daddio
06-17-2004, 01:18 PM
I found this on bluetraxx.com............
There are a few areas on the YFZ450 that tend to start leaking. Thankfully, Yamaha has superceded some of the defective part numbers with better replacements. It is better to replace the parts before the leaks start, or more parts will get damaged in the process and need replacing. (much of this information was obtained from Weller Racing, jetjock16 and Vibeguy)
1. Water Pump Leak (does not apply to the black YFZ450 Limited Edition)
Symptoms:
How do you know that your Water Pump is leaking? There is a weep hole below the Water Pump that the coolant will leak out of. Usually it will leak rapidly, especially after the engine is shut off. DO NOT JUST PLUG UP THE HOLE! It is put there to keep the coolant from going into your oil.
If the weep hole under the water pump has not begun to leak yet, the preventative fix is cheap and easy. Just replace the one defective oil seal (#6 on the Water Pump microfiche). The original part number was 93102-11004-00, the NEW part that prevents this leak is 93102-11008-00 (runs about $4). The procedure to replace this one seal does NOT require the engine case side cover to be removed, just the coolant pump cover (this was taken from someone else on the other web site):
"order the new seal.. the one that goes on the impeller shaft.. then yes ya gott pop the hose off.. some fluid will drain.. unbolt the three bolts that hold the cover one... no need to change that $2 gasket o-ring as you said.. thats not the problem.. remove the impeller by putting a socket on it with the bike in gear so it wont turn.. when it pops off use a flat screwdriver to pry out the old seal... coat the updated seal in lots of grease and use a socket of the same diameter to push it in evenly.. retightne the impeller.. than the cover, than the hose.. you can get the coolent full by just keep adding it to the overflow bottle start the eng and itll suck it in... takes like less than half a gallon total... process takes 20 minutes.. now that ive done it.. if it leaks again i could change in five minutes." - [jetjock16]
If you wait until you have a leak, you may also need to replace the following parts as well. Once the one seal is badly worn, the impeller shaft can get marred and it can damage the other seal and shaft bearing, requiring the engine side case to be removed to replace the parts.
93102-12106-00 Oil Seal (~$4)
93306-00105-00 Bearing (~$10)
5GR-12458-00-00 Pump Shaft (~$22)
2. Output Shaft Leak (oil leak around front sprocket)
Symptoms:
How do you know if your Output Shaft Seal is leaking? Just behind the shifter there will be oil running down the case. Usually when these go out they will leak quit a bit. Your skid plate will also have a good amount of oil on it.
The O-Ring on the output shaft has recently been updated from the original part number 93210-22164-00 to the new part number 93210-22298 (~$4). If there is no leak yet, you should be able to get away with replacing this single part. If you wait until it is leaking, then you may also need:
93102-32480-00 Oil Seal (~$7)
90387-2513F-00 Collar (~$11)
90215-21001-00 Lock Washer (~$3)
3. Decompression Plug (oil leak through plug hole from loss of plug)
Usually the stock decompression plug only pops out if you did the cam mod and/or you overfill the oil. It may be a good idea to replace it anyway as a preventative measure. When this plug blows out, your engine will start throwing oil out of the engine near the header pipe. The recommendation is to get the quasimoto racing decompression plug by Vibeguy (comes with the oil seal and an anodized aluminum plug) (~$16). The quasimoto decompression plug can be purchased at Thumpertalk and comes with Yamaha oil seal part number 93102-12224-00. The stock plug is black rubber with a circular aluminum disk built into the inner part of the plug. It is held in place only be the pressure on the sides. The anodized plug is held in place with a bolt that is already on the head of the YFZ whose sole purpose is to hold a decompression lever. First unscrew the decompression lever bolt (a little oil may leak out this bolt hole). To remove the stock plug, use a dremel tool with a drill bit so you can fit into the tight space and drill a hole through the stock rubber plug. It will be a little tough to drill because of the aluminum disk backing the seal. I usually screw in a dry wall screw inot the drilled hole so I have something to grab onto with pliers and then pull the plug out. Make sure to use a q-tip to remove any metal shavings that may have gotten into the decompression lever hole from drilling. Grease the oil seal on the inner ring and outer ring (do not fill the lip of the seal) and then put the decompression plug through the seal and then press the seal and plug into the decompression hole. Make certain the seal is flush and the plug and seal are pressed in all the way. Clean the oil off the decompression plug holding bolt and the hole it goes in, apply some blue loctite to this bolt and then tighten it in to the correct torque - DO NOT overtighten or you will strip the aluminum hole threads.
Also, it is always wise to inspect the engine mounts as it is fairly common to have these break (Engine Stay 2 and Engine Stay 3) and make sure they are not cracked.
Symptoms:
How Do you know if you need new front engine mounts? If you look at your 2 front lower engine mounts (they look like triangles with 3 bolt holes) there will be a large crack at either end.
