# stock exhaust glowing red help.........



## green750

I just traded my hmf for a stock pipe to quite it down and took it out this past weekend. We went for about a 50 mile ride mostly down wet trails but took a paved road back. That's when I noticed that the headers all the way up to the pipe and even part of the pipe was glowing red. We were only running about 25 mph. I stopped and let it cool off then took off down the road and and not even a mile later it was glowing red again. My hmf use to glow at the headers but only after riding it hard nothing like this. After I got the bike home and cleaned it up I noticed that sometimes on start up I have to give it a little gas to make it start and if I let off the gas to fast well riding it will shut off. The bike is a 2009 750 with mimb 2"snorkles. It's always ran good in the past. My question to yall is do you think I hurt something ? The bike also does not have a programmer. I didn't think you needed one with the stock pipe but the way its looking I might need one worse then I did with the hmf. What do yall think. Thanks greatly for any help.


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## BF2012

pull the plugs and look at them.
you changed nothin else?


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## drtj

needs a programmer. your running lean


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## MY07BRUTE

yup, your running lean


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## green750

Nope nothing but the exhaust. I forgot to add that it has a knn air filter but it was in it with the hmf also. Is there any way the stock pipe could be clogged? Causing it to have to much back pressure? And if so could I just do the exhaust mod to help it flow? Sorry for all the questions but iv got a ride this weekend that I really want to go on. Thanks for the help.


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## RedNeckBlueCollar

MY07BRUTE said:


> yup, your running lean


^ x2


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## wyo58

The only way to know for sure is to check the plugs. But I think 2" snorks on a EFI would make it run rich. A slight rich condition could also make your exhaust glow if conditions were just right. But usually glowing exhaust is a lean condition.


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## green750

Here's a pic of one of the plugs what do yall think.


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## oft brute

kinda hard to see for sure but looks a little lean. try putting a stock air filter back in it and see if it helps.


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## drtj

put new plugs in it & do a plug chop. I think thats what its called. do a search for it. It has been explained a few times.


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## greenkitty7

i dont see how the stock exhaust could be getting more flow than the hmf, unless the hmf was clogged (which could be the case if the spark arrestor was clogged, or if the stock pipe is modified any.)


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## jrfonte

Check your headers for leaks where they bolt to the heads. Your plugs don't look lean when there lean the porcelain usually looks white n blistered and the electrode tips are clean


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## oft brute

these fi brutes are very picky and do some crazy things when you change exhaust or air flow. moded fi's just about haft to be dyno tuned to run right. most fi brutes also need a 3'' intake snorkle reguardless of the pipe or air filter.


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## oft brute

was the pipe a full or slip on? the reason i ask is i have seen a bike i know for sure to be lean do the same thing. the thiner headers from hmf dissapate heat faster than the stock headers only making it glow at the head where it is thickest. so if you had them and put the stockers back on the heat will stay in them longer making them hotter. could be way off with this bike but i still think it is lean.


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## BF2012

If you are glowing the headers and exhaust under a rich condition,which IS very possible,you will know it.
Just stand behind the quad and smell the exhaust. If it is that rich, it will make yer eyes water and burn. It should have a very strong gas/exhaust smell coming out.
side note, don't wake up dead in a garage due to carbon monoxide poisioning cause a dummy on the internet told you to smell your exhaust..:smokin:


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## green750

Thanks every one.Bf2012 I do notice a bit of a gas smell some times. Mostly well I'm backing up. The hmf I had was a slip on that came with a rear header and it did not have a spark arrestor and thinking back on it now it did get pretty hot also but now the bikes acting weird it won't start in less I'm on the gas and when it does start it idles very low and will stall sometimes. I thought maybe the stock pipe could have been clogged so I did the exhaust mod last night but it made no diffrence it still glows and and idles wired and now its back firing. Other then that the bike runs great. Still has all its power.


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## drtj

i would get a programmer for it.


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## green750

Ok I'm going to start looking for one thanks .


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## green750

Do yall think I can get by with a hmf optimizer? I'm pretty short on money right now.


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## Polaris425

what snorkel set up are you running? all 2"? If so switch to a 3" rubber 90* at the box and see if that helps.


