[tenacres650]

However, I did notice that it didn’t want to die during gear changes from high to low, coming to a corner/stop, like it used to before.

I have noticed that same feeling since I've had the bike, slowing down through the gears, it felt like it was a second or 2 before it would take off again, I changed to a NGK plug and it helped a little.
Could you tell me why do you think that removing it helped? I would be interested to know.

[Freddy1]

A really good job.
But 'I do not understand' cause the decompressor does not work well.
For example in my B5 the decompressor does not have problems even with the minimum set at about 550 RPM.

[caricabasso]

Thanks.  GHG and SteveThackery both e-start their bike. No decomp. Another member in a similar situation is caricabasso, who's been without the decomp for more than 18.6k miles, and I'm sure he e-starts it also. So, it is a very good 'bet'  that your starter motor will be fine, and the sprag should be good also. In the unfortunate situation, where something does happen to the sprag (which really shouldn't), it is also straightforward to replace. Singh5g has a video on YouTube demonstrating just that. The beefier sprag hasn't failed like the previous sprags used to on the AVL and Iron barrel models.

On a side-note, the bike was idling flawlessly (no misses) around 600-650 RPM today after a decent ride. It didn't want to die at the traffic lights either. I'm quite happy.

I removed the decomp at about 10,000 kilometers, I do not remember very well
Now the bike has traveled 44,000 kilometers without problems.

[GSS]

Great job JVS!

[JVS]

Great job JVS!

Cheers GSS 

A really good job.
But 'I do not understand' cause the decompressor does not work well.
For example in my B5 the decompressor does not have problems even with the minimum set at about 550 RPM.

That's quite interesting. It's not supposed to be like that. You lucky guy  If you bought the bike brand new, did it have any decomp clacking before? Any that you can notice below 550? Or when you turn the bike off, do you hear one or two decomp clacks during the final dying power stroke(s) as the engine is shutting down?

What might've happened is that your decomp spring + arm combo was installed in a way such that it is 'tuned' to activate below 550. There is no set procedure or particular setting for the decomp. Each bike is different, however it is supposed to engage below 700RPM. This may vary, some might engage below 900, some 700. Probably quite dependent on the spring within the decomp assembly.

Do you kick-start often, and do you find it difficult? When you reach compression, and as the kick-start lever suddenly stops, is it easy for you to get past this stage? Or it takes a lot of effort? If it takes a lot of effort, then I think your decomp isn't engaging at all. Maybe it was removed/disabled by the previous owner or the dealer (which I'm just assuming). Or, it's just kapoot.

I have noticed that same feeling since I've had the bike, slowing down through the gears, it felt like it was a second or 2 before it would take off again, I changed to a NGK plug and it helped a little.
Could you tell me why do you think that removing it helped? I would be interested to know.

I myself have an NGK plug. Had the BPR6ES for a long time and recently I switched to the BPR6EIX (iridium version). Even with the BPR6ES, it would tend to die sometimes coming to a stop at a corner/turn (rarely).

Imagine this: You're coming to a corner/stop, going from high to low gears. You've gone to first gear now, and you're holding the clutch lever in as you're braking to make a safe turn. As soon as you pull the clutch lever in, the RPMs drop to your idle RPM. The ECU is trying to maintain a certain mixture, and for one of the time periods/pulses (Steve Thackery might be able to elaborate) during that clutch lever pull, the ECU has squirted a bit too much fuel, causing the idle to drop below your actual set idle RPM. This momentarily engages the decomp ever so slightly, and with one clack (decomp being engaged), the engine has suddenly lost some compression and has shut down.

This has happened to me a few times over the young life of the bike. With the decomp out now, even if the idle drops momentarily, there is no sudden loss of compression that can occur, therefore it shouldn't just shut off at a corner or a stop. I was at numerous stops/traffic lights on the weekend, with low idle clutch pulls, and it kept going. Until and unless the idle you've set is terribly low, then that is a different story.

[tenacres650]

I myself have an NGK plug. Had the BPR6ES for a long time and recently I switched to the BPR6EIX (iridium version). Even with the BPR6ES, it would tend to die sometimes coming to a stop at a corner/turn (rarely).

Imagine this: You're coming to a corner/stop, going from high to low gears. You've gone to first gear now, and you're holding the clutch lever in as you're braking to make a safe turn. As soon as you pull the clutch lever in, the RPMs drop to your idle RPM. The ECU is trying to maintain a certain mixture, and for one of the time periods/pulses (Steve Thackery might be able to elaborate) during that clutch lever pull, the ECU has squirted a bit too much fuel, causing the idle to drop below your actual set idle RPM. This momentarily engages the decomp ever so slightly, and with one clack (decomp being engaged), the engine has suddenly lost some compression and has shut down.

This has happened to me a few times over the young life of the bike. With the decomp out now, even if the idle drops momentarily, there is no sudden loss of compression that can occur, therefore it shouldn't just shut off at a corner or a stop. I was at numerous stops/traffic lights on the weekend, with low idle clutch pulls, and it kept going. Until and unless the idle you've set is terribly low, then that is a different story.

Thanks, that is a very good description of what happens to me, it is always at the same sharp right hand bend in the road followed by a short uphill climb after changing down quickly through the gears back into first gear, it seems to hesitate a moment before catching again. I'll listen closely to see if I hear the clacking sound.

[gashousegorilla]

  I'm thinking as the decomp activates , when the rpm's drop low enough...and as the compression pisses out through the exhaust valve, so to does a portion of the air and fuel charge. Making the bike hesitate and at times stalling the bike.

[idk]

Thanks for the replies. 

[SteveThackery]

With the decomp out now, even if the idle drops momentarily, there is no sudden loss of compression that can occur, therefore it shouldn't just shut off at a corner or a stop

Hmmm.......  that might be one cause, but that unstable idle and stalling is so well known and widespread (and on mine definitely did not involve the decomp) that I think we can only blame the decomp on a fairly small number of bikes. 

Having looked at it extensively, I'm satisfied that it's due to a peculiarity in the mapping in the sub-1000rpm range.

[tenacres650]

Hmmm.......  that might be one cause, but that unstable idle and stalling is so well known and widespread (and on mine definitely did not involve the decomp) that I think we can only blame the decomp on a fairly small number of bikes. 

Having looked at it extensively, I'm satisfied that it's due to a peculiarity in the mapping in the sub-1000rpm range.

I did notice a change for the better after swapping the plug to an NGK, so I might hold off removing mine for now until I need to, the don't fix it unless broken approach. I've only heard the load clacking once when cold starting it and after that I always use the fast idle/choke so it starts at a higher RPM, but at least I now know I can fix it if I have to.

[JVS]

If you think it contributes to your stalling issues, along with leading to more carbon deposits than necessary (due to on-going clacking) and if you prefer a more relaxed idle, then you'll have to say goodbye to it.

If it's working as it is supposed to, or you're content with it, then there is no need to remove it. However, the option is there to remove it, if you ever need to