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Hard to start in cold outside temperature

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I think you guys must be sick of hearing the same stuff about DRZ400s, but I am really struggling here. I've had this a few months now and it's brilliant, been all over the place on it and not really had any issues, apart from it's near on impossible to start before work in the morning, but starts first kick after work. It is between -2 and 4 degrees C in the morning and 10-18 deg C in the afternoon.

It's a 2008 S with 3x3 airbox mod, K&N filter, Dynojet kit and standard exhaust, 11000km on the clock.

I had the carb in bits this week, I set the kit to exactly what the Dynojet kit says, needle 4th clip from the top and 142.5 main jet with fuel screw 3.5 turns out. It runs absolutely perfect apart from starting, I am currently 2800ft above sea level but do a lot of riding in the mountains and had no issues anywhere apart from starting.

I put a new NGK plug in yesterday and checked the valve clearances and they're all perfect, i'm getting fuel and i've tried it in the PRI setting and ON on the petcock so I guess the vacuum system is fine, i've replaced the vac line from the carb this week as well and everything seems to be working alright.

On the plus side, kicking it over 15-20 times certainly warms me up in the morning! The electric start works, it turns over quickly but I don't use it because i'm trying to keep the neighbours happy first thing in the morning! With the electric start though, even when it's been running and it's hot it doesn't always want to start using it, but starts first kick which is odd, i've not had it on a set of leads from my car because it won't start by kicking it in the morning so i'm imagining the battery is all good.

Choke doesn't seem to help...if anything it seems to start better with no choke?

Any help would be greatly appreciated!

Thanks,

James.

 

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Edited by JamesE36

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By the jet sizes I'd say he has the bsr , no accel pump so does nothing to twist the throttle . What pilot jet size ? normal is 22.5 , I had a 25 in my bsr for winter before I switched to the fcr .

Check your starter jet , I've even drilled a few out if you can't wait to order one , but only .001-.003" bigger at a time and try . It'll make your "choke" add more fuel with the same amount of air as normal, thus richer .  You shouldn't need choke when motor is hot even if it was -20C ,so not sure where that fits in , seems it isn't getting good vacuum through the ports when starting to pull fuel in quickly.

 

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Edited by jjktmrider

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On 10/21/2018 at 6:07 PM, jjktmrider said:

By the jet sizes I'd say he has the bsr , no accel pump so does nothing to twist the throttle . What pilot jet size ? normal is 22.5 , I had a 25 in my bsr for winter before I switched to the fcr .

Check your starter jet , I've even drilled a few out if you can't wait to order one , but only .001-.003" bigger at a time and try . It'll make your "choke" add more fuel with the same amount of air as normal, thus richer .  You shouldn't need choke when motor is hot even if it was -20C ,so not sure where that fits in , seems it isn't getting good vacuum through the ports when starting to pull fuel in quickly.

 

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You're right it's a 22.5, I don't have any other pilot jets unfortunately but I could find some if needs be.

I had all the jets out and 'cleaned' them (probably not thoroughly enough, but everything seemed clean).

This is driving me absolutely mad, I went out this morning to ride to work, I must have turned it over on the starter for 2 minutes on and off, and kicked it 30 times and absolutely nothing. Luckily i'm fortunate enough to have a truck as well at the minute so I drove to work instead. I got home from work, jumped on the bike and it started first kick.

I've removed the battery (tested 12.83V) tonight, i've put it inside the house tonight so it stays warm (no chance of having the bike inside unfortunately) so i'll put it back on tomorrow morning and give it a try to discount a crappy battery that's getting killed by the cold. If there's no joy with that then i'll do the same with the ignition box...if there's no luck with that then I really do not know what to do next! 

 

James.

 

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See if the moisture in the air makes a difference . If the battery is cranking fast enough , I had one bike that when left outside wouldn't start in the morning 4am , crank and crank and nothing . come home and it would fire up instantly . If I left it in the garage it would start in the morning . One day I went to work and stopped for some food at a store and it restarted then shut off , not to start again. Ignition coil , replaced it and no more issues .

 

.

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Oh, yep no accel pump on Mikuni carb , Can try tip bike over with throttle open, gas should drain out over flow hose, and into intake richer. Have done this on my other bikes saves a lot of  kicking !
Would those other bikes happen to be 2 strokes? Not sure that will do much for the DRZ and BSR.

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All the older cars I had you just pumped the gas pedal to squirt fuel down the intake for winter time ,first pump set the choke automatically in the carb, no need to dump gas , well maybe if it had sat for 8-10 months or more.  It was common for people to flood out the fuelies when they first came out because they were used to stomping the pedal while cranking , a no-no with the throttle bodies .

 

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Edited by jjktmrider

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Yes , pumping the gas for the accelerator pump to squirt gas down the throat  also sets the choke , but on those real cold days -20F sometimes they just would not start then had to spray starter fluid down carb and get a boost so they would turn over fast enough to start .

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Try a 25 PJ, 3.5 turns out on idle mixture runs the risk of falling out.  Be sure to peak your idle.

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You could try installing a carb heater

 

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First determine if it needs more fuel to start on those cold mornings.
Do you have a propane torch? Take the air filter out and spray some propane into the carb while cranking in the morning.
If it still struggles to start, you have an other problem.

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The first question to resolve, after finding and correcting any vacuum leakage, is whether there is a shortage of gas or too much. A bit of experimenting will clarify what the engine needs to start cold;

Are you setting the choke full on?

When it does fire up in the morning.....are you opening the throttle wide....as in clearing a flooded condition?

Is the idle speed set too low....it fires just a tiny bit, then dies quickly?

Does Bucket list's plan with the propane work when cold?

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I think I’ve found the issue...
3E63992F-712F-4A98-8E87-DB165901F0D8.thumb.jpeg.0d2706b4d478f126a025d78d88ae95e1.jpeg

Pretty common unfortunately with aftermarket stators they don’t get the wire length or grommet location just right and you get a loop of wire big enough to rub on the flywheel

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