MotoPecane Repair Help (ongoing questions)

Hey guys.

I have a build thread, but I feel like I will get more attention posting a repair thread where I can ask ongoing questions here.

I'm finally making progress again. Got the moped wired up. I'm using a trail tech rectifier and le partie CDI.

I have av7 cases with performance crank, new seals, ported airsal 74cc cylinder, stock head.

This is a video of the spark. Hard to see I guess.

Then I put fuel in it, tried to crank it with my drill and no fire.

I'm using a sha 15 and a BH7S NGK plug. Fuel is flowing to the bowl.

I removed the stock crush washer on the plug because my trail tech says to remove it to use the temp sensor washer thing.

I pulled the plug to see if I have fuel, and the gap was gone. I'm guessing removing the crush washer put my plug tip deeper ;) and hit the piston?

I put in a BH6S with the OE crush washer and looks like the tip didnt get hit.

Still, cranking the motor with my drill, no start. The plug isn't wet at all.

Not sure what's going on. I gotta think about it. I don't get why my plug would be dry if I have fuel at the bowl? Should the plug be wet??

IMG_9737.jpg
IMG_9738.jpg

(edited)

Re: MotoPecane Repair Help (ongoing questions)

Richard Eberline /

Light are on a regulator!

Ground issues, need a good ground and no paint. disconnect kill switch and all lighting. you need a resister cap or plug. time at 1.0 to 1.2 btdc, The more grounds the better.

Re: MotoPecane Repair Help (ongoing questions)

Did you take the restrictor washer thing out of the ball joint for your Doppler pipe? If not, do so.

Re: MotoPecane Repair Help (ongoing questions)

Spark issues - you need a bonding strap between the engine and the frame ALWAYS.

Video link does not work for me it says it is private so ???

You also would best served to get rid of the stock wiring and the master switch from hell and wire in the lights directly and just add a kill switch for the ignition.

If the piston is pounding the crap out of the plug then you have no clearance between crown and plug. Did you properly index the cylinder? Use a slightly thicker head gasket if you overshaved the head, lower compression will allow the pipe to overstuff the combustion chamber without knocking a hole in the piston crown.

No fuel getting into the jug, time to do a leakdown test and find the vacuum leak. Did you put the spi seals in with the garter springs facing out?

Frenchwontstartmaze.png

Re: MotoPecane Repair Help (ongoing questions)

> Dirty Mike Wrote:

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

> Did you take the restrictor washer thing out of the ball joint for your

> Doppler pipe? If not, do so.

Yup its already off. Thanks!

Re: MotoPecane Repair Help (ongoing questions)

> Richard Eberline Wrote:

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

> Light are on a regulator!

>

> Ground issues, need a good ground and no paint. disconnect kill switch

> and all lighting. you need a resister cap or plug. time at 1.0 to 1.2

> btdc, The more grounds the better.

I'm timed at 1.5 BTDC.

No good?

Re: MotoPecane Repair Help (ongoing questions)

> Rebel Moby Wrote:

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

> Spark issues - you need a bonding strap between the engine and the

> frame ALWAYS.

>

> Video link does not work for me it says it is private so ???

>

> You also would best served to get rid of the stock wiring and the master

> switch from hell and wire in the lights directly and just add a kill

> switch for the ignition.

>

> If the piston is pounding the crap out of the plug then you have no

> clearance between crown and plug. Did you properly index the cylinder?

> Use a slightly thicker head gasket if you overshaved the head, lower

> compression will allow the pipe to overstuff the combustion chamber

> without knocking a hole in the piston crown.

>

> No fuel getting into the jug, time to do a leakdown test and find the

> vacuum leak. Did you put the spi seals in with the garter springs

> facing out?

> >

Hey Rebel!

My bad, you should be able to see the video now.

I need to post my wiring diagram up here. It's all custom started from scratch, unfortunately haha.

I will post it once I'm done drawing it out.

I didn't touch the head, only the case ports. How do you measure whether there is enough room betwen head and piston??

Yes, I put the seals with springs facing out, I remember seeing your post before doing it. (This while a long time ago). I don't have any pictures though so now you have me doubting myself lol!

