My bike's siezed up :o(

[stevo as b4]

Yeah its not always neccassary to re-jet when you de-restrict the motor, unless the manufactuer specifies it. Many 125's dont need any re-jetting, after de-restriction, but a few do, like the Mito etc.

Its true what people say about you need to at least take the top end of the motor apart before you can even begin to find out what went wrong. You mentioned the sparkplug colour is ok, with no signs of weak mixture or overheating. Its similar to my KMX200 when it went pop. basically there was a loud metal clancking sound whilst the motor was on the overrun, and i didnt pull in the clutch straight away, beacuse it freed off, but stopped anyway. When i checked the bike over at home, it seemed like there was little resistance to the kickstarter, so the compression has obviously been lost. The plug was very black and sooty, so it certainely wasnt running lean. The only other clue i had is that there was a continuous dripping of transmission oil from the bottom of the engine. Ill take the motor out over Xmas for a stripdown, but i think that my bikes problem is a bottom end one. Possibly blown crankcase seals/ broken main bearings, or a big end break up that might have even cracked the cases somewhere.

If your problems are top end, then i would have a go yourself, at doing a re-build, just get a Haynes manual, and make sure you have plenty of boxes and containers to store the parts in order as you remove them. My KMX will probably need a re-plated cylinder, as its done 20'000miles, and i want to tune it anyway, so i want to start with every engine part being replaced with new, so that its reliable.

parts are not really that cheap for engines either, it cost me about £90 on a KMX to replace two broken powervalves, head gasket and all the other seals, O'rings and gaskets required. So paying a garage labour on top would make for a big bill.

Im estimating my motor to need about £400 in parts for a total re-build, as all the bearings, seals, gasket sets, etc add up. A crank re-build or a new crank will probably be £200 on its own!

[Fallen Angel]

Thanks everyone, you're help is very much appreciated!!

Got some mates who know that their talking about coming over on Saturday to help us take it apart to see what the problem is and we'll go from there!!

Again - thanks
Fran
____________________
I have an asshole tolerance level of -10
www.cliqueyclanmcc.co.uk
www.bebo.com/fallenangelfran

[synaptyx]

Bummer, hope the repairs all go well and don't end up costing you tonnes.

[Fallen Angel]

ANOTHER UPDATE

Not that anyone will be interested

Just stripped the top end of the engine down and it looks like I'll need a new barrell (it's not the kind that can be re-bored apparently) and a new piston, as bits of it have actually melted off. There's also parts of the piston ring missing - some of it was in the exhaust, but we're still missing a section of about 1inch somewhere!!! If I dont' get a complete new engine, we'll have to strip down the lower part of the engine too just to check that that bit of the piston ring isn't floating about somewhere it shouldn't be!!!

So, I'm on the hunt for either, a new engine, or a new barrell and piston if anyone knows!

Looks like I'll be bike-less for a bit.

p.s. incase you're wondering, we didn't do this on our own, "we got by with a little help from my friend"
____________________
I have an asshole tolerance level of -10
www.cliqueyclanmcc.co.uk
www.bebo.com/fallenangelfran

[binge]

I know how you feel, My top end went on my scooter, I needed a new barrel cos the bore kits cant be rebored, and also it needs a bottom end rebuild cos the piston ring is in thousands of little bits in the bottom of the engine...

try
www.beedspeed.com
They do parts for most bikes...

<|Ben|>
____________________
- Honda XL125S - CBR400 NC29 - VFR400 NC30 - CBR400 NC29 - TL1000R - TeeZeR Pit! - Bandit 12 - YZF450 - LuckyMX125 Pit! - Demon X XLR 140 Pit!
- Stomp KZ 160 Pit! - Demon X D-link 140 Pit! - CRF50F Mini-Pit - MonsterMoto 155cc MiniSM - Honda Chaly 150cc - Yamaha 98' R1
- Honda Chaly 140cc - Thumpstar 190cc 4v MiniSM - Aprilia RS125 Pit-Bike -

[Fallen Angel]

Cheers Binge
____________________
I have an asshole tolerance level of -10
www.cliqueyclanmcc.co.uk
www.bebo.com/fallenangelfran

[binge]

Its not too expensive on there, and they also do next day delivery!
If you want a new engine, have a tinkle on Ebay

What bike is it you have?

<|Ben|>
____________________
- Honda XL125S - CBR400 NC29 - VFR400 NC30 - CBR400 NC29 - TL1000R - TeeZeR Pit! - Bandit 12 - YZF450 - LuckyMX125 Pit! - Demon X XLR 140 Pit!
- Stomp KZ 160 Pit! - Demon X D-link 140 Pit! - CRF50F Mini-Pit - MonsterMoto 155cc MiniSM - Honda Chaly 150cc - Yamaha 98' R1
- Honda Chaly 140cc - Thumpstar 190cc 4v MiniSM - Aprilia RS125 Pit-Bike -

[tatters]

the cyclinder is Nicosil plated so it can not be re-bored but you should be able to get it replated. l had mine done by stan stephen also sells the pistons and gaskets all you need for a re-build.


https://www.stanstephens.com
____________________
Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650 Present:G650XC,C12,KZ750,1190ADV

[Fallen Angel]

[binge]

Slightly off topic here, But it saves me posting a new thread for 1 small question...

