Wierd 2 stroke issue (carb?) Running in

[HD]

Okay so I have finished building my bike now.

It has lots of oil coming out of the exhaust and actually drips down so obviously this needs to be toned down a bit. Not sure if this will affect my actual question though.

Basically I am running it in and taking it easy. The bike now has a bit of a powerband where it never had before. But before this powerband it crackles and splutters as if it is cold. Really hard to get up hills as I want to keep away from that while running in.

However, when cruising along the flat it does splutter [i]a bit[/b] but not too much. Also I did check the plug t'other day. It hasn't been running for that long but the spark plug eas slightly black. Wiped straight off but I am aware that it needs to be brownish. Its an iridium if that means anything?

So would this be a carb issue as this was also rebuilt with new jets and up jetted for my new exhaust? Or is it the mixture?

Also how could I tell if I need to lean/richen that air/fuel mixture? More air=? More fuel=?

Also on a side note, how far do you think I should run it in for? My mechanic said 200 miles when he rebored my barrel for me. My dad said stay to 30 and dont go too mad. So if I stay out of the powerband a bit (god it is addictive ), stick to 30 and ride it normally for 200 miles will it be okay?

I was then gonna be gentle for another 50, slipping into the powerband a bit more and step it up to 40ish.

Then at 300 I was gonna go flat out and see how it runs then fine tune it accordingly. But I dont want to run it in if it isn't set up right. So can anyone give me a hand?

Ps. More information at this thread

Thanks guys
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Rusty '02 Vito Camper + CBR600F3

[evoboy]

Dont see an issue going into the powerband. Youll probably do more damage labouring the engine while running in.

Be best to use the engine as normal, just be a bit more gentle on it for a while. ( no full bore take offs, no prolonged periods of wide open or constant throttle etc)

Id run it around a bit like that first, then see if it still struggles/splutters.
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Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

APT Motorcycles

[ms51ves3]

I wouldn't even run a bike in. Once up to temp, I'd ride it to the redline.

[Lynxx]

To lean the engine is to take away the fuel and add more air (smaller jets, screwing the air screw out, lowering the slide needle)

To richen it is to add more fuel (bigger jets, screwing the air screw in, raising the slide needle).

I would break it in the 200 miles then if it still pushes alot of oil out the exhaust, repack the fibre glass in the muffler and check your oil pump is set up corectly. If you mix your own 2 stroke and petrol make sure your ratio is correct.
Your mechanic will have oiled the engine up when he rebuilt it, and may have also put oil in your petrol to make sure it wont burn up the new top end right away.

[P.addy]

[Robby]

If you aren't riding it hard, it will oil up, which explains the oil and black plug. I won't get involved in how you choose to run it in, but don't fiddle with anything you've ridden it hard and cleared its throat.

[JD-234]

running in for about 50miles on a iron bore will be enough and the oil will probly be because its only just rebuilt.

[woll]

I've had oil coming out of my senda exhaust when i first got it and i was running it in, garage said it was because i wasn't giving it enough so the bike wasn't burning off the oil. So that explains why you've got an oily plug. As for running it in the garage i got my derbi off told me to keep the revs low and try not to thrash it much, i did that the first time then when they derestricted it, the bike would only hit about 45-50 indicated. Then i blew up so it got rebuilt, this time i got some advice off some mates that have had 2t bike's since they were little. They pretty much all said start the bike get it to running temp kill it let it cool, then do the same again. Then run it as normal, the trouble with ridin git gently is you don't get rid of the honing marks on the bore so don't get as much compression as is possible. I did that with the derbi and it used to go off the clocks, not sure how fast it was but it kept up with traffic on nsl roads.
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Current Bike- Suzuki DRZ400 SM K6
Previous bikes - Derbi Senda Xtreme50r, Honda CBR 125, Kawasaki ZZR 250, Yamaha DT125R, Suzuki Bandit 600, Gas gas ec 250, Honda CBR600FW
Damaged spleen, damaged kindey, 2 popped lungs, 2 broken ribs, broken face, broken wrist and 5 back fractures... remember kids walls hurt

[MaybeGuy]

i reckon you have a sticky float bowl
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[HD]

Sorry I couldn't reply yesterday. Went out for a meal and then Virgin wouldn't let me on the internet again (was doing it all day).

