Cold-Seize

[Live2Ride300]

Has anyone cold siezed their engine before? I'm thinking about blocking up the radiator on my R before doing some heavy winter riding with it. What do you think?

[Fordtrax]

This is just my opinion but i dont think blocking your radiator is a good idea .
Ive ridden 250rs plenty of times in near zero temps and as long as you let them warm up a bit they love the cold!

[chris46250r]

Cold seize is done at start up. You can take the rad completely off a still cold seize it.

[beobe99]

Agreed with above. A cold seize cant happen after the engine is fully warmed up. Its actualy possible to cold seize in the summer. If you cold START the quad and go and wack on it right away you threathen a cold seize to happen.

A cold seize is when the piston expands faster then the sleeve correct?

[250r4life]

dont touch your radiator... just sit there in neutral and let if warm up for several minutes before you ride...

[pdxbigfoot]

North Dakota and rode year round. I would use a small heating blanket wrapped around the cylinder as a "block heater". Now keep in mind im talking about SUB ZERO weather,sometimes it wouldnt get over -20 degrees yes minus 20 and that was a nice day. I have ridden in temps as low as -35 and that doesnt include the windchill factor.This was on various watercooled Honda atvs and the last being a 89TRX R. Check your anti-freeze to water ratio,change your jetting and let that motor warm up at idle until the cylinder and hose's are warm / hot to touch.....Have fun!!!

[Jer250R]

what jetting specifically would you recommend for very cold temps?
i'm still trying to get mine running properly and jetting seems to be a big issue with it...what symptoms would you have of incorrect jetting?

[pdxbigfoot]

"jetting" on this fourm there are a TON of threads with do's and dont's...good luck!

[GPracer2500]

Originally posted by Jer250R
what jetting specifically would you recommend for very cold temps?
i'm still trying to get mine running properly and jetting seems to be a big issue with it...what symptoms would you have of incorrect jetting?

Richen the jetting for colder temps.

One main jet size for every 20f-25f degree drop (from whatever temp you were jetted for) should get you in the ballpark. Screwing IN your air screw will richen the pilot circuit--you may or may not need to change the pilot jet. Lowering the clip on the needle will raise the needle itself which is a richer setting. Make one clip position change at a time.

[GOTFEAR]

dam that's cold and I'm complaining about 48 deg. man

[wilkin250r]

I've heard of some people having problems riding in extremely cold temps, like outdoor ice racing.

But the problem wasn't a radiator problem, it was an OIL problem. When riding, the cold air hitting the front of the engine would actually cool the engine cases, which in turn cooled the oil. When oil gets cold, it gets thick, and eventually it was a sludge that wouldn't move through the engine and gears.

I can't remember exactly what the solution was, but I think it was a basic wind screen and some sort of insulation to keep the wind chill off the cases.

[86 Quad R]

i'd use ATF in those frigid temps as opposed to regular tranny oil. :cool:

[Live2Ride300]

I've richened her up quite a bit. Should be ready to go!

Kind of off topic, but has any Nikasiled a stock cylinder before?

[86 Quad R]

i've seen it done before.

[wilkin250r]

The benefits of Nikasil are because you can replace the iron sleeve with an aluminum sleeve.

But you wouldn't bother to do that on a stock cylinder. The benefits don't even come close to justifying the cost.

When people nikasil the stock cylinder, they usually do it on the last bore to save the porting. If you re-sleeve it, the porting would all need to be redone.

[Live2Ride300]

I got some time to tear into my engine last week. It turns out a couple of the fingers on the clutch basket broke off and got wedged in between the primary drive gears and locked it up. :eek2: Top end is still good.:D

[86 Quad R]

be sure and check all of that stuff out REAL good while your in there. :cool:

[Rich250RRacer]

Originally posted by wilkin250r
The benefits of Nikasil are because you can replace the iron sleeve with an aluminum sleeve.

But you wouldn't bother to do that on a stock cylinder. The benefits don't even come close to justifying the cost.

When people nikasil the stock cylinder, they usually do it on the last bore to save the porting. If you re-sleeve it, the porting would all need to be redone.

I have a Nikasiled stock cylinder on one of my R's, and it was done for just that reason. It was at .050 over and .060 wouldn't clean it up, so I had it Nik'd back to .050. Like you said there's no real performance benefit, other than it's very durable. I ran the R lean last winter and melted the piston, smearing it all up the front of the cylinder. A flapper wheel on a die grinder, then a light touch up with a ball hone and it was good to go. Same compression as when I first put it together too.