Jump to content

Cold starts great, but dies as choke is pushed in

Recommended Posts

Having some issues getting my DRZ400SM warmed up. It will cold start great with the choke pulled all the way out. Once the idle drops the bike will stumble a bit and if I push the choke in (to either setting) the bike will die and will then require a fistful of throttle to restart. Once it gets going a bit it idles and runs fine.

This is a new issue and began happening after a re-jet. Wondering what I might need to adjust? Should I leave the choke out all the way longer, or do I need to adjust the jetting, or carb? 

2006 with Moose/DJ jet kit (stage 2 jets), 3x3, full yosh RS2.

Edited by MotardMike1

Share this post


Link to post
Share on other sites

unless its really cold like less than 40F you shouldnt need the choke for more than 30 seconds before it should idle steady on its own .... it could be a few things, i'd start by draining the float bowl and making sure the idle is actually high enough .. then tweak on the mixture screw, try 1/2 turn out/in at a time and see if it makes a difference .. you may want to make sure your oil isnt flooded with fuel at this point, if you have to change the oil to satisfy yourself then do that ... as far as jetting im not familiar with the dj sizes so make sure you got those right for your pipe ect .. after all that i'd suspect something actually wrong in the rebuild of the carb, dirt ect, something out of place ..

Share this post


Link to post
Share on other sites

My experience in cold weather (I mean really cold, well below freezing) is that you the bike needs a really long time to warm up. I don't have an exact time, but I find that the best thing to do is start it up using the choke and push the choke in after you start driving. It takes several kilometres (or miles) before the bike will idle without choke.

Share this post


Link to post
Share on other sites

It's possibly jetted a bit lean and cold blooded . The odd thing is needing to add throttle to get it started again . I'm wondering if the idle is too low to start with . The "choke" ads air along with fuel so it will run 500-800rpms higher on choke as it warms up (been a while since I had the Mikuni to remember exact rpms). When shutting the choke knob off I always had to push it in slowly or my motor would shut off , don't know why it did but it would 100% of the time unless I went slow each notch till shut off. Try that once , after it has been idling for 30-60sec slowly push the choke in , holding the knob with your fingers so it doesn't snap in, go to half choke pause then shut completely.

 

 

.

Edited by jjktmrider

Share this post


Link to post
Share on other sites

It idles fine once warmed up, and Hot starts are ok. Haven't had a chance to test much since the bike has been stored all winter (carb work was just completed this week) and the weather is not conducive to getting it up to regular operating temps. Basically I don't want to do cold starts and than park it immediately.

The most recent cold start was with temps at 50 Fahrenheit, started up immediately with choke full out, revs began to drop after about 30 seconds, but sounded like it was cutting out so I pushed in the choke and it stalled right away. Cranked and restarted with choke all the way in, but died as soon as I touched the throttle. After a bit it starts to idle fine and once warm it runs great.

Will have to check small adjustments to the mixture screw and starting it with the choke all the way in.

I'm a carb noob, so I am otherwise at a loss for ideas.

Share this post


Link to post
Share on other sites

Ya, it's most likely just jetted rather lean at idle . What you can do is turn the mixture screw 1/2 turn o ut and see how much better it runs , then another 1/2 turn . Next time you shut the choke off , do as I said , push it in slowly , see if it doesn't shut down. Mine would always kill for some reason if just pushed in normally.

 

.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×