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

That fuel tank situation is a problem. If it were my bike i would start there. Then proceed with your additional problems. Gotta sort the dirty fuel issue out first.

A tip, I've had to clean a couple maxi tanks and one was terrible. I ended up putting two utility hooks into the garage ceiling and hung the frame by ropes. This allowed me to really get a good shake without my arms tiring out. I like vinegar and rock salt it really helps to scrub and knock that rust loose. Just takes some extra effort to get it all out.

Bottom line dirty fuel = poor performance.

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

Overpriced Parts /

> Drake Abrahamsson Wrote:

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

> 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?

Sounds like you got points jump,

Your point cam on the flywheel need to be perfectly smooth and lubed, your points at pivot need to move freely yet not be to loose or they will have to be replaced

if your points are jumping around all over the place at hi rpm/at speed that could be a cause of overheating, you got to detail all that stuff out to have your timing mark/line stay stable at speed

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

Barry (Bob) Brown /

As for your tank, I used a brush and cut the handle off, attached to a drill, then ran it up and down the tank and kept flushing, it worked really well. I pulled the petcock and blocked off the hole first.

brush.jpg

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

Search "Oxalic Acid". I think it was PD that did a write up on it when he did some bits on his Simplex (I might be wrong, I might be making it up completely, but I remember Oxalic Acid looks the shit at cleaning).

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

Drake Abrahamsson /

> if your points are jumping around all over the place at hi rpm/at speed

> d that could be a cause of overheating, you got to detail all that stuff

> out to have your timing mark/line stay stable at speed

When I saw my points jumping everywhere I’d only been running the moped for probably 30 seconds. I’ll check the cam. What should I lube it with? The red Sta-plex stuff or something more liquid-y like WD-40

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

Drake Abrahamsson /

> Barry (Bob) Brown Wrote:

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

> As for your tank, I used a brush and cut the handle off, attached to a

> drill, then ran it up and down the tank and kept flushing, it worked

> really well. I pulled the petcock and blocked off the hole first.

This is so much better an idea than what I had. I was just gonna get some wire & clamp a nut & bolt down on the wire then have it flail around the inside of my tank like a mace attached to a drill

735DCBD9-C6EB-4BF3-8F89-CC9BD4348A29.png

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

Overpriced Parts /

I remove the flywheel and with fine paper remove any rust pits, going completely around and around don’t just sand in one spot then I lube with hi temp grease and I clean/reverse the fiber cleaning pad in the Stator and put some oil on it,

Sometimes though the cam is machined incorrectly and there’s lines going down it and there’s nothing you could do about it except change the flywheel to keep points follower from jumping around on they hit those machined lines

Za50 and e50 have the steep part of the hump that snaps open the points On opposite sides so you got to use the correct rotation flywheel (e50 clockwise, za50 counterclockwise)

6965EDDB-D00E-4607-9A37-7DE6ED00BE70.jpeg
2BE8A9D6-8AA4-4E1F-9A8E-295A768E7567.jpeg
CCDD5AF3-0AF2-4C96-A1CD-4505E87F8CFE.jpeg

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

> Barry (Bob) Brown Wrote:

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

> As for your tank, I used a brush and cut the handle off, attached to a

> drill, then ran it up and down the tank and kept flushing, it worked

> really well. I pulled the petcock and blocked off the hole first.

That's a good idea!

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

> Ryan Graeme Wrote:

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

> Search "Oxalic Acid". I think it was PD that did a write up on it when

> he did some bits on his Simplex (I might be wrong, I might be making it

> up completely, but I remember Oxalic Acid looks the shit at cleaning).

Well, I did a week of Vinegar rinses, then a good neutralization with baking soda. I ran a lot of water through and got out a piece of petcock and Puch Cap measuring cup. Now I'm doing a day of Evaporust. I'm planning on dumping the evaporust and then drying as best possible, then adding a full gallon of cheap motor oil to coat the surfaces and stop any rust.

