A good rinse with the right ratio fuel maybe? I'm no expert though.

A CDI kit is well worth the money if it doesn't already have one.

 

wait im confused. It started first hit of the button so finished the assembly of small things?

It started after the rebuild?
It doesn't start after the rebuild?

 

It started after the rebuild I then fit exhaust and engine covers etc I ran it for all of 4-5 seconds if that

 

I wouldn't think you fouled a plug if it was a new plug but if it was an old plug it might be on it's last legs. I would also just chuck a bit fuel in to flush it out a bit. and leave the plug out to air it off and the and try again.

Whats the carby like ????

 

Carb is as it was stock didn't get to pull it to Reset because it wouldn't start... It was the old plug with who knows how many klms on it... It's done 22 or so thousand ks

It ran like a charm since got it so there hasn't been an issue until now I'll go walk some fuel down the plug hole and turn it over see how that goes...

Hoping it's just the plug I don't have a compression tester to be sure something didn't go wrong but everything went together smooth

 

I've just mixed some 2t up and syringed it into the bore and kicked it over and repeated plug has been out for a couple Of hours still no sign of life... Gah I hate when this sort of thing happens hope. I didn't waste money on the big bore kit

 

Test for spark? Doesnt take a lot of compression to get these things going. The kill switch hasnt somehow earthed itself to the frame when you shut it off? dicky kill switch?

All my issues with 2-strokes come down to the ignition. Check everything ignition related I would.

 

It is sparking but it's not a strong spark imo... But I've never tested it until now as it always went so I have nothing to compare it to. my motocross days (cr80)etc they would have spark but no go when the plug was in the barrel new plug and they would so I'm Hoping it's that just very coincidental I mean it was very well lubed up when It started and I didn't rev I to clear it up etc just switched straight back off

I love 2 strokes because of their simplicity... I was doing my own top end at 12 yo but they always get you eventually lol

 

they would have spark but no go when the plug was in the barrel


Iv come across this a few times over the years with some 2 stroke bikes iv had.

Miss my old cr500. Was the only bike iv had that would throw me over the handlebars just kickin it over.

 

yeah mate live and learn hey, ive had my share of head scratching.....

Spray a bit of start ya bastard down the intake and give it a kick?

 

Carburettor is rooted.

 

What makes you say that mate?

I tried start ya bastard and no go, not even a pop out of it fuel down into barrel plug back in and still absolutely nothing

 

if it starts and runs and dies quick id say fuel delivery, as bloke said start ya bastred.

kick it/start whilst spraying ol cheapo fly spray into the carb throat/airbox.

Ive started 30 odd year ol IT490s with flyspray.

2 smokes are simple....fuel, spark, bang. Thats all.

Check the first 2 (fuel,spark)

how much oil did you lube the bore/piston/rings with during the rebuild? may have well rooted the plug.

I restored an 82 CR80 and when it sits under blanket up to 6 months at a time, i squirt up to 100-200ml of engine oil in the spark plug and rap on the kick start a dozen times and replace plug.. (not 2 smoke, ol delo 400) 2 smoke and moisture = moisture wins.

It starts 3rd kick and smoky, but thats to be expected.

unless you used a litre during rebuild I cant see it killing a plug. But for 5 bucks give it a new one and see.


should result in bang

 

Just replace the plug, that'll eliminate one of the main suspects and they're cheap anyway.
Have you double checked the spark lead is making a good connection? Tested resistance?

Since you've tried start ya bastard, kicking it etc, it may have flooded.



IT's are cool old bikes.

We still have my dad's old IT200 down in the shed.

 

I used to have motorbikes, all sorts. If they didn't go it was either spark or fuel.

Take the carby off and clean it out. Filters, jets and float seal. At least you'll know that's one part of it fixed, it's pretty straightforward. If that doesn't work then do a clean-up of the electrics.

 

Try taking the spark plug cap off the lead and see what sort of a spark you get.

 

just put a screw driver in the spark plug cap, touch it to the barrel and whilst holding the shaft of the driver start it.

