Hi guys, I was on my way to work the other day - bike was running the best she's ever ran and 5 mins later she was losing a bit of power, then engine started sounding rough and next conked out making the most horrible noise ever from the engine. Engine was extremely overheated, kickstart is stuck at top and electric start won't turn over. Anyone any ideas

all the best n happy riding, Louis

Sounds like lack of lubrication. Take a look and see if it has any oil in it.

Story heard time and again, oil runs out and for a short time the lack of drag on the internals gives a bit of a false impression of smooth performance. (I'm not preaching I have done it myself more than once, too much to do to check the oil, was ok last time) Then once the oil drops beyond the critical level, the metals contact, bearing faces go and she's dead.

Large aluminium doorstop created.

Unless your lucky the damage will be everywhere that the oil did/does go.

Yep as above, you've fucked it! Take it apart and see how much damage there is, if the mains / small end and barrel are toast look for a replacement motor. Not a "cheap" option but it means your bike will be back on the road quicker than faffing around tryin to fix it in the dead of winter. Then you can rebuild it while still having a bike to ride to work on. Plus you can sell it on once you have your original motor sorted.

Seen a  clip on Tv,      in a car park,   they lifted 10 bonnets, and 8 out of  10 were low on oil,    owners never checked them EVER,

Just been out to check oil level and she's sitting pefectly at top mark. Bike always gets well looked after. I'm not getting spark from the engine either btw...

15 hours ago, 125fightingmachine said:

Just been out to check oil level and she's sitting pefectly at top mark. Bike always gets well looked after. I'm not getting spark from the engine either btw...

Well if the starter wont turn and the kick start is stuck at the top then the engine is seized, oil in the engine or not it can happen. 

There are two types of sized engine, a "soft" size and a "hard" seize. A soft seize is caused by overheating, the engine can usually turn over again after it cools down and maybe even run, a hard seize is a mechanical failure meaning something inside is stuck, bent, twisted or broken. Does the engine turn over now, or is it still stuck? 

The issue with spark might have been caused by an overheating, engines, nor the delicate electronics inside them are designed to get that hot. 

hit the nail on the head there vario! Sounds about right.. Will take the side cover off over the next couple of days. Cheers for all the help

 p.s. She's still stuck 

1 hour ago, 125fightingmachine said:

hit the nail on the head there vario! Sounds about right.. Will take the side cover off over the next couple of days. Cheers for all the help

 p.s. She's still stuck 

you certainly won't get a spark unless the engine turns over, the system for generating a spark relies on the engine to have rotation. no rotation = no spark.

keep us informed, would love to know what has happened to it.

If she has oil it could be either an air leak or an ignition fault giving the extra performance, generating more heat, causes the piston to overheat and either pick up on the bore because the piston has expanded past its limits or the top has melted through.

The fact she wont turn over is pretty damming.  An engine that is solid needs tearing down to find the solid part(s).

sounds like quite a dawnting task so might take it into the bike shop at some point. Could be a while from now as we live so far up north

Easy if you have the manual and some where warm(ish) to work. Should take about 2 hours with a set of tools and a cup of tea. Save yourself some money by taking it apart yourself and just get the bits that are fucked to the local engineering shop.

 

9 hours ago, slice said:

Easy if you have the manual and some where warm(ish) to work. Should take about 2 hours with a set of tools and a cup of tea. Save yourself some money by taking it apart yourself and just get the bits that are fucked to the local engineering shop.

Agreed, a Haynes manual gives you all the info you need, last time the top end had to come off my engine (the same engine) I managed all of it with a 1/4 socket set and a sketchy cheap torque wrench. It's really not as hard as it sounds, but, since it doesn't turn over even after it's cooled off it sounds like the engines fucked to be honest. You can pick up another YBR engine for £250 on ebay, that might be the best option

I agree with the above. Pickup a replacement engine and then strip and rebuild the original at your leisure. That way you'll be on the road and get experience of stripping and assembling the engine