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**Akash_Kiran _ Balram** · 06-02-2014, 03:52 PM

Re: INFO: A Guide On Technical Jargons

Originally posted by hss View Post

I had the habit of always braking with clutch pressed in. But for the last few days, I have been practising braking without pressing clutch. What I experience is that if I just close the throttle and apply the brakes without pulling clutch, I experience a sudden jerk forward. Am I doing something wrong?

The sudden jerk occurs because when you begin braking you reduce the speed of your bike to a point where your rpm and speed are both too low for that gear in particular. To avoid these jerks you'll need to kick down before braking or apply the clutch just as you start braking.

Originally posted by hss View Post

And sometimes when we just have to close the throttle (without applying brakes), should we still not press the clutch?

This is called engine braking, and no, you shouldn't apply the clutch in is case as it'll eliminate the engine braking and your bike will move under its own momentum, unopposed.

Ride hard. Ride safe.
Akash.

**Akash_Kiran _ Balram** · 06-02-2014, 04:09 PM

Re: INFO: A Guide On Technical Jargons

Originally posted by wallpapers123 View Post

I believe slipper clutches have lesser engine braking than wet clutches..
Please quote someone if I'm wrong..

Sent from my iPhone using Tapatalk

The job of slipper clutches is to avoid the rear wheel to slip or hop while kicking down aggressively.... It only reduces the amount of back-torque produced. It doesn't have anything to do with engine braking.

Engine braking is the effect caused by a vacuum that's created in the motor when you close the throttle.

Closing the throttle restricts the amount of air entering the air-intake manifold and the work that the motor now has to do against this restriction provides the braking effect.

Ride hard. Ride safe.
Akash.

**SparKot** · 06-25-2014, 03:33 AM

Re: INFO: A Guide On Technical Jargons

Originally posted by hss View Post

...
Sorry, didn't get you. When you say don't disengage clutch while closing throttle, you mean engage the clutch meaning press the clutch while closing throttle. Is that right?

Disengage clutch => press clutch lever

a photo from dansmc.com for easy understanding:

**hss** · 06-25-2014, 04:57 PM

Re: INFO: A Guide On Technical Jargons

Originally posted by SparKot View Post

Disengage clutch => press clutch lever

a photo from dansmc.com for easy understanding:
[ATTACH=CONFIG]148427[/ATTACH]

That helped. Thank you.

**albyjose** · 06-25-2014, 07:27 PM

Re: INFO: A Guide On Technical Jargons

Originally posted by arijitmaniac View Post

Excellent explanations right there!!

To add, may I suggest resonance?? Maybe the engine vibrations of the RTR have just the right frequency to cause the handlebars to resonate? Thats probably the reason the vibrations are large enough to be actually felt. I dont have an RTR and I cant opine specifically, but this does seem plausible. Maybe the whole bike frame doesn't resonate (that would probably be disastrous!), but certain components like the handlebars or footpegs do. Most bikes have weights on the ends of the handlebars to prevent the vibrations.

I feel you are right.Every bike has a particular rpm at which resonance cause the vibrations to amplify and can be easily felt on handlebars.For many bikes this rpm is quite low like in splendor,where at a particular point of revving we can fell the mirrors vibrating with rigor. In apache sadly the resonance rpm lies somewhere around 5-6k rpm ie around 65kmph,average riding speed.Using taller gearing I managed to remove peak vibrations from my normal commuting speeds.

**Farhan Kashif** · 11-02-2014, 02:58 PM

Re: INFO: A Guide On Technical Jargons

An Insight Of Engine Valve Train:

We always talk about the configuration of an engine's valvetrain when we refer to the technical specification of a bike; the bike has SOHC configuration or DOHC layout. What are these SOHC/ DOHC configurations are? and what is this Valvetrain all about???

**RonnieB** · 11-03-2014, 11:53 AM

Re: INFO: A Guide On Technical Jargons

Really good thread nice contributions from all

**viju** · 12-04-2014, 12:50 AM

What's a refined engine?

Hi xbhpians,

You must have heard about this phrase umpteenth number of times - "The x vehicle's engine is quite more refined than the ... ". When a reviewer says what does he mean? For me it is, squeezing out more power / mileage out of gas it uses, less vibrations in reasonable running conditions. It's a huge question mark - what exactly is more refined but the biggest thing - How did they come to know by just riding it for sometime?

**BPD** · 12-27-2014, 02:19 AM

Re: INFO: A Guide On Technical Jargons

Originally posted by Farhan Kashif View Post

An Insight Of Engine Valve Train:

We always talk about the configuration of an engine's valvetrain when we refer to the technical specification of a bike; the bike has SOHC configuration or DOHC layout. What are these SOHC/ DOHC configurations are? and what is this Valvetrain all about???

If you can clear this please... What is the advantage of DOHC over the old SOHC? If SOHC necessarily be used in two valve engines?

Soulfuel @ 9830072897

**Farhan Kashif** · 12-27-2014, 03:01 AM

Re: INFO: A Guide On Technical Jargons

Originally posted by BPD View Post

If you can clear this please... What is the advantage of DOHC over the old SOHC? If SOHC necessarily be used in two valve engines?

Soulfuel @ 9830072897

DOHC engines are relatively more efficient due to its design which allows extra space for multiple valves with sparkplugs. No SOHC configuration does not refer to 2- valves setup. A SOHC can have multiple valves for eg; 2,3 or 4 in a single cylinder head.

Hope you got the answer.

