Why do my legs reek of gasoline/exhaust after a ride?

[mitchelldanger]

I'm a new guy, mechanically, and I've come by the mechanics stuff slowly so I would love any help I can get.

The bike:
I am running an 07' Busa with 16k miles and a Yoshimura twin full exhaust system and minimal modifications AFAIK (I wasn't ever informed about the type of tuning, though I imagine it must have some sort of tune based on the exhaust).

The problem :
Only within the last few months of riding have I noticed that after a good burn of the throttle the pipes make a loud popping noise. I don't know much about it and the reading I've done suggests that this is normal but really I don't know enough to know if I'm asking the right questions. I've also noticed that the bike idles pretty high in Neutral, noticeably higher than if I held in the clutch lever in 1st gear. Also, the smell of gas fumes is pretty noticeable while at a stoplight.

My attempt at diagnosis:
From what I've read, the idle issue is something seen in the early timing retard eliminators that map the fuel map of every gear to 5th gear, so the bike looks like 5-5-5-5-5-5-5 instead of 1-N-2-3-4-5-6. The new SmartTREs idle slower in N than the old ones. Aside from that, I have no idea what the problem could be, let alone a solution.

TL;DR:
1. Pipes pop loudly after I finish twisting the throttle.
2. The idle in N is much higher RPM than in 1st.
3. The bike smells like gas when I'm at a stop.

Thanks! Any help is greatly appreciated!

 

[RedBull]

The bike:

I am running an 07'
Hayabusa with 16k miles
and a Yoshimura twin full
exhaust system and minimal
modifications AFAIK .

The problem :
Only within the last few months of riding
have I noticed that after a good burn of the throttle
the pipes make a loud popping noise.

I don't know much about it and the reading I've done suggests that this is normal but really I don't know enough to know if I'm asking the right questions. I've also noticed that the bike idles pretty high in Neutral, noticeably higher than if I held in the clutch lever in 1st gear. Also, the smell of gas fumes is pretty noticeable while at a stoplight.

My attempt at diagnosis:

Thanks !

Any help is greatly appreciated !

 

[Nastee]

I would prop open the tank & look for a leak of gas at the rail injector site. Maybe an injector O ring gone bad or a leaking line into fuel rail. This my thought since you say smell near legs & not from exhaust also stronger smell when stopped which means motor is not pulling or using that extra fuel which decreases the leak volume. Just a place to start from a novice.

 

[Nastee]

Could be creating a lean condition if you hear popping pinging while on the gas. DETONATION?

 

[Kiwi Rider]

I would prop open the tank & look for a leak of gas at the rail injector site. Maybe an injector O ring gone bad or a leaking line into fuel rail. This my thought since you say smell near legs & not from exhaust also stronger smell when stopped which means motor is not pulling or using that extra fuel which decreases the leak volume. Just a place to start from a novice.

As above, visibly check for fuel leaks while the bike is idling with the fuel tank propped up, use a flashlight to see all around the fuel hoses at the pump fuel connections at the bottom of the fuel tank. Then look all around the fuel injectors at the throttle bodies.

Could be creating a lean condition if you hear popping pinging while on the gas. DETONATION?

Quite the opposite . . popping/back firing usually caused by over fueling with excess fuel exploding in the exhaust . . . or may be an air leak in the exhaust flange/muffler joint.

re the high idle speed, there is a idle speed adjusting remote screw on the right side just above the clutch cover.
Turn that back a little and drop the idle speed to 1200rpm, then put it in 1st gear with clutch in and if the idle drops back, raise the idle speed a little more.
I've never heard about the TRE altering idle speed in neutral, new one to me, but it may be right. What was the source of info on that?

 

[Mr Brown]

Remove the TRE, ride and see if anything's different.

 

[ottafish]

The op says, bike pops loudly after twisting the throttle. So I assume engine is off load, ie on decaleration. Also mentions a full yoshi system.
Could that be the result of the exhaust and pair vavles not blocked off?

 

[Nastee]

As above, visibly check for fuel leaks while the bike is idling with the fuel tank propped up, use a flashlight to see all around the fuel hoses at the pump fuel connections at the bottom of the fuel tank. Then look all around the fuel injectors at the throttle bodies.

Quite the opposite . . popping/back firing usually caused by over fueling with excess fuel exploding in the exhaust . . . or may be an air leak in the exhaust flange/muffler joint.

re the high idle speed, there is a idle speed adjusting remote screw on the right side just above the clutch cover.
Turn that back a little and drop the idle speed to 1200rpm, then put it in 1st gear with clutch in and if the idle drops back, raise the idle speed a little more.
I've never heard about the TRE altering idle speed in neutral, new one to me, but it may be right. What was the source of info on that?

