Jump to content

Recommended Posts

YO!!! UPDATE!!!!

IT RUNS!!!!!!!!!!!!!!!!!!!!!  I got it running today 4/26/2020!!  The first time this LI has fired since I bought it back in 2017.  It was a basket case back then.

Here are some pics of the progress.

CARB-4-2020.thumb.jpg.f67e4f792f9d6825cd946c443f804c96.jpg

I finally solved my choke cable issue.  I had purchased both cables, the one for a carb with an elbow and the one for a carb without an elbow.  Neither of them worked.  The non elbow cable did not give me enough inner cable to hook up to the choke.  The cable for the elbow, gave me far too much inner cable.  So I stole an elbow from the old basket case carb and solved the issue.  Time to move on.

CARB-4-2020-01.thumb.jpg.f93a5c323be739165d017af9f5b376f7.jpg

Plumbing!!  Got the fuel line and breather lines hooked up.

CARB-4-2020-02.thumb.jpg.c1546d1642ba26accddf4d27279d5649.jpg

CARB-4-2020-03.thumb.jpg.a08d34ac02b85b790edcf22d86290532.jpg

Before you all freak out...YES I did install the fuel shut off valve handle in upside down.  I didnt like the idea of the pointed handle aiming out toward my leg and cuffs when in the run position.  This seemed like a safety hazard to me.  So I flipped it. Now when its on, it is aiming in toward the center of the scooter.  This makes sense to me.

HEADLIGHT-4-2020-02.thumb.jpg.63e14a040d68196aa676dc8020e1ef9e.jpg

I hooked up my lights.  Before you FREAK again, Yes I know that the headlamp LOOKS like I installed it improperly.  But This is how this light was made.  I dont see a way to align the lens.  

HEADLIGHT-4-2020-01.thumb.jpg.f41bfa6b1f12a28e4b3ab7f9a811491d.jpg

I was able to install my headlamp eyelash too.

TOOLBAG-001.thumb.jpg.63933e99872aaea6f97fee0aaaf63aa5.jpg

I sewed up a tool bag for my lammy too. It is so much better than that crappy one I purchased years ago...back when I thought this would be on the road 2 months after I bought it...little did I know. :)

RIDING-4-2020-001.thumb.jpg.84820dcf65bedd1da34f9ea56ade18a1.jpg

Finally, here is a pic of me riding my Lambretta LI125 for the VERY FIRST TIME!!!  

This is my first ever ride on any 2 stroke scooter.  I've never owned one before this.  I've never ridden one ever...That Honda Spree doesn't count. 

In my book, this is a MAJOR score. I purchased this as a project, to learn how to build a 2 stroke and to own a Lambretta. I am so happy to see how far I've come in this endeavor.  I'll sort out the fine details next.  But sooner of later you'll be seeing me on the road, like it or not, and I'll be riding my Lammy proud.  

 

I hope that you are well and that your family is doing good.  There are lots of reasons to be feeling down these days.  I hope that this private victory of mine, brings you a smile.  I'm looking toward the future, when I can ride with you, beside you all and actually take part...rather than standing on the sidewalk thinking about 'SOME DAY'.

Cheers and look forward to joining in .... soon.

For video, please visit my Instagram feed.    https://www.instagram.com/p/B_bFoH5g0qs/?utm_source=ig_web_copy_link

  • Like 1
  • Upvote 3
Link to post
Share on other sites
  • 2 weeks later...
  • Replies 89
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Sorry I'm late! I didn't know we were talking about piston conversions!! Ha. I still do a bunch of iron barrel 186cc tunes. I prefer not to shorten the cylinders these days, but its still a good optio

YO!!! UPDATE!!!! IT RUNS!!!!!!!!!!!!!!!!!!!!!  I got it running today 4/26/2020!!  The first time this LI has fired since I bought it back in 2017.  It was a basket case back then. Here are

Thanks for sharing this info.  Obviously others have questions and this might help others.  I'll look into what you suggested because right now I have no clue what your talking about.  But I will soon

Posted Images

I'm hoping that some of you will be able to point me in the NEXT direction.  I need some input.

These are some observations when riding.

- riding down the street, the motor seems to hesitate, skip or flutter a bit. When I give it more throttle (between 1/8 and 1/4 turn from idle) the motor seems to open up and run a bit better, but still will skip.  Only in 4th gear do I get a great motor sound of it really working and clearly making out each beat.  I'll try to get better audio of this.  It might simply be my desire to avoid over revving this brand new motor.

