YAMAHA21 Posted July 14, 2016 Share Posted July 14, 2016 The light had been on for a little while but last time I checked there was still a fair amount in the reservoir, just forgot to check today and unfortunately it ran out while I was going down the road. I know I f**ked up. I just ordered some oil yesterday as well. The bike died similarly to as if it had run out of petrol. I pushed it home and changed the plug and put some cheap 2 stroke in it that I had in the garage. Tried starting it and at first it would die straight away and sounded different. I then unscrewed the oil pump bleed screw and left that out until oil was flowing from the drain hole. Now when I start it, it will idle okay but it still sounds a bit different (not as bad as at first though). What should I do from now? Is it just a matter of letting it idle for a while or should I take it for a gentle ride? EDIT: I think the oil issue is sorted now because the bike idles and revs as it used to but I'm worried that something was damaged when the bike died. There is a very noticeable 'rattling' or 'chattering' sound at idle and it gets worse when you rev the bike. Anybody know what this could be? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted July 14, 2016 Moderator Share Posted July 14, 2016 Oh you tit, I know exactly how you feel cos I did the self same thing a few years ago, although in my defence the bulb in the oil light had blown. Basically start saving, you will have done irreparable damage to the rings and to some extent the piston. It will never be the same as it was but relax as there will only of been damage to the upper cyl, the bearings will not have run dry. You may well get thousands of miles out of it, or, it may go in 500. Chances are good if the bike is in good normal health that will just mean the rebore will be needed earlier. The small rattle is most likely the little end bearing, another casualty but will be ok if mildly irritating. Like I said start saving, the clock is ticking but only a little faster than normal, it is a 2 stroke after all. Link to comment Share on other sites More sharing options...
YAMAHA21 Posted July 14, 2016 Author Share Posted July 14, 2016 I hate the fact that it might go at any point though, I use it to commute. Would replacing the piston, rings and bearing but leaving the cylinder make it any more dependable? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted July 14, 2016 Moderator Share Posted July 14, 2016 Nope, it is actually better as is than fitting a different piston and rings now. It would be like fitting a new chain to knackered sprockets. Your looking at maybe 100 quid to sort it, if your fitting a new piston you would be a complete plumb not to bore it, or if your really stuck, chance a good barrel and piston from a breakers. 2 Link to comment Share on other sites More sharing options...
YAMAHA21 Posted July 14, 2016 Author Share Posted July 14, 2016 When you say 100 quid to sort it, do you mean the cost of just the parts or is that about what it would cost to get done at a garage? Is that including a rebore as well then? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted July 15, 2016 Moderator Share Posted July 15, 2016 Lol. Thats you doing it my friend. 2 Hours to strip. Hour messing about with the rebore. ie sending it away. Another 2 hours to rebuild with fresh coolant and gaskets. I would expect it to be under 500 from a good independant. But in the smoke. Who knows. 1 Link to comment Share on other sites More sharing options...
slice Posted July 15, 2016 Share Posted July 15, 2016 Yep as above, £40 to £50 an hour plus tax and the parts plus anything else they can hang off of the bill. D.I.Y are the watch words for smoker owners. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted July 15, 2016 Moderator Share Posted July 15, 2016 1 hour ago, slice said: D.I.Y are the watch words for smoker owners. Amen to that. Its dead easy to do. So long as the exhaust nuts come off easy your fine. As to economy. E.ay is your friend. Dont be scared of gen parts from fowlers there is little difference cost wise except for yam headgaskets and piston/rings. The pistons are made of gold i think. DO NOT SKIMP THE HEADGASKET. GEN OR ATHENA ONLY. Cereal box will do for the base gaskets and such. Make sure to re radius the powervalve as well as clean off all the crap that will be there. Like i said its an easy engine to work on. Dont even need to pull the carb. Disconnect pv , drain the water, 1hose, 6 head nuts (watch the temp sensor) 4 base nuts. 1 piston circlip. Im genralising a little but it really is that simple. Clean off old gaskets. Reverse opperation with new/worked parts. Leaving the piston gudgeon pin in the freezer for an hour helps too. As well as fitting the LHS piston circlip before you try to fit the piston. Link to comment Share on other sites More sharing options...
blackhat250 Posted July 15, 2016 Share Posted July 15, 2016 Grampian Enginering [Liverpool,], theyre the dogs,, just send the barrel, they will supply piston, and see if it needS + 25-.50, Depending on cylinder out of round or grooved, , turn around fast too. Yeh Jason, its a pure bstd , when you need a light to tell you, that oil tank is 1 ltr, capacity , and you shove in 50 ltrs of fuel , and pump ratio is 30/1, Link to comment Share on other sites More sharing options...
Moderator Cynic Posted July 15, 2016 Moderator Share Posted July 15, 2016 Ah. So you say but. Last year i did the entire trip without needing oil. Had over 600miles on the clock before the light came on. Running the pump means you can be way down. Like 60 or even 70 to 1. Least i knew which turn to take. 1 Link to comment Share on other sites More sharing options...
YAMAHA21 Posted July 16, 2016 Author Share Posted July 16, 2016 He shoots, He Scores... I'm gonna order the parts and do it myself. I know a rebore place so I'll just drop the cylinder off to get rebored. I checked the small end bearing and there wasn't really any play, there was a bit of play coming from the crankshaft though. I'll order a new bearing just for the sake of it though. Thing is, I need the bike fairly soon but the 0.25mm o/s piston and rings aren't in stock at fowlers. Would it be terrible to rebore it to 0.50mm o/s just because they are in stock? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted July 16, 2016 Moderator Share Posted July 16, 2016 .25 is a really optimistic option, its only actually 0.1mm of material removed from the bore which is not much. .5 would be my choice, when my tdr blew I had to go a full 1.0 oversize because of the damage to the bore. You can get o/s pistons up to 2.0 mm so don't worry. If its any help the black around the rings on that piston suggest quite a bit of ring wear anyway, you probably only had a couple of thousand miles before she popped anyway. 2 Link to comment Share on other sites More sharing options...
blackhat250 Posted July 16, 2016 Share Posted July 16, 2016 Hes right, .50 will take out the oval wear too, . that's why Grampian supply, ,, saves you buying a.25 piston that you cant use, Don't ask how I know,, Link to comment Share on other sites More sharing options...
YAMAHA21 Posted July 21, 2016 Author Share Posted July 21, 2016 Any idea what piston ring goes where? I have a thin one and a slightly thicker one. I know the expander ring goes under the bottom ring so I'm thinking the thinner ring goes on the bottom? EDIT - Don't worry, just figured it out. Link to comment Share on other sites More sharing options...
YAMAHA21 Posted July 21, 2016 Author Share Posted July 21, 2016 So I've rebuilt the top end and the bike works. However it's quite sluggish and doesn't rev as much as it would have with the same amount of throttle as before. How do I know if the power valve is set up properly? I've adjusted the cables so that the gap on the pulley lines up with the hole behind it. Does that mean the power valve is set up 100%? Or is it a matter of running the bike in and it will start to rev better? One other thing, I can now notice a slight rattle/tapping coming from the power valve, Is that normal? EDIT- I've just seen this thread, my pv rotates clockwise when I rev the bike, Is this wrong? Link to comment Share on other sites More sharing options...
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