Jet Recomandation For Below Freezing Temps.

[ditchdigger]

I'm taking my 450r out ice racing in cold temps, this machine is completly stock. do i need to change the jet in it to ride in this cold weather?

thanks

[Sjorge450R]

Originally posted by ditchdigger
I'm taking my 450r out ice racing in cold temps, this machine is completly stock. do i need to change the jet in it to ride in this cold weather?

thanks

just ride it. You'll be fine. On race motors you only have to bump the main one size.

[GPracer2500]

Originally posted by Sjorge300EX
...On race motors you only have to bump the main one size.

I'm not sure what you're saying. :confused:

[GPracer2500]

Originally posted by ditchdigger
I'm taking my 450r out ice racing in cold temps, this machine is completly stock. do i need to change the jet in it to ride in this cold weather?

thanks

A general rule of thumb for main jets is go one size richer for every 20-25 degrees colder.

[400exrider707]

Originally posted by GPracer2500
A general rule of thumb for main jets is go one size richer for every 20-25 degrees colder.

For every 20-25 degrees you only go up in main size or do you use this rule of thumb for ever circuit?

I myself usually just bump main one size and pilot one size, seems to work for me, but I was wondering as you are more knowledgable on the subject than I. Thanks.

[ditchdigger]

Yeah i took it out today and rode the hell out of it and it ran fine. the only thing is, and this don't have to do with the cold weather but when i mash on it, it throws up at first. no matter what rpm i'm at when i hit it cuts out. whats with that. its hard to get out of the corner when its like that.

thanks

[d3ktrix]

Originally posted by ditchdigger
Yeah i took it out today and rode the hell out of it and it ran fine. the only thing is, and this don't have to do with the cold weather but when i mash on it, it throws up at first. no matter what rpm i'm at when i hit it cuts out. whats with that. its hard to get out of the corner when its like that.

thanks

has it always done that or just once it started getting colder out?

[ditchdigger]

basically since i've had it. (may) it almost feels like some kind of safety thing. it sucks i know that for sure.

[mcleod]

i use mine yesterday, in my area the temp was -26 !

harder to start took almost 6-8 kick to start! but run just fine with stock jet... it's a stock bike btw.

but you should bump the main one size if you race.

[ditchdigger]

does yours have a flat spot it you mash it? I might have to bring it in and have warranty work done on it. the throttle response sucks.

[mcleod]

no i dont have.

only make strange noise at low rpm

im guessing that im gonna need the crank mod.

[GPracer2500]

Originally posted by 400exrider707
For every 20-25 degrees you only go up in main size or do you use this rule of thumb for ever circuit?

I myself usually just bump main one size and pilot one size, seems to work for me, but I was wondering as you are more knowledgable on the subject than I. Thanks.

The main is probably the most critical thing. But the other circuits are effected by environmental changes too, just not as dramatically as the main. On the pilot, sometimes fiddling with the fuel screw is enough. If it isn't, then you know a larger/smaller pilot is needed. The behavior of a fuel screw is a good indicator on if the pilot jet size is correct or not. The needle is probably the last thing I'd change for temp swings. The overlap in the main and needle circuits helps straighten out the needle if the main is adjusted. When in doubt, making a clip change and testing it out is the best way to go.

$0.02

[GPracer2500]

Originally posted by ditchdigger
Yeah i took it out today and rode the hell out of it and it ran fine. the only thing is, and this don't have to do with the cold weather but when i mash on it, it throws up at first. no matter what rpm i'm at when i hit it cuts out. whats with that. its hard to get out of the corner when its like that.

thanks

Is this an 06+? What you're describing sounds like an accelerator pump not keeping up. And on the 06+ it's an easy fix by changing the leak jet.

If your quad is showroom stock, you should seriously consider the Honda HRC kit (or a similar package of mods). They're pretty corked up in showroom stock form. The HRC kit gets it running "as it should".

[GPracer2500]

Originally posted by mcleod
i use mine yesterday, in my area the temp was -26 !

harder to start took almost 6-8 kick to start! but run just fine with stock jet... it's a stock bike btw.

but you should bump the main one size if you race.

Richening your pilot circuit should help with the cold starting. Even just backing out the fuel screw should help.

[mcleod]

yeah i know! but i really dont take it much in winter, and it's only 2month that we have temp below 0!

so i dont toucht anything.

[ditchdigger]

thats what i was thinking that the pump ain't keeping up or its putting to much fuel in the carb when i mash it.

whats the hrc kit that you brought up?

[GPracer2500]

04/05 HRC kit:
http://www.hondapartsworld.com/ProductImages/hondaoem/TRX450RPOWERUPKITLARGE.jpg


06+ HRC kit:
http://powersports.honda.com/assets/images/accessories/c106_116_accessories_all/pop_ups/06100-NLZ-A00_large.gif

Basically, they are intake and exhaust mods plus a new camshaft. You also get a new airbox lid (for the 04/05 kit, on the 06+ you just remove the lid), some jetting (including the hard to come by leak jet for the 06+), some crankcase breather mods, and the 06+ kit comes with a little wiring harness plug that gives the engine an extra 1000 rpm.

They are Honda produced items available as a complete kit from your Honda dealer or any online source that sells OEM parts. Check around for quite reasonable prices. It's great bang-for-your-buck AND you get the piece of mind from sticking to all OEM parts. Some people don't care about that but since your machine is still stock--maybe you do.

IMO, the HRC cam is the cam the engine should have come with from the get-go.