Engine Trouble PLEASE help....AGAIN!! Engine stuttering

[KCvale]

Im in Arizona[/B])...

Hi fellow Zonie ;-}
I have been building and riding MB's here in Phoenix for close to 2 years now and the summer heat can be brutal on these 2-stroke air cooled motors and the rider as well you know ;-}

1. Premium Fuel.
Excellent choice, that's all I run, not because the higher octane helps, it is just typically cleaner fuel with less Ethanol, that **** is not friendly on our gas lines and does not burn near as well as gas without it.

At 4 months you should be plenty broke in, mix 32:1 (1/2 cup quality synthetic 2-stroke oil to 1 gallon of gas).

2. Oiled the throttle cable.
Not a good choice, especially here in the desert.
You don't fix a sluggish throttle by putting oil in the cable, Graphite maybe but never oil, it will soon be worse than it was and may cease to move at all over time.
Too late now, the throttle cable is the one cable that has two ends so you can't pull the cable out that most likely wasn't the problem to begin with.

Good 'throttle snap back' ranks right up their with dual brakes as a major safety thing. The LAST thing you want if you take a spill is the throttle sticking open.
Just like no new build bike leaves my shop without front and rear brakes, they don't leave with a sticky throttle either. I know that sounds a little anal but I have a little higher set of standards for my builds than most.

My solution is pretty simple.
Never use the gas tank mount plates to hold your throttle cable, any cable for that matter, it pinches it causing friction in the cable.
Then when I assemble the throttle I put a little dab of grease (not oil) between all the moving plastic parts that touch inside the throttle as well as a light smear on the handlebar the plastic throttle barrel rides on.

3. Iridium Plug.
I don't know about other motor brands but any Skyhawk motor will take an Iridium plug, I love the suckers, it's like a instant boost you can actually feel and I keep them in stock.
With summer here in full force now an 8 is your best heat range bet for them.

Being a fellow ZOnie check out my web site and sign up for the forum, the link is in my sig.

Hope that helps ;-}

 

[tbrookes2000]

Thanks KC! Yeh...registered...if you can PM me ..I have a question about the silver bike with the maxxis tires...BADASS! i wouldnt mind having one! Also if you could let me know what plug (Iridium) you would recommend for me to use in my bike. I ride from Maricopa to Chandler everyday and would like to get the most from my ride.
Thanks!

 

[Lunardog]

Sounds like a minor fuel/air mixture issue going on if it stutters a bit when cold and runs better when warmed up.

 

[KCvale]

Thanks KC! Yeh...registered...if you can PM me ..I have a question about the silver bike with the maxxis tires...BADASS! i wouldnt mind having one! Also if you could let me know what plug (Iridium) you would recommend for me to use in my bike. I ride from Maricopa to Chandler everyday and would like to get the most from my ride.
Thanks!

NGK BPR7HIX, maybe even an 8 for your long brutal ride.
That full suspension Silver Shifter was actually mostly built by the customer.
He got everything mounted but couldn't get it function mechanically so he brought it to me.

66cc Skyhawk, high compression head, X-chamber, NuVinci hub with drum brake, completely upgraded electrical for everything but the Mag and kill button, etc.

I don't know how much he had in it but it was at least $1200 in just parts.

 

[motorpsycho]

1. Premium Fuel.
Excellent choice, that's all I run, not because the higher octane helps, it is just typically cleaner fuel with less Ethanol, that **** is not friendly on our gas lines and does not burn near as well as gas without it.

At 4 months you should be plenty broke in, mix 32:1 (1/2 cup quality synthetic 2-stroke oil to 1 gallon of gas).

2. Oiled the throttle cable.
Not a good choice, especially here in the desert.
You don't fix a sluggish throttle by putting oil in the cable, Graphite maybe but never oil, it will soon be worse than it was and may cease to move at all over time.
Too late now, the throttle cable is the one cable that has two ends so you can't pull the cable out that most likely wasn't the problem to begin with.

