YZ450F problems with over heating on tight trails?

[LOAM]

I'm sorry if this has been covered already, but I ddn't find anything-I'm probably not doing something right.

I'm looking to buy a late model YZ450F, but I just want to make sure that overheating isn't going to be a problem. I ride a lot of tight single track. I'm assuming that most of it will be first and second gear on the 450. Do they get pretty hot on tight trails? I've read that the WR's get pretty hot, but they have that resevoir. I don't want a WR becuase they're too heavy for my preferance. Any help is much appreciated. Thanks a bunch.

[cowboyona426]

The only time I've ever boiled my 426 or 450 was following a youngster on a TT-R 90 on my old 426. Never once boiled the 450. If you're that worried, rig up a puke tank, it's easy to do.

Welcome to TT, stick around as there is a ton to learn here!

[FinchFan194]

I ride tight single track in western Wa and don't have any problems just make sure it is geared up a tooth or two on the rear from stock to keep the RPM's up and help move that waterpump. I have never overheated even when on 1st gear single track currently running 13/47 which is higher than stock.

[cowboyona426]

I ride tight single track in western Wa and don't have any problems just make sure it is geared up a tooth or two on the rear from stock to keep the RPM's up and help move that waterpump. I have never overheated even when on 1st gear single track currently running 13/47 which is higher than stock.

I ran with stock gearing at Batey Bould last fall and never boiled. Stalled a million times, but never boiled

[Wiz636]

Keep it moving and you will not have a problem. KTM 300's overheat easier than my YZ450 does.

[tribalbc]

Keep it moving and you will not have a problem. KTM 300's overheat easier than my YZ450 does.

KTM's are always good for steam shows at races

[motocrotts]

Piano:bonk:

[STROKEDIESEL]

had my 07 very low use bike now for 2 weeks and so far 2 rides on tight single track here in shelton/tahuya (wa). hasnt boiled over while riding but will boil in a second if i let it idle for 30 seconds or more after coming to a stop.

[hillclimbguy]

I'm sorry if this has been covered already, but I ddn't find anything-I'm probably not doing something right.

I'm looking to buy a late model YZ450F, but I just want to make sure that overheating isn't going to be a problem. I ride a lot of tight single track. I'm assuming that most of it will be first and second gear on the 450. Do they get pretty hot on tight trails? I've read that the WR's get pretty hot, but they have that resevoir. I don't want a WR becuase they're too heavy for my preferance. Any help is much appreciated. Thanks a bunch.

I have an 06YZ450. I love the tight twisty stuff. I run the Evans coolant in my radiators, gearing is 53 13, I richened the pilot up two sizes and the main up two sizes. I dont have a recovery tank, but I never boiled over either. Hope this helps.

[Aka.Goose]

Look into the Zip-Ty racing coolant...it'll help you run a few degrees cooler...anyone who says that's bs, hasn't used it...

[FinchFan194]

I use Engine Ice not sure if it works though. . .

[thmperpower450]

I've got an 08 and ride in 115 degrees in the summer, i run regular radiator coolant and have never had a problem.

[cowboyona426]

had my 07 very low use bike now for 2 weeks and so far 2 rides on tight single track here in shelton/tahuya (wa). hasnt boiled over while riding but will boil in a second if i let it idle for 30 seconds or more after coming to a stop.

Hey I know you... from FTE and SnoWest. Long time no see man!

[STROKEDIESEL]

Hey I know you... from FTE and SnoWest. Long time no see man!

thats me.... i miss my stroke should of never sold a paid off truck

and i miss my sled same story. oh well loving the new 450!!!!

so i need to change the coolant on this beast then? you guys that say you have never boiled over are you shutting your bike off immediately when stopping to rest/ chat with a buddy or your bike just runs that cool. mind you this was while riding in 40* weather. has yet to do it while riding though.

[cowboyona426]

Check the coolant level... keep the coolant level with the top of the fins inside the rad. I can let mine idle for a few minutes to warm up, or for 30 seconds or so when on the trail (guessing there). Hell, I've left it idling until the carb ran out of fuel and never boiled it.

[ridg219]

I had a 2007 YZ 450 that I used for hare scrambles and an occasional enduro. It rarley boiled over but I melted the plastic on the clutch side of two pairs of boots, I even had a blister on my foot after a particularly long hot tight enduro. I rode a YZ 250f before the 450 and replaced the 450 with a 2008 YZ 250f and have never had this problem with either of them.

[rufusz]

I've just made an overflow tank for my 02 426 and wanted to test it. I've overfilled a little bit the radiators, started it up. I waited around 5 minutes with the engine idling, with some short throttle bursts, but nada. No steam, no overflow. I didn't have the heart to run it longer. Maybe on the next very tight/technical/muddy place I will actually see if the overflow tank works.

BTW, my 426 overheats very hard. Mostly I've got stuck in some muddy stuff and had to work a lot to get it, then I've seen some smoke.

[buzzfin]

If you're running exceptionally technical trails where you're abusing the clutch and barely moving, it will definitely overheat. I run at Red River Motorcycle Trails in Bulcher, TX (where they had the Last Man Standing race) and once I get into the really tight, technical stuff where I can't keep the bike moving, it gets hot fast! I put a WR overflow tank and a cooling fan on mine. Problem solved!

[Aka.Goose]

I put a WR overflow tank and a cooling fan on mine. Problem solved!

Could you tell us more about the cooling fan? What did you use, what powers it, pics, etc.???

[KAS]

I've ridden & raced a YZ450F ('07 & '08) for a little over 2 years now, and I've never even got it to spit coolant.

FWIW I've also owned two KTM 300's ('02 & '04) and they never boiled either. Even with the radiators packed with mud, holding it wide open hardly going anywhere during this race: