Cr85 help please!

[Fiddy@norway]

Yeah, No he doesnt race he just bought the bike for cheap and thrashes it around to get place to place most the time but yeah. I took the sparky off and there is spark just not a lot i also cleaned it so i dont no what the problem is it still doesnt kick over, Could the topend need a replacement finally?
what do you think i should do now because im doing it 2day later on with a mate

wait a minute now, does the engine turn over? if it doesn't then you've cold-seized it, if it does but won't fire replace the spark-plug, don't bother cleaning it, it won't help.

never use cheap oil in a 2-stroke MX'er, they need the good stuff!!! and I don't understand your mixing-ratios, 50:1, 32:1, 25:1.
I've always used % as a baseline when mixing my gas, I use 2-3% oil in my 2-strokes and have used that in all my years, never had any issues and my engines has lasted forever.

 

[sean01]

wait a minute now, does the engine turn over? if it doesn't then you've cold-seized it, if it does but won't fire replace the spark-plug, don't bother cleaning it, it won't help.

never use cheap oil in a 2-stroke MX'er, they need the good stuff!!! and I don't understand your mixing-ratios, 50:1, 32:1, 25:1.
I've always used % as a baseline when mixing my gas, I use 2-3% oil in my 2-strokes and have used that in all my years, never had any issues and my engines has lasted forever.

50:1, 32:1, 25:1
that is the standard way to mix 2 stroke fuel...

50 liters of fuel to 1 liter of oil
32 liters of fuel to 1 liter of oil
and so on..

can you explain your % way because i cant for the life of me see how that could work..

and to the op... awesome you got the bike going.......
and a bit of advice.....dont borrow 2 stroke motobikes they die too often...

 

[Peter1230]

i use 40:1 in my cr125 2003 model.
runs to rich at 32:1

 

[Fiddy@norway]

2 or 3% of oil in the gas, thats the standard formula when mixing over here...

 

[sean01]

never heard of it before...
well i spose it does work out 40:1 is 2.5% oil to 40 liters fuel...35:1 is roughly 3%

 

[Fiddy@norway]

it might be because we use the metric system, I find the % system easy to use, you fill a 5L jug of fuel you mix 150ml of oil, you fill a 10L jug you mix 300ml oil. (3% that is, thats what I mix my CR500 fuel at)

 

[sean01]

do you have any trouble with plugs at that ratio(32:1)?
lol we use the metric system here too m8

 

[DvDRip]

% system sounds logical to me, easier to understand than the ratio way.

 

[Fiddy@norway]

do you have any trouble with plugs at that ratio(32:1)?
lol we use the metric system here too m8

it isn't the oil that kills the plugs, it's too rich jetting, only one of my bikes have had a problem with fouling plugs and that was a 2000 KX250 that was jetted CRAZY rich down low, a properly jetted bike won't foul plugs at 3% oil.

I could swear you guys used gallons, feet, inches and all those weird units of measurement...

 

[bananas]

depends, most of the time when jumping, we use feet and inches, sometimes just for the sake of it say something like " it went for miles without much fuel" but its more of an expression. This happens on my 1999 rm 80, but what you have to do is just ride it round down low, only just getting into the band, then as it clears it self it will use the band properly, not just foul the plug. I find the band starts working better in 3rd gear first.

ohh yeah, and this may make it complicated for some of the people that arent familiar with 2 strokes. @ strokes actually have 1 valve, and it is the exhaust but other that that it has reeds.

 

[thump*140]

^^^not quite right... 2 strokes have an exhaust port, and most modern highpowered two strokes have powervalves, which are flaps in the exhuast port, that move up and down in the port, depending on revs... they alter the height of the exhaust port, thus affecting the power delivery... Basically powervalves were added to two strokes to increase bottom end horsepower, by giving them a variable height exhaust port...
but technically are not a Valve in the sense that they dont open and close the port entirely...
and yes i'm being technimacal..

 

[BradZ_09]

Just cheap stuff for his bike im not using my motul oil

Never ever use cheap stuff in a 2 stroke. I blew up my YZ in half an hour with cheap oil. I run Motul 800.

 

[thump*140]

oh my bad... two stroke "rotary valved" engines have an opening and closing valve on the intake port...but it's a rotary valve running concentric to the crank, and is basically a round disc with a hole in it, that is "open" on the intake stroke... Yamaha KT100 go kart motors have them... getting old, memory fading..

 

[jovian]

**** oil = fouled plugs

gumby mate = ****** bike

 

[sean01]

it isn't the oil that kills the plugs, it's too rich jetting, only one of my bikes have had a problem with fouling plugs and that was a 2000 KX250 that was jetted CRAZY rich down low, a properly jetted bike won't foul plugs at 3% oil.

I could swear you guys used gallons, feet, inches and all those weird units of measurement...

yeah i totally agree with you, what ppl forget to think about is most 2 strokes are tunned for top end and forgetting about bottom end, because lets face it any one that rides a 2 stroke spends most their time in the top end of the power range....

i have fixed/tuned quite a few 2 strokes that have a bad time with killing plugs, and i can tell you not all of them were from a bad tune or bad oil mix..
couple of them were killing plugs left right and center...i mean start the bike and let it idle for a minute to set the mixture and go to pull the throttle to take it for a ride and berrrr...dead plug....
those bikes were a mixture of bad earths under the coil(fresh powder coat) and deteriorating stator coils...quick fix for one was to replace the plug cap for a non resistor type(owner was a tight ass) lol was good till he killed top gear...

 

[Th3D3v1Ly]

yeah doesnt sound good, worst case scenerio, ur mate gona castrate you with a hammer, best case replace plug, warm it up and check again and she should purr.......*i mean she should whistle like a hair dryer* just like she should.