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elykyle15

One exhaust pipe getting visibly red

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elykyle15

Hi.

The issue: I'm finding that, when stationary in a garage, if I rev up the bike to around 4500 RPMs, the left-most pipe (when looking from the front) will get red hot. When riding, it sounds like there's subtle popping in the exhaust when holding RPMs.

The setup: I'm running an Akra exhaust with a K&N filter; snorkel removed. I've got a 2WDW flash.

The attempts:

  • Reconnected and resealed exhaust
  • Replaced air filter (to the new K&N filter)
  • Oil and filter change
  • Flashed stock tune and then purchased 2WDW tune

Back story:

  • About a year ago, a friend I ride with said he believes he was hearing my exhaust popping when accelerating.
  • Months later, I started having acceleration issues and brought it in. I had the spark plugs replaced. Acceleration issue was gone..
  • 6-8 months after that, the acceleration issues returned. The bike had a weird smell as if something was burning when I turned it over and smoke came out (I can't remember what color it was..). When tinkering with the bike to find out what was going on, I saw that, when it starts to have issues, around 4500RPMs, the exhaust was getting red hot. I replace the spark plugs again and the acceleartion issue and popping were gone, but the exhaust still gets red.

Shots in the dark:

  • Timing issue?
  • Clogged injector?

 

I'm planning on dropping my bike off on Monday to get the chain and sprockets replaced (I'm at 16,000 miles and theres corrosion and rust build up from the previous owner) and I'm going to mention these other issues. I'm just looking into some insight as to what could be going on.

Thank you in advance.

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shinyribs
Posted (edited)

How many miles? I ask to see if you're due for a valve check. 

Red glowing pipes can mean a few different things. Retarded ignition timing is famous for this, but that's sort of an old school tuning issue. Its highly unlikely with modern electronic ignitions, unless the ignition map for one cylinder got way out of whack for some reason. 

If you happen to have a tight exhaust valve ( not closing completely) you end up with a condition where the combustion process is partially taking place in the exhaust pipe rather than all in the combustion chamber. 

A vacuum leak can also cause this. If the throttle body isn't properly seated and sealing in the boots, or if the little rubber cap has come off the vacuum synch port, you could get enough free air in the system to create enough of a lean situation to make pipes glow red.

If you're confident that whatever flash has reliable ignition/timing values, and there's no vacuum leaks, I'd be tempted to check the valve lash. It might seem like a pain parking the bike for a bit, but if it's a tight valve you do run a decent chance of burning that exhaust valve(s). 

The smoke you mentioned came out of the exhaust? If so, that could be a clue pointing towards incomplete combustion ( you didn't get a clean burn, so it burped out some unburt fuel ) which can happen when valves aren't not seating properly, so back to a possibly tight valve. 

Not trying to sound scary with all the valve talk,  just throwing it all out there for you to consider. Good luck, and just us know what you find 👍

 

Edited by shinyribs
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elykyle15
Just now, shinyribs said:

How many miles?

16,000

I appreciate the input. It might help in the diagnosis.

I'll relay info to the tech.

Thank you.

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shinyribs

16,000 seems way early to need any valve adjustment. Pretty sure Yamaha recommends to check them around 25,000 miles, but I've seen a few reports of people checking then regularly and not needing any adjustment well past 50,000 miles. 

Very well could still be an intermittent spark issue. Fingers crossed for the easy fix! 

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Triple Jim

In general, a glowing pipe is caused by either very retarded timing or an overly rich mixture.  It seems counterintuitive, but the rich condition results in mixture that's still burning going out into the exhaust pipe.  Lean mixtures make the piston extra hot, but don't make the exhaust pipe abnormally hot.

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elykyle15
Just now, Triple Jim said:

In general, a glowing pipe is caused by either very retarded timing or an overly rich mixture.  It seems counterintuitive, but the rich condition results in mixture that's still burning going out into the exhaust pipe.  Lean mixtures make the piston extra hot, but don't make the exhaust pipe abnormally hot.

This is interesting because when I reinstalled the exhaust, I ran it without the headers and saw flames. Not sure if it was normal.

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elykyle15
Just now, shinyribs said:

16,000 seems way early to need any valve adjustment. Pretty sure Yamaha recommends to check them around 25,000 miles, but I've seen a few reports of people checking then regularly and not needing any adjustment well past 50,000 miles. 

Very well could still be an intermittent spark issue. Fingers crossed for the easy fix! 

I'm curious if this is relevant:

The short version is that I messed around with my factory belt tensioner and I had someone install a used one that I may have also messed up when I failed to install it..

They got it installed and made sure the timing chain was aligned. But I've been concerned about it since.

The bike sounds fine at idle.

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elykyle15
Just now, shinyribs said:

Red glowing pipes can mean a few different things. Retarded ignition timing is famous for this...

Could this be caused by a problem with the timing chain?

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Triple Jim
Just now, elykyle15 said:

Could this be caused by a problem with the timing chain?

I've never had it happen, but I suspect it could.  You should probably check the valve timing to be sure.  You may be one tooth off. 

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shinyribs
Posted (edited)
11 minutes ago, elykyle15 said:

Could this be caused by a problem with the timing chain?

You seem to have a condition where combustion is happening in the exhaust. Anything related to timing of the engine could be relevant. But if your camshaft is out of time then both cylinders should be affected equally. It's definitely possible, but doesn't seem super likely. Regardless , it couldn't hurt to double check. 

 

It just occurred to me about the automatic decompression system. Most engines with these operate by holding an exhaust valve open slightly. I haven't seen how these bikes are set up, so don't quote me, but if that's the case then it's a very likely culprit. Especially since whatever you have going on is only affecting one cylinder. 

