Well, frack.

RustyCoupe · 04-03-2018, 10:21 AM

So I recently bought an '08 yz450f, the bike was clean, with a few aftermarket goodies. It came with a Rekluse auto clutch, DRD titanium exhaust, break away levers and a few other things. I saw the ad on craigslist and called the owner, the next day I went to his house to look at it. I see and hear a cold start, we let the bike warm up and I take it up and down his road. The bike felt great, up and downshifted nicely and I didn't hear any unwanted noises. He tells me that the bike just had the suspension re-valved, the valves adjusted, new chain and sprockets, he also says that he is the second owner and the bike has sat for almost a year. After looking over the bike some more we agree on a price, we sign the title and I got me a bike. The next day I thought I'd be a good idea to drain the oil, see what it looks like and put in some fresh 10w-40. When the oil drained it was a little discolored, but I decided it smelled and felt okay, so it was probably from sitting so long. I change the oil, start it up and let it circulate.

The next day I noticed the coolant looked low, so I got a funnel and started pour some into the radiator until it was full. Then I started the bike and walked away and let it get warm. After a few minutes of idling I heard gushing and burping sound, I turn to look at my bike and I see coolant coming from a hose. I thought I had put too much and it just burped out the extra. Well, then I followed the tube it came out of and it came out of the top of the head, which I'm guessing is just a vent hose for the head.... So either I got a effed casting or gasket.

My question is, should I rebuild it the same, big bore kit, sell it, or some kind of combination of those three? I'm trying not to get in too too deep, I still got bills and a girlfriend.

Craizie · 04-03-2018, 10:50 AM

I didn't ready the whole thing, just the last line or so.

With all things if you have to replace it you need to go bigger / better / faster.

Ditch the girl friend.

bird_dog0347 · 04-03-2018, 11:25 AM

You need to find the problem before you choose a solution.

jammeejamm · 04-03-2018, 01:09 PM

word. sort it out before you buy parts. it never spit coolant on the test ride?

also, it is a 450. unless your sponsor is pushing you to win lorettas, a stock 450 is plenty fast enough. big bores are only used by older, slow vet riders that brag about how fast their bike is.

either way, you should probably stick with oem parts if you do anything. search on thumpertalk for all the quirks on the 08.

RustyCoupe · 04-03-2018, 01:57 PM

Quote:

Originally Posted by jammeejamm

word. sort it out before you buy parts. it never spit coolant on the test ride?

also, it is a 450. unless your sponsor is pushing you to win lorettas, a stock 450 is plenty fast enough. big bores are only used by older, slow vet riders that brag about how fast their bike is.

either way, you should probably stick with oem parts if you do anything. search on thumpertalk for all the quirks on the 08.

No, it never spit coolant on the test ride but it was also running low at the time. I'm going to check my oil and do some other poking around later today.

kingjason · 04-04-2018, 12:23 AM

Fill it up and ride it. Those bikes hate to sit still for any amount of time. Like a fine line between bike being warm enough to ride and hot enough to boil water. I have owned 3 of those. Hell even my KTM450SX absolutely hated sitting any. Rolling along, no issues, stop for a second after warmed up and it would start steaming. It hated following my wife around on her Ace 570, but loved wide open on the track.

Super Cubano · 04-04-2018, 07:24 PM

Quote:

Originally Posted by kingjason

Fill it up and ride it. Those bikes hate to sit still for any amount of time. Like a fine line between bike being warm enough to ride and hot enough to boil water. I have owned 3 of those. Hell even my KTM450SX absolutely hated sitting any. Rolling along, no issues, stop for a second after warmed up and it would start steaming. It hated following my wife around on her Ace 570, but loved wide open on the track.

This! You were likely boiling it out.. how long was it sitting still running ?

Fatass · 04-14-2018, 01:59 PM

Something is going on. None of my 450s from a cold start idling for a few minutes would be hot enough to boil, even creeping along through bills woods I never boiled one over. It's april, not the third week of august. Once you do figure it out I'd recommend engine ice though. 2T FTW.

