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Vrod muscle cherry hot exhaust.

5K views 18 replies 8 participants last post by  Dracon 
#1 ·
Hey guys I’m still new here but I have a question. 2015 vrod muscle. AkrapOvic exhaust , dyno jet tune , 26 tooth front pulley. I noticed today riding with a few of my buddy’s tonight my rear exhaust at the flange at the back cyclinder was cherry ? red.. I’m not seeing any topics on this but I do know that it’s not that good any ideas ?
 

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#2 ·
The rear cylinder is running lean, use your tuner and increase the fuel by 3-5 steps in the rpm band where you were running and see if that fixes it. If not you can always add more or put it back where it was.


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#4 ·
Hey guys I need help the problem has not been fixed. Nor do I know how to fix it with the tuning program. The bike was pretty much cold I started it up with a steady throttle at 2500 for not even 1 minute the exhaust was getting cherry red. I have a video but it will not let me post it.
 
#5 ·
Short answer you need to tune it, not just run some generic cal or some other persons tune. Sounds a bit lean for sure but is it rear only or both. Without some log data throwing fixes at it is dumb. Make a log to identify what's going on first and go from there. I assume you have a PV tuner to do this? With a data log, at least then there's some direction to make correct adjustments with.
Ron
 
#7 ·
Target Tune would have been a better choice but the pro will get the job done. It will be rich as set for tuning but this can be modified and you understand how it works later. Problem is , once you go back to NB sensors, the Akro bungs need to be trimmed to minimum for good NB sampling and the low end retuned for NB using clb tables. Pro version is best suited for gathering data at higher loads and rpms, then removed from the bike. If you can switch out to TT instead on the order your life will be much easier.
Ron
 
#10 ·
Check timing too ... retarded timing + too rich = cherry headers

Basically, retarded timing will spit unburned fuel out that burns in the header instead of the combustion chamber... add fuel and it can get worse (more fuel being burned in the exhaust port)
 
#11 ·
Check timing too ... retarded timing + too rich = cherry headers

Basically, retarded timing will spit unburned fuel out that burns in the header instead of the combustion chamber... add fuel and it can get worse (more fuel being burned in the exhaust port)
 
#13 ·
Just throwing this out there... The Akrapovic is made from thin single wall stainless steel, this is so it is very light - it's a good thing. But this also makes it much much easier to glow red - just because the Akro is red doesn't mean it would be happening if you had the exact same free flowing exhaust made from a heavier dual walled steel.

I'm not telling you that you are fine and don't have to worry about anything, but I had the same thing happen and after talking to Akrapovic and Fuel Moto, they both said it's normal for those pipes. I also logged exhaust temps, changed to the stock map and exhaust temps stayed the exact same, At night the Akra would glow after startup when it was just idling in the driveway on both the stock and tuned map. I did get a custom tune and it still will glow. I've talked to other Akra owners who have had a similar experience, I'm curious if anyone who has warned of your bike running lean has an Akrapovic exhaust and it doesn't glow?
 
#15 ·
I have a 2013 NRS with Akrapovic exhaust, topless, and K&N filter. Had a PowerVision Tuner on it when I bought it. I don't ride at night very often, but the other day I was traveling through town at a steady 30MPH and I looked down and my rear header right at the flange was cherry hot.

Well, I was wanting a Target Tune anyway, so I ordered one, installed it today, as well as the FuelMoto map they provided. Went for a ride, and I thought the glowing exhaust was gone (my decel pops and gurgling were gone!), but I was riding down a long city street, 2nd gear, 40MPH, 4K RPM, very light throttle to maintain speed, and my rear header started glowing again. Not nearly as bright as before, but definitely a red glow.

Ran a fairly long AutoTune session - Interstate, country highway, city stop and go, steady low speed, and tried to hit as much of the map as possible. Loaded the new tune and took another ride, 2nd gear 40MPH, 4K RPM, and still had a glow.

Did a quick AutoTune session focusing on the 4K RPM range in 2nd gear, and then loaded that new tune. Still glows, but seemed dimmer than before. I'm in the process of adding fuel to the map in the 3750 and 4000 RPM range at 7, 10, and 15% throttle position. I'll see what that does tomorrow night.

I tend to lean towards those saying it is just normal for these pipes, because it seems to happen no matter what I do.

Now my PV screen blanking out...That's another battle I'm going to fight tomorrow as well.
 
#16 ·
In reality, what choice doe the pipe have but turn red when under steady rpms. There's a flame coming out of the head, be it bluish or orange which changes how far down it turns red. Lean is closer to the head, more bluish and further down if on the rich side of yellow orange. Richer will glow a bit less as it's not a complete efficient burn but that pipe will still turn red hot in spots. Thicker stock pipes of mild steel will take more to get the effect then the thinner SS pipes on the Akro. If the engine runs nice and smooth, it's a better indicator of afr then what you see on the pipe .
Ron
 
#19 ·
I wonder if it couldn’t also be just a visual difference. In the daytime I can’t see either of them red, at dusk when the sun starts to go down I see the rear pipe is red before I can see the front, but when it’s already dark they both turn red at the same time. I think it’s because the rear pipe is tucked in further and your leg shields some of the light getting to it so since it is a darker space you can tell it is red before you can tell the front one is. It would be interesting to have a laser thermometer measure each when it appears your rear cylinder is glowing but the front is not.
 
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