[Racing_joe66]

Ok the sled starts right up and idles perfect. from a dead stop or a slow stop the sled will rev right on up to 8000 grand and move the sled then after like 2 seconds the RPM drops and the sled bogs down to like 5000 rpms like it lost a cyl. Out on the trail I can only get 6000 rpms out of it. and occasionally very occasionaly will it rev past the 6000 and actually move!! this is what i have tried:
changed the TPS didn't help
changed the computer didn't help
changed the plugs didn't help none of them were fouled or wet
the computer isn't flashing any codes or anything.

does anyone have any idea what it could be? as i am lost as to what it could be!!!

thanks

 

[2manyhobbys]

Have you tried a different stator assembly and or exciter coil? (all behind the flywheel) Either can cause power loss at high rpms. If that doesn't work I would still suspect the processor...unless it's NOS. Three years ago I had a 500 EFI that did all sorts of weird things. Changed/tested every electrical/ignition and fuel system component...even took the entire wire harness out and tested every wire individually. I wasn't about to give up...but suicidal thoughts began to creep in. Finally trashed the entire EFI system and converted it to 38mm Mikunis. It ran beautiful and my wife rode it all next winter without a single problem. Sold it to a young kid and it's still going.

 

[Racing_joe66]

I tried 3 computers and the same problem and 1 was brand new. The TPS I tried was even brand new. As when Ive had an issue like this before its been a TPS. Man you did everything to the 500 didn't ya!!! I love my EFI's but when theres a problem like this it sucks. I will have to pull it apart tomm and change the stator assembly. But how can that cause it to only do that at higher RPM's??

thanks

 

[2manyhobbys]

I'm not going to guarantee the stator or exciter coils are bad...but it's something I experienced in the past. I had two RXL's in the past and I loved 'em both...never had any problems. But that damn 500 gave me a real reason to drink. Good Luck!

 

[Racing_joe66]

Thanks

 

[Ugly_old_Poo_kid]

Did you change the fuel filter, check the fuel pressure?

Could also be the spring in the primary clutch..

 

[xlts-and-zrts]

dido, i would check fuel pressure, sounds kinda like the filter could be pluged or pump is getting weak.

 

[baldur]

sounds like a clutch problem

 

[Racing_joe66]

I will check the fuel pressure. How would you go about to check the clutch?

 

[Racing_joe66]

Any other suggestions?

thanks

 

[Ugly_old_Poo_kid]

Pull the spring, and make sure it has the proper tension. If it's weak, the primary clutch will shift out too quick, and you'll never reach the power band.

 

[Racing_joe66]

The thing is it will reach the power band for like 2-5 seconds and then bogs down to 5000 or 6000 rpm. so it reachs it, but acts like it looses a cyl or all power and you can even hear the engine sound different.

 

[Black_Storm]

I had something kinda like that happen I am not sure what the rpms were doing on mine but it would bog down and the engine sounded different. When we got looking all three pucks on my secondary clutch were worn out and started scoring my helix.

Not sure if yours has a roller secondary or not but someone will hopefully correct me if I am wrong.

the pucks are cheap and pretty easy to replace.

good luck

 

[oneski]

Could be just a Bad plug sounds like a Bad cylinder though.
Does it rev to 8000 during a no load condition like on a support stand?
If it does, Apply the brakes put it under load see if clutches are shifting.
Mark clutch sheaves with a black marker see if it gets rubbed off it should be gone after a run.
I guess you dont have EGTs, but you could get high temp markers, if you rub it across the exhaust flange pipe only the working cylinders will melt it quickly, and at the same time.

 

[Ugly_old_Poo_kid]

If you can go on and off the throttle and get more rpm's out of it, it is definitely the clutching.

 

[Racing_joe66]

I haven't tested a no load situation yet. I will try that today or tomm. Thanks

 

[92Indy500EFISP]

I haven't tested a no load situation yet. I will try that today or tomm. Thanks

Sounds like a Clutch problem for sure. Its sounds like the secondary clutch is opening to soon and not allowing a full shift out and bogging your engine at the 5000 rpm. I am guessing the secondary clutch spring is weakening. I saw a spring chart at the beginning of the Polaris forum I think its a sticky. I would start there a new one is pretty cheap.