Buick355 · 04-15-2018, 07:44 AM

My 09 YZ450F would boil over in Bills Woods occasionally on 100+ deg days.

If it was coming out of the head vent you've got problems. May just be a bad head gasket, but I would pull the head and look, if you don't see the problem have the head magnafluxed. You don't wan't to keep riding it and ruin the bottom end.

04-03-2018, 10:21 AM	#1
RustyCoupe Punk Ass Newbie Join Date: Feb 2015 Posts: 3	Well, frack. So I recently bought an '08 yz450f, the bike was clean, with a few aftermarket goodies. It came with a Rekluse auto clutch, DRD titanium exhaust, break away levers and a few other things. I saw the ad on craigslist and called the owner, the next day I went to his house to look at it. I see and hear a cold start, we let the bike warm up and I take it up and down his road. The bike felt great, up and downshifted nicely and I didn't hear any unwanted noises. He tells me that the bike just had the suspension re-valved, the valves adjusted, new chain and sprockets, he also says that he is the second owner and the bike has sat for almost a year. After looking over the bike some more we agree on a price, we sign the title and I got me a bike. The next day I thought I'd be a good idea to drain the oil, see what it looks like and put in some fresh 10w-40. When the oil drained it was a little discolored, but I decided it smelled and felt okay, so it was probably from sitting so long. I change the oil, start it up and let it circulate. The next day I noticed the coolant looked low, so I got a funnel and started pour some into the radiator until it was full. Then I started the bike and walked away and let it get warm. After a few minutes of idling I heard gushing and burping sound, I turn to look at my bike and I see coolant coming from a hose. I thought I had put too much and it just burped out the extra. Well, then I followed the tube it came out of and it came out of the top of the head, which I'm guessing is just a vent hose for the head.... So either I got a effed casting or gasket. My question is, should I rebuild it the same, big bore kit, sell it, or some kind of combination of those three? I'm trying not to get in too too deep, I still got bills and a girlfriend.

04-04-2018, 12:23 AM	#6
kingjason Notorious PIG Join Date: Jul 2003 Location: Down South Posts: 7,559	Fill it up and ride it. Those bikes hate to sit still for any amount of time. Like a fine line between bike being warm enough to ride and hot enough to boil water. I have owned 3 of those. Hell even my KTM450SX absolutely hated sitting any. Rolling along, no issues, stop for a second after warmed up and it would start steaming. It hated following my wife around on her Ace 570, but loved wide open on the track. __________________ Whos your Daddy?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

04-03-2018, 10:50 AM	#2
Craizie Cracka VIP Member Join Date: Jun 2004 Posts: 11,891	I didn't ready the whole thing, just the last line or so. With all things if you have to replace it you need to go bigger / better / faster. Ditch the girl friend.

04-03-2018, 01:09 PM	#4
jammeejamm Lifer Join Date: Mar 2004 Posts: 1,482	word. sort it out before you buy parts. it never spit coolant on the test ride? also, it is a 450. unless your sponsor is pushing you to win lorettas, a stock 450 is plenty fast enough. big bores are only used by older, slow vet riders that brag about how fast their bike is. either way, you should probably stick with oem parts if you do anything. search on thumpertalk for all the quirks on the 08.

04-14-2018, 01:59 PM	#8
Fatass Lifer Join Date: Jun 2001 Location: mexico, disneyland for anarchist perverts Posts: 6,714	Something is going on. None of my 450s from a cold start idling for a few minutes would be hot enough to boil, even creeping along through bills woods I never boiled one over. It's april, not the third week of august. Once you do figure it out I'd recommend engine ice though. 2T FTW.

04-15-2018, 07:44 AM	#9
Buick355 Lifer Join Date: Jan 2001 Posts: 17,430	My 09 YZ450F would boil over in Bills Woods occasionally on 100+ deg days. If it was coming out of the head vent you've got problems. May just be a bad head gasket, but I would pull the head and look, if you don't see the problem have the head magnafluxed. You don't wan't to keep riding it and ruin the bottom end.