Aight let's hear how many modded ex's are no starting mfrs ?? Redik

[Thumpin440ex]

I've been dealing with this happy horse **** since this bike was new and stock.. it refuses to start when it's cold out.. Now after I have done the big bore/head/stg 3 cam/450r carb it still refuses to start when it's cold.. I didn't ride it for almost 2 years.. Went completely through carb, and bought a lipo battery with 275 cca, still when it's cold it does not want to start. I've built plenty of engines and never have had a rotten thing as much as these ex's. I need to find a way to hook the choke up but there isn't a way to get a lever on the choke with this carb.. yes valves are spot on and carb is spot on with jetting, just went over all of that. I'm planing on going to HM trails mid March and I don't need this thing not starting when it's cold. Anyone else out there have a pita bike trying to fire up when it's cold ? RANT OVER HAHAH

[BlasterEaten250]

I'm assuming you have tried installing the next size larger pilot jet?

[Thumpin440ex]

The bike is jetted right.. 52 pilot.. only thing I see today after looking down the throat of the carb was a small section where there is a low spot in the boot ( OEM ) between the head and carb.. Fuel seems to be laying in there instead of being fed into the actual head.. Even blipping the carb the accelerator pump can not spit the fuel over this area.. Pulling it shortly and just going to trim that section out, port match the other side while im at it.. Only thing I can see that is a real issue.. Other then the cam having to much over lap where it is actually blowing the fuel back out of the head when cranking ( which is also possible ) Intake and exhaust valve being open at the same time.,.

[DragonGunner]

Changed the plug or at least pulled it to check for spark….? If spark, put some gas down plug hole and put plug back in and see if it fires….if it fires but then dies then fuel not getting there from carb.

[Thumpin440ex]

Changed the plug or at least pulled it to check for spark….? If spark, put some gas down plug hole and put plug back in and see if it fires….if it fires but then dies then fuel not getting there from carb.

100% getting spark. This is a cold start issue, as in cold weather. Nothing when it is warm. Plug is butter looking, as in running perfect .. I'm going to relate this to a vacuum leak or a issue where fuel is not getting to the head.. in the process now of port matching the boot to the carb and the head to the boot. Only reason I can physicslly see where fuel can't get into the head..

[DragonGunner]

100% getting spark. This is a cold start issue, as in cold weather. Nothing when it is warm. Plug is butter looking, as in running perfect .. I'm going to relate this to a vacuum leak or a issue where fuel is not getting to the head.. in the process now of port matching the boot to the carb and the head to the boot. Only reason I can physicslly see where fuel can't get into the head..


I just saw you have a Sparks CDI…..think I may of found the problem. I have a WB CDI since about 2001 on mine and when really cold it is impossible to start. I saw this as it got colder and colder out until one day so cold it wouldn't anymore….I put the stock CDI in and it fired right up. So in winter I put the stock cdi back in……once its warmed up you can put out the other cdi in and it will take off also….until it sets and gets cold again.

[witech]

I agree on going back to the stock cdi box.

[Thumpin440ex]

This is exactly what I have come to the conclusion of.. I have basically eliminated every other thing.. Only other thing I am thing is a weak coil.. Going to grab a stock cdi at the shop monday.

[witech]

We used to ride with a guy who had the aftermarket cdi and it needed to be tow started in the winter. So after a while he got sick of it and went back to stock.

[Thumpin440ex]

Any of you guys running open air boxes ? I have eliminated everything. I am thinking the pilot jet is not enough.. it's a 52.. Going to try a 54... This ***** is just ignorant in the cold.. I run no lid, just a uni and a cover on it..

[DragonGunner]

Any of you guys running open air boxes ? I have eliminated everything. I am thinking the pilot jet is not enough.. it's a 52.. Going to try a 54... This ***** is just ignorant in the cold.. I run no lid, just a uni and a cover on it..


I run open air box…however in cold winter when the air is much denser I have to put the a lid on with a few 1" holes in it….its just enough to cut down on the air and that way I don't have to re jet for winter months.

[Blodg]

My 416EX with 450R carb and stock 48 pilot starts right up when it's cold out after I give the throttle 3 or 4 pumps. Now since there is no choke it will often stall after a few seconds when it's really cold but the instant I hit the starter again it starts right back up. I may have to do this 2 or 3 times and she is running.

[honda400ex2003]

while mine is often times harder to start in the winter, it is because it is pretty lean. If i put my lid on, that helps a bunch.

I am running a 58 if i recall, but man it has been a long time since ive been in my carb.

its certainly worth getting a few bigger pilots and trying it out. now that it is warmer, it probably wont be a big issue. my 450 carb is super finicky... ive often contemplated just putting my stock one back on and calling it a day, its much easier to tune when the carb is the limiting factor instead of the engine.

steve