Bike will not rev past 6-8k rpms at wide open throttle.


#1
It's an 08 with 7k miles. I just bought it from the original owner.
The bike sat for a few years but he said he started it up once a month. I don't know how true this is.
The gas smelled bad but it did start right up and run so I rode it.
I went wide open on a 2nd gear roll on. about 6-8k rpm or higher it'll fall on its face. I start to let off of the throttle and it will start to pull again. I didn't see if it would reach a higher rpm with less throttle say 1/2 or 3/4 throttle but wide open it will not.
We drained all the old fuel out and ran it dry. Put fresh fuel in it thinking it is the fuel but it is not. It still does the same thing with fresh fuel. I've been driving it daily but it still has this issue.

Why would it fall on its face when wide open or at higher rpms?
Is there something that is triggered when higher rpms or wide open throttle takes place?
I saw another set of injectors, what are these for?
I read a similar post that a secondary throttle blades may not be opening. What would this do if they do not open?

Any help would be appreciated gentlemen. Thanks.
 
#2
My best guess is that It falls its face because its starving for fuel. You most likely clogged the filter when you ran that bad fuel. They are not cheap for that bike so call Justin from Honda East (one of our board Sponsors) and he will hook you up.
 
#3
Do a search on here for back flushing the filter. If you flush it and it runs better then you know for sure the filter is toast. If you look you can also find free downloads for the shop service manual.
 

Postal

Donating Member
Registered
#4
Here is what you may need to do:

1. Send your injectors off to MPS and have them cleaned.
2. Clean your fuel system out, be sure to get the bad gas out of the pump too.
3. Replace your fuel filter.
4. Maybe replace your plugs.

That should do it.

P.
 
#5
All of the above is correct! Filter costs around $250.00. There are no aftermarket options. Talk to Justin!
There are two sets of injectors on Gen 2s. The ECU conrols their sequencing based on TPS and other factors. This means getting your injectors done costs twice as much.
The filter is very efficient and blocks the finest particulates. If the integrity of the filter medium is compromised the injectors will need cleaning. There is a screen on each injector on the supply side and if you remove the fuel rail you can clean them with some carb cleaner. If they are truly clogged you will need to hve them cleaned professionally. Don't even think about replacing them because they are like 175 bucks a piece. Cleaning costs 50.00 a piece I believe. Sometimes the injectors are okay so do the filter first and if your performance comes back to where it was, Techron may finish the job for you.

Good Luck!
 
#6
Ok I will look into that back flushing the filter thread first.
That is one expensive fuel filter there.... Damn... $250 well back flushing first it'll be.
I found a few service manuals but I couldn't get my iPad to download em. Apple sux at times....
I will also clean the injectors to ensure they are firing off. A simple method on you tube works wonders before I have to send em off and spend big money on them to get cleaned proffesionally. I did this on my 99 that I let sit for a few years and they work perfect after a few cleanings on the you tube method.
I've ran almost a full tank of gas through the tank, fuel pump and injectors. Maybe the 2ndary ones are clogged and aren't opening up. Ill clean those first n see what happens and do the back wash filter method.

Someone told me to drain the tank, run straight race fuel through the system and see what happens. I guess a gallon of c16 couldn't hurt or could it? He also said to put something else with the race fuel to help clean the fuel system area. He works on bikes all the time so maybe just maybe he may know something n maybe not....
 
#7
Why on earth would you run race fuel through a motor not designed to take it? I would be afraid of being too lean and burning up a piston but that's just me (I tend to be overly cautious as to not break my stuff) . The additive he was probable talking about is SeaFoam. I would start with a new filter and then check/clean the injectors. It's a pretty safe bet to say that filter is toast. It's a typical paper type filter so bad gas tends to ruin them. Search the org and you'll see where a few people the spring have already had to replace there filters for the same reason as you. Search bad fuel pump, filter back wash, and gen II fuel filters so see the latest issues other people have been having.
 
#8
If it sat long, and was stored improperly, I'd bet there was a bunch of rust collected in the pump screen area.
I'ts a recess, and all the crud collects there. Drop the tank,. Pull out the pump and clean it out before you go
dropping $100's of dollars like some have suggested.

This was precisely the issue with my 06, it sat for a number of years before I bought it.
 
#10
Corpus Christi, just south of you lil c... No he didn't say sea foam it was something else.
I will take the tank off when I get the fuel level low enough one day and clean it out first and look at the pickup assemble where the fuel enters. That's only my time cost as mikbusa stated. Ill eventually take the injectors off and clean them next, I just hope the orings don't break or leak as they are expensive from the dealer. If not ill take one to a local gasket place and try to match this metric oring. I really enjoy riding it as I'm just cruising is around and getting the feel of it. Smoother than my 99 busa.
 
#11
Ok so today I took apart the fuel system starting with the injectors. When I took the complete fuel rail off, I wanted to see if all 8 injectors were working. Well the 4 that spray directly into the heads worked, the 4 on top of the throttle bodies never worked. You couldn't hear them open as the others did. So I cleaned them up by boiling all 8 tips in water first as it works to get them to open up. i also had a running ruff idle when the engine was cold for a few minutes then it would go away. i then started using tb cleaner by back flushing them real good several times then flushing them regular flow with the cleaner and compressed air set low at 30 psi. The spray pattern was nice n smooth after all this cleaning. I then took the fuel pump out but didn't see any rust just crystallization all over the pump. I cleaned it up, but didn't take the fuel pump apart. I used cleaner and kept putting it in the filter area and poured it out and it got a lot of stuff out. Did a full can of cleaner till it looked clean enough. I put everything back together and now the bike rips azz. No stumble at all. Pulls all the way to 11k.

If I have more problems in the future, ill pull the pump apart and clean the screen area or buy a new filter and pull the injectors off the rails and really clean the injectors and filters on top of them.

I hope this helps anyone else that may have a similar issue. This cleaning only cost me $10 in tb cleaner and regular tools if you work on your own stuff. Compressed air, a 9 volt battery with wires to fire/open the injectors, 5/16 fuel line to put over the injectors to back wash em. Cheap fix before shelling out big money and a good way to keep your injectors clean especially if you've let it sit for months or years.....
 
#13
I just saw this thread and I'm glad it worked out for you.
I was gonna recommend using some SeaFoam.
I've used it in my cars and bikes and I've noticed a pretty good inprovement.
I was a little skeptical on using it on my first bike (04 600) but After putting some in the gas tank and running thru a full tank, I've noticed the idle being much, MUCH smoother and the throttle more responsive.
When I got my 08 Busa in March, I seafoamed it in april and noticed a slight inprovement with idle and throttle response.
Obvious the fuel system wasnt was bad as in my 600.
I would definitely recommend using seafoam just in case something was missed.

Good Luck
 
#14
Whilst fuel starvation is possible i don't see how it would be a sudden cut off....is it at the same revs in every gear ?
The control of the secondary injectors may be a problem.
If the owner was honest saying he ran it every month then at some point he should have had to top up the tank so unless he took it from a dirty container it should have been ok.
The ECU monitors all sorts of stuff and low fuel pressure or secondary injector problems I would have thought should bring up an Fi warning.
The stock plugs die big time on these 1340 engines when not used regularly and my old Bking hated bad plugs and would cut out without warning...changed them each year..never missed a beat....with bad plugs it wouldn't pull past 6-7k revs in low gears and struggled beyond 5k in 5th/6th
From my experience unlike the older CR9E's from the gen 1 the iridiums in the Gen 2 behave like an on/off switch somewhere between 5 and 8 thousand miles depoending on how regular the usage is.....non stop use they get 8 ish but stop start low usage kills them.
 

dadofthree

Seasoned Beef
Donating Member
Registered
#15
I'm willing to bet it was gasohol and that stuff goes bad in months and starts gumming up the works. At idle I'm not sure the secondaries kick in. If That the case the fuel in them just sat basically. Hope you got it fixed and hope your methods don't cause any issues down the road.
 
#16
It's fixed now guys. The secondary injectors were 100% clogged up and not working at all. After I cleaned them the bike can go wide open and keeps pulling in the upper rpm range.

When I did a roll on in any gear from 2-6, if I did a half throttle it was ok and still pulled but if you go wide open it won't pull. It'll fall on its face. I don't like this secondary bs, as if you ***** foot the bike for a long time or it sits, the secondary's may not open up to get fresh fuel in them. Maybe in neutral they don't open up and only do under a load. I honestly do not know if the guy started the bike up once in a while either while it was parked. So who knows.
 
#17
that makes sense...secondary injectors are throttle %,rpm and gear dependant so they could have gummed up from old fuel ...good work sorting it.
Agree that all the tech stuff is a pain but wait til you see what future bikes have in store as such....my other bike is almost completely ecu controlled...even the lights are run by it.
Be sure in future to add a fuel stabiliser if you plan to lay the bike up....having read you woes i know i will.
 

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