If you feel the love through your teeth its good, if not its not good.

dont wear shoes either, bare foot is best

 

I'll give that a go tomorrow after work spud truck.... 
I need to grab some plugs so I can do a couple of plug chops to tune it for the 70cc so I'll be pulling the carb and upping the jet size. Aswell so I'll be covering both bases... Hopefully it's nice and simple I'll. Update with more info tomorrow.

For now I've got the plug out and also have rinsed the barrel out with some fresh 2t mix

The oil I used was full synthetic race oil for my old bike so that may not have helped the situation?

I've been bit before motomuzz lol

 

lol you caught me.

Dont run in on full syn any way bud. run a few tanks of active 2t or similar mineral.

Your first post stated new jets for the big bore kit. are they in?

Might be too rich on the pilot circuit?

 

No jets aren't in yet ran out of time before dinner etc
I certainly didn't use a litre of oil but all Parts had a very generous coating

It's not running full syn in the tank just all I had to use for assembly it's a self mixing setup no need to premix in the tank

There was alot of carbon build up on the head and exhaust port on the old 50cc barrel I De coked the exhaust so that's not blocked
And plug was who knows how old... I got it cheap because the previous owner played with the throttle and didn't connect the cable back up to the twist tube.....so wouldn't rev... They thought it was stuffed took 2 mins to fix and have ridden it all week
So servicing wouldn't have been kept up with them

 

Well not good news...
I'll let the pics do the talking

Barrel

Piston

Head

All I can say is I am far from happy... Ring has clipped the rear intake port 1/3 of the ring is missing so more than likely inside the engine..?
It had less than 10psi compression...

What are peoples thoughts on getting a replacement from the retailer considering it didn't get to run for even 5 seconds?

 

The only time I've seen something similar to that on a fresh reco engine was because the piston was put in the wrong way round. This lets the end of the ring drop into one of the ports with results similar to your photos. I'd say the missing piece of ring has gone out the exhaust port. It is highly unlikely it has gone down a transfer port into the crank case. Pull the exhaust and give it a shake and see if it rattles. If you are sure the piston was the right way round then I can't offer any suggestions to the cause.

Cheers,

 

Easy to prove it was right way around scores in bore line up with the piston and arrow pointing to exhaust port so I know that's all good... Nothing was notchy when I spun it over by hand before starting it. And no noises at all while or after it ran so has me stuffed?

 

I found one piece of ring however some smaller bits are still Mia and there's nothing in the exhaust our on the floor

 

ummm wtf? what was the ring end gap to the bore? You did have the arrow marker to the exhaust port?

I always relieve the exhaust port bridge as its common to nip the rings there on expansion . But never heard of clipping rings on the intake.

Ill see what overboard is saying and it makes sense.

Thats a what the for sure dude.

Edit:

You just said arrow to exhaust port so it has me stumped.

Cheap charlie piston/ring kit?thats all ive got

 

Definitely the right way

This is the ring gap don't have measuring equipment at home so exact dimension is hard to tell would be around 0.4mm at most?

 

wheres the second ring end locator on the piston ring groove?

ok I see it further to the right.End gap by eye doesnt look bad.

Well....heres what Id do.

Another ring set and start again. Never seen rings snap like that on 5 seconds of fire.

Is it a cheap charlie kit?

Edit oh its cut the piston. Sorry dude my eyes and pics on the interweb just aint playing the game tonight.

 

Further around the piston. around 45 degrees In the opposite direction. Second ring is lost as **** so it's just sitting there

 

you didnt twist and weaken the second ring whilst putting it on? Its let go. So just wondering what made it exit stage left, or cheap china rings.Thats all ive got bud but Id start again thats all you can do now.

I rebuilt my nephews 50 back in 92. I carelessly assembled the gudgeon and didnt set the circlip in the piston right.

It let go after about 30 minutes of run time and cut the piston and both rings and barrel as the gudgeon clip "seized" her to a halt.

I was devoed i can tell ya, but another 400 bucks and a learning curve ( and a kick in the pants by my sister) well ive learnt from that.

I still have the piston.
Ill post up here if ya like