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## hp488

If it is running lean going to a 3" snorkel is not going to fix it. You said it is starting to backfire and idle real low, I would check your throttle position sensor you have a problem that needs to be fixed before doing any more mods to it.


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## green750

Where is the throttle position sensor and how do I check it.?


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## hp488

The tps is on the side of the throttle body.


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## hp488

Sorry had to run to the store, the easiest way without removing it would be to unplug it and start it up and see how it runs.


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## green750

Ok so if I unplug it and it runs the same then its bad ? Or is it the other way around.


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## wyo58

If it were me I'd change the snorks to 3" like 425 said way before I'd get the programmer. The plugs in the pic look slightly rich to me btw. So, 3" intake snork and new plugges and see what you have.

Good luck keep us informed.


Also if it's backfiring, where is it happening? As a general rule backfiring through the exhaust is usually a rich condition. through the intake is uaually a lean condition. If your running rich the plugs will start to foul which would cause a rough idle for sure.


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## Astaelan

Simple way to find out, remove the snorkel for your intake box, slip it off and see if you are still getting similar sputtering and backfiring. If removing the snork helps, then you're running rich, also try partially covering your 2" intake snork, if this helps it run better, then you are running lean.
In my case, I bought my machine used, and it had a muzzy on it, previous owner didn't do his research and was running okay, but a little rich (too rich for my liking, was going to rejet). Then I did my 2" snorkels first, and bingo, I was running almost perfect at 3000 feet on stock jets. No more backfire from the muzzy, no woozy-head exhaust. A CDI can help in the long run for either issue, but I'd narrow it down before throwing one in for the sake of it, unless you're looking for the other benefits as well (reverse override, etc). The CDI is one of the last things on my list.


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## green750

Ok ill try taking the snorkle off and see if that helps and ill put some new plugs in it and see what happens.


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## green750

Ok so the rear plug was fouled out so I put new ones in and that fixed the weird idle. Next I waited till it was dark out and ran it down the road( around a half mile at 30 mph) stopped and checked the exaust it was glowing red from the motor all the way to the pipe and even some of the pipe was red so I let it cool then repeated the run but this time I took the snorkle riser off at the body and made the run stopped and checked this time only about 3/4 of the headers were red so I let it cool and made one last run this time I took the lid off the air box and made the run then stopped and checked the exhaust was red all the way to the pipe and even most of the pipe. During all the runs the bike would back fire when I let off the gas but only after the motor was warmed up. So if I'm right the bike is getting to much air with the lid off and running lean but with the snorkle on all the way it being restricted and running rich. What do yall think I should do ???????? Sorry its so long.


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## oft brute

sounds like a tuner and a trip to the dyno is needed. i know you said your sort on $ but you'll be money ahead getting a good tuner like the msd.


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## green750

I no its no msd but I can get a good deal on a hmf optimizer right now do you think it would work for now or should I just save the money and get the msd?


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## wyo58

Go from the 2" to the 3" snork I think. If your plugs fouled I think your glowing is from a rich condition. When you removed your air box and ran it was glowing from a lean condition.

The backfire on throttle let off is comon on the fuel injected brutes, mine did completely stock. Come to find out when you let throttle completely off the ECU retards timing too, thats whats causing the back fire with a combination of your snorkles. In other words what ever area is slightly rich in stock form will be amplified if you make it more rich.


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## green750

Ok that sound right on thanks for the info wyo58 I'm going to do the 3" snorkle today and see what happens.


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## BF2012

wyo58 said:


> Go from the 2" to the 3" snork I think. If your plugs fouled I think your glowing is from a rich condition. When you removed your air box and ran it was glowing from a lean condition.
> 
> The backfire on throttle let off is comon on the fuel injected brutes, mine did completely stock. Come to find out when you let throttle completely off the ECU retards timing too, thats whats causing the back fire with a combination of your snorkles. In other words what ever area is slightly rich in stock form will be amplified if you make it more rich.


 I concurr, i believe are fuel rich.
Let us know if it improves.


