms of riding, and the engine would fire only after 8-10 kick starts. What could be the reason for this? |
A sudden appearance of an engine misfireing during rains usually indicates a loss of spark at the spark plug.
In most cases, this is due to water seeping into the joint between the high voltage spark plug wire and the ignition coil or the spark plug cap.
While the joint may be totally adequate at preventing an escape of the high voltage when it is dry, water acts as a conductor which can short out the wire.
Check the wire connections at both ends to make sure it is tightly installed. Also, wiping off any dirt or grime that has covered the wire will help to eliminate the problem.
While your checking the wire, also make sure the spark plug cap is fully seated on the spark plug.
The spark plug cap (connector) has a rubber seal at the bottom (mouth) to prevent water from entering. This seal only works when the cap is fully seated. Applying a coating of di-electric grease to the spark plug insulator can also help this joint seal against water.
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Originally Posted by KkVaidya
Dear Arizona Jim: Have always found your posts to be technically sound and easy to understand. Thank you for all the contribution we get from you.
I would like to know what is the reason for smell of petrol, kind of un-burnt, that also gives a slight burning sensation to eyes in a closed area? Is it an indication of a rich mixture even if there is no visible smoke from the exhaust? I have checked for any external leakages and found none ; although a leaking petrol has a different smell. |
The smell is due to a slightly rich air/fuel mixture.
Petrol engines runs best at idle speeds with a slightly rich mixture so one could consider it to be normal unless black smoke is being emitted from the exhaust pipe.
Although modern vehicles have design features to reduce emissions, they aren't perfect and often, people will disconnect or remove them under the (usually false) idea that doing this will increase performance.
It rarely accomplishes the increased power/fuel economy goals but it always increases the amount of hydrocarbon emissions (like the smell of raw fuel in the exhaust).
I'm not suggesting that you frinkled with the emission devices or that anything is really wrong with your motorcycle. I'm just saying some people do.
If your engine is running fine, don't worry about it.
By the way, if you notice this smell it indicates the engine is producing carbon monoxide, a deadly gas that can easily kill you if your in an area with poor ventilation. NEVER run a petrol engine in an enclosed room.
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Originally Posted by thirst4torque Raising this query on behalf of a friend who is not a T-BHP member.
Can anyone tell me what is the exhaust gas temperature and pressure at different RPMs at exhaust manifold of a RE engine (preferably for 500cc engine). It is for an educational project. |
The question is too broad to answer with any real values because the exhaust temperature is totally dependent on how much power the engine is producing and what speed it is running. As these are constantly changing I can't give a good answer.
I can say that when the engine is just idling, the temperature will be roughly in the 170° C-260° C (350° F-500° F) range.
At wide open (full) throttle and high engine speeds the exhaust temperature will be over 870° C(1600° F) at the exhaust valve.
In all cases, the exhaust pressure will depend on the size and length of the exhaust pipe (in addition to the throttle setting and engine speed).
Although larger in diameter and shorter in length reduces the exhaust pressure, this is not always good for producing large amounts of power.
(Many think it is.)
In fact, decreasing the exhaust pressure can have a negative effect.
This enters a very complex subject area iand in this limited space I cannot get too far into it but I will touch on a few things.
A small diameter exhaust pipe will create higher pressures but at the same time, it will increase the velocity of the gas in the pipe.
High speed gas has more energy than low speed gas.
The gas being ejected into the pipe is in pulses as the exhaust valve opens and closes, and it is this that makes the thump at idle or the ROAR at Wide Open Throttle (WOT) conditions. Obviously, at WOT conditions there is a lot of energy present that could be put to work.
It's an interesting fact that as these positive pressure pulses travel down the pipe and reach the end, they create a negative pressure pulse that travels back up the pipe to the exhaust valve.
Because of the way camshafts work, towards the end of the exhaust stroke, while the exhaust valve is closing, the intake valve is opening. In other words, there is a short period of time when both valves are open.
Now, if we time that negative pressure pulse just right by using a exhaust pipe of the right length, the negative pulse will enter the still open exhaust valve and not only pull the last bits of exhaust from the cylinder but it will also pull some new, fresh charge of air/fuel into the cylinder thru the intake valve.
This in effect, supercharges the engine and can result in a noticeable increase in engine power.
This works in both 2 and 4 cycle engines and riders of high performance 2 stroke bikes are well aware of this when the engine "comes on the pipe".
I've ridden both 2 and 4 cycle motorcycles with "tuned exhaust pipe(s)" and can say, at lower engine speeds, opening the throttle to WOT the engine starts to pull strongly.
As the engine speed increases, suddenly, the negative exhaust pulses start to reach the exhaust valve or port at the correct time and pull in the extra air/fuel and the power increases to the point that the handlebars try to pull out of my grasp and the seat pushes on my rear as the front wheel goes into the air.
It is definitely a Power Rush, one hard to forget.
My apologies to our members if I got carried away with this answer.
Now, back to the regularly scheduled questions about Royal Enfields.