Intermittent cut off with hard accelleration....

BroHay

BroHay

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Ok -- intermittent -- but it has lit the fire under my arse to get the jet kit/airbox/timing advance/ported boots..

Since I put the fairings on an odd development has recently occurred. Above 5k the bike starts spitting and sputtering (intermittent) when accellerating. Nothing has changed other than restricting the airflow that was once available without the fairing.

Now it has been close to the century mark -- but can someone give me a basis for what is occurring??

Too warm, not enough fuel delivery, choking itself out??

Thanks,
Adam
 
Last edited:
BroHay said:
Ok -- intermittent -- but it has lit the fire under my arse to get the jet kit/airbox/timing advance/ported boots..

Since I put the fairings on an odd development has recently occurred. Above 5k the bike starts spitting and sputtering (intermittent) when accellerating. Nothing has changed other than restricting the airflow that was once available without the fairing.

Now it has been close to the century mark -- but can someone give me a basis for what is occurring??

Too warm, not enough fuel delivery, choking itself out??

Thanks,
Adam
Click to expand...

How about coincidence?? I don't feel that the fairing is hindering any air going to your airbox. I've had no ill effects on having the fairings and aside from my jet kit, I am running the stock air filter with no mods to the airbox at all.
 
well, I thought I'd bump this TTT to see if anyone had any input -- it is intermittent. One hard accelleration it is prominent and the next, it is if nothing is wrong....

Adam
 
have you taken a look in the airbox?

from the sound of things, you're running out of fuel... maybe something rolling around in the bowls, and only when you're using gas at an alarming rate (E.G. Over 100mph) that bit of something rolling around falls into just the right spot and kills fuel delivery....
 
hmm---well, I guess I'll know soon enough....just have to get the bike back here to be able to take a peek.

But I have not had anything apart and as stated, started occurring after I installed the lower fairings....


Adam
 
it might not be an air or fuel issue per se.... it might be that the added heat trapped in by the fairings is causing the fuel to atomize inside the carbs before it has the chance to make it to the combustion chambers....

don't know why it would be intermittent though... unless you have a float that's not moving its full range of motion.... and because of that, the bowl isn't getting as much fuel as the rest....
 
well, I'm still having the issue -- just waiting on a replacement boot to finish the install one of two things comes to mind----

1) I'll check the plug on the driver side to make sure that the boot is seated properly.

*******I had pulled it off to check the operation of the sparkplug wrench I p/u, but doesn't account for why it is intermittent.....

2) Is there a safety mechanism tied to the oil resevoir if it is slighty more than full??
 
Ok -- so I fixed part of my problem in that the plug cap was not seated all the way on the outside spark plug on the left side -- I got my 1 and 2nd with being able to clear 6k and not have it sputter -- but I still have the problem with 3rd/4th where it still cuts out above 5k ----

guess I'm just trying to get a basis -- so when I have it all apart in the upcoming weeks I can address it better.....

Adam
 
here are all my symptmoms....

  • I do have an increasing popping on deceleration (from what it was)
  • I had lost the ability to clear 4-5k in first or second (but regained this after I refit the sparkplug wire.
  • I now experience the same phenomenon in 3/4
    *****I should mention that it is with a hard accell but is present if you try and creep up on it (just not as pronounced)
  • replaced the original body work with present skunk maybe 3 mos ago and did not have an issue with the hard accelleration until after the day I mounted the lowers

hopefully all of this will be a distant memory when I do jet kit and airbox. But for the meantime, tis a road I must travel and helps me understand the mechanics (or try to anyway)
 
culprits....???

throttle cable out of adjustment
excess heat trapped in fairings
cracked boots
airfilter clogged
pinched fuel line
fuel line blocked

.....any others?
 
should of posted this after I talked to the guy.....but the service department actually had some useful information from my local stealer.....

Yamaha runs 132.5 mains and those are too rich given the elevation of just over 5k feet here in Albuquerque. Because I started experiencing the problem, right after I put the lowers on, is because I'm not getting enough air to the engine so it is essentially choking itself out b/c of the restricted airflow.....something else about the drag co-efficient of the lowers.....but laymans terms, not enough air is getting to the engine!

He told me that I should drop 2 sizes in mains (127.5) to be able to run with a K&N and airbox mod. Here is where I'm at the mercy of someone more mechanically inclined --

The jet kit I have is for a slip-on and uses 122.5 mains with use of stock filter and non modded airbox. I'm finding information, from the manufactuer himself, saying that if you run aftermarket filter and modded airbox, you should have 127.5.

Does anyone know where I can obtain the main jets only?

I was hoping to get this done this weekend, but guess I'm still on the hunt for information......

Adam
 
just when I thought I found the culprit -- I had one of the plugs that are on the carb boots completely dry rotted -- I replaced this am and was on my merry way. Well, on the way home, around 90 degrees (and could feel the heat off the engine) I was putting her through the paces and she was keeping up. It was not until a fourth gear hard roll on, that I'm sad to report, the condition is back......

messed with the throttle -- to take up some of the slack, could that have an impact??

just trying to throw all options out there...

Adam
 
messing with the throttle wouldn't do it... I'm still leaning towards a stuck float... or plugged pilot jet... or something of that nature...

here's a question though... on a good hot day, stop after riding for a good long while and open the gas cap... does it make a sucking noise or whoosh of air when you open the cap? i'm wondering if you have a plugged vacuum line or vent line somewhere...
 
I am curious as to whether you've done the carb bypass mod? It's the line from the radiator that runs antifreeze through the carbs so that in winter the gas won't freeze. I am wondering that with all that desert heat that the gas may be boiling?? The only reason I say this is that its weird that you keep smelling gas once you shut her down.
 
but again -- I just find it odd that all this started happening after I installed the lowers -- I'm going to town this weekend and dropping the fairings and will ride around to see if the problem goes away.....

I'll keep pluggin away until I strike paydirt......

Adam
 
I seriously doubt the lowers have anything to do with it. Where does the airbox get its air? From under the seat.

Does it sputter going through the midrange (~5K) and clean up and higher RPMs?
 
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