First dirt bike

WudzRydr said:
Fans can't keep up when you get into the low speed stuff on a big bore 4t. Mud, rocks, hard climbs, etc....
Not talking trials here. Woods bikes are meant to be moving
Passed many overheated 4 strokes on the cord when I rode it a few years back. My 2t didn't even need a fan.
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Switch to 50% race fuel it runs cooler.
... and ride faster ;)
 
WudzRydr said:
Fans can't keep up when you get into the low speed stuff on a big bore 4t. Mud, rocks, hard climbs, etc....

Not talking trials here. Woods bikes are meant to be moving

Passed many overheated 4 strokes on the cord when I rode it a few years back. My 2t didn't even need a fan.
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I'll second the overheating .... FE 390 4T would overheat regularly on me, spilling out coolant all the time. Bike came with no fan, I later mounted a bottle to at least recover the coolant. But even people with fans in hotter climate still had issue, riding slower, hilly and sandy stuff. Now I ride the same trail on TE300, never had any issues. Coolant level still at it's original mark and I don't even have a bottle mounted up ....
 
Wrenching every weekend? who are you getting your news from? Trump!
Any wrenching i have done to my 2T this year was to add mods and stuff that i did because I wanted to. There are less frequent oil changes than a 4T since it does not require engine oil changes, only transmission oil. The air filters need to be cleaned as often as a 4T, in regards to doing top ends depending on how many hours you put a season you will only have to do a top end at the end of the season or even can easily last you 2 or 3 season and the work is easy, fast and CHEAP.

I am not sure what wrenching you are talking about? adjusting and lubing your chain? same as a 4T, carburation once you figure you jetting there is no need to play with it anymore and I can change all jets and needle on my carb in like 10 min so I am really not sure what you are talking about.

kiwi said:
Funny., I went with a 4T woods bike (WR250F) as the two stroke would be more frequent maintenance compared to the 4T.. and I'm not ready to be wrenching every weekend ;-p plus I'm a N00b!
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I think he was sarcastic in a way .. .admitting to be wrong. Like you or me, when we got our first bikes ...
 
My kx250F use to over heat constantly in slow sessions and when we had to stop and wait for someone that had an off, my yz250 has never over heated so far and I put a lot more ours on the yz.
Trials said:
I agree with everything except the over heating part, don't you have a good radiator with a fan on it?
fuel injection can really make your fuel tank hot, i'll give you that.
... just keep it mostly full.
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Maybe... doubt it. People tend to repeat a lot of wrong information they hear from others that are trying to sound like they know what they are talking about....

Which makes me wonder, what is the version of tim horton's parking lot talk on the dirt bike word?

Edit: I read his post again, maybe you are right, maybe it was a sarcastic post.


mxs said:
I think he was sarcastic in a way .. .admitting to be wrong. Like you or me, when we got our first bikes ...
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I spoke to plenty of trail riders who had 150hrs on their original 2T piston. Less wear when you're not going WOT from turn to turn on a track I assume. Most YZ450 guys go 100hrs or more on one and YZ's are consistently touted as the most reliable 450 by mags. All in all I figure maintenance comes out similar in the end although if you grenade a 4T it will be of course cost more to fix.

I never boiled over my YZ450 last year. Running a woods map/timing may have helped it run a bit cooler. RMZ's have been known to overheat more easily so again I assume overheating is more model specific.
 
Similar to interval, but not similar to rebuild in costs ... top end in 2T and top end on 4T is not the same cost. So I have been told, not by my own experience as I let 4T go early and 2T has only 60 hrs since rebuild.
 
WudzRydr said:
Stick to your trials bikes old fella.
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ok

but I used to ride MX and Enduro and never had a problem:|
mind you in the olden days you could buy higher then 100 octane at the pump ;) young man.
 
mxs said:
Or just get a 2T and use regular gas ... LOL
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2T thrives on paint thinner! and full synthetic allows you to run the oil mix leaner and that keeps the octane higher!
 
ZX600 said:
No fan but neither does the 2T
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well theres your problem, gasoline burns hotter then water boils, a radiator without a fan is pretty useless and those big wide rads with big wide plastic fins hanging out the sides is silly, 2T or 4T

... you know a 4 stroke does have a very high exhaust temperature, but it only fires half the time ;)
 
Try running without a rad at all and see how useless you think they are then. 2T's run a lot cooler than 4T's. I didn't have a fan on my old YZ250F, never overheated until I filled the rads with mud in the giant mud-hole at Ganny. haha...

ZX600 (we should give you a new name eh? ;) ) I wonder if your old KX was jetted way too lean. It was a real ***** to start when hot, more so than every other 4T I've been around.
 
doozerdave said:
Try running without a rad at all and see how useless you think they are then....
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If it didn't have a rad that would make it an air cooled engine and some of those are not so useless. They also don't have fragile cooling chambers hanging out on both sides of the motor and wider then anything on the bike other then the handlebars.

Everything you read about ram air bikes overheating the recommendation is to put a fan on it :/ so why not just put a fan on it from the get go! My bikes that don't even have a battery still have a fan. Light weight cooling fins can't cool if they don't have air flow. Air cooled engines rely on massive cooling fins and plenty of surface area to heat sink the barrel and head. The only place you don't need either of those solutions is on a boat.

"old YZ250F, never overheated until I filled the rads with mud in the giant mud-hole" what good is a dirt bike that can't be ridden in mud! MX bikes follow other MX bikes and they are all trying to stone each other to death most of the time, what good is it having maximum frontal surface area covered with aluminum cooling fins. .... ram air cooling on an MX bike is an ill conceived solution!
 
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Uhm....

22904881986_5a9e0b32cb_o.jpg


You've really got a hate on for MX bikes it seems... It's not hard to put rad guards on.
 
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