Posted January 12, 201312 yr Moderator Well figured i'd go through this on here as it might help others see how problem solving goes. First up the surgery. With bike on my front paddock stand i made a start. Thing is an engine failing can have many causes. Rushing will make fixing much harder. A steady approach checking as you go is needed. As such i checked around the motor first. Head gasket good, base gasket good, ah... Bottom of the reed block is damp. The damp was coming from the carb rubber. The rubber has lost its shape and the jubilee clip was weak. These together caused a carb leak that leaned her out causing this.... And... You can see the swarf across the cases. The odd bit is the sheer size of the hole. I said the bike has done a couple of plugs and poor starting. The weak mix will have caused the poor starting and the dissintergrating piston will have fouled the plug. The inside of the exhaust is silver ffs. There is even swarf in the carb. The mains sound a bit ify. The big end seems good. The little end though is toast. So for reliability sakes new crank seals and bearings will go in. At the minute i have just the gear selector mech to remove then i can split the cases.
January 13, 201312 yr Author Moderator Actually its been an easy strip. I have a clutch tool. All the bolts are allen stainless. So no chocolate posidrives. I considered cleaning out and re using the mains but they sound horrid. One good thing. That piston you pointed out on the bay long time back will come in handy...
January 13, 201312 yr Dont take any chances bud, why not have that piston/rod mounted on a plynth as a momento? , they had one in cyprus from an old gokart when i was there last year You have 2 tins of roses propping up yoor B&D workmate... what the fuck dude? O.o
January 13, 201312 yr Author Moderator Steve those roses tins are worth their weight in roses. Ever needed stackable metal containers for parts. Did you not see the engine is sitting in a turkey baster. Reuse recycle. Or from my point of view. Squeze every advantage. More money for the bike. My touring rack for the tdr is 3 pieces of 1 1/4 by 1/2 inch timber. On a more serious line i will have a better line on the big end when the cranks out.
January 13, 201312 yr Moderator I am looking forward to this thread. Roses (and the like) tins are invaluable.
January 13, 201312 yr Author Moderator Several people have now pointed out the Ethanol problem. Looking like that may have been another nail in the coffin. If you run a 2stroke. Kicking the main up a size could save you some pain.
January 13, 201312 yr Blimey Jason, If you think your shed is cluttered look at mine. I'm sure there is some booze in there from at least two Christmas's ago.
January 13, 201312 yr Author Moderator Here you go.. Could have been worse. Looks like the swarf has stayed away from the bearings. Gut feeling says change the bearings and i'm not going to argue with it. The sounds like scrunchy bearing turns out to be swarf stuck between the crank and cases. Now the crank is out i can give it a proper rinse. The crank seals will go. Too important to risk for the time and money to change them. So order the bits and reassemble. Should be good for the weekend providing i can get the rebore done. 70hr weeks are a bitch.
January 13, 201312 yr Moderator is the rebore a consequence of what happened or just needed one anyway Jason?
January 13, 201312 yr Fk me jase " how hot must that have been,, was thier a pinking noise pior to the Blow,,
January 13, 201312 yr Author Moderator Fk me jase " how hot must that have been,, was thier a pinking noise pior to the Blow,, Nope nothing 50mph coming home from work same as any number other times. Just cut out. Thought it was fuel first.
January 13, 201312 yr Author Moderator is the rebore a consequence of what happened or just needed one anyway Jason? I have a. 25 piston and the bore although not scored has blued in places. A bore with a new piston and rings will be no bad thing. Will be looking at that temp gague though....
January 14, 201312 yr Moderator I have a. 25 piston and the bore although not scored has blued in places. A bore with a new piston and rings will be no bad thing. Will be looking at that temp gague though.... Ahh just give it a rub with some wet/dry and fit this little badly listed beauty http://www.ebay.co.uk/itm/NOS-YAMAHA-DT1275-GENUINE-PISTON-0-25-/261107092166?pt=UK_Motorcycle_Parts&hash=item3ccb320ac6 Seriously...It'l be cheaper than a rebore and pattern piston, the bore would have to be buggered to not give this due consideration IMO
January 15, 201312 yr Author Moderator Ha. No its a 0.0 bore and thanks to an eagle eyed bloke in some dodgy northern village. Who pointed me at one a while ago. Bit of an airhead apparently. I have one of them. Parts are on there way from Doug as we speak.(tytrials)
January 15, 201312 yr Author Moderator Its 0.25 not 0.0 ? No my bore is a worn 0.0. I have a. 25 gen yam piston.
January 15, 201312 yr Moderator kinell...not many o those around, now I get ya...youre saying I pointed a 0.25 your way in the past eh
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