Yes I thought it was rich as well from what he 1st stated about off throttle but if on throttle I wanted him aware of Detonation which is not good at all! Kiwi is a real mechanic & knows what to look for good luck.

 

[JINKSTER]

I'm hearing "Full Twin Yosh" and "TRE" but I'm not hearing anything about a High Flow air filter (like BMC Race or K&N) and I'm not hearing anything about any fuel mapping or air/fuel ratios so here's the deal the way I see it...

The OP went with a full exhaust system allowing the engine to exhale real well but is probably trying to inhale through a tight micron stock paper air filter where the call for fuel is increased but the stock filter is not permitting adequate air flow resulting in both a rich condition when rolling on (hence the smell of gas) along with a lean condition (causing popping on decel) when rolling off.

Cure?: High Flow Air Filter/Dyno/EGA/Remap

 

[mabupa]

I'm hearing "Full Twin Yosh" and "TRE" but I'm not hearing anything about a High Flow air filter (like BMC Race or K&N) and I'm not hearing anything about any fuel mapping or air/fuel ratios so here's the deal the way I see it...

The OP went with a full exhaust system allowing the engine to exhale real well but is probably trying to inhale through a tight micron stock paper air filter where the call for fuel is increased but the stock filter is not permitting adequate air flow resulting in both a rich condition when rolling on (hence the smell of gas) along with a lean condition (causing popping on decel) when rolling off.

Cure?: High Flow Air Filter/Dyno/EGA/Remap

Off topic, but that screen name doesn’t come up very often. It got my attention due to reviewing several times the “jinkster attacks suspension” thread. Welcome back!

 

[mitchelldanger]

As above, visibly check for fuel leaks while the bike is idling with the fuel tank propped up, use a flashlight to see all around the fuel hoses at the pump fuel connections at the bottom of the fuel tank. Then look all around the fuel injectors at the throttle bodies.

Quite the opposite . . popping/back firing usually caused by over fueling with excess fuel exploding in the exhaust . . . or may be an air leak in the exhaust flange/muffler joint.

re the high idle speed, there is a idle speed adjusting remote screw on the right side just above the clutch cover.
Turn that back a little and drop the idle speed to 1200rpm, then put it in 1st gear with clutch in and if the idle drops back, raise the idle speed a little more.
I've never heard about the TRE altering idle speed in neutral, new one to me, but it may be right. What was the source of info on that?

The pipes are full of soot, so overfueling is likely. Have my hands on it now and I don't see any obvious leaking, but when I am looking into it I do smell fuel. Maybe that's typical? I don't know I'm going to start with your suggestion and change the idle speed and see what happens with that.

Also, can you recommend a good maintenance manual for the bike?

 

[mitchelldanger]

I'm hearing "Full Twin Yosh" and "TRE" but I'm not hearing anything about a High Flow air filter (like BMC Race or K&N) and I'm not hearing anything about any fuel mapping or air/fuel ratios so here's the deal the way I see it...

The OP went with a full exhaust system allowing the engine to exhale real well but is probably trying to inhale through a tight micron stock paper air filter where the call for fuel is increased but the stock filter is not permitting adequate air flow resulting in both a rich condition when rolling on (hence the smell of gas) along with a lean condition (causing popping on decel) when rolling off.

Cure?: High Flow Air Filter/Dyno/EGA/Remap

I'll order a new filter ASAP and see how that goes

 

[JINKSTER]

The problem with adding a high flow air filter (along with your high flow exhaust system) is you may rid yourself of the smell of raw fuel but you will also be making things rather "LEAN" across the board which can cause some serious engine damage...you bit off a good chunk going with a full exhaust and it only makes sense to make the most of it with a high flow air filter but to make the most of both of those items you really need to address remapping the air/fuel ratios or risk damaging your engine.

 

[Kiwi Rider]

The bike needs to be dyno tuned by someone that knows there stuff.
With a power commander fitted, the air fuel ratio can be smoothed out across the rpm range and on throttle position thru the range also.
This is VERY important to have your motor tuned on a dyno when adding more air and a free flowing exhaust.
Re the maintenance manual you asked about, just stick with the factory service manual, I downloaded mine free for the gen 1.
Hope it all goes well for you buddy, let us know, oh and pics please, we all love pics!!

 

[JINKSTER]

Like so...