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Cr magnesium case question

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I recently picked up an 85 cr250. I knew all about the magnesium clutch side cover long before I bought  the bike. The cover looked perfect on the outside so i figured it had been replaced.  Well it was replaced not with the newer aluminum style but with another magnesium cover. My guess is someone had a nos cover left over when it was replaced. Right now the cover is off the bike. I needed to look at the kickstarter and i thought the water pump seal might be leaking.  The case looks very good on the inside of the water pump area. 

So here is my question,  how long do you think the case should last. Will using waterless coolant make it last longer.  I know it will eventually rot out but how long are we talking about. 5 years 10 years,  20? What do you guys think? This bike I'm planning on keeping for a while should i buy tne aluminium cover for the future. 

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You think there might be some kind of coating you could apply on it to protect it from rotting out? Just a thought. I myself don't know of one but maybe some else here has some experience and may know of something.

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I recall reading that someone got a new Honda replacement aluminum cover for under $100. In that case, I'd do that. Is the sidecover common with an '89? Maybe he had a later model? If so, I think he found a new one cheaply. For my '83, some guy in Australia, I think, is remaking them, but they are like $500 or $600 dollars with shipping...

 

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45 minutes ago, Sofiedog said:

I recall reading that someone got a new Honda replacement aluminum cover for under $100. In that case, I'd do that. Is the sidecover common with an '89? Maybe he had a later model? If so, I think he found a new one cheaply. For my '83, some guy in Australia, I think, is remaking them, but they are like $500 or $600 dollars with shipping...

 

I did some research today on the 89 parts. For everything i would need new im looking at $250- $275 . You need the inner case, outer case , kickstarter seal, waterpump seals and bearing, alignment pins, oil fill cap, another plug and a 4 gaskets.

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Well, in that case, if I had a mag alloy cover that was relatively corrosion free, I would just run the waterless coolant. Are you replacing your hoses? The water fittings on the '83 sidecover were mag alloy also! That's a place where moisture sits, between the hose and barb. Anyway, check those too and chip away any corrosion on the mag alloy.with a dental pick.

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I don't know if this will work on your bike, but for our antique tractors there is a thing we put in with distilled water and it's like an epoxy type thing that coats all surfaces. It will seal leaking radiators and other parts that corrode. It's a corrosion inhibitor I think.

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15 hours ago, Sofiedog said:

Were you seeing a drip through the weep hole? Is that why you thought it was leaking?

Gearbox oil was milky. When I pulled the water pump apart you could tell the seal was bad. I don't think it was a bad leak but was still leaking. 

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5 minutes ago, Sofiedog said:

Sounds right. It should be straightforward to replace the parts. Probably means the water seal and the oil seal were bad.

Replaced them last night . Didn't quite get it all back together , about 30 minutes more work and she will be ready to test out. I'm glad I pulled the cover. I found a piece had broken off the arm that controls the ATAC exhaust valve. It was sitting on the bottom of the case. If it had made it into the gears the transmission would have been destroyed. 

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Dang!!! See...regular maintenance to fix the little things often turn up potentially larger issues...
I read the ATAC doesn't really affect porting like a power valve? It opens an exhaust chamber at low rpm? My '83 doesn't have that. I think '84 and '85 had them then Honda changed in '86 to a different concept?

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4 hours ago, Sofiedog said:

Dang!!! See...regular maintenance to fix the little things often turn up potentially larger issues...
I read the ATAC doesn't really affect porting like a power valve? It opens an exhaust chamber at low rpm? My '83 doesn't have that. I think '84 and '85 had them then Honda changed in '86 to a different concept?

84 and 85 had the ATAC, 86 had the power port. The bike runs just fine with the ATAC not working, it was more of a sales gimmick than functional. 

Back on the magnesium case I found this coolant at my local bike shop

20170622_181300.jpg

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in my old 85 cr500 magnisem cover i cleaned it all in the water pasages and pump cover and epoxied everything so it can not corode any more.

i have heard of guys draining the coolant between rides in order to limit corosion.

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