Slight "surging" / jerky running 07 ec450fsr

[Why Z?]

Hi, bike starting fine (issue seems resolved with learning the bikes "personality")
Running mostly okay but a couple slight issues:

1) bike is a little hesitant/boggy in 1st from a stop, and between 1st and 2nd when accelerating
2) at "cruising" speeds on roads for instance, I notice that it sometimes hesitates/surges while the throttle is held constant. For instance I will be cruising at say 45 mph and then after a few seconds I will get this "ht" outta no where. Not uncontrollable but not "NORMAL" either.

3) One day I took it out to warm up before changing oil, it was after dark and after running/riding it maybe 5 but less than 10 min, (in the dark) I looked down and noticing the header was starting to glow RED. NOT BRIGhT red, but glowing a bit.

What could be causing the surging/nt smooth running?
Too Lean????

Also, bike came w 2 ECU's, not sure why though and Prev. Owner wasn't sure . (It was a research bike for the company he worked for).

'07 EC450 FSR
-I have had bike for about a few wks now
-bike has very low miles (fresh rebuild when I got it)
-gas: 91 Pump gas non-ethanol (non dedicated pump though)
-oil/filter: Rotella T6 5w40 ("full synthetic")
changed twice since I had the bike (prob about 2 hr apart)
-air filter: when I first took out to change after a dusty ride, found a tear near the seam where it seals to the bike. Now have a UNI (seems SUPEr bulky) and a FLO (seems to fit better). Did the no toil on this one(I tend to over-oil a bit maybe w regular oil)

[Why Z?]

Wanted to let you guys know, I think I figured out the problem, so this thread can be closed (I have another question yet but I think I will post it in the general forum as it is not 4 stroke specific)

Basically, there was an air leak that I believe was responsible for my problem.

Where the air boot mounts on to the air box, didn't look 100% air tight or flush. I am not sure if it was assembled incorrectly or missing a part, or if part was damaged previously from heat (there is some evidence of this , plastic is a bit charred/ rougher on both the air boot and airbox on the exhaust side)

I taped it up with Electrical tape (hi-temp) and took it for a ride, and :

1) No more surging/hiccuping at cruising speeds!
2) No more bogging from stopped, or between 1st an 2nd
3) Starting even a bit easier/warms up easier!
4) in about 40km, not a single random stall out on decel!
5) HUGE REDUCtIOn in backfiring/popping!!!

Now I am just trying to find a permanent fix. (Was the problem because it got damaged or was it damaged because it was installed incorrectly?) - GG manual/parts diagrams don't do a great job at this unfortunately

[Jakobi]

Glad you found the issue. An air leak/lean condition will cause all the symptoms you've described. I'd have to check the parts fiche etc to confirm which part you are talking about though. Generally the airboot fits in the airbox the same way a gromet does. IE it doesn't actually have to seal against the airbox. It just pushes in and the filter seals directly against the lip of the boot. Where did you have to tape it?

You've probably noticed not a whole lot of discussion re the 4T models. Most of us are on the bangers.

[Why Z?]

Yep, I *think* I found the problem but I am less sure on the solution.

I taped it on the part where the air boot has sort of a "lip" that "seals" (presses up against) the air box.

However, after tearif the thing down further and trying to get the airbox off to inspect/clean the throttle body (btw.... Wow this is a lot more complicated than undoing the airbox on a Jap MX bike omg) and taking the filter OFF I am seeing more how this part works and :

It looks like the air boot/air box where it "seals" on ea side looks like one piece. Looks like the air boot has the big stomach shaped part, with 2 layers of "gasket type lip thing" molded in, one on ea side of the air box.
(Hope that made sense)

So basically from left to right/front to read, looking at the non exhaust left side of the bike:

Air boot body > air boot "gasket" (part of airboot) > air box wall > air boot "gasket" (part of airboot still) > Air filter rim with the grease > air filter body.

I wish I had a pic and I have taken a dozen but it is tough bc all the parts are black and some of them glare etc so it's impossible to see what your looking at.

Basically mine, the air boot gasket is kind of tilted slightly "away" from the air box on ea. side.

It almost hurts my head to think about. I don't get

Note: the parts diagram shows a "air flow restrictor" or a part that basically looks like the cutout shape of the cross section of he air filter between the airboot and air filter.

I don't think I have that! Anyone else not have that or know if that's a common mod to increase airflow that does NOT eff up the bike?

[Jakobi]

As I said above, its one big piece of rubber like a gromet. The airfilter seals to the intake, and the intake seals to the throttle body.


It doesn't actually seal against the airbox, nor does it have to. I have an airboot in my spares kit and I will happily take a photo of it if it'll help.

Its possible that your airboot has cracked in one part though and the tape has helped seal it.

The airflow restrictor is used to meet emissions controls in some countries. Very unlikely to find a bike with one installed.

[Why Z?]

Excellent info, thanks Jakobi!

If the airflow reducer is not "meant" to be on there such that the other parts would be molded for it then I guess I don't really care. If Fitment was designed for it though then I would rather run it for the sake of fitment and cut a hole in it so it's like a gasket? This is all hypothetical though.

If you have a pic if the airboot that kinda shows how it holds the air box in w/b sweet .

And yes I did get enough of bike taken apart today to see... Yupp a ton of no filter "grease" from the new install (I like the oil so far I think but the grease meedhhh I am not convinced peanut butter wouldn't work better) I did find some flecks of dirt/debris in the boot so far but havenot taken it off of throttle body yet

What's best way to clean throttle body when I get to that point?

I think I get how this thing works somewhat.
Getting in there and having to take the thing apart I am learning a lot :-)

K

[Why Z?]

I solved the problem!

It was not the air boot , I do not think.
I did a test with carb cleaner and it is not leaking .

Then I found that blue / yellow wire everyone is talking about.

I disconnected it now, (left the other black wire plugged in) and, no more surging/jerking! No more popping on decel!
It sometimes makes a huge gunshot sound when starting, and will only start with throttle half open.

Other than that, runs great!
Definitely better with the wires undone!
Seems the pipe also gets less hot.

[Jakobi]

Great work! Doesn't seem to be a lot of discussion around the 4 strokes in general, and even less now that Gas Gas has stopped production. Hope you get her running well and have many happy hours riding.

[Why Z?]

Update - bike has been running strong since!

Still has some starting quirks and needs the throttle held part open to start and the bike is not much of a "morning person" but overall has been real good, and it's quirks are reliable so I know how to handle them ...

I have a lot more confidence in my bike now, and am able to spend more time riding and planning new places to explore and less time thinking about what could go wrong and the endless paranoia that was before .

It still is crazy though that GG made the bikes to run on a fuel map, that IMO is not really good for the bike and could result in premature wear/failure (running lean is something me no likey - I would rather foul spark plugs all day than see my pipe glow red!)

It is crazy the manual doesn't mention this wire and that you should disconnect it - I vote it's time for a sticky on the blue/yellow wire !!!

Although painfully obvious to some, for those of us buying used bikes with less familiarity with the brand the bike and it's quirks I think it would make for lots more happy GG owners down the road and less head aches....

Also a related thread on fuel mapping for these Early- ish GG EFI bikes would be tremendously useful, I think. Seems to be a common theme around here!