2015 YZ450F a b*tch to Cold Start

[Dpre]

Hi Guys,

My 2015 YZ450F (relatively low hours) has always been a pain to start when cold and my right knee is rebelling. Specifically anything below freezing. I am forced to put a space heater on it in the mornings and watch the thermostat when I stop for lunch, forcing me to restart multiple times so as to not be stranded. I also run a hose from my truck exhaust to the engine cover to get it warmed up when trailering. My friends laugh but I am not in a position to buy a new bike.

I make sure it is in neutral (Rekluse CX) and am running Liqui Moly 10W-40. And, other than this issue the bike runs great!

My obvious question is am I missing something or doing anything wrong. A friend said I should input a new map, but had no opinion on the settings. It is currently stock.

Any help would be greatly appreciated, even if it is to confirm I'm not the only one with this problem.

Thanks in advance!

Dan

 

[Sheetmetalfab]

Jay marmount map runs great on snow.

Ran it on my 2014 yz450f for a couple seasons.

Worth checking your valves as that can make it harder to start.

 

[Dpre]

Thanks Sheetmetal, I'll look that up.

Also, I forgot to add I live at 6500 feet and ride above that.

 

[GlennRMK]

I had the same problem with my 09 CRF450R. Went back to a sled for a while since it was such hassle. Never could figure out how to make it start easily cold.

Now I'm on a 19 Husky 450 and it starts pretty well as long as its above 10-15 deg F. Colder than that and I have to use my enclosed trailer.

The enclosed trailer helps so much. When in the back of the truck it is just not happy.

 

[Speedy88]

I read on here one of the members uses two electric grip warmers, the sticky kind, on the bottom of his engine case then connects the wiring to his 12 volt trailer lighting system with a quick disconnect plug. You could probably put three or four of them on the Engine case if you had to

Keeps the motor and oil somewhat warm and easier to turn over.


Seems brilliant!

 

[Brayjay]

My 18 yz450 will start down to -15 C even when the bike is left outside all night. 5w40 oil and i'm running the - 3 fuel and + 3 ignition map and also using a lead acid 230 cranking amp battery that i keep in the house and then install on the bike when i get to the riding spot. Another huge help is a teaspoon or so of gas dropped on top of the pod filter with the throttle wide open so the gas goes straight into the throttle body. It fires right up.

 

[Brayjay]

I should add when adding the teaspoon of gas on top of the pod filter and into the throttle body with the throttle wide open I close the throttle and pull the choke to start the bike i don't try to start the bike with the throttle wide open.

 

[eric82930]

My buddies 14 starts great. Check the valves. Maybe 0 weight oil?

 

[M5-]

My 2011 will always start even better than my 2018. Yamaha has a cold start procedure as well as a hot start flooded procedure which are basically the same. First off the bike needs to be in N when you are kicking it. Your bike has a gear position switch which alters the fuel map when it detects N (richer). Step 2 slowly kick the bike over 3 or 4 times not even trying to start it but just get it moving, maybe more if its super cold. Make sure the cold start valve is pulled out on the throttle body set the bike to TDC then kick it like you mean it. Mine will start on the the 3rd kick usually regardless of the outside temperature. Typically if your valves are out of spec this will manifest as a hot start issue, normally they just start when they are cold. I've found patience and using the system works way better than kicking the $hit out of it. My buddies 2012 is the same.

M5

 

[eric82930]

Also I personally never owned a Yamaha but the position of where you start the kick has always mattered on every other brand so Its probably true for yami. The place I usually start is just past when the decompressor triggers by feel then let up and start at top.
I used to dead engine start desert racing in the days of kick only 4 strokes and there wasn't a guy who could get off the line faster. The clutch was out and running when my kick lever hit the peg and never had missed s start. When you find what it likes it works every time.

 

[aka Mr Floyd]

You are not the only one.

M5 has the straight dope on the start procedure for the Yamaha. My 2017 is a PITA to cold start, the 2010 Yamaha starts in the cold no problem even after the cold start nob broke and couldn't be pulled out.

Someone has already stated above that valves out of spec is worth checking.

I would add to also check your coil. I have had two snowbikes have coils go bad (one CRF and one on the Yamaha). They will still start, but spark is weak and they are really hard to start in the cold. Only symptom I found from this is if you pay attention, it slowly takes more and more kicks to start the bike when cold.

If neither of those are out of spec:

You already do the heater at the start of the ride. I did the glue on heaters to the bottom of the engine this season, seems to help a bit with first start at the trailhead.

I also have to make sure I don't leave my bike unrunning for too long just so I don't have to kick it over 100 times. One big thing I did this season that helped is run a full engine blanket and blocker at the back of the engine so it doesn't get encased in snow. Now I can at least leave if off for a somewhat normal amount of time and it will hold some heat in it, but I still watch the temp gauge when stopped for lunch.

