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Problem with my aprilia rs yamaha yzf r125 swap

169 Views 1 Reply 2 Participants Last post by  NorthCust
So here is the problem this is a yzf engine with 150cc it seems to run great but the problem is that when you give little gas it dies but once u give more or leave idle it runs normal what could be the problem do i need a powercommander or something?
Heres a video of it for context: Problem video
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whilst it's a bad idea to do so, people can and do run 150/180 kits on stock fuelling so whilst my knee-jerk reaction is "it's probably the fuelling" (e.g. pcv or similar needed) normally a bigger cc cylinder will still run on stock fuelling. It'll sound sh!t and you won't get much power but it ought to run.

So yes the fuelling may be a contributing factor to poor running, but it shouldn't really die like that just based on having a bigger cylinder.

Did this engine run before? as in is it known to be ok?
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