So in theory, my plug should be wet if fuel is getting into the cylinder correct?

If there is no fuel there where can I look? I have a brand new dellorto 15 on there.

The bowl has fuel. Got me worried now about crank case seals. Where else could I have a leak?

Thanks, (edited)

Re: MotoPecane Repair Help (ongoing questions)

Okay,

I need to review this but I think I have most of it.

MobyWiring.JPG

My kill switch works.

My front and rear lights work.

I have spark.

I'm timed at 1.5 mm BTD

I don't seem to have fuel if my plug is dry?

Re: MotoPecane Repair Help (ongoing questions)

I don't hav an image of the seals when I replaced it. Starting to make me doubt myself.

This was a while back, but I do recall seeing your recommendation on orientation, Rebel.

I messed around with it some more today and I get good spark.

I'm confident in the wiring. My plug isn't getting wet.

I'm hearing a woosh coming from the carb.

I'm able to turn the motor over by hand. Is that a sign of bad compression?

I've been cranking the moped with a drill, if that is of any info.

Maybe decomp valve? What should my first approach be?

Here are pics of the plug after cranking it for a while.

The float bowl has fuel. I took off the dellorto black cap and metal mesh to see if I could figure anything out.

After cranking it for a while it did smell like fuel, but my plug looked clean.

IMG_9778.jpg

Here are just random images of when I put this thing together a few months ago now.

IMG_0610.jpg

Here I took a pic of the cases after I dremmeled em to match the head.

IMG_3818.JPG

(edited)

Re: MotoPecane Repair Help (ongoing questions)

soapy water may help w finding air leaks.

i dont see a case gasket or any goo. To hear it pop u could spray some premix in the plug hole and give it a twirl.

Re: MotoPecane Repair Help (ongoing questions)

> pat splat Wrote:

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

> soapy water may help w finding air leaks.

>

> i dont see a case gasket or any goo. To hear it pop u could spray some

> e premix in the plug hole and give it a twirl.

Hey Pat!

I put one of those brown paper like gaskets between the cases.

I'll spray soapy water. I need to come up with a way to push air in the spark plug hole and block the exhaust to pressure test it I think. (edited)

Re: MotoPecane Repair Help (ongoing questions)

Justin Petraitis /

Couple of things: Like Rebel said, you need to have some kind of grounding strap between the engine and the frame. The frame pivots on rubber bushings, which electrically insulate the motor. Sounded like you have everything grounded at that bolt that the engine pivots on? No good. You need a ground path back to the frame, or else just ground everything to the frame.

Second, the video appears that you're spinning the engine backwards. If you're trying to get it to start with a drill, make sure you're spinning it the correct way, and that you timed it for the correct direction.

None of that explains a dry plug though, so I can't help you there.

Re: MotoPecane Repair Help (ongoing questions)

Finding vacuum leaks is easy on piston ported engines. Take off the exhause, take off the carb, put the piston at TDC, have the spark plug in, use a piece of hose that fits the intake tight, block the exhause with your hand and try to create a vacuum in the carter by drawing out the air with the hose using lung power.

If you do not get a partial vacuum created then you have a leak somewhere, maybe if your hearing is good (mine is crap) you can hear if it is seal or gasket. You can look for the leak with 50/50 soap/water and 'paint' the joints with the solution and blow air into the carter and look for the bubbles.

Often, if the two garter halfs are not well together they will leak, sometimes you need to give the location of the periphery of the bearings a whack with a piece of soft wood (pine or spruce) so the bearings seat well in the carter half once the casing bolts are tight. Then double check the case bolts after, then give each nose of the crank a whack so the bearing gets its set on the crank nicely as well.

When assembling I always wet the paper or fiber gaskets with a little 2 stroke oil, it helps them to cling to the mating surface so they dont put up a fight, it also wards against them getting a crease or tear when tighting components together.

CDI - did you put sealant onto the mounting bolts that go into the carter half to hold the stator plate to the engine? Those two holes go into the carter, so they can (likey will) leak. Easy remedy to take one out at a time and give it some sealant and return it to its home. ALSO set the timing at 1,2mm BTDC for CDI, that is where it is at or close to its very happy place, 1,5mm BTDC is for points ignition.

