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Discussion Starter #1
Correct me if I’m wrong but an engine brake works by not allowing cylinder compression to release in to the exhaust .
If that is correct my Burg’s engine brake releases around 8 or 9 MPH . My question is what is releasing the compression ,
is it electrical ,through the computer,mechanical ???? All 3 ? Any one know ?

TheReaper!
 

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I dont think you can prevent cylinder compression releasing into the exhaust as the valves are mechanically operated. I think the engine drag/braking is just a mechanical thing and I'm guessing that the clutch disengages at around 8/9 mph. I'm sure I'll be corrected if I'm wrong!
 

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When the driver releases the accelerator on a moving vehicle powered by a diesel engine, the vehicle's forward momentum continues to turn the engine's crankshaft, drawing air into the cylinders as the pistons move down and compressing that air as the pistons move back up. The pressure of the compressed air pushes back on the up-going pistons, tending to slow the vehicle.
But, without a compression release mechanism, as the piston passes through top dead center and heads back down again, the compressed air in the cylinder acts as a spring and pushes the piston down, returning most of the work done in compression back to the crankshaft, creating very little braking effect. The engine turns freely and the vehicle coasts.
When a compression release engine brake is active, a valve releases the pressure from the cylinder before the piston starts back down, so the slowing effect is present on the up stroke, but no accelerating effect is present on the down stroke and the net effect is the vehicle slows down.
With a gasoline engine, the mechanics are different and a special valve is not necessary for engine braking to happen when the driver releases the accelerator. In the gasoline engine, with the accelerator released, a throttle prevents the free flow of air into the cylinders, so there is little pressure to release at the top of the compression stroke. The throttle itself provides engine braking through friction in the air flowing through it. But a diesel engine does not have a butterfly valve to limit air on the intake side.
A compression release engine brake uses an extra lobe on the camshaft to open a second exhaust valve at the top of the compression stroke. The stem of this valve telescopes during normal operation so the valve remains closed, but is locked at full length by a solenoid when the engine brake is engaged so that the valve opens as directed by the cam. This releases the compressed air in the cylinder as described above.
The driver controls consist of an on/off switch and, sometimes, a multi-position switch that controls the number of cylinders on which the brake is active. When the driver has turned on the compression release engine brake, it will activate when the driver releases the accelerator. There are also switches on the clutch and accelerator pedals that deactivate the compression brake when the driver disengages the clutch or presses the accelerator.
The name is derived from the manufacturer, Jacobs (of drill chuck fame), and was patented 1962–1965 by Clessie Cummins.[1]
Legislation[edit]

The use of compression release engine brakes may cause a vehicle to make a loud chattering or "machine gun" exhaust noise, especially vehicles having high flow mufflers, or no mufflers at all, causing many communities in the United States and Canada to prohibit compression braking within municipal limits. Drivers are notified by roadside signs with legends such as "Brake Retarders Prohibited," "Engine Braking Restricted," "Jake Brakes Prohibited," "No Jake Brakes," "Compression Braking Prohibited," "Limit Compression Braking," "Avoid Using Engine Brakes," or "Unmuffled Compression Braking Prohibited," and enforcement is typically through traffic fines. Such prohibitions have led to the development of new types of mufflers and turbochargers to better silence compression braking noise.
Jacobs claims that the use of Jake Brakes on signs prohibiting engine retarding brakes violates their trademark and discriminates against Jacobs brand products.[2][3]
 

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Combine v8eyedoc's and Steve D's responses and you have your answer.

Your Burgman does not have a engine brake because it has a gasoline engine.

What you feel at 8 or 9 mph is the centripetally activated clutch disengaging when the speed drops low enough for the springs to push the rollers out of the engaged position.
 

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A common misconception is that engine braking in a gasoline engine is provided by resistance to compressing air during the compression stroke. It isn't - it is created when the throttle butterflies are closed during the intake cycle which creates a vacuum since the piston cannot draw in enough air to fill the cylinder - very little air is present to compress inside the cylinder chamber.