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

How The Motorcycle Clutch Works

What is a Clutch? How it works? How important a Clutch is? all these questions and many more often come to our minds. For a better understanding of Motorcycle Clutch:

**Samarth 619** · 12-29-2014, 03:31 PM

Re: INFO: A Guide On Technical Jargons

Originally posted by viju View Post

Hi xbhpians,

You must have heard about this phrase umpteenth number of times - "The x vehicle's engine is quite more refined than the ... ". When a reviewer says what does he mean? For me it is, squeezing out more power / mileage out of gas it uses, less vibrations in reasonable running conditions. It's a huge question mark - what exactly is more refined but the biggest thing - How did they come to know by just riding it for sometime?

The literal meaning of refine means to clean, purify, etc. by a process.
In terms of an engine, we can say a refined engine is one which has passed through good R&D to improve its running characteristics.

Refined could be in terms of NVH:- Noise, Vibrations and Handling. In fewer cases, it is used to describe mileage.

Originally posted by bprashant View Post

Hi guys,
have a question, posted it on CBR 150R thread but didn't get any answer so posting it here.

I have been riding R15 since last 3.5 yrs and as soon as CBR 150 R was launched, was exited and instead of celebrating people started verbal battles and started mentioning pros and cons of each bike.

one of which was an closed loop FI in CBR 150 R, as far as I know an closed loop uses the measurement of exhaust gases(using o2 sensor/Lambda sensor) for precise fueling. but there's a catch, a closed loop is used only in the initial RPM's i.e. below 60% of max RPM(according to ) since CBR has 11.5 k as cutoff, the closed loop will work until somewhere around 5-5.5 k, and post this it works as a regular open loop(found in R15)

Now here's my question, CBR being a short stroke has to revved hard to extract power (suggested by owners themselves, the shifting of gears has to be done post 5-5.5 k) so why is the CBR having a closed loop instead of open loop system when most of the time it will work post the required RPM of Closed Loop.

right now trying to learn about FI's.

CHEERS

The quoted article is written in reference to high capacity sports motorcycles abroad. Note that the word "usually" is given there.
It means that its not necessary that CBR 150 stops using inputs from O2 sensor at 6000 rpm only. It may be beyond that, or it may not be.

I think in BS III, a motorcycle is tested upto 90 kmph for emissions.... I guess, that makes it around 7000 rpm for CBR 150's top gear, isn't it?

The main objective of Closed loop Fuel injection is to provide accurate fuelling to pass emission tests. Without it, at the worst, a vehicle usually has trouble operating in extreme temperatures, not otherwise.

AFAIK If weather is not favorable, even a closed loop can only maintain the Air-Fuel ratio, preventing the mixture from getting richer, but again, that's no guarantee for the best possible performance, as the engine needs its supply of oxygen anyways. Will have to check this though, not too sure about it.

**hss** · 12-31-2014, 06:52 PM

Re: INFO: A Guide On Technical Jargons

Hey guys,

Have a noob question. In many reviews about bikes (and cars too), when people talk about overtaking, they talk about dropping one gear. Then, I have also heard "drop a gear, and disappear". I am not clear with this. Why do we need to drop a gear to overtake someone? If I understand right:

- to overtake, we need to increase speed. Right?
- to increase speed, we should be revving more or shifting the gear up. Right?

The only scenario I can think of where we would need to downshift to overtake is when we are already in higher gear than the correct gear (or slightly lugging the engine), so that we can come in right rev range by dropping a gear.

Please clarify.

**TheArcher84** · 12-31-2014, 07:33 PM

Re: INFO: A Guide On Technical Jargons

Originally posted by hss View Post

Hey guys,

Have a noob question. In many reviews about bikes (and cars too), when people talk about overtaking, they talk about dropping one gear. Then, I have also heard "drop a gear, and disappear". I am not clear with this. Why do we need to drop a gear to overtake someone? If I understand right:

- to overtake, we need to increase speed. Right?
- to increase speed, we should be revving more or shifting the gear up. Right?

The only scenario I can think of where we would need to downshift to overtake is when we are already in higher gear than the correct gear (or slightly lugging the engine), so that we can come in right rev range by dropping a gear.

Please clarify.

My understanding of down-shifting and disappear is, When you downshift when you are at already higher speed, the Rev range or the RPM of the engine goes near the redline making the speed climb even higher as the engine RPM is also higher. So, you tend to generate more speed and go faster.

**Abishek94** · 12-31-2014, 08:08 PM

Re: INFO: A Guide On Technical Jargons

Originally posted by hss View Post

Hey guys,

Have a noob question. In many reviews about bikes (and cars too), when people talk about overtaking, they talk about dropping one gear. Then, I have also heard "drop a gear, and disappear". I am not clear with this. Why do we need to drop a gear to overtake someone? If I understand right:

- to overtake, we need to increase speed. Right?
- to increase speed, we should be revving more or shifting the gear up. Right?

The only scenario I can think of where we would need to downshift to overtake is when we are already in higher gear than the correct gear (or slightly lugging the engine), so that we can come in right rev range by dropping a gear.

Please clarify.

Normally when the bike is in a high gear at low speeds and the rider wants to accelerate, he downshifts. Though he can overtake/accelerate in the gear he was already in (say 4th), he will shift down to 3rd gear to be in the powerband of the engine and hence the acceleration will be greater meaning he will overtake faster in 3rd gear than in 4th gear.
You may observe that most of the times, be it car or bike, the driver/rider will downshift before overtaking and upshift once he is ahead of the vehicle he wanted to overtake.

**shrirang Shivankar** · 01-11-2015, 07:33 PM

Re: INFO: A Guide On Technical Jargons

You may have observed that engine torque is specified at a particular rpm, at same vehicle speed, if engine speed is increased, one will get more energy per second, so a downward shift in gear increases the energy output per second as more cycles are completed in same time.

Sent from my Z10 using xBhp Connect mobile app

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