What damage have I done?
After a fairly hard ride through the forest, I was going through a field and bike suddenly sounded awful then died on me. I did manage to restart it briefly (probably stupid) but only using full throttle and it died shortly after.
Once back home I have removed head/cylinder as I thought maybe rings or piston had gone. Nothing catastrophic looking here though (was expecting bits in the exhaust!), although some points of concern to me.
- Rings look suspect (but both there!)
- Top of piston very black and looks as though wearing a dome into it! (didn't clean it as a mate wanted to see the parts in the condition they came out of bike to diagnose issues)
- Cylinder looks scratch free, but this was done in poor light. There do, however, appear to be small chips on the edge of at least one port.
- Conrod. Fairly sure I can feel some up/down movement there which I can only imagine is bad news...
When it happened the noise sounded horrendous and nothing like the video, but does it give any clues to anyone?
Just so you know, I am pretty clueless when it comes to engines - most knowledge has come from reading rather than practical experience so forgive my dumbness!
I will try and get pictures of the pieces to give you guys a better idea.
Bike sounds a bit flat but that could be all sorts.
Notice how you lost all power when the engine died. Do you have a battery on your bike?
If the bottom emd gave up then it would have destroyed the barrel. So without further photos it would be hard to tell.
What sort of mielage has thr engine done.
I'll listen mkre when I get time and offer some advixe.
In the mean time just check the fuses and make sure the ypvs does a cleaning cycle when you turn the ignition on amd off. You should hesr a motor whirl around when the ignition.turns on and off.
I will keep an eye on this and help where I can.
Yes it has a battery. I changed it just after I bought the bike as it was fubarred and not charging.
Before the incident it was doing the pv cycle at ignition. I had to(!) check incase exhaust was restricted so made sure that pv was working at the same time, but now that the top end is off I can't at the moment.
I have no idea what the maintenance of the bike has been like, but now suspect slightly lacking! Previous owner very upfront about battery and it needing new chain kit but rest of the bike was very tidy for a '97.
Will figure out how to post up pics and put some up of the various bits!
I'm wondering whether I hit the kill-switch now after watching again, it's possible I panicked hearing the noise.
However... You know what you're talking about and I dont, so will put stuff back on the bike to check pv is still operating!
Thanks a lot for helping.
Pv all works when back on bike. Although exhaust port and valve are very sooty (like piston/cylinder head) everything seems to move freely.
Battery still good, but sorry I forgot to check all fuses while I was out.
I took some photos of piston/head/cylinder incase they are a clue (sorry about quality), and I'm now pretty certain there is vertical play in the conrod.
Have I got a big shopping list?!
Literally just paste the image location. Nothing else required.
Don't know what's going on now, hopefully you can view it here...
Edit: I give up, removed http from link
I had another look at the bike this evening, and although nothing looks to have gone top end - there is a lot of play on the connecting rod. Side play tolerances I have not looked up yet, but i'm almost certain that there shouldn't be at least 2mm play up and down!!
If that's gone south and it means splitting the engine is this cost effective or am I flogging a dead horse? Would be such a shame as I really love the little beast!
Yep not a problem mate.
There should be no up and down play. And little side to side play is to be expected and within tolerance.
Sounds like the engine needs to be stripped down.
Again this is standard practice for two strokes and is incredibly simple job to do.
No real specialist tools required othwr than the crank will need to be sent away for a rebuild.
The rest of the engine can be rebuilt at home.with basic tools. Only a flywheel puller, clutch holding tool, torque wrench and a rubber mallet will be needed.
The bearings can be removed and inserted by placing the engine in the oven for a few minutes and letting the metal expand which will release the bearings. The rest is just simple stuff.
The most complicated bits will be rebalancing the engine. Which is self explanatory. Just matxh up the notches on the primary drive vogs. And balancing the clutch, which I have documeted here.
After thay it is just a case of using decent gaskets and genuine or Athena headgasket. Personally I would buy a full Athena engine gasket. And take lots of photos.
OK well it looks like I will be doing a crash course in mechanics then!
So apart from the tools you listed, is this what I should be getting?
Full gasket set (Athena)
Thinking about it, do I also need to take cylinder somewhere to be measured/checked incase of re-bore?
I would get the cylinder honed against a new piston. You will need to have a new piston to hone against. I would let whoever is doing the honing buy the piston. Or ask them if it needs a rebore. If they say no then buy the same sized piston.
There is probably a few tools I missed off the list. A good set of spanners and screwdrivers. So nuts and bolts to replace the ones you use is not s bad should.
Yeah, get it to a shop and ask if you will be fine with a hone. In my experience you don't tend to save much money by buying the piston yourself.
I mean sure, if you can get the piston cheaper then by all means. But the risk of buying the wrong one could outweigh the savings you might make.
OK so not much progress since last post, but I have now at least removed engine from the frame...
Still not made it to a shop to check cylinder, but have ordered a flywheel puller and made up a holding tool for clutch/flywheel which I'm chuffed with!
All prepped and ready to operate after a good clean. B-)