The replacement parts for these are:
5TG-21316-00-00 Engine Stay 2 (~$7)
5TG-21317-00-00 Engine Stay 3 (~$7)
my 2 cents
quadsonly.com has billet yfz mounts
fantomzatv.com also has "decompression plugs"
or pm me for more info
There are a few areas on the YFZ450 that tend to start leaking. Thankfully, Yamaha has superceded some of the defective part numbers with better replacements. It is better to replace the parts before the leaks start, or more parts will get damaged in the process and need replacing. (much of this information was obtained from Weller Racing, jetjock16 and Vibeguy)
1. Water Pump Leak (does not apply to the black YFZ450 Limited Edition)
Symptoms:
How do you know that your Water Pump is leaking? There is a weep hole below the Water Pump that the coolant will leak out of. Usually it will leak rapidly, especially after the engine is shut off. DO NOT JUST PLUG UP THE HOLE! It is put there to keep the coolant from going into your oil.
If the weep hole under the water pump has not begun to leak yet, the preventative fix is cheap and easy. Just replace the one defective oil seal (#6 on the Water Pump microfiche). The original part number was 93102-11004-00, the NEW part that prevents this leak is 93102-11008-00 (runs about $4). The procedure to replace this one seal does NOT require the engine case side cover to be removed, just the coolant pump cover (this was taken from someone else on the other web site):
"order the new seal.. the one that goes on the impeller shaft.. then yes ya gott pop the hose off.. some fluid will drain.. unbolt the three bolts that hold the cover one... no need to change that $2 gasket o-ring as you said.. thats not the problem.. remove the impeller by putting a socket on it with the bike in gear so it wont turn.. when it pops off use a flat screwdriver to pry out the old seal... coat the updated seal in lots of grease and use a socket of the same diameter to push it in evenly.. retightne the impeller.. than the cover, than the hose.. you can get the coolent full by just keep adding it to the overflow bottle start the eng and itll suck it in... takes like less than half a gallon total... process takes 20 minutes.. now that ive done it.. if it leaks again i could change in five minutes." - [jetjock16]
If you wait until you have a leak, you may also need to replace the following parts as well. Once the one seal is badly worn, the impeller shaft can get marred and it can damage the other seal and shaft bearing, requiring the engine side case to be removed to replace the parts.
93102-12106-00 Oil Seal (~$4)
93306-00105-00 Bearing (~$10)
5GR-12458-00-00 Pump Shaft (~$22)
2. Output Shaft Leak (oil leak around front sprocket)
Symptoms:
How do you know if your Output Shaft Seal is leaking? Just behind the shifter there will be oil running down the case. Usually when these go out they will leak quit a bit. Your skid plate will also have a good amount of oil on it.
The O-Ring on the output shaft has recently been updated from the original part number 93210-22164-00 to the new part number 93210-22298 (~$4). If there is no leak yet, you should be able to get away with replacing this single part. If you wait until it is leaking, then you may also need:
93102-32480-00 Oil Seal (~$7)
90387-2513F-00 Collar (~$11)
90215-21001-00 Lock Washer (~$3)
3. Decompression Plug (oil leak through plug hole from loss of plug)
Usually the stock decompression plug only pops out if you did the cam mod and/or you overfill the oil. It may be a good idea to replace it anyway as a preventative measure. When this plug blows out, your engine will start throwing oil out of the engine near the header pipe. The recommendation is to get the quasimoto racing decompression plug by Vibeguy (comes with the oil seal and an anodized aluminum plug) (~$16). The quasimoto decompression plug can be purchased at Thumpertalk and comes with Yamaha oil seal part number 93102-12224-00. The stock plug is black rubber with a circular aluminum disk built into the inner part of the plug. It is held in place only be the pressure on the sides. The anodized plug is held in place with a bolt that is already on the head of the YFZ whose sole purpose is to hold a decompression lever. First unscrew the decompression lever bolt (a little oil may leak out this bolt hole). To remove the stock plug, use a dremel tool with a drill bit so you can fit into the tight space and drill a hole through the stock rubber plug. It will be a little tough to drill because of the aluminum disk backing the seal. I usually screw in a dry wall screw inot the drilled hole so I have something to grab onto with pliers and then pull the plug out. Make sure to use a q-tip to remove any metal shavings that may have gotten into the decompression lever hole from drilling. Grease the oil seal on the inner ring and outer ring (do not fill the lip of the seal) and then put the decompression plug through the seal and then press the seal and plug into the decompression hole. Make certain the seal is flush and the plug and seal are pressed in all the way. Clean the oil off the decompression plug holding bolt and the hole it goes in, apply some blue loctite to this bolt and then tighten it in to the correct torque - DO NOT overtighten or you will strip the aluminum hole threads.
Also, it is always wise to inspect the engine mounts as it is fairly common to have these break (Engine Stay 2 and Engine Stay 3) and make sure they are not cracked.
Symptoms:
How Do you know if you need new front engine mounts? If you look at your 2 front lower engine mounts (they look like triangles with 3 bolt holes) there will be a large crack at either end.
The replacement parts for these are:
5TG-21316-00-00 Engine Stay 2 (~$7)
5TG-21317-00-00 Engine Stay 3 (~$7)
my 2 cents
quadsonly.com has billet yfz mounts
fantomzatv.com also has "decompression plugs"
or pm me for more info