help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

Running a 72 jet with a treats 70cc kit, high compression head, 14mm bing (2.20 atomizer, 24 slide), tecno circuit pipe, metal mesh filter. I also just replaced the float needle. I was scared I was running lean but this tells me I’m running really rich. What the heck is going on? 72 seems like an appropriate size for the setup from what I’ve heard/learned. This buildup is from probably 2 hours of riding MAX. My clutch lever snapped but my moped stopped running right before so I decided to take the head off and see and to my surprise there’s all this carbon gross buildup. The cylinder walls look good so that’s cool I guess. Also my spark plug is red? I’m so confused please help...

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Re: help me: low-to-appropriate jet but high carbon buildup

Carbon build up doesnt mean your rich, it means your piston is getting hot and causing the oil to flash on the dome of the piston. I bet its not timed properly and you are using some random 2 t oil. Red plug means rusty tank.

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

It’s timed at 15* BTDC checked with a timing light. I set the point gap at .017” with feeler gauge however the flywheel was blocking it at TDC so I had to bend it all funky so I wouldn’t be completely surprised if the gap was greater than .017”. Could that be it?

Re: help me: low-to-appropriate jet but high carbon buildup

> Drake Abrahamsson Wrote:

> -------------------------------------------------------

> It’s timed at 15* BTDC checked with a timing light. I set the point gap

> at .017” with feeler gauge however the flywheel was blocking it at TDC

> so I had to bend it all funky so I wouldn’t be completely surprised if

> the gap was greater than .017”. Could that be it?

When setting the point gap you want the flywheel to be a little past TDC, 15 degrees or so. Also, what's your oil ratio? And do you know what your compression/squish is?

Re: help me: low-to-appropriate jet but high carbon buildup

> Chris Straub Wrote:

> -------------------------------------------------------

> > Drake Abrahamsson Wrote:

>

> > -------------------------------------------------------

>

> > It’s timed at 15* BTDC checked with a timing light. I set the point

> gap

>

> > at .017” with feeler gauge however the flywheel was blocking it at TDC

>

> > so I had to bend it all funky so I wouldn’t be completely surprised if

>

> > the gap was greater than .017”. Could that be it?

>

> When setting the point gap you want the flywheel to be a little past

> TDC, 15 degrees or so. Also, what's your oil ratio? And do you know

> what your compression/squish is?

Yes^

So many variables.

Too much oil and different types can cause build up while being hot. Are you running a temp guage???

Do so if not.

That color looks more like rust than chocolate. Pics of inside of fuel tank are in order here.(edited)

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

Oh, I thought you set your gap exactly at TDC. Woops. Concerning the word “past TDC” do you set it 15 deg before or after TDC? Also I do not know compression nor squish. I just made sure to get the same thickness base & head gasket as the owner before me who had already kitted it. I know that’s kinda bad but I did it anyways.

Re: help me: low-to-appropriate jet but high carbon buildup

> Drake Abrahamsson Wrote:

> -------------------------------------------------------

> Oh, I thought you set your gap exactly at TDC. Woops. Concerning the

> word “past TDC” do you set it 15 deg before or after TDC? Also I do not

> know compression nor squish. I just made sure to get the same thickness

> base & head gasket as the owner before me who had already kitted it. I

> know that’s kinda bad but I did it anyways.

Monkey see monkey do.

Never assume that p.o. knew anything. Always investigate on your own.

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

I let the tank soak in evaporust for 48 hours & then flushed the tank with gas twice but I still get rust dust in my in-line 53 micron fuel filter. I also kept the one in the banjo inlet. I don’t know what to do besides keep changing filters lol this is my second one and I ordered more.

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Re: help me: low-to-appropriate jet but high carbon buildup

Holy shit!

Excuse me but that is a major problem.

You are not done cleaning your fuel tank.

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(edited)

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

I knew it was odd! Last time I flushed it the gas was crystal clear & I let the stream hit a paper towel & zero specks! But as soon as I put it all back in order, it starts to build up like crazy! Suggestions?

Re: help me: low-to-appropriate jet but high carbon buildup

The 2stroke motor buzzed that shit loose with vibration.

Drain tank and clean again. You aint done.(edited)

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

Gotcha. Will I ever be? (no). Good thing this stuff is fun!!! What should I do about the carbon buildup? Re-set timing and gap?

Re: help me: low-to-appropriate jet but high carbon buildup

fill tank with pennies bolts washers etc. Shakea Shakea.

Re: help me: low-to-appropriate jet but high carbon buildup

> Aaron Blair Wrote:

> -------------------------------------------------------

> fill tank with pennies bolts washers etc. Shakea Shakea.

One better is to derust with whatever water based cleaner you want then use ice cubes. They melt and always come out. The others?? Well, its unnecessary work getting them out.

Re: help me: low-to-appropriate jet but high carbon buildup

How the heck to you shake an entire moped with the tank in the body?

I'm cleaning one up now with Vinegar. Been three days and it's starting to look good. Now the debate is whether to try and put a coating in there. Same problem, how to shake and roll it around.

