Ok, I am a newbie, With that said, I bought a blaster that ran but blew smoke.It had 100 PSI in the cylinder. Once opened, the piston was missing the entire skirt from one side. I was amazed on how the bike ran after a catastrophic event .It appears than the remains went into the lower case. I shook the case and removed most of the metal. The bore is 2.57 measured with a calibrated micrometer and no scratched on the cylinder walls and a hone should do the trick. I need to open the case and manually remove all debris from the crankcase and replace the connecting rod that has a "wobble " to it. Does anyone want to share any hints, tricks or just stuff they can give advice on. I have no problems going in. Any thoughts. The clutches look great and evenly spaced.

 

Sound like you have experience with these things but, I'll give ya a little fyi. Me and my bro rebuilt a little blaster while back. The electrical housing thing, ah.. I'm having a brain fart and can't remember what it's called...anyway I think you can figure out what I'm talking about. It's pressed on. You need a puller that you can get at yamaha or about any shop to pull it off. I didn't know this and everything was closed for the weekend. Put me at a stand still the entire weekend.

 

Also, if your in there anyway check all the bearings. There are quite a few in there and on ours about 3 had missing rollers.

 

check out boomer/rydin dirty.com great site for mods and how to's good luck

 

I think it's Hot Rods that makes a nice stroker crank while you're at it. Imagine that along with a 240 top end conversion...

 

we had a quadzilla mess up a piston.we chained the whole zilla upside down from a tree and sprayed the motor out with carb cleaner and it did the trick.while we was spraying the carb cleaner we would spin the crank with the piston rod.

 

Ok, I am still a newbie, just an Ignorant one. I have played with cars and this is my first project / basket case on 2 or 4 stroke. Everything was assembled and ran which amazes me to begin with. If the skirt of the piston went south, I can only assume that I need to crack the case to do it right and it will be beneficial to inspect / check and replace any worn component. lets start with the separation of the case. Can I leave the magneto /flywheel side intact and just remove the clutch side gears and separate the case. I am worried about separating the case in half and then a pile of parts will jump out without knowing how they went. I am more concerned with the shift fork assy. As for the bearings. If it looks good and rolls smooth, just leave them? How are these inspected and decided on if they should be replaced or not. The crank / rod piston balancing question. Is this a concern for a two stroke. I need to replace the crank bearings / rods anyway. is there a cheap balanced kit. I am not looking for speed but reliability. Any comments are welcomed.

 

Well, I think you have a good idea to begin with. Ask all those questions BEFORE the rebuild.

I'd highly recommend a manual of some sort. The tolerances and wear limits will be listed. Also the configuration of all the innerds.

Looking for the proper parts to rebuild, will be a matter of confidence. If you don't have confidence in the seller, then don't buy it. I recommend some web research (some sites already listed here for performance upgrades, but dependability is a different approach I think). If you want depndable, buy Yamaha parts or well known name brands. Wiseco is a great brand piston kit(as an example).

Go slow and ask around some more. But Certainly a manual on ebay at the very least is in order.

 

If it was me I would spend the $s and get a yamaha shop manual beofre spliting the cases. The Clymer manuals are a lot less $s but not really all that informative .

 

have ordered a manual on EBay 2 days ago. I will need to get the torque specs . Everything else should be straight forward. I am currently spending the next few weeks wire wheeling the frame clean and replacing the front bushings and swing arm bearings. I need a few cables as well so I may be replacing all of them because they are cheap. I guess I really need to take my time and take apart the engine slowly . If I buy a gasket kit /seals, Will it include the part numbers for each piece. lets say I have this O-ring and I don't know where it goes and perhaps the place it needs to be is missing it, Can I search on the part number in the manual and find the location. Does that make sense? Will the parts come with numbers or will it be a scavenger hunt *l*. I also have a question about the reed valves. How to inspect them, Know when to replace them and how do they function and what symptoms will they show if bad. I have no idea what these things do *lol* Also if the case is opened, What is the determination for replacing any internal bearings. if it looks good and moves freely should I just leave it alone?
Thank You