When to re-jet
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After fitting a full depp system and turning the power valve so it’s working as it should, should I be re-jetting the carb if so what did you find works best? Currently it cuts back at top end after 6000rpm. I’m just wondering if this has something to do with it??
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i turned the powervalve quite a long time ago so it was flush with the port and it ran fine with plenty of power for 5 or 6 long rides after that so I'm guessing that's set fine? it just recently its starting cutting back around 6000rpm and really spluttering. i haven't messed with any jetting on it thats all complete standard still. i did notice the spark plug was slightly black with a bit of wet oil but that's about it. is it worth just putting a spark plug on that burns hotter? current one is a BR9ES
i got the bike completely standard as a french import with 8000k on the clock. i put a full depp system on it, have turned the powervalve so its flush and moved the reed switch nothing else has been touched.
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@dtlee Depends what you mean by "turned the powervalve flush with the port".
The powervalve needs to be setup appropriately, not just abitrarily moved, unless pinned. To see if it's the PV I usually just pin the valve in the open position and disconnect the servo. If it's running sweet past 6K after then you know that you've messed the PV settings.
If not, then you know the problem lies elsewhere.
Is it jetting? Unlikely, the bikes default jetting is spot on.
Always Originate, Never Pirate!
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@calum cheers ill give that a try first, see if i can rule one thing out at a time. i want to mess with as little as possible as my mechanical knowledge is near nothing, although i di like to try and understand how it all works and learn for future.
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@dtlee Take the exhaust off, turn the ignition on and the powervalve should automatically go to its most open position. If it's not, then you'll need to adjust the cables and switch the ignition on and off to reset the valve. Repeat until the valve is completely flush with the exhaust port. Then disconnect the connector block that powers the valve.
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Don’t change the plug temp. Find out and fix the fault. Check your filter isn’t blocked. Black and wet indicates rich running, not burning all the mixture. Make sure the choke is closing properly. Rule out these then if not fixed check ignition...
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Thanks for the reply’s, I’ll pin open the powervalve and check that and while I’m there I’ll take the carb out and give it a clean as it’s not been taken off in the two years I’ve had it, the bike doesn’t get a great deal of use. It has a new air filter in it so that should eliminate that being a problem.
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@dtlee the bike doesn’t get a great deal of use? Maybe that's your problem as it can only take a few weeks for the fuel in the carb to gum up and cause a partial blockage and even more so if you premix. maybe you just need to give all the jets a good clean. If you know it won't be used for a while it's good practice to turn off fuel tap whilst still running and let it run out of fuel so the carb is empty.