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## green750

I still haven't got to the store to get the 3" rubber 90 so I just took the snorkle off from the air box and its running pretty good. Only the rear header is glowing now and that's only after beating on it . I did get some good reading with a temp gun before and after taking the snorkle off. It seems that with the full 2" snorkle on after running down the road and back( about 1/4 mile at 30mph) the temp at the header flange was around 765 deg and after removing the snorkle and making the same run it droped it down to around 658 deg that's a diff of 107 deg just by removing the 2" snorkle


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## wyo58

green750 said:


> I still haven't got to the store to get the 3" rubber 90 so I just took the snorkle off from the air box and its running pretty good. Only the rear header is glowing now and that's only after beating on it . I did get some good reading with a temp gun before and after taking the snorkle off. It seems that with the full 2" snorkle on after running down the road and back( about 1/4 mile at 30mph) the temp at the header flange was around 765 deg and after removing the snorkle and making the same run it droped it down to around 658 deg that's a diff of 107 deg just by removing the 2" snorkle


Good research guy! The 3" should help, however it may only be partial because of the stock fuel map in the ECU. But it's way worth the time and money to try it. 3" intake snork is better no matter what it the outcome is. You may have to have the programmer in the end, but why go through the time and money if you don't have too?


Incidently, The temerature just outside the head on the exhaust pipe can tell you quite alot. At 1100 degrees F you start to cause problems to your motor. At 1200 she's done if it stays at that temp for very long. So if you keep it down in that 600 to 700 degree area you know your not hurting anything in the motor. It's kind of funny because this temperature extreme holds true for all motors, two stroke, four stroke, and diesel engines. So as long as you get it to run good with the 3" and your EGT's are down you have it made!


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## green750

Yep that's what I was thinking but after doing a search on line I found that metal will glow red at around 760 deg I think is what it said? I might be a little off on that but I think its close it just makes me a little uneasy when I look down and see the exhaust glowing on my nice expensive toy


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## wcs61

Posted on this same problem in another thread but I'll add here as well. 

First let me back up and give some of the details. Bought the Brute 750 used and after a while noticed a lot of abnormally high heat coming from the left side opening and making it uncomfortable to ride long rides. Thought this was possibly normal for 750 engines. Reworked the snorkels last week and while at the river this weekend noticed the header pipes glowing red and never noticed this before the re-snorkel job and naturally higher heat. Same diameter pipe but shorter run. The previous owner told me Saturday night it has always glown red especially since he modified the exhaust, added the snorkels and Power Commander. Well we all know glowing red is not normal and I've been advised to run a 3" snorkel to the air box from some of you.
Now before completing the 2" snorkel job as I read on here it's better to run a 3" for the intake I tried the following....
I warmed the bike up to normal temp and removed the snorkel from the air box 3" inlet and worked the throttle. It spit and sputtered badly. I then slowly covered the inlet with a piece of cardboard to about half way. At this point the throttle was very very responsive with fast rpm gains but the exhaust did smell lean at this time. Clean crisp revs and absolutely no sputtering or backfire at all. Installed the 2" snorkel and again it would rev good but backfire after letting off the throttle. So after reassembly and a trip to the camp the Brute runs fine and only backfires after letting off at high revs but there are the glowing header pipes. After discussing with a few seasoned veterans and an ex motocross rider there we agree,as with any engine, if you run lean you will glow the exhaust and possibly melt engine parts, but we have never seen a rich engine glow the pipes. The only time I ever saw a glowing exhaust other than a lean engine was when a catalytic converter was clogged trapping unburnt fuel in the system. I now know the exhaust isn't clogged since the stock muffler baffles were punched through.(??Could be the backfire issue??)
All engines vary and some of you are Brute mechanics so I'll take you advice on this. Tell me this, if I'm running lean how can going from 2" to 3" snorkels and adding more air improve a already lean issue?
If I'm possibly running rich why does the open 3" air box inlet make it run like poo
Is it yes I need 3" but also need the small amount of restriction that three + feet of snorkel provides? I'm open to suggestions and have plenty of time to order jets or what ever is needed while at work for the next month. One thing I need help on is shimming if needed!