Thanks for the advice guys. So not much to worry about then?

And I forgot to mention I think we put the washer thing on the wrong notch. Either one higher or lower, cant remember but it was accidently. My dad did it as I dont really get carbs (yet ) and didn't check.

As for my mechanic rebuilding it, he didn't. We did but we did polish the piston head and really stick some oil in the barrel and on the piston and gudgeon pin too. It was 3 in 1 oil though as my dad recommended that. We didn't have any 2-stroke at the time. I trust my dad has done everything right apart from the carb needle. I mean, come on, he has 30 years of experience

But what wouldn't explain it being very jittery and spluttery at mid revs just before the powerband kicks in?

Thanks
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Rusty '02 Vito Camper + CBR600F3

[Robby]

If you set the needle height wrong then it will run poorly on a medium to full throttle. Fix it.

As for the oil, 3 in 1 isn't as good as two stroke but it doesn't make a difference after the first few miles then the assembly oil is burnt off and the petroil is doing the lubing.

[HD]

[Lynxx]

the problem could be the spark plug fouling or fouled, i had the same problem with my 125 2 stroke, when i first rebuild it it lasted about 20 miles then was spitting and backfiring anything above 7000rpm. changed the plug today and it fixed it right up. no point changing the plug untill you break it in or if it stops running

just to add my spark plug looked perfectly normal, it was brown and not oil or carbon fouled, just didnt work hardly.

[HD]

[Lynxx]

i wouldnt put any in until you break it in, because its a waste of spark plug.. but i would carry arround a spare spark plug and the tools to take it off. i used to foul plugs all the time on my KDX250, always had to have a spare plug and a chainsaw spark plug tool. if you want you can change the plug it will fix it but dont know how long it will last because of it going low rpm for breaking in.

[Lynxx]

[HD]

Well Im currently running the BR8IEX (iridium) and the spare is BR8ES.

Tbh, I would rather stick with what they recommend :/

Not sure I wanna fanny around with spark plugs until I know my bike is running perfectly.

Thanks anyway!
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Rusty '02 Vito Camper + CBR600F3

[truslack]

[HD]

[Lynxx]

the Br8es is a softer spark plug (it gets hotter) and the Br9es is a harder plug (it gets cooler). i always go 1 number up on my recomendation because its safe, one number up is cooler and it will not do any damage to the engine other then foul itself. if you use one thats hot it will melt your piston, score your cylinders and rings will stick, also the spark plug will melt

[Lynxx]

i baught my Br9es today for 2 pounds the normal plugs are cheap as chips the iridiums are ripp off like 4-8 pounds

[HD]

Ah, may do that then. And yeah, every pound counts at the moment. Being on a paper round doesn't help... :rolls:
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Rusty '02 Vito Camper + CBR600F3

[Lynxx]

Heres a chart i made for NGK spark plug heats, from what i know and have been told by other mechanics.

Br 1 2 3 4 5 6 7 8 9 10 es (spark plug number eg. Br1es)
hot - Medium - cold (spark plug heat output)
Soft - Medium - Hard (spark plug alloy strengh)

so in short a 'colder/harder' spark plug will not hurt your engine and may keep it running cooler, but at the risk of oil fouling spark plugs and slower engine warm up on cold days.
a 'hotter/softer' plug has a good chance to burn a hole in your piston, stick the rings, scratch the bore and melt the spark plug. because it is making everything hotter then it is meant to be.

And as far as irridium goes it just makes the engine fire a little better and there is less chance of oil fouling on spark plugs, but at what cost, a regular plug is 2 pounds and a iridium is 6 pounds.

hope this helps your understanding of spark plug heat ranges

[HD]

[Lynxx]

well i have been told this by my freind in america who races motocross and builds flat track engines. My best freind/ neighbour in america that rebuild and fixed dirt bikes in his garage and 2 motorcycle shops.

If you dont belive me you can go into a shop, tell them your bike, and ask if a Br9es would do any damage to your bike and they will most likely agree with me unless they do not know what they are doing. I went into FF motorcyles today and he knows my make and so forth he said he was out of Br8es, so i could have a B8es the R means electrode i think. anyhow i asked about a Br10es and he said he didnt have any of those but a Br9es would work and do no damage, then he explained about the soft and hard spark plugs and the heat ranges again to me.