| Author | Message | ||
     Stirz007 |
I'm throwing this out there in case someone on the almighty BWB has had a similar experience. This issue came up suddenly, as in: two practice sessions, no problem - third session this happened: (2008 1125R with race can, ECU, race harness.) Bike pulls strong up to about 6000 rpm, then abrupt loss of power. At WOT, rpms will continue to rise, but much slower than normal. Doesn't matter what gear you're in, same thing happens. What it isn't: Battery and charging system OK. ECU OK, I even swapped another with no positive effect. Fuel pump and delivery pressure is good, injectors good, stick coils good, new plugs, TPS OK, fuel pressure sensor good, grounds solid front and back. The loss of power is not intermittent like a short and persists at rpm above 6000. I've had to scratch two race weekends in a row trying to sort through this - so for now, I'm left with racing the Ninja 250 (fun, but not quite the same) The next step is to go through the entire harness, which I'm hoping to avoid. Anyone who has experienced something similar and has determined cause - please post up. | ||
| Froggy |
Anything on the display when this happens? I saw a race bike that did similar, it would randomly display CT COLD and then retard the motor. Perhaps yours is doing similar? New thermostat didn't fix it, ended up getting the ECM flashed and that fixed it. I doubt that is your issue though. | ||
| Brumbear |
plugged exhaust? | ||
| Stirz007 |
Nope - no banana in the tailpipe. Frog - it is a race bike with race harness, so I can't scroll through error codes and that crazy (H-D) system means I can't use a standard car code reader - I also don't have ready access to ECM spy. One theory is that sometimes the wiring will separate inside the insulation and at higher rpm, it's enough to cause signal loss. | ||
| Zane_t |
Just a wild guess here. If the throttle butterflies were zip-tied and the zip-tie broke, that may or may not cause erratic throttle operation at higher rpm's because of the spring loading in the linkage. | ||
| Ljm |
I had a weird thing w one of the 1125's, bought used. Very limited power, much like you described. It turned out to be mechanical rather than electrical. Bottom of the airborne sagged onto the throttle linkage and couldn't get WOT. Trimmed the rib on bottom of airbox about an eighth and fixed. Noticed that didn't happen when airbox off but did when buttoned up. (Message edited by ljm on May 24, 2013) | ||
| General_tso |
Stirz Have you had any luck solving the issue? I wish I could offer some assistance... | ||
| Stirz007 |
General (love that chicken) Tso - as near as I can tell, the ECU is working fine, as are coils and injectors, fuel pump, etc. Somewhere between appears to be the problem - a buddy who used to campaign XB's and is now a tech at H-D said that the harnesses (Buell and HD both source from same place) sometimes have partial wire separations inside the insulation, leading to loss of signal at higher rpm - too much data for a partially broken wire. I think I have it narrowed down to 10-12 wires in the main engine harness. The plan is to check ohms on coil and injector wires to see if one is out of whack, put a jumper across it, and terrorize the neighborhood to see if that solves the issue. Not exactly convenient to trailer the race bike somewhere at each iteration, so the neighbors will just have to deal or call the cops. Long term fix requires me to drop the motor to get to the harness. Hope to have it worked through by the weekend. Side story: I managed to salvage last weekend's MoM Round 2 by racing my son's Ninja 250 - this round was on the Perimeter (AMA/SBK) course with the 2/3 mile front straight. I ran Supertwins (cuz I needed the points and after giving everyone behind me in the grid a heads-up what my line off the start would be, as I gridded front row), 250 production class and Moto3. I think I topped out at a whopping 90 mph with the massive, awe-inspiring 20hp on hand, and got two 4th place finishes (and a dead last in Supertwins). The cool thing about the 250 is that you don't need the brakes much, suspension limitations are 'interesting' and you can run WOT pretty much all the time. Apparently, my full turtle-boy tuck everwhere I could was big amusement for my comrades. I also decided that a pretty yellow vest would reduce my chances of asspackedness.  | ||
| Dannybuell |
LOL! nice report! | ||
| General_tso |
You've solved the issue of the new barriers at MMP! All classes should be limited to 250cc. Nice report. Your competitors must have been shaking in their boots. I took the YCRS class at MMP a few weeks ago and was impressed with the facility. We ran the East and the West Courses and my preference is the West course. I'd like to return one day to run the perimeter course but Toole is a Loooonnnnnnggggg way from Durham. Have you reached out to EBR for help? Hope you find the cause of your issue. | ||
| Stirz007 |
The barrier issue has been largely addressed after some discussions with MMP (as you may have gathered from the WERA board). Quite the back story there. Witchcraft only comes into play on Perimeter and should be OK - although I took a flier off there a few years ago that would have been unfortunate with the new barrier. The 'Faster' barrier has been moved back from original position - I haven't experienced that at speed yet, so we'll see when we run East in late June. Yes, the 250 is truly a fearsome machine. You should have dropped me a note when you were in town and I could have turned you on to the eateries of note - limited as they are in these parts. I used to live in Wake County, so I feel your pain. Michael was great in checking my ECU and getting me parts in a quick, expedient manner - I love that guy (no homo) - I talked to him on Wednesday afternoon and had my ECU and parts by 8:30 the next morning. Other than that, they weren't able to figure out the problem over the phone. Still working on getting Dugger out here..... (Message edited by Stirz007 on May 29, 2013) | ||
| Jdugger |