I haven't changed the stock map, if you do that and it helps, definitely PM me. Lol.

 

[56pdlx]

Put an iridium Ngk spark plug in it and make sure it’s gapped correctly. Also, I have a rekluse clutch and it starts best in neutral. I’m running -3 for all fuelling and +3 for timing. What is your intake setup?

 

[Dpre]

I can't thank you guys enough for taking the time in your thoughtful replies. I feel a bit honored at the kindness shown in this community. I hope someday to return the favors.

I won't get back to my bike until the weekend, but thought I'd do a quick summary for both myself and others who my have a similar issue.

First, my 2015 YZ450F is all stock. The only additions are a temp gauge, thermobob and engine wrap.

What I intend to do this weekend:

-Follow M5's instructions to the tee. I was unaware that neutral alters the fuel map, nor did I know to slow kick 3 or 4 times before the TDC starting kick.
-Switch to 0 weight oil
-Test both Jay Marmount and -3 Fuel/+3 Ignition maps

What I intend to do if the above fail to work:

-Adhesive engine case warmer
-Iridium NgK plug
-Valve check
-Coil Check

What I intend to do if the above fail to work:

Buy a new bike.

Thank you, Thank you, Thank you!

Dan

 

[aka Mr Floyd]

Alot of engine wraps do not block out the back of the engine where the track packs snow. If you haven't done it, cut up some plastic to put back there, guys have done testing and it makes a huge difference in keeping the heat up in the engine.

...and I wasn't joking about the maps, if that helps, please let me know!!!

Todd

 

[Sheetmetalfab]

I can't thank you guys enough for taking the time in your thoughtful replies. I feel a bit honored at the kindness shown in this community. I hope someday to return the favors.

I won't get back to my bike until the weekend, but thought I'd do a quick summary for both myself and others who my have a similar issue.

First, my 2015 YZ450F is all stock. The only additions are a temp gauge, thermobob and engine wrap.

What I intend to do this weekend:

-Follow M5's instructions to the tee. I was unaware that neutral alters the fuel map, nor did I know to slow kick 3 or 4 times before the TDC starting kick.
-Switch to 0 weight oil
-Test both Jay Marmount and -3 Fuel/+3 Ignition maps

What I intend to do if the above fail to work:

-Adhesive engine case warmer
-Iridium NgK plug
-Valve check
-Coil Check

What I intend to do if the above fail to work:

Buy a new bike.

Thank you, Thank you, Thank you!

Dan

I had loose wire connections going to the coil make my 2014 hard to start one day.

 

[BeeDoo]

I've got a Big Buddy Heater I'm going to throw in the trailer. Should warm everything up to make easier to start. Also, will make putting gear on much more pleasurable.

 

[cbc76am]

M5's run down is the biggest part of it. The EFI bikes without a battery use a capacitor to prime the fuel pump and the 3-4 slow kicks open that relay to power and prime the fuel system before attempting your ignition kick. The mapping is the next thing that's critical. More fuel is good, but you actually want to retard the timing at idle for a better cold starting bike.

The valves being in spec is also important as noted and should be checked, but more likely it's just the map since it runs and starts fine when it's warm. Lash being off isn't going to change the lift enough from cold to hot expansion to cause a major change in compression for starting. The exhaust cam decompressor is still cracking that thing open otherwise you'd barley be able to get it kicked over when cold. my2c having owned that bike and maintained 7 of them for my buddies on the snow.

 

[Dpre]

SUCCESS!!

19 degrees F this morning and the ol' girl fired up on the 5th kick from TDC!!! That has never happened. I almost fell off in amazement then danced a little jig. Thank you all again! Had a wonderful morning session and just back for lunch.

My non-mechanic opinion is the same as cbc76am's professional opinion ... follow M5's instructions above, neutral and 3-4 slow kicks the key. I switched to 0W oil and uploaded the -3 Fuel/+3 Ignition map prior. Although, I must admit that other than what I have gleaned here and on YouTube, I really don't know what that means. cbc76am? ... is that consistant with your comment "more fuel is good, but you actually want to retard the timing at idle for a better cold starting bike"? If not, would you mind providing the numbers you might recommend?

Thanks in advance.

I am headed out again for some afternoon fun. I intend to upload the Jay Marmount map tomorrow morning (prediction in the low 20's) and see if there is a difference (will keep you in the loop Todd).

Round of drinks on me!

Dan

 

[cbc76am]

That's correct, plus 2 or 3 fuel, and neutral or neg 1 or 2 timing should start best. Retarding the timing to to prevent an early fire that kicks back (same as flame outs)

 

[M5-]

Glad it worked out for you, kicking the sh!t out of it gets exhausting pretty quick. I've started mine with my hand down in a trench before.

M5