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## wyo58

wcs61 said:


> Posted on this same problem in another thread but I'll add here as well.
> 
> First let me back up and give some of the details. Bought the Brute 750 used and after a while noticed a lot of abnormally high heat coming from the left side opening and making it uncomfortable to ride long rides. Thought this was possibly normal for 750 engines. Reworked the snorkels last week and while at the river this weekend noticed the header pipes glowing red and never noticed this before the re-snorkel job and naturally higher heat. Same diameter pipe but shorter run. The previous owner told me Saturday night it has always glown red especially since he modified the exhaust, added the snorkels and Power Commander. Well we all know glowing red is not normal and I've been advised to run a 3" snorkel to the air box from some of you.
> Now before completing the 2" snorkel job as I read on here it's better to run a 3" for the intake I tried the following....
> I warmed the bike up to normal temp and removed the snorkel from the air box 3" inlet and worked the throttle. It spit and sputtered badly. I then slowly covered the inlet with a piece of cardboard to about half way. At this point the throttle was very very responsive with fast rpm gains but the exhaust did smell lean at this time. Clean crisp revs and absolutely no sputtering or backfire at all. Installed the 2" snorkel and again it would rev good but backfire after letting off the throttle. So after reassembly and a trip to the camp the Brute runs fine and only backfires after letting off at high revs but there are the glowing header pipes. After discussing with a few seasoned veterans and an ex motocross rider there we agree,as with any engine, if you run lean you will glow the exhaust and possibly melt engine parts, but we have never seen a rich engine glow the pipes. The only time I ever saw a glowing exhaust other than a lean engine was when a catalytic converter was clogged trapping unburnt fuel in the system. I now know the exhaust isn't clogged since the stock muffler baffles were punched through.(??Could be the backfire issue??)
> All engines vary and some of you are Brute mechanics so I'll take you advice on this. Tell me this, if I'm running lean how can going from 2" to 3" snorkels and adding more air improve a already lean issue?
> If I'm possibly running rich why does the open 3" air box inlet make it run like poo
> Is it yes I need 3" but also need the small amount of restriction that three + feet of snorkel provides? I'm open to suggestions and have plenty of time to order jets or what ever is needed while at work for the next month. One thing I need help on is shimming if needed!


Your atv has quite a few mods to it when you purchased it from what I gathered. A 3" wide open hole in the air box should make it lean unless it was jetted for it. You still have to run your snorks which will add some restriction. Brutes seem to be kind of indivigualized when it comes to fuel/air ratios as stated in multiple forums. The previous owner of your atv said it always glowed red after he made the mods, which means he probably should have re-jetted at that time. When/if you add your 3" intake snork you will have to check your plugs, exhaust conditions, to see what direction you need to go. 

The formentioned atv in this thread is a little different in that he is working with a pre-determined ECU fuel map. So what he does with his will be some what different than what you have to do. The stock inlet on the airbox is slightly larger than 2", so running 2" snorks logically is going to choke the air coming in by itself, let alone adding bends in it. Thats why the 3" is probably the better way to go. It should be a closer match for air flow into the airbox.

As for lean conditions causing exhaust to glow red, I'll agree that usually that is the case. However a slight rich condition and retarded timing could also make them glow as well, because you get unburned fuel in the exhaust ports and pipe. Then the retarded spark fires late allowing the fuel to burn on the exhaust side. Best way to tell is looking at your plugs and using a temp gauge on the exhaust pipes. This way you can zero in on what the engine is doing and how to adjust to a better air/fuel ratio.


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## wcs61

^^ I'll have to check it later. Have lots of to-do's I need to get done before leaving for work. Guess I'll go ahead and order that jet kit while away and prepare for 3" intake snorkel.....Thanks for the tip.


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## wcs61

Okay I'm convinced it's running rich. Why? Since it's blowing black smoke and back firing, shooting a good flame after letting off a full throttle, it has to be rich. Guess I'll have to add the 3" snorkel.


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## wyo58

wcs61 said:


> Okay I'm convinced it's running rich. Why? Since it's blowing black smoke and back firing, shooting a good flame after letting off a full throttle, it has to be rich. Guess I'll have to add the 3" snorkel.


Ok wcs keep us informed on your progress!


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