The Burgman transmission is designed to 'gear down' during deceleration - it is programed somewhat aggressively and even more-so if you are in 'Power' mode. It emulates a manual transmission being 'geared down'. I sometimes use the power mode when coming to a stop from 60-65mph. It works great and saves on the brakes.

Many riders do not like the engine braking effects the 650 is preprogrammed to do. You can avoid much of the engine braking effect by using the manual transmission function and just don't shift down as you come to a stop. As rpms decrease the effects of the engine braking is decreased and there is no automatic 'gearing down' by the computer.

Personally my only complaint with this braking effect is the engine's tendency to surge engine rpms when transitioning back from the braking effect to part throttle - especially in corners. This has the effect of causing the bike to surge forward some. Seems like a reprogramming of the fuel injection is needed to get rid of this surge effect. The only solution I've come up with so far is to use manual mode to help control this surge effect. I'm not sure if this is an isolated problem only found on my bike or if all 650's have this surge effect. It shouldn't take an educated throttle hand to dampen this ill behavior.
 

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Discussion Starter #6 (Edited)
A common misconception is that engine braking in a gasoline engine is provided by resistance to compressing air during the compression stroke. It isn't - it is created when the throttle butterflies are closed during the intake cycle which creates a vacuum since the piston cannot draw in enough air to fill the cylinder - very little air is present to compress inside the cylinder chamber.

The Burgman transmission is designed to 'gear down' during deceleration - it is programed somewhat aggressively and even more-so if you are in 'Power' mode. It emulates a manual transmission being 'geared down'. I sometimes use the power mode when coming to a stop from 60-65mph. It works great and saves on the brakes.

Many riders do not like the engine braking effects the 650 is preprogrammed to do. You can avoid much of the engine braking effect by using the manual transmission function and just don't shift down as you come to a stop. As rpms decrease the effects of the engine braking is decreased and there is no automatic 'gearing down' by the computer.

Personally my only complaint with this braking effect is the engine's tendency to surge engine rpms when transitioning back from the braking effect to part throttle - especially in corners. This has the effect of causing the bike to surge forward some. Seems like a reprogramming of the fuel injection is needed to get rid of this surge effect. The only solution I've come up with so far is to use manual mode to help control this surge effect. I'm not sure if this is an isolated problem only found on my bike or if all 650's have this surge effect. It shouldn't take an educated throttle hand to dampen this ill behavior.
Well I have the same surging with the new to me Burg , my 2009 Tmax has an engine brake too but nooooooooo where as severe as the burg . My Honda Big Ruckus has none . I got used to the Tmax engine break rather easily , but on the burg I'm way behind on the learning curve .......so far .
I'm going to spend the day in the saddle and see if I can get a handle on it ,
I'm sure if there is a way I'll find it .........hopefully :confused:

TheReaper!
 

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Crack the throttle open just a little and much of the braking effect will go away. With practice you can get the 650 to almost coast to a stop.
 

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Discussion Starter #8
Crack the throttle open just a little and much of the braking effect will go away. With practice you can get the 650 to almost coast to a stop.
That's what I did yesterday when I was out with it ............until my hand started to cramp up :D

When I got my first decent scooter , my Big Ruckus , I was complaining to a guy who had a scooter shop that I had to re-jet the carb , buy a $300 Bitubo rear shock and a $300 jcosta variator just to get the scooter safe and running right . He laughed and said I was lucky I bought a scooter that could have all he gremlins exorcised for $600 worth of parts . He went on to explain that scooters (all of them) came stock with gremlins , and some are never able to be fixed . I hope I can get used to this thing , cuz I sure like the way it rides and handles . My only fear now is terminal whiplash :laughing4:

TheReaper!
 

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After 116,000+ miles and 8 years on 650s I don't even think about it anymore. Using the throttle to modulate the braking effect is second nature.
 

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I'm with Buffalo, after the learning curve it becomes second nature. Learning the finer nuances of feathered rear braking and throttle control will greatly improve with experimentation and experience. So, that coasting to a stop, tight turns in the twisties and slow speed maneuvers will be much safer and smoother.
 