- My clutch or transmission seem to slip or jump from gear from time to time.  This seems to happen when I'm shifting from 2 to 3.  I seem to find a neutral in between each gear.  Sometimes when I accelerate (usually in 2nd  & 3rd gear) the bike will lurch and the motor will rev.  This feels just like missing 2nd gear when shifting up from 1.  except my hand is not on the clutch and the selector is pointing to #1 or #3.  When this happens I'll let off the throttle or move the gear selecter and then the bike hooks up and we're off as normal.

- My plug is black w/ soot. I know the motor is running too fat.  I have a Dellorto PHBH 30BS.  I'm currently 2-3/4 turns (180 degrees = turn in my book).  I started at 3 turns out. I'm slowly turning the small mix screw in to lean out the fuel air mixture.  

- I mixed my fuel at 3% w/ Motul 2T 710.  I used regular gasoline. (am I supposed to use premium??)

- 1st gear is very hard to grab, especially at a stop.  how do you set up your linkage?

 

So these are the next things I need to figure out.  

 

This is an awesome ride and for the most part it is coming along well.  Just need to start learning the fine tuning techniques.

Thanks for reading and replying.

Link to post
Share on other sites

It sounds like your cables need adjusted.

To adjust my shifter cables, before I thread the cables through the trunions, I put my bike in 1st gear by hand as in the picture. Screw out the fine tuning adjusters on the top of the motor about half way. Thread the cables thru the trunions. Have a friend hold the shift handle on the "1". Using the 3rd hand tool, put tension on the cable that pulls the shift arm forward (inner cable). Next, using the 3rd hand tool, put tension on the cable that pushes the cable (all while in 1st gear) in the opposite direction (outer cable) and tighten. Roll the bike forward and shift to neutral, then to 2and to see how close you are. Then fine tune. New cable will stretch and may need readjusted.  I will connect and adjust the clutch after the shifter cables. 

I am not familiar with dellortos but where in the rev range/throttle opening are you rich? In general, if you are doing a plug chop that would show you half to full throttle mixture. On a mikuni turning the air fuel mixture screw only affects your idle. 

A motor will feel "tight" after a rebuild and after some miles will feel better. 

Yes, sounds like you are shifting before you need to imo

Screenshot_20200509-163245_Chrome.jpg

  • Upvote 1
Link to post
Share on other sites
19 minutes ago, Stu aka S.Hanson #17 said:

It sounds like your cables need adjusted.

To adjust my shifter cables, before I thread the cables through the trunions, I put my bike in 1st gear by hand as in the picture. Screw out the fine tuning adjusters on the top of the motor about half way. Thread the cables thru the trunions. Have a friend hold the shift handle on the "1". Using the 3rd hand tool, put tension on the cable that pulls the shift arm forward (inner cable). Next, using the 3rd hand tool, put tension on the cable that pushes the cable (all while in 1st gear) in the opposite direction (outer cable) and tighten. Roll the bike forward and shift to neutral, then to 2and to see how close you are. Then fine tune. New cable will stretch and may need readjusted.  I will connect and adjust the clutch after the shifter cables. 

I am not familiar with dellortos but where in the rev range/throttle opening are you rich? In general, if you are doing a plug chop that would show you half to full throttle mixture. On a mikuni turning the air fuel mixture screw only affects your idle. 

A motor will feel "tight" after a rebuild and after some miles will feel better. 

Yes, sounds like you are shifting before you need to imo

Screenshot_20200509-163245_Chrome.jpg

Thank you for your reply and your info.  I did not employ the third hand tool...I'll need to do that. I had not thought about cable stretch. great suggestion.

I assume that the fuel air mix is rich because my plug is soot black.  But i need to ride it more.

More to come!!  Thank you.

  • Upvote 1
Link to post
Share on other sites

UPDATE:

"Huston, We've got a problem!"

Background: Several times, over the past 2 weeks, I've taken my scooter out for some laps. Each time going further out.  Each time I got back I'd look at my plug.  I'd adjust the fuel / air mixture screws (circled in red below)

COD_3343CC_400.jpg.13e66670682c6ffec37e905a56b44078.jpg

I good friend of mine suggested starting out with 3 full turns out.

half-or-full.jpg.4c29f0a4d5cdc586067ca6188cc60bff.jpg

In automotive turns, which I'm more familiar with... A full turn is 360º degrees.  However, if I do 3 fulls turns on my Air / Fuel mix screw, the darn thing nearly falls out.  So I decided to do 3 half turns out.

This was working great, the scooter fired up, nearly first kick each time.  

The Isle Speed screw never worked for me.  I could crank it all the way in or all the way out and the idle never changed.  The way I was able to get this to idle was adding tension on the throttle cable adjustment screw.  

Each time I went out for a ride, I had a good ride and was trying to tune the carb.  I was getting a sort of sputtering or stalling from time to time. Another good friend said that condition was most likely too rich of a fuel / air mixture.

