OzVMX Forum
Marque Remarks => Honda => Topic started by: rls840 on July 25, 2009, 08:02:54 pm
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Got a beautiful 84 CR250 with the dreaded coolant leaking into the gearbox. Anyone recommend someone who could repair it. Hopefully there's someone out there who knows a good trick to keep it from doing it again anytime soon.
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Try emailing Bruce (Magoo) at www.red-devil-racing.com
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Thanks for the tip Ross, I've sent those guys an email. Hopefully I'll get some success. Anyone else got any ideas?
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Most of the time repairs are done with devcon or a similar product ( a 2 pac epoxy, liquid metal type product)
I've done the same repair to my Husky, not to hard, just make sure you remove all the affected magnesium.
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Hi rls840, they are a very hard thing to weld and I have 3 off these bikes and have Devconed them all. one has been done for over 3 years with no problems at all.
Shane
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i have the same problem were do i find devcone?
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Devcon - or other metal replacement mix - usually better auto shops. Can also get 2 tube premix jobs which work well also.
cheers
Rossco
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Thanks stw and Rossco. it has been fairly heavily devcon'd already but I guess a little more couldn't hurt!!! Is there any particular coolant that you recommend that is easy on the magnesium??
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Any peice of magnesium that comes into contact with water (even if mixed with coolants will only slow the corroision down) is going to rust! My advice to anyone is to treat or paint the insides of any component be it engine cases,wheel hubs,backing plates ect ect because most of the little surprises we find are the ones we cant see. You dont have to paint the outside if you dont want to (if your after a certain look) because you can wipe it off and keep an eye on it. Water will seep into anything and then sit on the bottom under oil ect even in non water cooled engines. There are plenty of good products out their so theirs no excuse for not doing it. The worst thing with magnesium is trying to weld it so this is definnitly one for preventitive maintainance. Cheers John.
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I've repaired a few Hondas with the same problem over the years. Trick is to get rid of all the corrosion by having the affected area sandblasted. Then use JB weld and press it into it and shape it before it goes hard. The stuff is great and it shouldn't leak ever again. And I also paint the expose magnesium to prevent further corrosion. I had one on a Cr500 that rotted right through inside and out and worked great.
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rls840 all good advise from the guys so remember you are not alone on this one.
Go for the better brand of aluminium putty (devcon is a brand name an is one of the best), if you can bead blast the affected area first and then apply. If Pianting use the VHT hi-temp exhaust paint is sets like concrete and is very hard to remove specially if you do the baking process they advise.
Any good bearing shop stocks Devcon, it can be filed and even machined if applied correctly.
Shane
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can the cover be welded up and then have it machined?
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can the cover be welded up and then have it machined?
Well yes it can but you need someone who isa very good welded to do it as the alloy is not of high grade.
Shane
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yes, as Shane said (providing it has never been repaired before by Devcon of similar stuff, if it has it must be TOTALLY removed before welding) there is a degree of risk getting them welded, you need to take it to someone that is VERY experienced in this kind of work, and has done it many times before with success. don't take it to someone who says "i will have a go"
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magnesium welding is a very expensive, each rod is worth about $20-00 each :o and if he gets it too hot it will catch fire
Mega poxy is the same as Devcon ( and can be worked by hand in water ) drys in about 12 hours ;)
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Yeah the Magnesium filler rods are expensive allright.
Never set fire to a case yet.
Surprised to see a lot of you guys recommend this putty stuff, personally I hate it as the cases that come to me still leaking means I have to dig all that shit out to be able to weld it.
I guess the ones that work are the ones I never see.
I wouldn't say the Mag. is low grade alloy, it's just mag, that's the price you pay for lightweight.
Do you have a picture of the problem area RLS/
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Ill take one and post it ASAP. Cheers
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I wouldn't say the Mag. is low grade alloy, it's just mag, that's the price you pay for lightweight.
Yes Geoff you are correct it is not a low grade (usually) but the cases Honda made early on were not of a high percentage (to be more correct in what I am saying) of magnesium but just high enough to make them a real pain to weld specially with 20 years worth of corrison on them.
I can and do tig weld but tend to say away from high magnesium do to the trouble with welding it, but if you are doing it day to day I am sure it comes a lot easier.
The types of devcon on the market these days is very good and it is a lot easier for the usual Joe blow to use then having welded, but in your case Geoff I am sure it is not beyond you.
Shane
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Geoff - good to catch up at the Nats - good to put a friendly face to a name. I have just opened up the 83 CR250 I have bought (low hour machine) and found some corrosion in the water pump area (surprise surprise) and what looks like a buggered water pump seal. Anyway I find "liquid metal" ie Devcon etc to be pretty good as I didn't think it was possible to do such a small repair through welding etc. Seriously is it worthwhile sending through to you to have a look at or should I use the Devcon etc mode. I am just a big believer in doing a repair once and once only??????????
As always Geoffery I rely upon the expertise of GODS such as yourself for those of us not so mechancially minded!!!
cheers - your best customer (oh sorry not enough bikes thats right ;D)
Rossco
PS - I can always send the case over with the footpegs if I dont mind getting protested for oversize footpegs :D
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Yeah, good to meet you at last Rossco, but at the moment Brad's one of my best customers as he wins more titles ;D
Repairing properly first time is best advice on many things but I really need to see the case.
I only charge $100.00 for free advice if you want to send it over with the pegs. ::) ;D
Welding corroded Mag is like welding rusty steel, you have to cut away the crap to get back to some good material, & these side covers are compounded by hard to reach nooks & cranny's.
These putty things only seem to stick in the nooks & cranny's, & it's the hardest spot to dig it out of. I guess it may depend on how clean it is when its put on.
I believe Red Devil can help you with seals.
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Geez - you really know how to make a guy feel good don't you - class 101 how to win friends and influence people.
Geoff - might send it over so you can have a look mate.
I don't think I can ever comepte with Brad regards titles but maybe I can send more work your way !!!!!!
cheers
Rossco