| Author |
Message |
    
Tony216
| | Posted on Thursday, May 16, 2013 - 07:39 pm: | 
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I have an early XB12. I've ridden it twice this season and it's become unrideable. It back fires through the throttle bodies really hard. The bike nose dives, bangs through the throttle bodies and then repeats or wheelies.
It ran great at CMP for practice and my first sprint race. Second race, it ran like shit. Twin sprints weekend, second day, ran great, except for minor backfiring through the throttle bodies.
Went to NJMP, ran good in practice and first race, DNF second race. It was stupid scary. On pit out, wheelies after back firing through the throttle bodies and then did it again second lap, fast corner before the bridge.
Just fixed what I thought was wrong, everything looked good. So, I took it for a ride around the block and no dice.
Bike:
Old Hal's bike
Last night we changed the intake gaskets, an exhaust stud and plugs (one degree colder than stock, NGK).
About 10 sprint races on the following:
3 13/16" 10.5:1 Wisecos
Valve springs, valves and seats
Other older stuff:
Millenium jugs
Stock cams
Beson exhaust
08 cases/crank.
I was hoping to race at Summit next weekend, but I think that's done. |
Reepicheep
| | Posted on Friday, May 17, 2013 - 08:12 am: |
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If it wasn't a race bike I'd be thinking maybe Cam Position Sensor. Got a portable scope you can put on there while its running badly? |
Tony216
| | Posted on Friday, May 17, 2013 - 10:04 am: |
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Only runs bad under load. I was talking to a friend last night about it. He had the same issue with a fuel pump. Unfortunately, I can't get the thing out to check it. |
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Troubleshooting (Poor Starting/Running/Handling/Ride Issues) »
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Back fires through the throttle body at 5,000 rpm XB12