Good 'throttle snap back' ranks right up their with dual brakes as a major safety thing. The LAST thing you want if you take a spill is the throttle sticking open.
Just like no new build bike leaves my shop without front and rear brakes, they don't leave with a sticky throttle either. I know that sounds a little anal but I have a little higher set of standards for my builds than most.

My solution is pretty simple.
Never use the gas tank mount plates to hold your throttle cable, any cable for that matter, it pinches it causing friction in the cable.
Then when I assemble the throttle I put a little dab of grease (not oil) between all the moving plastic parts that touch inside the throttle as well as a light smear on the handlebar the plastic throttle barrel rides on.

3. Iridium Plug.
I don't know about other motor brands but any Skyhawk motor will take an Iridium plug, I love the suckers, it's like a instant boost you can actually feel and I keep them in stock.
With summer here in full force now an 8 is your best heat range bet for them. ;-}

can you please elaborate on all of these?

Premium fuel? Why do you think it's a good choice for these cheap 2 stroke engines?
They are low compression and any high octane fuel that you put in them is just money going out the exhaust.
High octane fuel is not required and is a waste of money. These engines run best on 87 octane.


WHY is oiling the throttle cable not a good idea?
I agree, you don't fix a sluggish throttle by oilin gthe cable...BUT, you DO maintain the throttle cable by oiling it.

4 months to break an engine in?
wow...that seems like an awefully long time. summer (in the midwest) will be over by then.
Run 1 tank of fuel at 20:1, and then drop the mixture to 32:1 and you're good to go. (my opinion)

Never use the gas tank mount plates to hold your throttle cable?
if you do it right, and run the cable through the tank mounts so that it isn't bound up or smashed by the tank mount plates, it'll be perfectly fine.
you have to make sure that the cable has freeplay and isn't bound up.
I agree on the grease on the throttle assembly.
on my bike for example, there is a gap between the gas tank studs and the gas tank mounting plates (with the tank tight against the top frame tube) I ran my throttle cable through that gap which allows the cable to move around. It's not bound up and is free to move.
I guess in some cases, there will be someone who smashes their cable between the tank and the tank mounts which will bind it up.

an irridium plug?
Really??
I don't get that one. are there any proven results that it gives you a power boost?

sure, irridium plugs will last a very long time, and will probably out last the engine. But really...just go with a standard ngk (b6hs or whichever works best for you).
why waste the money on an irridium plug?
do you really think that an engine runs hotter in the desert than it does in the midwest?
think about it, an engine will get up to 250-300 degrees and ANY ouside air will cool it.
if it's 100 degrees out or if it's 50 degrees out, the outside air temp will always bo cooler than the engine temp. Even if it gets really cold out, the engine will still build up heat in the 200-250 degree range.
an air cooled engine will not run hotter because it's in a hotter climate.
the only way an engine would run hotter than normal due to it's environment is if the outside air temp gets up above the operating temp of the engine i.e. 250 degrees plus.
OR if the engine is running extremely lean.
this is just my opinion, and my thoughts...I could be wrong.

sorry but i don't want to come off, sounding like i'm knocking what you're saying. I just wanted to see why you specified these things, and to post up other options that work.

 

[Big Red]

Huh?

1). Cheapest gas I can find. Stuffs too expensive as it is.
2). I ALWAYS oil all of my cables at first install then every now and then as needed.
3). I run perhaps 2 tanks for break in. Just want to make sure.
4). I ALWAYS run the throttle cable through the tank mounts. It keeps them up out of the way and usually allows the cable to fall straight to the carb.
5). B6HS... Thats all...
Big Red.

 

[motorpsycho]

1). Cheapest gas I can find. Stuffs too expensive as it is.
2). I ALWAYS oil all of my cables at first install then every now and then as needed.
3). I run perhaps 2 tanks for break in. Just want to make sure.
4). I ALWAYS run the throttle cable through the tank mounts. It keeps them up out of the way and usually allows the cable to fall straight to the carb.
5). B6HS... Thats all...
Big Red.

exactly!