2010/11 Cold wheather and backfire


22 replies to this topic
  • tech24

Posted December 06, 2010 - 12:36 PM

#1

I did about 50 miles of riding yesterday. Trail was a wide open but very rough 18 mile loop and it was about 30 degrees. I was running woods map because thats what I have been using all year regardless of conditions.

I noticed a lot of decel pop/sputter and an ocassional backfire. Silencer was also coated with a good bit of black inside. I assume do to the cold and some high speed the bike was running rather rich and in combination with late ignition timing from woods map that this is what was causing this. I should've tried a different map I guess and checked w/t reading but tuner was nice an warm in my basement.

Any thoughts? Anyone else have this situation?

  • grayracer513

Posted December 06, 2010 - 12:52 PM

#2

The only solution is to either tape over at least part of one radiator, or install a thermostat. Your guess is correct.

  • tech24

Posted December 06, 2010 - 12:56 PM

#3

The only solution is to either tape over at least part of one radiator, or install a thermostat. Your guess is correct.


It did run well except for a split second I come of a small ledge and almost stalled and lost all throttle resonse for a split second, hopefully just flooded for a second. Don't know if my oil got contaminated or not didn't notice an increase in level or anything. I really would like to install a t-stat might have to figure out some plans for that. I'll see how the quads are set up maybe I can trasfer some parts and/or ideas

  • brentn

Posted December 06, 2010 - 01:17 PM

#4

It's -1 here right now, probably the same tomorrow.

I didn't get enough speed to notice any problems at all last time, but now that I have the proper tires maybe I should tape up half of a rad...

  • tech24

Posted December 06, 2010 - 01:28 PM

#5

It's -1 here right now, probably the same tomorrow.

I didn't get enough speed to notice any problems at all last time, but now that I have the proper tires maybe I should tape up half of a rad...


Maybe with the advanced timing of the Jay map you wont have any or have little sputter/pop/backfire. But it would be nice not to run so rich. I'm looking into t-stat ideas now. Might not be too bad to do.

The old raptor 660's have a t-stat housing which may be the right hose diameter but it has a 90 degree elbow in it. I wish the WRs had them it sure would be easier.

  • tech24

Posted December 06, 2010 - 02:20 PM

#6

I found this through searching on TT

http://www.fastech-r...thermostat.html

Can I install something like this in hose 13 without any ill effects since there is no bypass?

Posted Image

  • grayracer513

Posted December 06, 2010 - 02:51 PM

#7

The bypass might be an issue, but that would be the hose to install it in. Check out some of the KTM models. They have a straight through T'stat housing, for one thing, and you can see what sort of bypass they use.

  • brentn

Posted December 06, 2010 - 03:31 PM

#8

What is a bypass?

  • grayracer513

Posted December 06, 2010 - 03:36 PM

#9

In cooling systems the bypass is an alternate route coolant can move though while the thermostat blocks the path to the radiator.

  • tech24

Posted December 07, 2010 - 05:09 AM

#10

The bypass might be an issue, but that would be the hose to install it in. Check out some of the KTM models. They have a straight through T'stat housing, for one thing, and you can see what sort of bypass they use.


I was looking at a couple of them, kind of a screwy design at least on the schematics I saw. I'll check more out. The raptor's setup looks like an inline with no bypass unless its built in the housing. I guess I could try the in-line thing and see what happens. Maybe it has a small port for a bypass or something built in it. Some more info would be nice at least some port sizes for hoses. Wish it wasn't so expensive 130 bucks is a good bit to gamble with.

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  • HRC

Posted December 07, 2010 - 07:32 AM

#11

To me the Yamaha seems a little more sensitive to cold weather than Honda CRF 450. Did not notice any problems with my previous bike but I must say the Yamaha was a little hard to start when it had been standing out in the cold for a while.

Any tips on how to start the 2010/11 YZ450F in general ?

Also when the motor is warm and you stall, how do you guys start it ? As I wrote in my ridereport, I got best luck when I slighty turned the throttle, it fired up quite easy then. But is that the right way to do it on the Yamaha ?

Any tips on starting bike Hot or Cold would be preciated. :thumbsup:

  • tech24

Posted December 07, 2010 - 07:42 AM

#12

To me the Yamaha seems a little more sensitive to cold weather than Honda CRF 450. Did not notice any problems with my previous bike but I must say the Yamaha was a little hard to start when it had been standing out in the cold for a while.

Any tips on how to start the 2010/11 YZ450F in general ?

Also when the motor is warm and you stall, how do you guys start it ? As I wrote in my ridereport, I got best luck when I slighty turned the throttle, it fired up quite easy then. But is that the right way to do it on the Yamaha ?

Any tips on starting bike Hot or Cold would be preciated. :thumbsup:


I have had no problems when cold as long as the cold start knob is pulled. When hot that is a different story. The starting a/f ratio seems a bit rich. The only 2 things that work for me are nuetral with cold start knob out = 1 kick. Or crack the throttle slightly to add some air but it seems if you miss on 1st kick your done. It will start in gear these ways to but not as consistent.

I'd really like to have a lever like a hot start attached to the "cold start" knob. Also I haven't confirmed it yet but the power comander may give the capability to change starting a/f ratio but not sure.

  • tech24

Posted December 07, 2010 - 10:26 AM

#13

Well I emailed fasttech for some more info and got little but there is no built in bypass and the fittings are for 5/8 hose which should be close enough.

I wonder what the results would be with no bypass? Cavitation or hot spots in cylinder or head?

  • tech24

Posted December 07, 2010 - 11:12 AM

#14

May have found my soulution

http://www.epicincor...y=11&ItemKey=15

Now if I can get it to work without looking terrible. Looks like my only problem is the dual radiators. Looks like I'd have to cut the metal pipe (4) to install bypass hose.

  • brentn

Posted December 07, 2010 - 11:14 AM

#15

Mine is taking 5 kicks with the cold start on, curious to try it without the cold start to make the mixture richer... But then again I have a power commander which may change the mixture at startup from stock.

I can tell you that when I was using maxima FFT the bike would take about 20-25 kicks to start cold, it was just horrible. Found out that the freezing air really thickened up the filter oil on the filter, making it impossible for the bike to breathe. For winter now I'm using UNI which is much thinner and the bike starts easier.

Just my thoughts. This is for weather at 0 degrees or less.

  • brentn

Posted December 07, 2010 - 11:17 AM

#16

May have found my soulution

http://www.epicincor...y=11&ItemKey=15

Now if I can get it to work without looking terrible. Looks like my only problem is the dual radiators. Looks like I'd have to cut the metal pipe (4) to install bypass hose.


This looks like it would work, but how would you route a bypass hose on the 2010?

  • tech24

Posted December 07, 2010 - 11:32 AM

#17

This looks like it would work, but how would you route a bypass hose on the 2010?


I'd have to route it before the y pipe coming out the the head and the more I think about it I don't want to. I would be spare parts and it will look terrible along with beign expensive.

I spent some time viewing some shifter kart forums and the IAME in-line has some bleed holes in it to allow coolant to flow through. I even seen a regulation sheet that only allows the use of a thermostat without a bypass system. So they must work. I also found it for 99 bucks.

My only question now is being only a 122 degree t-stat, what will that be in actual water temp? If it doesn't get much above that temp it will be usuless to me. Might just have to find out the trial and error way.

  • brentn

Posted December 07, 2010 - 02:42 PM

#18

I'd be worried about the non-bypass system because by the time the hot coolant gets to the T-stat the coolant that is in the head may have overheated. At least with a bypass there is flow and the hot coolant can instantly get to the T-stat and activate it when it's time.

But I also see what you mean about it being complicated and looking like crap.

I guess it'll be cardboard then?
lol you could make different sized pieces of cardboard based on windchill and temp :thumbsup:

  • grayracer513

Posted December 07, 2010 - 03:29 PM

#19

The bypass is one small extra hose running from the T'stat housing (which should be located behind the shroud) down to a T fitting in either of the hoses running back to the water pump. Nearly all of that should be mostly hidden from view, for the most part. (the bypass is important because it runs the heated water past the thermostat while it is closed so that it is aware of the water temp, and will open when it reaches the preset. )

Can't dispute the criticism about being expensive, though.

  • tech24

Posted December 08, 2010 - 10:13 AM

#20

The bypass is one small extra hose running from the T'stat housing (which should be located behind the shroud) down to a T fitting in either of the hoses running back to the water pump. Nearly all of that should be mostly hidden from view, for the most part. (the bypass is important because it runs the heated water past the thermostat while it is closed so that it is aware of the water temp, and will open when it reaches the preset. )

Can't dispute the criticism about being expensive, though.


You know what, I was looking at it backwards. I was thinking hose 13 went from radiator to pump and after reading your post I realized it went to the head which as you described makes things simple.

Correct me if I'm wrong but coolant flows from the head to the top of the RH radiator which would be the best place to put the t-stat housing. Which as you stated could be located behind the shroud. And T into hoase 15 for the bypass.

I only have one concern: do you think coolant would flow from bypass to T in hose 15 and go back through the radiators, out hose 16 to w/p? Or do you think it would maintain its flow from bypass - T - w/p? (I know thats mouth full)

I really like the idea as I could leave a setup like this in place even during the summer, theoretically anyway. Now to get past the price :thumbsup:





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