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Starting Problems - NOT jetting related

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I'm having troubles starting my 08 450 SX-F. My problems started a few months ago when the temperatures dropped in the 30s. During this same time I had battery issues which turned out to be a bad battery, so I attributed my starting problems to a weak battery, improper jetting, and too-thick oil for the cold weather.

Fast forward to today; it was in the mid 50s outside, just installed the JD jet kit, an iridium plug, fresh oil change, and a brand new YTZ7S battery. My bike refused to start with the electric starter. I cranked and cranked, off and on, until the battery was almost dead. Even when the battery was fresh, it sounded like the starter was struggling to turn the engine.

I put my bike in gear and held the clutch in, pushed the bike, and pressed the start button (while pushing), it fired up immediately. The drag of the clutch was enough to give an extra boost to get the engine turned over.

I recall reading something about issues with the automatic decompression mechanism on the 08 450 SX-F, is this correct? I searched and couldn't find anything, but this sounds like it could be the problem. The starter is struggling to turn the engine over. Bump starting is not a problem; I can catch it in gear and it fires up immediately.

My other thought is that I did some damage to the starter the last time I was having battery issues; by cranking it over too much, could I have damaged the starter? How reliable/durable are the KTM starters? Are there any tests I can perform to determine if the starter is no good?

What about valve clearances? I haven't checked my valves yet (probably have 35 hours on the bike since new)

Now that I think about it, my engine always seemed difficult to turn over, ever since it came off the showroom floor.

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Apparently the decomp issue was only on the EXC/XCW single cam engines.

I'm down to valve adjustment (valves too tight - decomp not fully releasing) or electrical/starter problems. I've heard a few stories of bad connections caused by mud/water getting everywhere. Either that or the new battery is bad.

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Check the valves. If they check out then check all the connections thoroughly. Every last one of them.

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I just found a loose ground connection on my starter relay which was creating all sorts of starting issues. Weak turnover and no re-charge of the battery. It would fire up with a jump-pack real well though. Even wore out a new battery in no time trying to start it. The loose connection makes perfectly good sense now I think about it.

Good luck, I feel for you...

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I've had some starting issues subsequent to re-ringing my bike. Turns out I was flooding the bike. The new rings with the better seal put a stronger signal on the carb causing easy flooding. Anyways, try this for a test, hook up jumpers from your car, DO NOT start the car. See how she cranks, it should turn over plenty fast (and start readily). If it doesn't you may have a starter issue. I finally figured out that I was flooding when the bike started after I pulled the hot start while the choke was on. In my situation, the bike would fire cold w/ the choke + 2 throttle cracks. If it ever flamed out cold, it would not want to restart (until I figured out to use the hot start to clear it out). FWIW, I also had my pilot jet fall out recently. The bike just died and I thought I blew it up. I ran the batt down trying to start it and eventually jumped it w/ my car. The bike still didn't want to start until I held the throttle wide open. It finally started but ran like it jumped a tooth. It runs perfect now! Also, it's worth checking but, I wouldn't count on the valves being bad. Mine were perfect after 55 hrs of pure MX racing.

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I solved my starting problem, and I think it was a combination of issues. I went over all electrical connections and there was mud and corrosion on the connectors for the starter button, on the fuse for the starter relay, and the main ground connection was a mess. I cleaned the connections with some sandpaper and used dielectric grease when reconnecting. The starter motor sounds like its spinning twice as fast now! When I first started it , the bike was on the stand and (accidentally) in gear, and it still fired right up! I don't think the starter ever sounded as powerful as it is now. I can finally start the engine with the bike in gear (clutch disengaged of course).

I also left my battery on the charger/maintainer all week so it was topped off. Its very possible that the new battery wasn't fully charged - Chinese quality!

I'm thinking the ground was the main issue. That would also explain why it never seemed to recharge properly. Even with my original Yuasa battery, I was having problems.

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I am new to the thumper bikes (I rode 2 strokes in the 60's) I recently purchased a 06 450XC-G. Aside from being only 5-8" (in top physical shape--deadlifting 330lbs I have a $%@time starting my bike!! I was recently told that I should never start it with the E/S when cold (should start with one kick)?? can someone teach this "old dog" a new trick, like do I choke, crack throttle? find TDC? or what works best??

Thanks--

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have you read the threads about jetting the carb, JD carb jetting kits are well worth money. My starts better hot and cold after installing one.

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E-start is fine on a cold engine - in fact it's the only way to start a SX-F!

The only real trick to starting a thumper is to never touch the throttle when kicking (or using the magic button) EXCEPT when the engine is cold, then you give it a twist or two of the throttle before kicking or e-start - your accelerator pump squirts a stream of fuel into the engine which it needs to start since the fuel doesn't vaporize well in a cold engine. Just don't give it a handful of throttle every time you kick (like you do on a two stroke) or you'll flood the engine - this happens because the accelerator pump squirts fuel every time you twist the throttle.

My lesson learned is that good electrical connections are required for your bike to start properly with the e-start. I was talking to a friend who rides a kfx400 (yes I associate with 'that' kind on 4 wheels) and his bike was sputtering and just wouldn't run smoothly. He had bad connections in his ignition circuit and it was causing the bike to run like crap. He too found corrosion and mud/dirt/rust on most of his connectors. I'm hoping the dielectric grease will help prevent this. An even better solution would be a more watertight airbox - all the KTMs I've owned (08 450 sxf and 04 250exc) have muddy airboxes which doesn't help when your battery and starter relay are right there.

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Here´s a thing to do after every wash - Blow all the connections dry with compressed air and give them a shot of WD 40 once cleaned and dry. After every 10th or so wash every connection should be checked and re-lubed with die-electric grease.

I always use clear silicone on ALL el. connections (and ,of course , die-el grease) to seal them before i ever ride a new bike.

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This bike is hard to start when cold, I had a 2006 RFS 450 never had starting problems. I have jetted the bike changed the battery, does not matter, these bikes are hard to start when it is cold. The XC4 motor rips in comparison to the RFS but starting it is tricky. I think the bike has a tendency to flood and then good luck getting it going.

Tips when starting the XC4 do not touch the throttle at all...It helps.

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My RF4 is not a problem to start at all when it's cold. No issues whatsoever, now that I have correct jetting and my electrical issues have been straightened out.

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That´s exactly what i mean when i tell people "fix the jetting" and "get a JD kit".

Now you know what i mean. Once jetted correctly (and i recommend going one step richer on the blue needle on sea level to 300 feet / not overly hot weather from the rec. setting) the bike not only starts easily ,cold & hot , but it also pics up considerable low end/mid range power and torque.

Keeping all the elec. connections (and i don´t mean just connections for the e-start) in working order should come as second natur to any bike owner.

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I am going to start using die-electric on my connections, trick is finding all the connections? Few by air cleaner, few up front by steering stem, after getting the tank an seat off, maybe I can find most of them.

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I was afraid of not being able to find all the connections, but its really easy. Start to finish took a little over an hour. Remove the airbox cover on the left side, remove the seat, and remove the tank and you'll see everything. The SX-F is pretty simple.

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