Coolant coming out overflow after rebuild. Help Please.
Posted June 19, 2013 - 08:47 AM
I called around to different yamaha shops and got a variety of suggestions as to what it might be.
1. Bad head gasket or O-ring that is pressurizing the coolant system.
If this were the case you'd think it would speed up the flow out of the overflow when I'm riding and giving it throttle, which it didn't. It almost stopped the faster I went.
2. Bad radiator cap
Possible I would think with it being 12 years old, but it was good when I took it off.
3. Air pocket in the coolant system
Most likely I would think because the coolant was frothy coming out of the overflow and had some head on it when I opened the radiator cap after it cooled off a little. It also was low on coolant after each ride. This could have obviously been because it's spitting it out too.
As far as the particles in the coolant I'm a little puzzled about that. I still haven't drained the oil to see if there's coolant in the oil. I will probably do that tomorrow morning when I get off work. What color would the oil have if there were anti-freeze in it?
Tell me what you guys think. I would really hate to have to tear the top end apart and spend another $80 for a gasket kit if I don't have to. I'd like to take it on a riding trip the first week of July so I want to get this fixed as soon as possible.
Posted June 19, 2013 - 08:51 AM
A quick look of what I rebuilt. I'll post before and after pics in a new thread when I get it fixed.
Posted June 19, 2013 - 09:00 AM
I normally leave the radiator cap off fill it to the top there is a bleeder air bolt on the side of the right cylinder If I remember right crack that open to make sure there's no air coming out.
I also run the bike with out the radiator cap off to get the air bubbles out before putting the cap back on and run the bike.
If the bike is idling sitting still it going to over heat it don't take long or much fro the bike to over heat this way.
IM me about gaskets,.
I running engine ice in my 426.
Posted June 19, 2013 - 09:31 AM
Well after starting it and warming it up at idle for 4 mins with the choke on and another 10 or so without choke it it started pushing antifreeze out of the overflow.
You're the first person I've ever heard of who got away with idling a 426 for longer than 5 minutes without blowing coolant everywhere. They don't like that. I suggest you refill the cooling system just to the point of covering the tops of the radiator tubes and take it for another 10-20 minute ride. Let it cool a little and see where the coolant level is.
Posted June 19, 2013 - 05:22 PM
Posted June 20, 2013 - 11:27 PM
Posted June 21, 2013 - 06:33 AM
That would be a worn 5th gear pinion and the 3rd gear pinion that locks it, and a bent shift fork to go with it.
Posted June 21, 2013 - 08:28 AM
Posted June 21, 2013 - 05:23 PM
Do a plug reading After running the bike wide open.
Posted June 21, 2013 - 06:20 PM
Posted June 21, 2013 - 08:03 PM
Posted June 21, 2013 - 09:08 PM
Posted June 22, 2013 - 03:35 AM
Posted June 22, 2013 - 07:17 AM
Where are you're floats set at is you're vent tube from the gas cap plugged.
Is the spark plug cap screwed all the way in to the coil wire.
Check the wiring that runs along the frame the frame make sure there's no bare spots that's grounding it self out.
Disconnect the kill switch see if this grounding out.
Posted June 22, 2013 - 07:56 AM
The trans was used but in good condition.
Maybe not that good. The wear that causes this is at the locking lugs/slots on the sides of the 3rd and 5th gears on the main shaft. The other two forks are not involved. The lugs are supposed to have a very slight undercut so that the driving loads hold them together. When this wears away to the point that it's gotten slightly reversed, they push away from each other until the disengage by flexing the fork, then the fork snaps them back into engagement and it starts over.
If it only does this in one gear, and the problem can be controlled just by increasing or decreasing the load on the drive train with the throttle, it's the trans. An engine performance issue like spark plugs or jetting would affect operation in all gears.
Posted June 22, 2013 - 11:36 AM
I put a WR trans in my YZ and it was just sitting on a self in my garage before I gave to Dennish87.
This why I think it not the trans I could be a shifter fork.
I using the same shifter forks that came out my YZ for the WR trans in my 426.
But he might not pushing the bike as hard in the lower gears and revving out in 5th farther this why I asking it could be the jetting or is the hot start hanging open just enough can cause the motor to stumble ask me how I found this out LOL.
Most of my riding is wide open in top gear 5th so I know when I was using the YZ trans it worked fine.
The WR trans works better for the type of riding I do now still 5th gear I am in most of the time more top end speeds but at normal cruise speeds I not revving as high anymore.
Edited by marv02, June 22, 2013 - 11:44 AM.
Posted June 22, 2013 - 11:39 AM
Try the other stuff before you tear engine apart again.
Thinking about Yamaha 250... by Arctic Pride
2016 YZ450 by CaptainKnobby
YZ450F 03 Sparks driving me crazy by SirAttard
Yamaha YZ450F 2017 by Chris.GVS