wild foamy Posted October 14, 2008 Share Posted October 14, 2008 hi everyone where's the best (cheapest) place to get a head gasket for a Yamaha DT50MX (1990) or would it be possible to cut one out of gasket paper (if so what thickness gasket paper) - Steve Link to comment Share on other sites More sharing options...
joshh Posted October 14, 2008 Share Posted October 14, 2008 my stepdad, and mum (who by the way were both very into bikes) tell storys of how they used to make gaskets out of cerial boxes lol! and i had to make one for my dt175 and it worked fine lol! Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 14, 2008 Moderator Share Posted October 14, 2008 Head gaskets are made from copper and are quite critical so i would be buying new ones. Any motorcycle shop will be able to get head gaskets for your bike. You can make the base gasket at the bottom of the barrel from gasket material, cereal boxes are especially good. Link to comment Share on other sites More sharing options...
wild foamy Posted October 14, 2008 Author Share Posted October 14, 2008 well i fired up my trusty thrusty yammy today and noticed it was blowing from the head. inspection with a torch revealed that there is a little leak around the seal of the head, so im assuming the gasket has been cooked or the head hasn't been tightened correctly (which would ruin the head gasket, no?) my nearest dealer is ProBike, and im not waiting another 3 weeks for them to get a head gasket in... took them 4 weeks to get me a sprocket, would rather mail-order from the 'net Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 14, 2008 Moderator Share Posted October 14, 2008 well i fired up my trusty thrusty yammy today and noticed it was blowing from the head. inspection with a torch revealed that there is a little leak around the seal of the head, so im assuming the gasket has been cooked or the head hasn't been tightened correctly (which should ruin the head gasket, no?) my nearest dealer is probike, and im not waiting another 3 weeks for them to get a head gasket in... took them 4 weeks to get me a sprocket If its a copper gasket and youre in a hurry, get a blowtorch hold the gasket with some long nosed pliers and heat the gasket around its circumference until it glows red, this will soften (anneal) the copper and is good for using head gasket one more time, Dont forget to use a torque wrench on the head nuts, If you use too much force on these old bikes you can pull the studs out of the threads so use the recommended torque setting. Link to comment Share on other sites More sharing options...
Moderator mervin Posted October 14, 2008 Moderator Share Posted October 14, 2008 Ere you go my old mate Dave,( Yambits) has the top end set £6 + postage DT50 gasket set Link to comment Share on other sites More sharing options...
wild foamy Posted October 15, 2008 Author Share Posted October 15, 2008 i'd be best putting a new gasket on methink, the bike has done 22k so its bound to need replacing (the rest of it is almost pristine though). will log into ebay and get one when i get home. have had t take the seat and tank off to get to the head though Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 15, 2008 Moderator Share Posted October 15, 2008 If she's done 22k do yourself a favour and decoke it. Sounds posh but when you take the head off have the barrel off as well and then clean off all the carbon from the piston and the exhaust port. Give the exhaust a good seeing to as well if its the original, something stiff like a bamboo garden cane to clear the tubes roughly then leave it overnight with a really strong causic mix, not some daft kitchen cleaner like cilit bang but a proper caustic, you can buy the crystals and make a strong mix. This will clean out the bits you can't get at and will not touch the metal. Give the piston the once over as well checking for scoring and any serious blow past of gasses,(indicated by a dark stain down the sides of the piston). It will be far easier on you and the bike to catch anything like a worn piston early. The little end bearing is also something to check as when they fail their component parts generally end up in the big end bearings and they were never meant to meet. Then you have a few weeks to get the parts/cash together at your leisure if you need anything rather than a big rush cos its siezed in the rain somewhere really awkward (it always is). Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 15, 2008 Moderator Share Posted October 15, 2008 then leave it overnight with a really strong causic mix, not some daft kitchen cleaner like cilit bang but a proper caustic, you can buy the crystals and make a strong mix. Caustic is a very good way to clean carbon yes, only use it on steel exhausts, not on anything aluminium. Wear gloves and goggles too because you will get serious burns if you get any on you. Link to comment Share on other sites More sharing options...
wild foamy Posted October 15, 2008 Author Share Posted October 15, 2008 the bike had the engine completely rebuilt because the perosn that owned ti before the bloke i bought it from ran it out of oil and it seized. not sure what happened to the gasket though... will be sure to give it a good seeing to when its all stripped down though. the exhaust has only done about 5k as its an after market "BIgOne" (coupled with the correct expansion chamber.) btw, what tourque should i be using on the head bolts? i havent been able to find out Link to comment Share on other sites More sharing options...
wild foamy Posted October 21, 2008 Author Share Posted October 21, 2008 erm, anyone got any ideas RE: the torque on the head bolts?. now have a head gasket so am just about ready to change it Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 21, 2008 Moderator Share Posted October 21, 2008 In the absence of anything better use the torque wrench to see what torque you need to REMOVE them and then use that to tighten them up. Not perfect but for want of anything else will get you about right. And more importantly they will be even, dont forget to do them gradually and in a diagonal pattern. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 21, 2008 Moderator Share Posted October 21, 2008 erm, anyone got any ideas RE: the torque on the head bolts?. now have a head gasket so am just about ready to change it What size socket fits...13mm? The torque setting for my 175 is 18lb/ft or 2.5 kgfm, this has 8mm threads so 13mm socket (sometimes 12mm), these settings will be fine for yours too assuming they are the same size studs. Link to comment Share on other sites More sharing options...
wild foamy Posted October 21, 2008 Author Share Posted October 21, 2008 its around 13mm, wouldnt imagine its that much smaller. thanks for the advice, will give it a try at the weekend when i got some spare time Link to comment Share on other sites More sharing options...
Dufferz Posted October 25, 2008 Share Posted October 25, 2008 its around 13mm, wouldnt imagine its that much smaller. thanks for the advice, will give it a try at the weekend when i got some spare time i've got a copy of the Dt50MX manual laying around somewhere on this pc, if you still need it i will gladly upload it, it has all of the torque settings Link to comment Share on other sites More sharing options...
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