When I get my scooter back, It will have another performance engine on it, Now I know to stick to sort of 30mph ish for the first sort of 500 miles, But obviously with it been a performance 2 stroke, its not going to last more than 9 months really without the rings going, then eating the cylinder again...

Would it be relevent if I changed my Piston rings every 6 months or so?
Or is there anything else I can do to stop it from blowing up again...

<|Ben|>
____________________
- Honda XL125S - CBR400 NC29 - VFR400 NC30 - CBR400 NC29 - TL1000R - TeeZeR Pit! - Bandit 12 - YZF450 - LuckyMX125 Pit! - Demon X XLR 140 Pit!
- Stomp KZ 160 Pit! - Demon X D-link 140 Pit! - CRF50F Mini-Pit - MonsterMoto 155cc MiniSM - Honda Chaly 150cc - Yamaha 98' R1
- Honda Chaly 140cc - Thumpstar 190cc 4v MiniSM - Aprilia RS125 Pit-Bike -

[tatters]

its not months, just mileage. depends on what you,ve done to it. more likely your bottom end will pack up as its desgined for a 50cc top end and the more power produced will strain the crank/gearbox etc. oppersite on a CB250 superdream as they were oringaly desgined as a 400cc but for the 250 market a 250 top end was put on the cb400 bottom end which made it very reliable.


some seriously tuned performace 2 stroke enignes with single ring pistons need there rings changing every 200 miles, your best bet would be to find out from the manufactor of your big bore kit when they recommend the rings should be changed. for a normal standard bike 10,000 miles, so maybe 5,000?
____________________
Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650 Present:G650XC,C12,KZ750,1190ADV

[binge]

[Fortuna]

[tatters]

fallen angel, this page should help you find out what caused the seizer


https://www.apexleisure.co.uk/pistondiagnosis.htm
____________________
Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650 Present:G650XC,C12,KZ750,1190ADV

[Fortuna]

Here found the Stan Stephens link.
https://www.stanstephens.com/index.html?nico.htm~contents
Ring them as well as sometimes they do an exchange if they have one done already.
For CPL they do loads for the KR-1S

[Kickstart]

Hi

You cannot rebore a plated bore. You can get the old plating off and get them replated or you can bore them out and fit an iron liner. With iron liners you can just rebore then engine out to take the next size piston.

The cost of replating the barrel will be round £100 + a piston and gaskets. New parts from Dave Silver spares will be cheaper (£100 for the barrel and piston) than getting the existing one sorted out.

There are very few people around who can replate barrels, and I am fairly certain Stan Stephens is not one of those people but merely sends it on. I know PJ Engineering in Wolverhampton can do it, and Langcourt Engineering down near Bristol.

The piston rings should be a metal that is magnetic. So with the barrel off poke around in the engine with a magnet and see if you find anything. 99% of the time you will get away with just putting on a new top end and not stripping the bottom end. Chances are the bit of ring went down the exhaust and is now buried in the radiator of the car that was following you.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Fortuna]

[Fallen Angel]

Thanks again for all your help guys. Sorry for my delay in replying, not been on the PC much lately!

Looking at that link that CPL left, it looks like the problem lies with the gasket leaking, so we will order these parts from David Silver Spares - thanks for thatlink.

If that is the reason it went wonky (don't you just love my technical ability) then great, but, we're not sure, even still, whether not having the re-jetted had anything to do with the problem - do you think once we replace the barrell, piston and gaskets that a normal garage would be able to advise whether it needs to be rejetted or not?

Fran
Forever Grateful For All the Help
____________________
I have an asshole tolerance level of -10
www.cliqueyclanmcc.co.uk
www.bebo.com/fallenangelfran

[Fortuna]

I'm pretty sure just for derestriction you don't need to re jet. It's only usually for tuning.
What year is it? And did you sort a barrel and piston in the end.
If you aint sure and need reassurance you could always ask a pro if it requires a jet kit. Just to be safe so to speak.
One thing it might need is the carb rebalancing the fuel/air ratio.

[Fallen Angel]

It's an '89 model Fortuna - reassurance would be good and probably will ask a pro - do you think most garages would be able to rebalance the carb / air ratio?

Haven't ordered the parts yet, money's a bit - haywire what with Christmas, etc., etc.!!
____________________
I have an asshole tolerance level of -10
www.cliqueyclanmcc.co.uk
www.bebo.com/fallenangelfran

[Fortuna]

Hi again.
All I did apparently was cut the hole out of the front of the exhaust and readjusted the fuel/air. They are slightly restricted in the back box as well which is why I bought a Micron in the end
IIRC they have an ATAC thingy valve. You don't need to really do anything to this and is more trouble than it's worth. In fact forget I mentioned it
I think that TBH your problem may have been there to start with, but the extra power pushed it over the edge. My father says that mine too died straight after derestricting. After rebuilding it was fine for ages so not to worry.
NS125's do need TLC and the piston is prone to giving up in these models.
One thing I would say is buy the best piston you can and not some cheap OEM clone. You can tell just by looking at a good one and a crap one. The rings will be less likely to break on a good set as well.

[Fortuna]

[Fortuna]

Do you have a Haynes manual?

[Fallen Angel]

Yeah we do Fortuna, will have a read through it tonight!
____________________
I have an asshole tolerance level of -10
www.cliqueyclanmcc.co.uk
www.bebo.com/fallenangelfran