I strongly suggest against using the upper engine mount bolt as a common for your electrical grounds. Best suggestion for CDI is a bonding strap between the engine and frame with a lanyard of wire between one of the lower carter nuts and one of the counter spring perch bolts on the frame. If you were on points then a strap between one of the carb studs and the lower external coil studs is best practice I have found.

Hope that helps

Re: MotoPecane Repair Help (ongoing questions)

Your observation of perhaps not having enough compression

- did you check the ring gap before installing the cylinder? If you have no manufacture spec it is 0,004 per 1,00 of bore.

- did you index the cylinder to the engine? Check at TDC if the periphery of the piston crown is align to the floor of the ehxause port.

- what head gasket are you using? If you read somewhere a 'trick' to not use one so you have higher compression, it is not such a good idea. Properly set up you will make good power with lower compression as the expansion chamber will work properly to over stuff the combustion chamber. So use a head gasket that is correct diameter for your overbore cylinder.

Re: MotoPecane Repair Help (ongoing questions)

Hey, dumb question... what direction are you spinning the drill?

Re: MotoPecane Repair Help (ongoing questions)

Hey guys!

Thanks for all the responses.

I think I will give this post a format so we can keep track of these items.

Please don’t take my confidence in how I did things as ignorant. I did things the way I did because it conceptually made sense. So if I ask questions or am persistent, it's because I want to understand why I should make a change :)

Believe it or not I'm an ME, and I can't get my moped going haha. But really, I like to understand so thanks.

Timing/Motor Orientation:

I’m spinning the magneto clockwise. This makes sense to me. If I were to pedal, it would go that way, unless I was pedaling backwards.

For timing process. I put in my timing gauge through spark plug hole. I spun the motor until it hit TDC.

When it hit TDC, I spun the piston down, then I screwed my timing gauge 1.5mm. Then I spun the piston back up to tap the gauge. Then I took the magneto cover, lined up the firing marks and tapped it on there. Then I secured the magneto cover with a clamp and made sure nothing moved as I tightened.

That all makes sense to me.

Electrical:

Diagram is posted. Sounds like the recommendation is ground strap from motor, to the frame.

My question is, why do I need to ground to the frame?? What’s wrong with grounding to the motor, is the ground mass too small? Since I’ve floated the lighting coil, I’m not grounding anything else to frame.

Rebel, I like the idea of lower carter to spring, thanks. I got a nice strap I can use. I just want to know why we wanna ground to frame.

Motor assembly:

From my recollection, I assembled the crank seals with springs facing outward. I remember reading Rebel mobys posts.

I did have binding of the piston in the cylinder initially. I took a mallet and loosened up the crank. It spun up and down the cylinder nice and smooth. I didn’t gauge it. Maybe I will if I de-assemble.

Rebel, I bought high temp gasket maker for those CDI mounting bolts!!

If I had to question something, it would be the paper gasket between the cases. I do remember it was a PITA to get it to fit. I thought I had it clean-o, maybe not.

I checked the ring gap, I wish I wrote it down. I also made sure the arrow on the piston was pointed at the right direction. I will post a picture.

I’m using a metal head gasket recommended for the 74CC kit since I guess it melts other gaskets.

Thoughts:

After reading all this, I’m questioning leaks in general. If my plug isn't getting wet and I have fuel in a brand new 15.15 shaa, we should go and find a leak right????

I think I need to come up with a good test to determine whether I have a leak. That would be best way to diagnose before ripping everything apart, correct?

I hear my carb sucking in air when I crank the motor.

Rebel, should I be able to crank my motor by hand?

Do you recommend a compression tester gauge? I will buy one.

I will also do a leak test somehow. I will start with lung power test and come up with something more technical maybe for the soap and water test. (edited)

Re: MotoPecane Repair Help (ongoing questions)

Using the frame as a common rather than running a parallel ground just takes extra wires out of the equation when there is a electrical issue (also my huge hate for earlier antique bike's wiring schemes with factory ground wires and terminals from hell)

Re: MotoPecane Repair Help (ongoing questions)

I still don't have a clear direction on diagnosing this.