Checking my plug after each ride, it went from oily wet, to pitch black dry soot. Each time I would turn the Air / Fuel screw inward (tightening) bit by bit. I knew that I was going the right way because my plug was looking better.  I was shooting for that Hershey's brown color I've read about.

 

TODAY!!

I went for a longer ride.  I always take suburban streets. 40MPH max. I rode for about 15 - 20 miles. Stopping every now and then to tighten that Air / Fuel mix screw because I was still getting that miss or stutter.  It seemed as if I was on the right track. Each minute twist seemed to make a noticeable, although slight, difference.

BUT, then my motor began to race out of control. The RPM's climbed yet my hand was solid on the grip. I pressed the KILL switch and shut it down pronto.  My good friend told me about vacuum leaks that can cause a motor to race out of control and cause mega damage.  

I pushed my scoot off to a shaded spot. Popped the pans and looked around. I checked my throttle cable to make sure it was no hung up. make sure it was still connected to the carb. All looked good. I fired it back up and it ran great. So I geared up and headed back out.  5 blocks later, the motor began to race again. I killed the motor again.  I took a closer look at things. I kicked it to life and it raced out of control. So I called my local rescue truck (my brother) and got it home.

At home I kicked it to life and it ran great for several minutes. I scratched my head. HMMM, this has something to do with heat I think.  The motor was cold due to the long wait and drive back to the shed.

I fired it back up, and as I allowed the motor to warm up I sprayed some carb cleaner around the intake and base of the barrel, expecting the motor to die or stumble (like it does with a car). But I got no reaction at all. Before I could try the spray idea again, the RPM's jumped beyond the comfort zone and I dared not allow that to continue just to spray some stuff that might or might not locate a vacuum leak. so I killed it.

I pulled the plug and it was wet and oily. I decided to loosen the throttle cable tensioner, to lower the idle.  I tried to kick it and it would not fire up at all. I kicked like crazy. I pulled the plug and it was really wet. I dried things out, checked for spark and I was getting a strong flash. 

I did this several times and Could not get the motor to fire or even pop. Each time the plug was soaked.  

PROBLEM:

How do I trace the problem? I want to start simple and work up from there. Any suggestions of where to start? Your advice will help me greatly. this is the fist 2 stroke I've ever built or worked on so this is an opportunity to learn something. Thank you.

Link to post
Share on other sites

This video was taken yesterday. You might be able to hear the studdering and misses. Excuse my poor shifting...This is the first scooter I've ever ridden and my hands are not trained yet. Also I'm trying to not over rev the motor, so I slip the clutch a bit when I take off, trying to avoid stalling it.  I share this vid for the audio and also to let you see it actually running.

Cheers.

Link to post
Share on other sites

Your video isnt playing. It sounds like you are running rich on all jets. I would try to find the possible air leak first. I wouldn't worry to hard at this point about over revving yet.

Adjusting the idle/air fuel mixture screws will not have an affect on your mixture at 1/4, 1/2, 3/4 or wot. It will only affect the idle (when the slide is closed). It should be adjusted when the motor is warm. The highlighted blue screw raises the slide for more air. By your description you have not adjusted that correctly and have bypassed that adjustment by using the throttle cable tensioner on top of the carb instead. The red highlighted screw will allow more or less fuel into the airflow being sucked through the carb at idle (slide closed). As soon as you twist the throttle the other jets come into play. If I had an idle issue, I'd adjust my idle jet size, possibly the throttle slide(valve) cutaway and work with the air/fuel ratio by turning the screws to get the proper balance. 1/4 throttle adjust needle jet, 1/2 to 3/4 needle height, 3/4 to wot main jet. Yes, the picture is for mikuni but should be similar in concept to dellorto.

The racing engine sounds like a familiar problem.  Is it smoking excessively? Try spraying starter fluid, it might have a more noticeable effect than carb cleaner. Could be binding/tight throttle cable, head gasket,  loose plug, intake manifold, loose carb. Fly side crank seal leak sucks air and can seem like a lean carb issue, drive side sucks oil, then air when you run out of case oil and can at first look like a rich condition. Both cases lead to hard starting.Hoping it's not that. It gets worse the longer it persists. Keep us posted. Have you done a search on the site for the issue ? The racing sounds like air leak

 Think I am remembering someone had a stutering motor that was an electrical issue and that's why its familiar 

Screenshot_20200510-230301_Gallery.jpg

Link to post
Share on other sites

Stu, Thanks for your reply.  I'll look into each of your suggestions soon.  You're right, I'm just twisting knobs and screws without really understanding how they work or what they even do.  This is all apart of the learning curve.  I'll get it eventually.

