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VStar650CL »
https://forums.nicoclub.com/vstar650cl-u299034.html
Tue Dec 13, 2022 6:57 am
Rock and Nissan NA websites won't have interchanges for a JDM part, but with items like coils or brake pads the differences are usually in manufacturing and qualifications and not how the part functions. Coils are actually "emissions" parts and the USDM version probably needs to meet different (and likely more stringent) quals than the JDM part. Everything JDM is always a crapshoot because of the dearth of documentation, so I'd never vouch 100%, but in this case 99%. For the most part, coils are coils as long as you don't mix and match them.
De-carboning is very easy, just make sure you have a spare spark plug on hand (I'll explain why momentarily). This is the method I use for my DD customers, I do it for them with every new air filter to prevent major buildup from ever occurring. Put some ATF (any kind) in a squirt can or bottle cap. Warm the engine thoroughly, then pull the brake booster hose loose and cap it with your thumb so the engine doesn't stall. Have an assistant hold the throttle at 3500~4000 RPM and put a teaspoon or so of ATF down the booster hose. That's all there is to it, the cold blanket of ATF vapor will crack the hot carbon and dislodge it, leaving your valves and piston crowns clean. In the old days before catalysts, small block Chevys and Fords could develop carbon on the backs if the intake valves so thick that a valve would stick open. The customer would arrive with a dead miss. When we hit it with ATF, quarter and dime sized chunks would come flying out the tailpipe. If the customer was watching, they'd usually turn white and mumble something like, "Holy s__t, that was in my engine??" You won't see any of that because of the cats, but the cats will burn up the dislodged carbon harmlessly. The reason for a spare spark plug is because in your case, the carbon may be equally thick. When it breaks loose, there's always a small chance that a chunk will get caught between a piston and a spark plug and bend the electrode shut. It happens rarely, but have a plug available just in case.