I agree, that level of carbon that fast means something is too hot.

Re: help me: low-to-appropriate jet but high carbon buildup

> Lee Snover Wrote:

> -------------------------------------------------------

> How the heck to you shake an entire moped with the tank in the body?

>

> I'm cleaning one up now with Vinegar. Been three days and it's starting

> to look good. Now the debate is whether to try and put a coating in

> there. Same problem, how to shake and roll it around.

>

> I agree, that level of carbon that fast means something is too hot.

Detachable tanks are easiest.

Step throughs are better done stripped to frame.

Re: help me: low-to-appropriate jet but high carbon buildup

> live ɘvil Wrote:

> -------------------------------------------------------

> > Lee Snover Wrote:

>

> > -------------------------------------------------------

>

> > How the heck to you shake an entire moped with the tank in the body?

>

> >

>

> > I'm cleaning one up now with Vinegar. Been three days and it's

> starting

>

> > to look good. Now the debate is whether to try and put a coating in

>

> > there. Same problem, how to shake and roll it around.

>

> >

>

> > I agree, that level of carbon that fast means something is too hot.

>

> Detachable tanks are easiest.

>

> Step throughs are better done stripped to frame.

Well, I have two step throughs. Not taking them all apart at this time. I may rig it up to a tree with some ropes to "roll it around" to coat tank. The Vinegar is working amazingly well, and I don't mind if it takes a week or more.

Re: help me: low-to-appropriate jet but high carbon buildup

> Lee Snover Wrote:

> -------------------------------------------------------

> > live ɘvil Wrote:

>

> > -------------------------------------------------------

>

> > > Lee Snover Wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > How the heck to you shake an entire moped with the tank in the body?

>

> >

>

> > >

>

> >

>

> > > I'm cleaning one up now with Vinegar. Been three days and it's

>

> > starting

>

> >

>

> > > to look good. Now the debate is whether to try and put a coating

> in

>

> >

>

> > > there. Same problem, how to shake and roll it around.

>

> >

>

> > >

>

> >

>

> > > I agree, that level of carbon that fast means something is too hot.

>

> >

>

> > Detachable tanks are easiest.

>

> >

>

> > Step throughs are better done stripped to frame.

>

> Well, I have two step throughs. Not taking them all apart at this time.

> I may rig it up to a tree with some ropes to "roll it around" to coat

> tank. The Vinegar is working amazingly well, and I don't mind if it

> takes a week or more.

That's cool but this is Drakes thread.

Re: help me: low-to-appropriate jet but high carbon buildup

Flush it on its side (after draining/catching gasoline) at the car wash with high pressure water through the fill up hole, sort of balanced horizontally on the right side pedal to pivot entire bike slightly to and fro, petcock removed and letting it drain out completely, intermittently, through petcock bung to truly wash all that loose crud out, use your finger to open and close flow. Do the $3 special long time rinse. Chase with several gallon bottles of distilled water, drain the same as before, then possibly one more night’s soak in evaporust. Drain evaporust and another quick rinse/drain with a gallon of distilled water both the same again. Hair dryer and/or compressed air through the fill hole for awhile, turn the bike upwards on front end holding the brake, with ass end towards the ceiling every so often to see how much water is still flowing around in tank. When you can’t see any more water sheen, pour some marvel mystery oil in there and swoosh it around, drain as before. Finally fill up completely with 2 stroke gas, and should be pissin clean at that point plus help keep rust from reappearing. Also make sure to have a good petcock with screen and functioning reserve setting, and only use reserve when necessary.

Re: help me: low-to-appropriate jet but high carbon buildup

> Drake Abrahamsson Wrote:

> -------------------------------------------------------

> Gotcha. Will I ever be? (no). Good thing this stuff is fun!!! What

> should I do about the carbon buildup? Re-set timing and gap?

Take some good clear pics of piston position (head off) in cylinder with relation to deck at tdc and exhaust/transfer ports at bdc with your current base gasket installed to visualize what’s going on in there. Might begin helping point to reasons for your carbon buildup.

Re: help me: low-to-appropriate jet but high carbon buildup

>

> That's cool but this is Drakes thread.

My apologies, didn't mean to hi-jack. What's next for Drake's heat and carbon issue?

Re: help me: low-to-appropriate jet but high carbon buildup

♣Slew Foot♣ /

Okay the vinegar will work but remember to deactivate it with baking soda when you rinse but to do it appropriately there are few steps that are a little advanced but give the best possible results 1 reverse electrolysis that is putting a piece of rebar that's isolated in a tank of washing lime you put the positive on the tank and the negative on the rod I'm pretty sure look it up in the wiki that will draw all the rust to the piece of rebar then when that's done you rinse it out with a little bit of vinegar left in it overnight to clean it the rest of the wall washing lime out then when you rinse it the next time after it dries get denatured alcohol and rinse it make sure you get it on all the metal parts then you use your tank repair gel of your choice whatever fiberglass or epoxy based stuff they have on the market and it will stick but you got to have a thin coat on the inside and it has to be complete you have to get everywhere inside of it and even coat stick it in the sundry and y'all have a tank that will last another 30-40 years for a step through if you can find a really really cool radiator guy it's a rarity that you can find one of these guys but they recoat the inside of Radiators they can do a step through they could recoat it with bronze and fix the worst of Tanks it costs but if you're really into it it's worth it