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Discussion Starter #11
After 116,000+ miles and 8 years on 650s I don't even think about it anymore. Using the throttle to modulate the braking effect is second nature.
I just went to the gym for my back therapy and took the long way to play around with this thing . I GOT IT ! I started treating the transmission on deceleration like it was a manual transmission that was always downshifting for me ......sort of . On a manual trans if you let off the gas when you are down shifting to a stop it will bog down on you just like the Burg does . Now that I treat like a manual trans when decelerating , every thing has smoothed out . I don't like it , but I get it :confused1: At least now I understand it and I've cured a good 90% of the whiplash . ;)

Thanks for the input , much better now . TheReaper!
 

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That surge when transitioning from closed throttle to part throttle could have been smoothed out by Suzuki. Apparently they didn't see the need to tame the engine's inclination to surge when half way around a corner when you turn up the wick to exit a corner. I seldom let the throttle close completely in a corner any more. I simply add a bit of rear brake along with the partial throttle. And that surge can't be good for the running gear long term.
 

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That surge when transitioning from closed throttle to part throttle could have been smoothed out by Suzuki. Apparently they didn't see the need to tame the engine's inclination to surge when half way around a corner when you turn up the wick to exit a corner. I seldom let the throttle close completely in a corner any more. I simply add a bit of rear brake along with the partial throttle. And that surge can't be good for the running gear long term.
Even on shifter bikes, I never got off the throttle all the way. I just eased off and feathered the clutch some during the apex and then when ready to shoot the final part of the apex, let off the clutch and apply throttle. With the Burg, I do about the same with my left hand, only this time I apply a bit of rear brake to "TRAIL" while giving the throttle enough to maintain speed. :love7: how I can corner a AN650.
 

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On a Burgman,..when you're on the throttle, the engine is running the rear wheel.

When you're off the throttle, the rear wheel is running the engine.

Engine braking is when the wheel is running the engine.
 

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Also,..engine braking isn't unique to the Burgman.

Any vehicle with a standard transmission will exhibit engine braking if you let off the throttle without disengaging the clutch.
 

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Also, at low speed (near the clutch-disengagement threshold), holding a little throttle and using the rear brake for speed control can keep the lurching to a minimum.

I still think there ought to be some sort of connection between the rear brake and the throttle to provide a more linear braking effect -- but it would probably be more trouble than it'd be worth.
 

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Also,..engine braking isn't unique to the Burgman.

Any vehicle with a standard transmission will exhibit engine braking if you let off the throttle without disengaging the clutch.
True. The 650, however, exhibits engine braking as though it were being precisely downshifted into each gear in turn rather than staying in the initial gear until coming to a stop. The RPMs are higher, so the braking effect is greater.
 

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I want some actual genius here (there are many, not me though) to develop a $70 item that plugs in about like a speedo healer and defeats the engine braking (whatever the root source) on these bikes. I will be first to buy. I find its pretty hard to mimic "no engine braking" by teasing the throttle and that is no fun anyway.

Cheers!
 

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I want some actual genius here (there are many, not me though) to develop a $70 item that plugs in about like a speedo healer and defeats the engine braking (whatever the root source) on these bikes. I will be first to buy. I find its pretty hard to mimic "no engine braking" by teasing the throttle and that is no fun anyway.
A custom engine/cvt controller. Would be easier on the '03-'04 which have a seperate CVT controller. I've often thought one with a Sport mode that like Manual but upshifts at redline and is smoother/more progressive in bringing RPM's up when decelerating would be nice.
 

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I want some actual genius here (there are many, not me though) to develop a $70 item that plugs in about like a speedo healer and defeats the engine braking (whatever the root source) on these bikes. I will be first to buy. I find its pretty hard to mimic "no engine braking" by teasing the throttle and that is no fun anyway.

Cheers!
Use manual mode - simply shift into manual when you are approaching a slow corner or complete stop. the transmission will shift into first gear as you slow down but you won't have the aggressive down shifting you get in automatic or in power mode.
 
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