> Still working on getting Dugger out here..... I've got my own parts problems from Hallett. I messed up a rear wheel and my cluster lost the tach needle -- it's just rattling around in there -- I'm trying to get parts for before NOLA. I'd really like to get up there and race, though. | ||
| General_tso |
You mentioned Trackstar in a thread a while ago and I didn't put 2 and 2 together. I met Kelly and Gage at MMP. Good guy. If I find my way out there again I'll definitely let you know. Would love to do a race weekend at MMP but the drive is in the 30 hour range. OUCH! From a Racing perspective Wake's not a bad place to be having 7 or 8 tracks within an 8 hour drive. How do you like the Tooele / SLC area in comparison to Wake County? | ||
| Reepicheep |
First, let me consider a bad crank position sensor. When mine failed on the Uly, it was fairly intermittent (time wise), so it would be fine, then chopping out for a few seconds, then fine. This went on for maybe an hours worth of riding, getting worse, until the bike pretty much would not start or run at all. When the bike was bucking and backfiring due to the crappy CPS signal, the tach would go *up* even though the clutch was still engaged and the bike was slowing down badly. I think that's the dead giveaway for a bad CPS, the tach goes up while the bike goes slower, or the tach goes to zero. I thought to look at this, because the CPS in my Saab had died a few months before, and you could diagnose it by cranking the engine... if the tach didn't register, the CPS was toast. Thats way different then your problem, which seems like a hard stop at 6000 RPM, and seems pretty consistent. It seems really odd that a CPS would work fine up to 6000 on the nose, then suddenly not work much at all. That sounds more like the ECM is doing something... odd. Going into some kind of safe mode because some sensor is reading some crazy value? From an electrical standpoint, the partially broken wire doesn't make sense either. Data can go find on a single intact strand of copper. Though you could have a completely broken wire with the two broken ends touching intermittantly, then "disconnecting" at some mechanical resonant frequency like 6000 RPM. ECM spy is definately your next step I'd say. Make sure all the sensors you can see are reading rationally, scan for codes, look for other hints. Then use the data while the bike is running at that 6000 RPM cliff, and see if any of the numbers go haywire there. The oscilloscope is good for things happening too fast for the ECM to see, like the crank position sensor. But in general, ECM spy is both cheaper and a much broader test. You can probably get the dongle on ebay for $40 or so, and they might throw in a CD with the drivers and software which makes things even easier. Handle the wire carefully, it's easy to break (at least my ebay cheapo one was). And going over every wire one by one flexing them in your fingers would not be a wasted hour or two either. At worst you will have peace of mind. At best you will find your problem, and maybe a couple other problems that haven't manifest yet. Check grounds also, just because the way you diagnose a bad ground is that you have a bizarro problem that goes away when you fix the bad ground.  Check for a cracked ECM as well (try and wiggle the connectors and see if it is better or worse). That's the best I have at the moment. Wish I was closer... | ||
| Stirz007 |
Reep - Thanks for the feedback. Since last post, I swapped out another race ECU during practice at the track - same symptoms, so I'm thinking the ECU per se is not the issue, although the idea of a funky signal sounds right. I've checked continuity and resistance of all injector and coil wiring and they all seem to be relatively close (no weird outlier). Wiggled wiring as much as I can without actually dropping engine to get to engine wiring harness. I've double and triple checked ground connections, but will go through ground wiring again to verify continuity. ECM spy is likely the way to go, so I'll start the acquisition process. Dry rev to 6000-plus makes me a bit squirmy, though, as I don't want the beast to grenade in my garage - but I may have to do what I have to do to get this sorted. | ||
| Reepicheep |
No kidding, I'm not squeamish about being near machines, but when they were winding up my 9sx to 7200 RPM on the dyno, it was pretty terrifying. I've not done it, but you can log the ECM data as well, so if you had a small laptop in a backpack you might be able to get live data from an actual ride. | ||
| 1125rcya |
I had major power loss and found that my injectors and intake manifold were real, real, really real dirty! I also had a leak in my rear head! Whoever I paid to do my last valve job didn't seat the the seal properly and tried to use silicone to seal it. Just a small bit of oil was weeping from it.  | ||
| Stirz007 |
Mystery finally solved (I think). Broken cam follower on one of the rear intake valves. Apparently, the 1125 runs pretty good on three intake valves until you get to about 6000 rpm, then runs like crap. It appears that more was missing than immediately found......  | ||
| Stirz007 |
And... the following outcome. Not one, but both followers were broken. Somehow, one managed to stay put. All pieces accounted for...Replace them and go racin'  | ||
| Stirz007 |
After replacement of cam followers, the bike made really loud valve clatter noise, so I shut that project down for remainder of 2013 race season. This past weekend, I pulled the engine and pulled rear head. As I was disassembling cam assembly, I realized that the cam sprocket had shifted about 10-15 degrees from where it should have been. Visible marks were on the sprocket where it had rotated on the mounting bolts and the sprocket witness mark was not parallel with top of head at TDC. This led to the intake valves barely contacting top of piston, thus causing cam followers to break, then the loud clatter when I replaced the followers and fired it back up. Moral of the story - make sure cam sprocket is tightly affixed to intake cam. |