I borrowed a compression tester from Oreily, got 120PSI. I didn't keep going, maybe could have been higher.

I got annoyed and pulled the engine off to look at it. The head is pitted but I doubt that would cause the problem. I ordered a new head off treats, with the machined squish for the 74CC cylinder. It also has no decomp. So that will take away one more variable. The New Head

FE5B30C6-1C02-4D7F-8EC8-45F882F0B833.JPG
557DB456-ADCF-4312-A634-5D16DECD21BC.JPG

I also see that the piston doesn't full clear the intake ports. (I think you said this in a post Rebel). I bought gasket material so I can clear it.

IMG_9808.jpg

I bought a piece of tube to try the vacuum test. It makes sense if I block exhaust with hand and suck the intake, I should be able to feel a vacuum.

I will do this test once I get the new head in (edited)

Re: MotoPecane Repair Help (ongoing questions)

What happens when you spray it with ether?

Dump fuel down the intake.

What happens?

Re: MotoPecane Repair Help (ongoing questions)

OK gentlemen she runs.

I will post a video.

I didn’t do much different. I shimmed the cylinder with 1mm gasket to try and get better intake port clearance. Then I put the new head I posted earlier. Timed it at 1.2.

Spark was looking good on the cylinder.

Cranked it last night. Nothing. Added some gas in cylinder. Cranked it. Throttle was stuck open it took off screaming. Magneto flew off... I didn’t torque it too much.

This morning I re-time. Use new hose clamp to hold the magneto and torque it nice and tight. I’m gonna order a torque wrench but I’ve been wrenching for years on vehicles and I know i passed 36 ft lb.

Cranked it with drill so many times. Nothing. Added some fuel in the top and then cranked. Nothing. Waited a bit. Then I really went at it with the drill and cranked it faster with some throttle and it kicked on. Ran for 20-30 seconds until I saw the nut came off. Cut the power.

The magneto nut keeps coming off !!!

I torqued the hell out of it (no torque wrench ) but def hit 36ftlb.

I think my drill is impacting it when I crank it forward and the drill stops. Jerks it backwards.

I’m gonna redo throttle cable, new chain clean up wiring and everything before I attempt to fire it back up.

I don’t think it’s a fuel issue even though I put fuel in it twice and it kicked on. My theory is that if it was a fuel issue it wouldn’t have ran for 20-30 seconds. I think it’s a cranking power issue. Using the drill I have sucks. Need to attach pedal and crank it better. That’s my theory. Someone comment. Thanks

Re: MotoPecane Repair Help (ongoing questions)

When using the drill , don't just fully let off the trigger . Try matching the motor RPM and slip the socket off the nut .

And , that bit of run on may be due to what fuel you put in having made it's way to the crank area and not completely being used up in the first few fired revolutions .

So , don't rule out the carb or intake .

Do a leak down test for any possible leaks .

Re: MotoPecane Repair Help (ongoing questions)

^drill starting without the nut jerking off is a little tricky.

hol drill at a slight angle, not straight on, pull off before letting go of trigger.

if theres an intake air leak, carb to intake, intake to cylinder, itll be lean on startup even w choke if its bad enough, r u even choking?

Re: MotoPecane Repair Help (ongoing questions)

Start it from the variator side, spinning counter clockwise. Then when it starts, it tightens the variator nut.

Re: MotoPecane Repair Help (ongoing questions)

Interesting, I will start it from the variator side.

I really want to get pedals and start it that way but I need to extend the pedal shaft and with this stay in shelter thing, I can't get to my buddies welder. Maybe I'll ask for a favor.

Okay one video of the moped running.

One video of my new chain. I learned a lot about the chain. One link made all the difference. Unfortunately, I have two master links on because It's one link too short.

It doesn't seem like it's turning smoothly, any suggestions?

(edited)

Re: MotoPecane Repair Help (ongoing questions)

And to calrify, the chain is not touching the grey or black trailing arm.

It might look like it in the video, but it's not.

