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Bike won't cold start without long choke

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So I recently bought an 06 DRZ400SM, 10,000 miles (it was clearly left in storage for years, tags are 4 years old) brought it back home, and wouldn't start the next day. It reeked of gasoline, so I checked the dipstick which smelled like gas too. I replaced the leaking petcock, cleaned and pine-soled the carb and jets, replaced valve seat/needle/oring, put it back together and changed the oil.

Now again it won't start unless I have the choke out and it warms up a little bit. If I pull choke out, start, and put choke in it dies immediately. I've tried playing with the idle screw and I can sometimes get it to start cold. On my previous DRZs I've always been to start without the choke, what's the cause of this? I ensured the pilot needle was clear when I cleaned the carb.

Other things to note are a little roughness in the powerband when WOT (but perhaps unrelated).

My next steps are to seafoam and valve check. Can you guys offer any advice or suggest what might be going on?

Edited by Rekmore

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I suspect the pilot circuit could have a partial clog or the pilot jet is still fouled.I prefer to replace jets when they are fouled instead of cleaning them,they are only about $6 or so for genuine.

Starting stone cold without choke is usually a sign of an overly rich pilot circuit.All 3 drzs that I've owned had to be started using the choke whether it had the Mikuni cv or a Keihin fcr.

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I use the choke and let it stay pulled out while I put on my helmet and gloves. Or around 30 to 45 seconds. Usually after that it retains normal idle and is ready to go. 

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That is the way every motorcycle I have owned works.   Pull choke, ( really its an enrichener)  start bike, let it warm up until idle stats to go high, push choke in half way for a min or two and then all the way in .

Some engines need longer than others to warm up.  Temp and quality of fuel plays a role also.

Don't worry unless it will never start with choke, or will not run without choke

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Awesome thanks for the info guys, this is reassuring news :thumbsup: I assume rejetting with the 3x3 mod and running it a little rich would allow for quick starts without choke? Would there be any downside to this?

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As said above, the choke experience you're having sounds normal for  DR-Z400S or SM. If you're going to put in a jet kit, I highly recommend the James Dean Jetting Kit. I have installed 5 of them following the instructions,  and all 5 worked great. Be sure to buy the Extended Fuel Screw from them too.

Edited by jackpiner57
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A slightly richer jetting actually make the most power , but too much and it tends to wash the oil off the cylinder walls and wears more . It does help starting . A  correct jetting will need choke (or a few accel pump squirts) to start and depending on ambient temps alters the length of time the choke(fcr) /enrichment (CV/CVK) needs to stay out . Too lean gets best mileage but a lazy power output and will need choke/enrichment for an annoying length of time .

 

 

.

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21 hours ago, Rekmore said:

Awesome thanks for the info guys, this is reassuring news :thumbsup: I assume rejetting with the 3x3 mod and running it a little rich would allow for quick starts without choke? Would there be any downside to this?

Yes, a rich idle circuit can make it really hard to start when it when hot, especially with a CV carb. And no hot start lever to lean it out. I set my carb. up with a lean pilot and mixture screw setting and even drop the float level 1mm for good hot start manners. So what if we got to use the choke for a minute.

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