Hi,

Please help.

I've not done any work like this before, but I've just completed a top end engine rebuild (small end, gudgeon, circlips, piston & rings) and now the bike won't kick - what have I done?

I followed the steps in the manual, the bike kicks over fine without the spark plug in, but once the spark plug is in the kick starter is solid and the bike is impossible to kick over.

The bike is a Cota 315r.

Hi Dacota: I have just completed a top end rebuild myself (see post under "more piston slap - how do I know), I have to say that I dod notice an increase in kickstarter resistance when I put it all back together but not a completely stuck starter, especially if it kicks over okay with no plug in. Hopefully someone with more experience than me can offer a solution on here.

not sure but as a young lad i did similar and i had got the piston in the wrong way round.

If it kicks over without the plug but is solid with it.. it must be either the plug fouling the piston or massive compression. will it not move foreward or back at all. how about putting the plug part in until it locks up ..i dont mean trying to start it just to physically turn it over whilst trying to feel any mechanical connection..I mean it is the right plug isn't it? you got your gudgeon pin circlips in? and piston rings fitted right?.. you wouldn't have got the barrel on if the rings wern't in place, is it possible to fit the piston backwards.. you don't want the ring stop pegs /ring ends running over any ports.

I don't think that it's possible to diagnose a problem over the internet. Sure we could all post a few suggestions as what could be wrong but to be brutally honest if you've not got the technical ability to do the job then please take it to a shop and get it sorted properly.

It could be as simple as too much oil in the bore and the bike is 'hydraulic locked' or wrong / missing gaskets giving too little clearance but I think you should take it to a good local dealer and have it checked out, you'll be far better off in the long term.

Forums are great for some help and advise but you need good basic engineering practices first.

I wanted to say that but am too nice ha ha... you're right though

Spins over good with the plug out but locked up with it in? Any signs of the piston hitting the plug? Was it just so down on compression before that now it feels like its locked up?

Providing he just rebuilt this rattlecan , this could be his first taste of what real compression really is in these things! Thay are tight! Yet, barring excess oil, whish should be mostly expelled when kicking over without plug, and the plug not being too long causing mechanical interferance, the lever should push through the compression stroke with slow constant pressure untill top center is found, then a good leg on it should get things spinning through.

And no, we never fix anything oner the internet, just get the ones at the other end pointed in the right direction so they can manage, hopefully!

Did you manage to fix this? if so, what was the issue in the end?

Hi all,

I just wanted to say thank you for all the encouraging (and even the less encouraging) support.

Paul W's note gave me the optimism to pull it all apart again. I was expecting that I'd done something daft like put the piston in wrong, but no - it was fine.

In the end I don't know what the problem was, but its working fine now and sounds great. I'd say the compression is more than I had before and maybe that was what I was worried about, maybe it was hydraulic locked, maybe it was all just over-cautiousness on my part, I'll never know.

I'm not a complete novice when it comes to car mechanics and have good quality tools, but I'm not overly well versed on motorbikes and especially 2-strokes, so this was all new to me and I've learnt a great deal from the experience.

I accept that diagnosis over the internet is impossible (I should know - I'm in IT), I really just wanted some ideas before going to the stealers as I'd already spent a great deal on parts.

Thank you all once again and all the best for your season's riding.

I don't think that it's possible to diagnose a problem over the internet. Sure we could all post a few suggestions as what could be wrong but to be brutally honest if you've not got the technical ability to do the job then please take it to a shop and get it sorted properly.

It could be as simple as too much oil in the bore and the bike is 'hydraulic locked' or wrong / missing gaskets giving too little clearance but I think you should take it to a good local dealer and have it checked out, you'll be far better off in the long term.

Forums are great for some help and advise but you need good basic engineering practices first.

Mostly I disagree!

The combined knowledge of the internet surpasses many professional mechanics.

Only ever take anything to a mechanic that someone specifically recommends.

hopefully when we find out what he did wrong we will all learn a bit more.