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Help changing Clutch side crank seal

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Well I am not too sure if you have to split the cases, but I was doing that anyways so I replaced all the seals. You at minimum have to remove the clutch components and then the gears attached to the crank.

The seal was a very tight fit, so I would imagine its going to be difficult to get out without splitting the cases.

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man, thats a lot of work just to replace something that might not even be leaking

how do i check to see if the seals are actually leaking?

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What kind of bike? I know on a CR500 you pull the waterpump case/right cover, clutch, primary drive gear and CAREFULLY drill a hole in the seal...there is a bearing on the other side. Get a wood screw and screw it into the hole. Grab screw with pliers and work the seal out. On the ignition side do the same but remove the flywheel.

If your seal collar is worn on the clutch side, as in slightly grooved....replace it...it will leak even with a new seal.

For a leak check on the ignition seal...spray chem-tool or alike starting fluid behind the flywheel with bike running...if you rpm's increase you have a leaky seal.

Clutch side seal....fouling plugs, bike runs crappy, loosing tranny fluid a lot of spooge out of the silencer. This could also indicate a leaking center gasket also....50/50 chance.

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it's a 2003 cr 125.

Crap, seems like i do have a leaky clutch side crank seal.

whats a center seal? how do i check for that :x man, i might just end up selling this bike if it's a lot of manual work.

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it's a 2003 cr 125.

Crap, seems like i do have a leaky clutch side crank seal.

whats a center seal? how do i check for that :x man, i might just end up selling this bike if it's a lot of manual work.

If your seal is shot you will be sucking transmission oil into your crank case and out your exhaust. A centre seal is used on a twin cylinder engine, between the main bearings, not on a 1 cyl engine.

You do have a centrecase gasket however, which is located between the two crankcase halves.

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Make sure to lift up/down and side to side on the flywheel and the primary shaft (clutch side) to make sure that your crank bearings aren't shot. Like the primary collar, if the bearings are shot, you're wasting your time/money by just putting seals in it - they can't seal if the crankshaft is not running true.

Even if you have to split the cases, it's not that big of a deal if you're a bit mechanically inclined. I certainly wouldn't sell a bike just because it needed crank bearings and seals.

Best of luck. :applause:

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Make sure to lift up/down and side to side on the flywheel and the primary shaft (clutch side) to make sure that your crank bearings aren't shot. Like the primary collar, if the bearings are shot, you're wasting your time/money by just putting seals in it - they can't seal if the crankshaft is not running true.

Even if you have to split the cases, it's not that big of a deal if you're a bit mechanically inclined. I certainly wouldn't sell a bike just because it needed crank bearings and seals.

Best of luck. :applause:

this bike ran good on the first run after i bought it brand new. every single ride after that, the bike went to h*ll. 3 years running and till this day i havent been able to jet it correctly. i even took it into a shop and they said they fixed it and said it'll run fine. 2 rides later everything went to heck again. Is it possible that the seal started leaking after the first ride? I've dumped way too much money into the bike trying to get it running right. Before it would bog out when trying to take off from a stop (trust me i gave it half throttle and dumped the clutch). I know how to ride a two stroke. My friends dad said i was being a girl and that i didnt know how to ride it. He jumped on and bogged and fell over.

i've got it fixed a little, it'll run fine for 30-40 minutes then the spark plug will just foul out (black and wet)

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ok, I drained the tranny oil and there seems to be more than what should be in there. (i probably measured wrong the last time).

the oil is a bit dark grey/black. My question is if the seal is leaking wouldnt there be more pressure in the cylinder causing fluid to shoot into the case instead of into the lower crank area?

How can i tell if the seal is leaking just by the tranny oil. or is there no method for that?

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well, i changed the seal on my 03 250 the other day. VERY VERY simple to do.

remove the rear brake lever and kickstarter

then unbolt the clutch cover (the bigish one, not the round middle one)

pull the cover off

unbolt all the clutch bolts (6 on the outside with springs under them and one in the middle)

pull the clutch basket off and unscrew the bolt on the primary gear.

pull off the primary gear and the bushing behind it that rides on the crank seal

if there is a groove worn in it, replace it.

to pull out the seal just take the smallest drill bit you have and drill a hole in the side of the seal. then thread a wood screw in the hols and yank on it with pliers, it should pop out.

put in the new seal. i drove mine in with a big socket. make sure you set the deapth of the seal right, on my 250 it was 1mm into the case. look in a manual to find that out.

reassemble everything and make sure its all torqued right.

any questions just ask

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thanks for the help guys... I took the easy way old. Sold the dang thing and bought a 2005 yz125 for an extra $250 lol

Smartest thing i've done in awhile. that cr 125 was nothing but headaches since day one. i've been stranded out on trails many times because of that bike!

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thanks for the help guys... I took the easy way old. Sold the dang thing and bought a 2005 yz125 for an extra $250 lol

Smartest thing i've done in awhile. that cr 125 was nothing but headaches since day one. i've been stranded out on trails many times because of that bike!

Sometimes you just gotta' know when to cut your losses. Congratulations on the new bike. :thumbsup:

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Sometimes you just gotta' know when to cut your losses. Congratulations on the new bike. :thumbsup:

I'm still a honda member.. Got a crf 450 still :thumbsup:

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What kind of bike? I know on a CR500 you pull the waterpump case/right cover, clutch, primary drive gear and CAREFULLY drill a hole in the seal...there is a bearing on the other side. Get a wood screw and screw it into the hole. Grab screw with pliers and work the seal out. On the ignition side do the same but remove the flywheel.

If your seal collar is worn on the clutch side, as in slightly grooved....replace it...it will leak even with a new seal.

For a leak check on the ignition seal...spray chem-tool or alike starting fluid behind the flywheel with bike running...if you rpm's increase you have a leaky seal.

Clutch side seal....fouling plugs, bike runs crappy, loosing tranny fluid a lot of spooge out of the silencer. This could also indicate a leaking center gasket also....50/50 chance.

I never had to drill any holes. I just pulled the collar and carefully pried the seal out.

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do these sound like simlar symptoms ?

hard to start when warm

burnt 2 clutch's out in a month gear box is about 150 ml down after 2 days riding

oil out of bottom of exuast

and well smokey when cold!!??

bikes a cr 250 2007 bought late 2006 so its done its fair share of work! if it is this seal ill pop a new one in tuesday, it still rides fine just a bit expensive doind a clutch that often!

cheers jason

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Is the header full of oil? Does it foul plugs? Are they wet and oily black color? Does the bike die at half to full throttle? Is your exhaust spraying black oil out the end? These would be signs of a crank seal failure or possibly a bad center case gasket.

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