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2003 VN750
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How did you do that? Is there a way to adjust timing on these bikes after all?

I'm still chasing my decel pops. The little 'blat' I get when upshifting sounds pretty cool, but the decel popping on my bike has always been outrageous. I've done everything mentioned here for addressing that but am intrigued to hear of a timing option. My coast enrichers are fine, my EGR system is gone and plugged up tight and I've addressed all the exhaust leaks I've found. The only way I've been able to get rid of decel pops is having the idle set higher than 1100. But then I'm basically not decelerating either which, needless to say, can be scary when trying to slow down. 馃榿
Sticking or inoperable coast enrichers will cause decel pop.
 

Super Moderator
2003 VN750
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Well Spockster, you have yet to be wrong about any issue or question I've raised here in the last few years, so I'm going to stop insisting that my coast enrichers are fine. Besides, I wasn't sure what to look for when I opened them up last time I had the carbs off. Everything seemed to be there and very clean. What should I be looking for next time I look? And is there a way to get in there w/o removing the carbs?
I must sound like a broken record, didn't remember that was you I told that.

The CEs are the round'ish like covers on the sides of that carbs. Two or three screws on them, should be able to remove with the carbs on. There's a rubber diaphragm with a piston in the center. They corrode up and stop moving, or the passages get blocked.

Mine popped after the earshave and coasters done all at once, and it was the first ride so it sat a while. A tank with seafoam fixed mine, but they couldn't have been that bad. Some CEs come out totally covered in crystallized corn.

This is what the coast enrichers do, they richen the mixture during coasting when there's high vacuum. To help prevent popping and to cool the combustion chamber and exhaust.
 

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2003 VN750
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So after looking at this post, I鈥檓 thinking it鈥檚 time for me to do my tensioners as well as I do have ticking going on. How hard are these to change? And how is the tension checked? I鈥檓 still learning the quirks of these bikes even after putting 8k on in less then a season lol
Watch Vulcan Frank's video posted yesterday, shows all you need to know.

Just don't partially remove an ACCT without resetting it, if you put it back on it will be too tight.

 

Super Moderator
2003 VN750
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I put an aftermarket ignition controller on my bike. I then ran some extra vacuum hoses to T the two vacuum ports together into a MAP sensor. The controller senses engine vacuum and adjusts based on load. Long story short, if you put the hoses and MAP sensor on like I did in the first link, the module is otherwise plug-in-play. I even left my factory controller installed in case something went wrong, but 1.5 years in I've had no issues with the new module. The rest of that "diary" is me waxing on about my discoveries along the way.

Here's the process for the extra vacuum hoses.

And here's my "diary" on the process of tuning the ignition.

Overall, the change gave me a slight bump in MPG (2-4 more), which was the motivation for the project. Not fuel savings, but increased range on a tank. But the additional benefits are well worth it in my opinion. I bumped the idle timing from 5 to 7 degrees. This allowed me to close the idle a bit more to maintain 1100 RPM, giving more deceleration than before. With the settings I'm running, I pull the ignition timing back to 10 degrees after top dead center (which causes popping) BUT it also further reduces the residual power during deceleration causing an even faster RPM drop. The engine overall feels a lot more responsive. I set up a 2nd ignition table for when I'm running on choke. This controller can change timing tables with an external switch. It runs significantly retarded ignition timing in this mode, causing it to idle at 1500 on choke, as well as rev down almost as quickly as the original bike off choke. It makes it MUCH more predictable to ride on choke.
If you like making loud noises....

If I unplug the vacuum on the right side and leave it open, it goes off like a cannon on longer downhill decels. Hasn't blown a muffler so far. 馃懝

I've only done it a couple of times, once by accident and once to see if that's what caused it.
 
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