Last I plan to drain the oil and then follow up with a bottle of Marvel Mystery oil that will be sloshed as best I can. Finally a slosh 6 oz of gas oil mix. Drain and hopefully off to the races. If it comes back, I will repeat but try a coating.

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

For as much as you spend on supposed cleaning and treatments , you could have bought a new moped . LOL

OK maybe not a new moped . ;)

For about 7 bucks and a couple days waiting , I'll stick with using oxalic acid .

Here's the write up with pics Ryan mentioned :

https://www.mopedarmy.com/forums/read.php?6,4160423,4160423#msg-4160423

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

> P D Wrote:

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

> For as much as you spend on supposed cleaning and treatments , you could

> have bought a new moped . LOL

>

> OK maybe not a new moped . ;)

>

> For about 7 bucks and a couple days waiting , I'll stick with using

> oxalic acid .

>

> Here's the write up with pics Ryan mentioned :

>

> https://www.mopedarmy.com/forums/read.php?6,4160423,4160423#msg-4160423

Cost me about $35. How many mopeds do you have for me for $35.00 that won't need some tank work. LOL. It's a labor of love. I could have bought a nearly new Tomas Ped, and saved a lot of money on parts. But I didn't own one when I was 15.

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

Yeah , I didn't own a moped when I was 15 . Actually , I've never owned a true moped .

All I had then was a bicycle , a horse and my '57 Simplex . Well , I did buy a '39 Ford - 2 door coupe with a '54 flat head 8 , but , I wasn't legally driving it 'til I was 16 .

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

♣Slew Foot♣ /

I would double check your flywheel hold the clutch or the back wheel and just move the flywheel back and forth and see if it has any play I have a feeling that your woodrift PIN has a Groove in there and that your timing is moving cuz I had a Tomas where the whole inner section of the flywheel was loose and it would only move like a millimeter each way so it always stayed within acceptable timing and never created a serious problem for two years and then all the sudden it was a serious problem

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

Drake Abrahamsson /

> ♣Slew Foot♣ Wrote:

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

> I would double check your flywheel hold the clutch or the back wheel and

> just move the flywheel back and forth and see if it has any play I have

> a feeling that your woodrift PIN has a Groove in there and that your

> timing is moving cuz I had a Tomas where the whole inner section of the

> flywheel was loose and it would only move like a millimeter each way so

> it always stayed within acceptable timing and never created a serious

> problem for two years and then all the sudden it was a serious problem

Hmm will do, I just put in a new crankshaft. I did notice that the woodruff keys on both side are the same & I'm pretty positive they're supposed to be different so I may just go ahead and buy new ones for both side just to set it straight once and for all.

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

Drake Abrahamsson /

> 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.

Okay I finally got around to taking some photos. I’m running a 1mm base gasket, treats 70cc cylinder, & hi hi head with a 0.4mm head gasket

2FA236A2-77C6-4A8A-95C5-143636CE2D31.jpeg
A54030FA-C063-40DA-8A96-36F5C2E667B6.jpeg
ACD8269D-8666-4862-A390-7B36B15AE7F7.jpeg

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

Timing is 17 to 21 degrees before top dead center for an engine not to explode

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

Spacing looks good. Those hi hi heads can cause a lot of compression, people commonly sand down/out the combustion chamber so that they don't run too hot.

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

Drake Abrahamsson /

> Chris Straub Wrote:

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

> Spacing looks good. Those hi hi heads can cause a lot of compression,

> people commonly sand down/out the combustion chamber so that they don't

> run too hot.

Thanks Chris! I’ll run a head temp gauge and modify if still running hot after making those timing fixes.

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

Drake Abrahamsson /

This is what came out after using the brush chucked to a drill. Chocolate milk! Thanks Barry for the suggestion, made a world of a difference & with ease! I used a snippet of leftover 3/8” vinyl tube to put over the brush spring cable thing so I could hold it and somewhat manipulate it. Gonna brush and drain a few more times before doing oxalic acid. Hopefully that’ll get me clean!

E1E6E2AF-1CE3-4AAA-B537-8465F9288D32.jpeg

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

That piston got really hot

« Go to Topic — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account