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Discussion Starter · #1 ·
Quick question for you all, or for those that are left. I have an 08', 30k on frame but swapped the motor out for a younger one due to trans needing to be rebuild on the other motor.

An issue that has stuck around from the last motor to the current is a terrible idle. I'm talking bike simply can't idle on its own when it's cold (first start) or when hot (sitting in traffic). gets about 30 seconds in and falls flat. comes back on idles for a bit and falls flat.

It's always had the rollercoaster idle due to my SBU Tune, but it's only gotten worse, and worse and worse. Last track day I was at I had to stay on the the throttle absolutely pelting the guy behind me with un catted exhaust fumes. three 3-4 years ago when it started it wasn't so bad but now it's at a point where the bike is borderline un-streetable.

My question; has anyone had to replace or have their fuel injectors cleaned due to similar issues? I can hear them all clicking in diag and all my exhaust pipes get hot. Plugs are fresh from the motor swap I did a year ago and valves clearances are all within spec. I'm almost certain it's a fueling issue; I know my fuel filler cap is weathered form time parked outside so I'm wondering if it could be vapor lock but at the same time it's never an issue coming back on, just staying on.

Ultimately I think the bike needs to be retuned but we don't have many reputable bike tuners in my area. Just looking for thoughts or advise - Cheers

 

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Vacuum leak maybe? Valve adjustment? Bad throttle body sync? Could be the tune or the injectors, but it also could be a whole lot of other things.

If it were mine, I'd pull and read the plugs and do compression and leakdown test. From there, I'd figure out where to go next. Good luck.
 

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Discussion Starter · #3 ·
Vacuum leak maybe? Valve adjustment? Bad throttle body sync? Could be the tune or the injectors, but it also could be a whole lot of other things.

If it were mine, I'd pull and read the plugs and do compression and leakdown test. From there, I'd figure out where to go next. Good luck.
Vacuum leak is possible, I'd question compression if this were new and the old motor had bad compression but I did check after removal and compression fluctuated between 195-220. New motor was was 220 almost across the board +/- 2 or 3. Bike def. doesn't get ridden as much since I've transitioned it to mainly a track bike but I still take it out twice a month to run gas through it. Took it out yesterday after doing fork seals (sat for about a month while I waited on parts) but she rode like absolute trash.

You do bring up a good point, I haven't done a throttle body sync and when I swapped the motor over I put new cables on and I'm sure I played around with the throttle linkages more than I should have. Maybe I'll start there and do a quick fuel system clean while I have it all apart.
 

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Grab a motion pro injection cleaning kit and douche them out real good while you're at it to knock that off the list bud. Good luck.
 

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Discussion Starter · #5 ·
So this past weekend I pulled the tank and fuel pump to clean things out and make sure I didn't have a bunch of crud in the system. Didn't seem too bad but there was gunk in the fuel screen so I cleaned it all out, trashed the gas and started fresh. Bike runs noticeably better but I have a feeling the injectors have debris in em so we're going to flush them out this weekend or next. Good news is I can now hold an idle through a traffic light and it only cuts out once 3-4 times on a 30 min ride through local roads. Previously it would fall on its face every time I stopped & idled for more than 15-20 seconds.
1019248
 

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Discussion Starter · #6 ·
So, I've done a lot and I'm def. seeing results from the efforts, but it's still lumpy at idle. It occasionally conks out but far, far less frequently. Cleaning the injectors & fuel pump definitely produce results which is good, bike's mid & top end feels stronger than ever; second gear hovers off the ground on hard accel again which I hadn't realized I lost until I got it back.

Ultimately, i think the SBU Tune just isn't a very street friendly tune. I've had it on the bike for 4-5 years now and while she's silky smooth above 3k RPMs, anything below that is just lumpy. At idle or while putting around the parking log. Fortunately this isn't being used as a street bike anymore so we'll live with it.

Just to recap:
Issue: Bike would die after idling for more than 20 seconds

Remediation efforts:
*Checked for vacuum leaks & TB Sync (eyeball AF Screw 1/2 turn out)
*Cleaned out fuel tank, fuel pump, fuel line
*Cleaned out fuel rail & Fuel injectors - Also cleaned up TB & Airbox and filter
*Replaced Lithium Ion battery for sealed lead acid in case it wasn't putting out enough juice / taking enough of a charge at the lower RPMs

End Result: Bike idles as well as I can remember since after having it tuned. Will idle at traffic light but doesn't like putting around below 3k. Midrange is all the way awake, almost 12 O'clocked 1st gear on my test run.

I don't think my tune or bike is anything record breaking but during track day's I've run down S1krr's on the straights and that was before I cleaned up the fuel system. Scheduling a track day soon so we'll see how she does this time around with a cleaned up fuel system and new fork seals & upgraded brake pads. OEM's survived 3 track days
 
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