 

Can anyone confirm that the auto decomp operates on a exhaust valve, and which cylinder it effects? 

 

Edited by shinyribs

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elykyle15

 

Just now, Triple Jim said:

You should probably check the valve timing to be sure.

I'll mention that to the techs. Thanks for confirming.

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M. Hausknecht
Just now, shinyribs said:

You seem to have a condition where combustion is happening in the exhaust. Anything related to timing of the engine could be relevant. But if your camshaft is out of time then both cylinders should be affected equally. It's definitely possible, but doesn't seem super likely. Regardless , it couldn't hurt to double check. 

 

It just occurred to me about the automatic decompression system. Most engines with these operate by holding an exhaust valve open slightly. I haven't seen how these bikes are set up, so don't quote me, but if that's the case then it's a very likely culprit. Especially since whatever you have going on is only affecting one cylinder. 

 

Can anyone confirm that the auto decomp operates on a exhaust valve, and which cylinder it effects? 

 

The decompression system operates on one exhaust valve in each cylinder. So, I'm thinking that isn't the source of the problem.

As noted, retarded ignition is often a cause for excessive heat in the header pipe, but with the CP2's ignition system the only way to alter ignition timing is through changes to one or more ignition maps in the ecu. The OP says " Flashed stock tune and then purchased 2WDW tune". 2WDW didn't screw it up, I imagine, but the "flashed stock tune"?  Dunno; I'm thinking this isn't it either.

I've read (but not experienced) that an excessively rich or lean mixture can cause excessive exhaust gas temps. Either way, the "bad" cylinder's spark plug should look different than the "good" cylinder's plug, so I'd check the plugs. The idea that the cam chain is off by a tooth is worth investigating, but I'd imagine the engine wouldn't run anywhere near normally while under power were that the case.

What about really out of whack throttle-body synchronization leading to bad mixture in one cylinder with low throttle openings ?

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elykyle15
Just now, M. Hausknecht said:

... the "bad" cylinder's spark plug should look different than the "good" cylinder's plug...

I thought maybe one could determine the issue by looking at the spark plugs and posted on the FZ07 Reddit page.

When I replaced my spark plugs again to deal with the acceleration problem, I took a picture and asked if anyone could determine an issue by looking at them.

Here's a pic.

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Triple Jim

They're certainly very black, which probably means you're running very rich for some reason. 

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ElGonzales

Black like coal, no wonder the spark plugs fail from time to time.
This is with 12k miles and no problems:
grafik.png.de2e209659a4f7c6557474446cd1dd12.png

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M. Hausknecht
Just now, elykyle15 said:

I thought maybe one could determine the issue by looking at the spark plugs and posted on the FZ07 Reddit page.

When I replaced my spark plugs again to deal with the acceleration problem, I took a picture and asked if anyone could determine an issue by looking at them.

Here's a pic.

Wow, way too rich but if you look closely, the bottom plug is worse (richer) or it also has burnt oil deposits on it. Oil deposits tend to be shinier than the black sootiness of a plug that is showing too rich.  Is the bottom plug from the "bad" cylinder?

 

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elykyle15
Just now, M. Hausknecht said:

Is the bottom plug from the "bad" cylinder?

Truthfully, I didn't keep track.. 🙄

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elykyle15
Just now, ElGonzales said:

Black like coal..

Because it's running too rich?

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M. Hausknecht
Just now, elykyle15 said:

Because it's running too rich?

Yes, much too rich and, possibly, burning some oil too. The photo of plugs from ElGonzales is what you want to see. If you've got a "tech" replacing plugs that look like yours and isn't also advising you there are significant problems, you need a new tech.

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elykyle15
Just now, M. Hausknecht said:

Yes, much too rich and, possibly, burning some oil too. The photo of plugs from ElGonzales is what you want to see. If you've got a "tech" replacing plugs that look like yours and isn't also advising you there are significant problems, you need a new tech.

To be fair, these are the plugs I replaced and not the ones the mechanic at my bike shop did.. although the issue was the same both times. 

They are unfortunately the closest reputable shop... there's another one I want to try but since last year they went to "Harley's only". Maybe I ought to take another look..

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shinyribs
Just now, elykyle15 said:

I thought maybe one could determine the issue by looking at the spark plugs and posted on the FZ07 Reddit page.

When I replaced my spark plugs again to deal with the acceleration problem, I took a picture and asked if anyone could determine an issue by looking at them.

Here's a pic.

Can you recall which tune you were on when these plugs came out? What kind of fuel mileage are you getting? 

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elykyle15
Just now, shinyribs said:

Can you recall which tune you were on when these plugs came out?

Stock with Akra fuel map and decel off (FTECU).

 

Just now, shinyribs said:

What kind of fuel mileage are you getting?

I just checked the readout for AVG MPG and it's 16.8..

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Triple Jim
Just now, elykyle15 said:

I just checked the readout for AVG MPG and it's 16.8..

Well, the rich mixture is confirmed.  That's at least 3 times the fuel it should be getting.

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elykyle15
Just now, Triple Jim said:

Well, the rich mixture is confirmed.  That's at least 3 times the fuel it should be getting.

Yeah that's way lower than I expected to see. I don't ride as often to actually notice.

@shinyribs thought that a valve check might need to be done as it could be the cause.

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Triple Jim
Just now, elykyle15 said:

@shinyribs thought that a valve check might need to be done as it could be the cause.

Now that we know your mixture is insanely rich, it would be wise to correct that and see where it stands.  I suspect that's your problem and that your valve timing is correct.  I also suspect shinyribs will agree, but I don't want to speak for him.   🙂

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