Scorpions + decat pipe= gas smell?

[MrTigerB]

Got an 06 Fazer. Still in the process of completing my 1st mod...

Bought scorpions off another member here and went to a local muffler guy who fashioned a decat pipe for me.(Sidenote: after he showed it to me, he told me he couldnt sell it to me, handed it to me and claimed he never saw it Wouldnt accept any payment despite my attempts)

Anyways, after my troubles fitting and eliminating the leaks, i got a strong gas odor after my 1st start and letting it idle for a few mins, not to mention a little smoke after i shut off the engine. Is this normal?? I have not taken it for a ride yet, just ran the engine for a few mins. I couldnt find an exact answer using the search tool.
I figure its running rich, but i had the battery unplugged throughout the whole installation process. Will the ECU eventually adapt?
As for the smoke, could it be some residual exhaust sealant burning off? No clue.. Can someone please give me the warm and fuzzy and tell me "everything is going to be alright"
Thanks..

 

[going going.....gone]

The smoke could be oil/grease within the new decat pipe you got (for free?? :-o) if im right in thinking when pipe/sheet metal is manufactured it gets a coating of oil/grease to stop it corroding, as for the smell of petrol I guess it could be a problem with running rich. I guess some kind person on this forum will come along with insight into this.

 

[Kaisersoze]

Engine runs rich at start up and idle due to FI System warming engine up. (Thats what other, more informed, members of the forum have told me when i asked about gas smell). The smoke however..

 

[DownrangeFuture]

Well, one of the things the cat does is use the unburnt fuel in the exhaust to heat itself up. That's why your exhaust can used to get hotter than your engine was running. With the loss of back pressure it should have leaned out the mixture a little bit. So you were probably running a bit rich before.

When the engine is below a certain temp, it should actually run leaner to heat the engine up faster. A choke is sort of like a clutch in that it's engaged for normal operation, but at start up you actually turn the choke off letting more air in with the same amount of fuel. A fuel injected engine does the same thing, but automatically. Running richer at startup would flood the engine and make starting hard at any outside temp below 80F.

The ECU should adapt some over time yes. And my guess is that now your exhaust is running cooler than your engine, it doesn't have the heat to truly ignite the fuel and it just smolders off. My old Katana always spit smoke when it first started and some leaked out of the pipe for a minute or two after I shut it off.

To help out the ECU I'd go into diagnostic mode and take a point or two off your fuel injectors. If you're still running rich, it probably won't ever go far enough down to run right now.

And you can tell your exhaust guy next time that cats still aren't required on motorcycles by federal standards, state standards may change. Or he could have sold it to you for "race use only". But getting the pipe for free was kick ***.

 

[TownsendsFJR1300]

I agree with the above, your probably smelling unburned fuel as the second cat is eliminated and the bike is still running rich as its cold (see picture #2, "K" section-cold start). The smoke is the oils buning off the newly installed de-cat pipe.

Attached are pic's from my FJR shop manual showing the FI system, how it works when starting, hot, cold, accelerating, de-cel, etc...

The systems should be pretty close between the FZ and the FJR with the general mapping the same..

None of this information is shown in my 2007 Yamaha manual but is good to know and understand..

 

[Motogiro]

The earlier model FZ6 may not have the additional CATs in the exhaust header. I believe the newer ones do have CATs in 2 separate areas. When you remove the CAT pipe you've essentially remove any back pressure and the ECU may not be able to cope with that much change. I'll assume that you removed the CAT pipe because you're looking for top end power and you plan to install an additional fuel management system and have the bike dyno'd.

When the engine is cold it needs a richer mixture, less O2 and more fuel. This is because as the engine heats to normal running temperature, detonation becomes more efficient because of heat and increased compression and it then needs less fuel to oxygen. It's important to understand that your motor will run healthy with a specific air to fuel ratio and you probably want to get a reputable tuner who will put a sniffer in the tail pipe and know what these ratios actually are. If I wasn't going to spend the extra bucks for a computer and a tune, and had to guess on anything I would put the original CAT pipe back in.

 

[Sparkybean]

Mine stank for ages when I first got it. It smelled like the insulating stuff inside it was burning. Doesn't do it anymore. But it was awful. I assume by gas you mean fuel? I don't smell any fuel but I do have the cat still in.

 

[jrevans]

I have a 2004 with a Laser-Quad exhaust and the cat eliminator pipe.

I don't get a raw gas smell, but I could definitely notice a difference once the cat was removed. Simply put, the exhaust stinks more now.

Having been riding street bikes for 27 years now, the FZ6 was my first bike with a cat on it. I didn't realize the difference in smell it made until I removed it. Now my FZ6 smells like every other bike I've owned....

 

[MrTigerB]

Thanks guys.. the info was much appreciated. I didnt think getting a PC was necessary, maybe to address low end performance, but I guess I should start looking into one. Ive heard mixed reviews about PC III but maybe the negative reviews are due to improper mapping? Any insight as to what i should look for?

 

[DownrangeFuture]

At the very least change the settings in the ECU. There are some threads talking about how to get your dash into diagnostic mode.

See if scorpion has any baseline maps for your setup. I know TwoBros does. Try to find a smaller shop with a dyno, or even better a company that only does dyno pulls. They need to have a dyno for motorcycles, as the extra weight of car ones skews results. I'd say $200 tops for an hour of tuning and pulls. If they want $100 or more for a single pull and tune, walk away. Tuning is an educated guess at best. A good tuner will usually do 2-3 pulls and tunes in between.

If you can get ahold of the ECUnlimited guys I'd have them re-flash your ECU. They need 2 pulls with different stats and your ECU. Something like that.

 

[MrTigerB]

At the very least change the settings in the ECU. There are some threads talking about how to get your dash into diagnostic mode.

See if scorpion has any baseline maps for your setup. I know TwoBros does. Try to find a smaller shop with a dyno, or even better a company that only does dyno pulls. They need to have a dyno for motorcycles, as the extra weight of car ones skews results. I'd say $200 tops for an hour of tuning and pulls. If they want $100 or more for a single pull and tune, walk away. Tuning is an educated guess at best. A good tuner will usually do 2-3 pulls and tunes in between.

If you can get ahold of the ECUnlimited guys I'd have them re-flash your ECU. They need 2 pulls with different stats and your ECU. Something like that.

Any where in Jax you would suggest? I was looking at thread that talked about tapping into the diagnostics, but i guess all im missing now is a dyno.

 

[novaks47]

Here's my 2 cents : Gas smell is from there being no more cat. No cat = unburnt fuel getting dumped straight out the exhaust. It'll be worse upon start up, due to the bike running rich at that point. As for smoke, well, it's a new exhaust! There's leftover manufacturing "slime", like greases and lubes, plus any anti-corrosion crud that they put on for shipping. Also, the packing material in the cans will smoke a bit too. It'll smoke even worse on the first major ride/flogging, then gradually dissipate the more you ride. A bit of vapor visible in the cans after a ride is totally normal too. Not quite sure what it is, but both my exhausts have done this.

A good way to check for any leaks, is to let the bike sit overnight, then fire it up. While it's idling, look at all the exhaust joints, and see if anything is leaking out. You'll see a mix of gas and water(condensation) oozing out the exhaust if there's any leaks. Keep in mind as the exhaust heats up, some of those minor leaks *might* self correct as the metal expands. They'll be back as soon as the exhaust cools however. Really no biggie though, as long as there aren't a bunch of them, and the ones present are really small. :thumbup: