2 stroke builds

[Jon Mutiger]

Isn't a proper operating temperature around, 160-190f? If I see my bike at 120 I warm it up.

But my bike is a 4t..But my logic can't be far off, water won't boil until 212f without pressure. Id re think your ideal temp. 120 isn't hot enough.

 

[mtn-doo]

Yes, 180/190 for a 4T. 2T much lower. 120/130 would be ideal for the smokers.

 

[tomk]

Here is a few questions for you guys about my 98kx500....

Every time I trailer my bike the engine freezes up to the point where it takes a lot of leg power to break it loose, anyone have a solution for that? I wonder if it is because I run the boondocker intake pod, I feel like it is still sucking in a bit of snow dust.


Since I am in MN fairly close to sea level I need to run a race gas/premium gas mix to keep the engine from knocking, but when it gets cold that race fuel does not like to ignite and days like today when I trailer the bike some where and it's 0f it won't start! Any ideas on what I will have to do. I am thinking to the future when we drive 4hrs up north and stay in a hotel with no garage, then what!?

 

[portgrinder]

Went thru some of that. Next time it won't start, take the tank off and drip a little fuel down your plug hole. If it fires first kick then go way up on your pilot.

Colder is better on a 2 stroke for a lot of reasons. Colder cases draw more air in, much better piston seal, protection against detonation.

 

[tomk]

just went out to the garage after the heat was on for an hour started 3rd kick

 

[ravenous]

Yo, Mtn-doo! It seems that some 2-stroke builder/tuners claim that cylinder wear increases dramatically at temps below 160. There may be a little extra power available running cooler ,but maybe its negligible.Any thoughts on this? And Portgrinder I dont Know how you fit yer temp sensor between the head and the left side rad. Mine will not fit.So on todays ride my temps with just the one rad and a t-stat dropped as low as 158 while riding in deep pow
and of coarse they went real high again riding down the trail.I wonder how come yer bike runs so different.

 

[mtn-doo]

No, that is an excuse. The ring/cylinder clearance is the same at room temp and at 300 degrees. They both expand and contract , the difference is the same. Someone trying to "over think". 4T need more temp for different reasons, your 2T at operating temp is happy and healthy. Clearance is the same, temp kills, and you're "cool". All is good.

 

[ravenous]

Hmm. Interesting thoughts Mtn-doo.So maybe that low temp high cylinder wear theory applies to cast iron liners that have a slower rate of heat expansion than the aluminum piston, meaning less clearance at lower temps.So that wont apply to our nikasil bores. But how do we arrive at the 120 deg ideal 2 stroke temp?

 

[mtn-doo]

Yes, I think what they were referring to was the old cold squeak.... Rapid expansion of the piston and slow expansion of the cylinder wall makes for a tight fit and you can squeak it. That is a different subject than "cooler running temps". 2T loves a cooler running temp. We have all felt the "hot fade" on a 2T after a long hard pull. High temps the 2T will do the classic "fade". Run no stat and check your temps, if too cold, start with a 50C.

 

[portgrinder]

What are you fellas running for intake filters?

I've got a boondocker filter like the turbo sleds use. Its on a boot that goes to the carb, and it's inside my airbox. Worked good till today. 30 seconds and carb is iced.

Ktm heater not helping. May actually be hurting. Too much cold air going thru the carb for that little element to keep it hot. May be just warm enough though for the snowdust to stick and accumulate.

Need to find a better filter I guess...

 

[rotax3006]

First let me say i dont have a snowbike (wish i did) but i do ride a CR 500 and have since it 98. If you are having a hard time getting your 500 to start in ther cold there are a couple things that work. The first old trick is to tip the bike over and wait until the carb floods and drains out the overflow vents. Stand it up and kick it like you are trying to kill a snake! This Is usually all it takes to get it rich enough to pop. You can pull the aircleaner and use a "windex" bottle to shoot a little gas in the cylinder (Make sure its mixed gas). Or if that dosent seem practical all the time, get a primer pump for an old skidoo 670/580 and put a T into your fuel line and drill a primer jet into your carb like the old sleds have. Be careful not to flood the bike with the pump. The old sleds only took about 1 or 2 good pumps to get them going id guess the bike takes one. I always get by with the old lean and stomp method but never really go dirt biking below 20F. I have used the windex bottle method a bunch to get them running in the spring, not really practicle for everyday but works in a pinch and is a lot easier than pulling the plug and dripping gas into the cylinder. Good luck the old 2ts run forever if you take care of them! (and have more power than the 12000$ 450s)

 

[tomk]

2 smokers check your stator covers for water, I pulled mine off my kx500 and it was half full of water! I can't believe it still ran! Every time I trailered it, the engine would freeze up and I couldn't kick it over, I always just thought it was moisture in the cylinder from the boondocker intake maybe letting snowe dust in, I guess I was wrong. I am lucky I didn't wreck anything,.

I can't figure out how it got in, it seemed to be sealed all the way around and rtv'd where the wires come through.

Check out the high water line on the cover

 

[Bigred1]

2 smokers check your stator covers for water, I pulled mine off my kx500 and it was half full of water! I can't believe it still ran! Every time I trailered it, the engine would freeze up and I couldn't kick it over, I always just thought it was moisture in the cylinder from the boondocker intake maybe letting snowe dust in, I guess I was wrong. I am lucky I didn't wreck anything,.

I can't figure out how it got in, it seemed to be sealed all the way around and rtv'd where the wires come through.

Check out the high water line on the cover

Had water in my KX500 before I rebuilt it. with new gasket and rubber where the wires go in. water intrusion gone. But I am checking it regularly

 

[nw-sickboy]

I just put the sx head and controller on my 2011 300. Any recommendations on jetting?

 

[summitboy]

Smartcarb !

 

[nw-sickboy]

I'd love a smart carb. If it was as easy as ordering on and it getting here in 7-10 days than I would for sure go that route. Kinda lame they don't have stock on hand.

 

[dhdey]

I'd love a smart carb. If it was as easy as ordering on and it getting here in 7-10 days than I would for sure go that route. Kinda lame they don't have stock on hand.

agreed. i still feel like it could be a ploy. get just a handful of people that actually have the carb to non stop blab about how awesome it is to get as many people to pay for it as possible without actually that much real world proof of how great it is...i'm gonna wait till people have their cast ones they have to waiting forever for and if then when mass people think they are amazing then i will order one

 

[summitboy]

No ploy. It just works. Once APT gets the pre orders out it will be business as usual. They have high standards and once you get the carb in your hands and on your bike you will see why u had to wait. The billets have been out for a while and have been available. The carb works well.

 

[summitboy]

I believe APT has some cast 38 left that would be shipped in the next couple of weeks if anyone is interested !

 

[mtn-doo]

3 in the mail....