Re: help me: low-to-appropriate jet but high carbon buildup

♣Slew Foot♣ /

What I would do is if it ain't a tank problem then I would check my Temps but the easiest way is just see if your pipe is getting cherry then you know the timing's off but if it just seems like the carbon is building up what I would do if I was you was run Marvel Mystery Oil instead of 2 stroke once a month but to feel better about it I usually mix it half-and-half with two stroke oil when you pull the head the next time it will look pristine but that carbon is actually a good thing it lowers the temperatures on the piston try a hotter plug NGK five or six if you're on an eight or 9 now I have tens that are super cold but they're non-fouler racing plugs I only use them when I'm running really really hot timing and by the way we should ride sometime I'm in Bethlehem right now I'm out of a bike and I'm waiting for a replacement.

Re: help me: low-to-appropriate jet but high carbon buildup

> ♣Slew Foot♣ Wrote:

> -------------------------------------------------------

> What I would do is if it ain't a tank problem then I would check my

> Temps but the easiest way is just see if your pipe is getting cherry

> then you know the timing's off but if it just seems like the carbon is

> building up what I would do if I was you was run Marvel Mystery Oil

> instead of 2 stroke once a month but to feel better about it I usually

> mix it half-and-half with two stroke oil when you pull the head the next

> time it will look pristine but that carbon is actually a good thing it

> lowers the temperatures on the piston try a hotter plug NGK five or six

> if you're on an eight or 9 now I have tens that are super cold but

> they're non-fouler racing plugs I only use them when I'm running really

> really hot timing and by the way we should ride sometime I'm in

> Bethlehem right now I'm out of a bike and I'm waiting for a replacement.

Slew foot,

This is Drake's thread and he's in CA. My bad for hijacking his thread. Drake sorry!

But Slewfoot, your a hop skip and a jump from me. Just north of Allentown in Bath. We should meet up.

Re: help me: low-to-appropriate jet but high carbon buildup

> ♣Slew Foot♣ Wrote:

> -------------------------------------------------------

> Okay the vinegar will work but remember to deactivate it with baking

> soda when you rinse......

That was the one part that always gave me trouble. Flash rusting when rinsing with water before I could neutralize the acid. I know I'm not the only one cause ive seen others complain about it.

This always lead me back to using phosphoric acid. The phosphorus in the acid leaves a "coating" that prevents the flash rusting when rinsing.

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

> ♣Slew Foot♣ Wrote:

> -------------------------------------------------------

> What I would do is if it ain't a tank problem then I would check my

> Temps but the easiest way is just see if your pipe is getting cherry

> then you know the timing's off but if it just seems like the carbon is

> building up what I would do if I was you was run Marvel Mystery Oil

> instead of 2 stroke once a month but to feel better about it I usually

> mix it half-and-half with two stroke oil when you pull the head the next

> time it will look pristine but that carbon is actually a good thing it

> lowers the temperatures on the piston try a hotter plug NGK five or six

> if you're on an eight or 9 now I have tens that are super cold but

> they're non-fouler racing plugs I only use them when I'm running really

> really hot timing and by the way we should ride sometime I'm in

> Bethlehem right now I'm out of a bike and I'm waiting for a replacement.

If “pipe is getting cherry” refers to the pipe turning red (sorry, not fluent in moped-speak quite yet), my pipe turned red. I’m running an NGK B6HS. I’d love to ride but yes I am in California which is quite the trek! haha & okay once I’m running the mystery oil idea sounds like a good one- been hearing a lot of good stuff about it since I started this adventure

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Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

Kinda lucky but my moped died right around the corner from my girlfriends house so it’s there right now. I’ll take those pictures when I go over later in the day. From memory, there was quite the noticeable gap between the deck of the cylinder and the perimeter of the piston head- but I’ll get those pictures both at TDC and BDC for sure. I really appreciate the help

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

So many different ways to de-rust my tank! The reverse electrolysis sounds quite difficult. I’ll probably go the vinegar or Chris Straub’s route. If I act quickly when rinsing it will I be able to beat the flash rust or is it literally “flash” rust and appears within minutes?

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

Actually, electrolysis doesn’t seem like such a difficult task- might do that one too, who knows.

Re: help me: low-to-appropriate jet but high carbon buildup

Drake Abrahamsson /

What about my timing? I was at 15deg BTDC at idle RPMs. When I opened the throttle the reading started to go everywhere but I just blamed that on my cheap harbor freight timing light. Is this an issue?

Also, I mentioned it before but my gap might be larger than the intended .017” because I had to bend the feeler gauge to get behind the flywheel at TDC. The somebody said I shouldn’t even be setting my points gap at TDC. If not, where do I set it?? The video TravisTutorial put up had him & his roommate setting the gap at TDC. Is there another certain degree I should set my gap at? And could a too large gap be the cause of this overheating?

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