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Discussion Starter #1
I have a question about the big bore kit 686 for the rhino. The rhino came with the kit installed by a shop or ? Not for sure ? The machine runs great with plenty of power etc.
My question is, does the big bore kit cause a hesitation while starting due to the extra compression? When I try to start it and pull out the choke during a cold start it basically doesn't even crank over, push the choke back to normal, it spins ok but still has hesitation but does start.
just thinking out load ! Decompression was installed wrong or not working or timing is off a tooth? Getting ideas before digging in. Trying to enjoy it before I tear it down.


The second owner didn't know much on the history of the machine except for the big bore was installed with two brothers exhaust with stock jetting.
 

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Mine does the same thing ever since I've owned it (stock 660). I did the grounding mods on this site and thought it cured it, but still does it. Can't help, but your problem isn't an isolated one. Others in the know will chime in.
 

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Discussion Starter #4
No primer bulb yet ! I do have the high flow Mikuni fuel pump, I just didn't do the clear tubing upgrade.
Quick question on starting, do you have a problem cranking while pushing the gas pedal ? It doesn't want crank over as well and hesitates or stumbles, let off the gas and it cranks ok.

Thanks again........
 

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Engineer
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If you have a stock carb, pushing the pedal isn't going to help. I switched to an HSR pumper carb, big change for starting. I pump the pedal twice before starting, puts raw fuel in the manifold. Starts on first turn, even in 10° weather.
 

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Discussion Starter #6
I'm going to try the primer bulb first, had a brain fart on the accelerator pump not being in the rhino carb.
 

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if it doesnt crank its not a fuel delivery issue my friend....that is either a tooth off on the camsprocket or the drive sprocket on the crank slipped, or the cam decompression pin has had its backside ground too far during a cam swap and the pin isn't opening the valves enough or the pad where the pin rides is too worn and isnt opening its valve...they will run a tooth off all the time,advanced or retarded....or you have a week starting system or you have a high compression piston...eitherway you need to verify some specs...
 

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Discussion Starter #8
Awesome, so I'm not crazy !! I guess its time to tear into her and find out what's going on, the rhino runs good and the starter, battery and relay have been replaced, I guess that lagging start just bugs the crap out of me. When my YZ 450F would have hard starting issue, it was time for a shimming.
Thanks again everyone !!
 
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