Re: MotoPecane Repair Help (ongoing questions)

Watching the video at 0,25 speed it looks like the chain is contacting the pulley, might be the shifting camera angles but it also looks like it is slopping off at the drive gear at the beginning of the video. Is the drive gear wornout? Maybe it is wandering? How is the chain alignment?

Re: MotoPecane Repair Help (ongoing questions)

> Rebel Moby Wrote:

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

> Watching the video at 0,25 speed it looks like the chain is contacting

> the pulley, might be the shifting camera angles but it also looks like

> it is slopping off at the drive gear at the beginning of the video. Is

> the drive gear wornout? Maybe it is wandering? How is the chain

> alignment?

Rebel,

I would agree with those two things.

1. The pulley definitely looks warped. I really didn't want to buy another one, but I

might.

2. Operating it, I do remember it kind of slipping. I took a picture of the pulley gear because I thought it might be worn. I've replaced every single part on the moped so far except for this gear, variator and pulley. Looks like I might need to get gear and pulley. Just when I thought the spending would stop, haha. The reviews on the treats pulleys don't look too comforting, one of the reasons I haven't gotten one.

I will check chain alignment. I think i can be better.

Is the best method to get both the gear at the pulley in plane with the rear sprocket to:

Shim at the wheel where the axle nut is, shim the pulley, shim the actual sprocket in the back?

IMG_9965.jpg

(edited)

IMG_9967.jpg

Re: MotoPecane Repair Help (ongoing questions)

Top picture it looks as if one tooth onthearm is engages and the other is not - that means you have the wrong sprocket for the arm - they should be a matched set or it will fail at some point in time.

Alignment should be close, so shiming would be for slight adjustment unless the swing arm is bent. If the bike was dropped a number of ties and the pulley was bent it would be warped. If the rear sprocket it bent it will also give troubles.

If the pulley is a bit bent rotate it and use a sharpie to mark where it comes close to contact the chain so you know where to push back straight. Push just below where the two halfs of the V come together so you straight the pulley and not distort the V.

If the pulley is lose on the shaft so it allows wobble then change those needle bearing cartridges. Bearings are 16x22x12 - trade number HK1612.

Re: MotoPecane Repair Help (ongoing questions)

> Rebel Moby Wrote:

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

> Top picture it looks as if one tooth onthearm is engages and the other

> is not - that means you have the wrong sprocket for the arm - they

> should be a matched set or it will fail at some point in time.

>

> Alignment should be close, so shiming would be for slight adjustment

> unless the swing arm is bent. If the bike was dropped a number of ties

> and the pulley was bent it would be warped. If the rear sprocket it

> bent it will also give troubles.

>

> If the pulley is a bit bent rotate it and use a sharpie to mark where it

> comes close to contact the chain so you know where to push back

> straight. Push just below where the two halfs of the V come together so

> you straight the pulley and not distort the V.

>

> If the pulley is lose on the shaft so it allows wobble then change those

> needle bearing cartridges. Bearings are 16x22x12 - trade number

> HK1612.

Hey so Rebel... How much do you charge per hour if I fly you over here hahaha!

The pulley is nice and tight on the shaft. No play.

Rear sprocket is brand new. Hopefully straight.

I wouldn't be surprised if this bike was thrown off a building. It had a huge dent on the gas tank when I got it. I will see what I can do to perfect pulley/sprocket alignment. I mean it looks pretty damn close with my eye.

I will try and bend the pulley first before ordering one. I think the cog is worn out and I try to order all my parts at once from treats. So looks like I will buy a cog, but I reallly really don't see any pulley options I like on treats. If anyone has a recommendation, place link here please.

It seems like the "oem" ones, have bad reviews, and the custom ones have a lot of tweaking needed.

Looks like both teeth make contact but they look worn.

IMG_9966.jpg

Re: MotoPecane Repair Help (ongoing questions)

What do you guys think I should get?

New cog/ try to straighten out OEM pulley

An iffy OE style pulley with questionable quality

Stock Pulley Replica

An aftermarket pulley I might have to shim and adjust. Also would lose pedaling home function :)

Phone Dial Pulley

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