The video wont play on my phone either, but it does play on the PC...at least it plays on my pc.

Cheers.  I'll start looking into it.

 

Link to post
Share on other sites

UPDATE:

Problem solved.

Turns out I did not have a vacuum leak or a sticking throttle cable.  I was running out of fuel.  I didn't know that a 2 stroke will begin to starve for fuel which creates a lean mixture, thus increasing the RPM's.

I tested this tonight. Other than looking at my throttle cable, my scooter was untouched from the time I got stranded.  I simply moved the fuel petcock to the RESERVE location.  Kicked the motor over and it ran just like it should.  I let the motor warm up for about 5-7 minutes.  Then as it idled, i moved the petcock to the 3 o-clock location (full tank).  in under a minute the motor began to fluctuate from idle to a higher rpm, then back to idle.  About a minute in the motor RPMs were really beginning to increase. At about 1.5 minutes, the motor rpm's began to race, like they had while I rode.  I quickly switched to the reserve.  In under a minute the motor RPMs dropped back to the regular idle.  I tried this a few times because I just didn't believe it.

Coming from a 4-stroke automotive background, my mind expects a motor to stumble and die when the carb is beginning to run out of fuel.  This lean scenario really F'd with my head for a while.

Any thoughts from you? Have you experienced this?

Link to post
Share on other sites
On 5/11/2020 at 10:56 AM, Roger Hudnut said:

You're right, I'm just twisting knobs and screws without really understanding how they work or what they even do.  This is all apart of the learning curve.  I'll get it eventually.

Ha! Welcome to the fun world of 2 stroke jetting. 

There are countless resources online, but before you start I'd recommend you;

  1. check engine for air leaks (if you haven't already)
  2. check fuel flow through tap and carb. Through the tap it should be flowing ≥400ml a minute (approx one US pint for those using still archaic forms of measurement). 
  3. set float height (Mikuni TM24 = 21mm, Keihin PWK28 = 19mm, for other carbs, such as Dell'Orto PHBL or PHBH, check the factory manual) and float needle is working.
  4. check choke is functioning correctly.

Here's a few resources to keep you busy in quarantine and help get you started:

My personal preference for kitted scooters, in addition to the above, is a wideband AF sensor to find the optimal stoichiometric AF ratio on every circuit. IMHO it takes the guess work out of jetting.

Good luck!  

  • Upvote 1
Link to post
Share on other sites

Do you have a specific wideband AF sensor you would recommend? Preferably uses a battery so I wouldn't need to splice into the ac power. There are a lot out there and prices are all over the place. I priced out a Koso BA004068 and with the meter, o2 sensor, and two stroke 02 sensor adaptor, that's $300.

And what kind of number/reading is considered safe/appropriate in a two stroke?

Any help is greatly appreciated!

Thanks!

Link to post
Share on other sites
On 5/15/2020 at 12:21 PM, Stu aka S.Hanson #17 said:

Do you have a specific wideband AF sensor you would recommend?

I've been using an AEM Digital wideband UEGO 30-4110 and can't fault it. They are ~$150 + shipping. The most crucial part is making sure whatever you buy  has the superior 4.9 LSU sensor. All of my scooters stateside are 'full DC', so I've just spliced it into my loom temporarily, but when I've lent it to friends with AC set ups they've just mounted a battery in a  legshield spare wheel cover and run it off that.

Don't want to derail this thread anymore, but if you're interested there is a wealth of info online about running these on 2 strokes, and if you really want to go down a very deep rabbit hole then this 60+ page thread from 2012 is what got me interested (a tabloid scooterboy site did an English-language summary here).

Good luck and PM or email me if you have specific questions.  

  • Upvote 2
Link to post
Share on other sites
On 5/16/2020 at 8:10 AM, vegansydney said:

I've been using an AEM Digital wideband UEGO 30-4110 and can't fault it. They are ~$150 + shipping. The most crucial part is making sure whatever you buy  has the superior 4.9 LSU sensor. All of my scooters stateside are 'full DC', so I've just spliced it into my loom temporarily, but when I've lent it to friends with AC set ups they've just mounted a battery in a  legshield spare wheel cover and run it off that.

Don't want to derail this thread anymore, but if you're interested there is a wealth of info online about running these on 2 strokes, and if you really want to go down a very deep rabbit hole then this 60+ page thread from 2012 is what got me interested (a tabloid scooterboy site did an English-language summary here).

Good luck and PM or email me if you have specific questions.  

Thanks for sharing this info.  Obviously others have questions and this might help others.  I'll look into what you suggested because right now I have no clue what your talking about.  But I will soon.

Currently, my project is running good and I've been putting miles on it as the weather and time has allowed.  

Cheers.

  • Upvote 2
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...