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never thought I'd be this frustrated

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05 YZ250F, about 13-14 hours novice to slow intermediate riding. Started (note past tense) easily 1-3 kicks never a problem, never ever used hot start, choke cold, no throttle, no choke ever when warm. Pleasure.

Put on an FMF Ti4 slip on and took to dealer to have valves "checked" and jetting from one of their knowledgable types and a zip-ty installed. I have no idea of what the stock position of the factory fuel screw was. Dealer dude said valves were fine, no adjustment necessary, which is probably true. Bike ran great, idled just fine, but did pop alot on decel (lean). Only real adjustment is that a one richer pilot was installed, a 45. Now bike is very hard to start. Also, if necessary like after a fall, how do you use the hot start? The bike will actually start with one kick when its warmed up....sometimes. Sometimes it takes 20 kicks, even after warm, like stopping in the pits to rest for a few minutes. So, I guess I have 3 ??'s. 1. Would the richer pilot make the bike hard to start? 2. How is the hot start employed? 3. How do you "tune" the zip-ty fuel screw? Thanks, Mark

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Yes if you are too rich on the pilot it can make it harder to start. I can't answer why your dealer changed to 45. Stock 42 works great for me in N. CA weather. Nothing wrong with having to use the hot start when the bike is warm. That is what it's there for. Just pull it in when you kick it over and release it when it starts. To adjust the fuel screw, I'd start at 1 1/2 to 1 3/4 out and test it. Then adjust in 1/4 turn increments as needed. Screwing out will richen, screwing in will lean it.

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swap the plug out. The rings let lots of oil past when you are breaking it in and that causes the plug to get a carbon glaze on it making it hard to start.

turn the fuel screw all the way in and then back it out 3/4 of a turn (factory is 1-5/8 turns out it's in the manual that came with it). try that and see if it helps. the way to set the screw is by turning it out an 1/8 of a turn at a time until it just stops popping on heavy deceleration. turn it an 1/8th haulass and test, then turn another 1/8 if it still pops. Do it when it's fully warmed up too.

You should have gotten 2 main jets with the bike when you bought it, put the larger one in. The Ti-4 pipe flows more exhaust than the stock pipe and needs to be jetted up for it. You may actually need to go one bigger than came with it too.

using the hot start is a learning thing. If I cant get the bike to fire within 3 kicks, I try without it for 3. Try cracking the throttle open 1/8th - 1/4 turn and kicking it too. If the plugs wet from dumping it this seems to help considerably.

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Thanks for the logical reply....didn't think about the plug since it was never hard to start before, particularly since it was coincidental to just changing to a richer pilot....2-strokes make it very clear when time to change the plug. The thing that has been most frustrating was that from brand new (2 months ago) until taking it in for the "work", it was ALWAYS a 1-3 kick starter, cold/warm-choke/no choke. Will give all a try, Mark

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I tried changing my pilot jet to a 45 and it ran like crap and wouldn't start unless I kicked it a million times. It ran way rich down low and I couldn't get it tuned in with the pilot screw. 99% of the time the pilot jet is never changed from stock. More commonly on our bikes the correct leak jet and main jet and a the correct clip position on the needle gets it tuned in perfectly. I would change the pilot jet back to a 42 and make sure your main jet is fatter...try a 180 and go up from there since you have a pipe. BTW a JD jetting kit would be a great investment. :naughty:

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