Go Back   DIY Go Kart Forum > Building Plans And Advice > Mini Bikes, Trikes, and Choppers

Notices

Reply
 
Thread Tools Display Modes
  #1  
Old 02-10-2019, 07:29 PM
Sticky_Molasses Sticky_Molasses is offline
Member
 
Join Date: Apr 2018
Location: Florida
Posts: 32
Thanks: 16
Thanked 3 Times in 3 Posts
Default Tomos Targa LX

Iím not sure if scooter talk is welcome here but Iíll ask anyway. A buddy of mine has a Tomos Targa Lx (49cc moped). Itís been having a few issues lately and I volunteered to help fix it. The main issue is starting the bike. Itís ďpedal startĒ and often take great effort to get going at all. Once it does get going anything above 1/4 throttle causes it to die. Iím think two options, fix and or replace the carburetor and air filter. Or two replace the engine although as it has been abused quite a bit. Unfortunately I donít have any pictures just yet as itís not my bike. Iíll take plenty of pics though when I start working on it.
Reply With Quote
  #2  
Old 02-10-2019, 08:15 PM
itsid's Avatar
itsid itsid is offline
Moderator
 
Join Date: Jul 2013
Location: Ruhrpott [Germany]
Posts: 9,712
Thanks: 1,325
Thanked 4,113 Times in 3,074 Posts
Default

not actually a scooter

Anywho..

"great effort to get going"...
what do you mean by that high resistance on the pedal,
or low resistance on the pedals but no combustion happening?

the latter I assume, since that'd match my assumption and could be the exact same cause for it dying at any somewhat open throttle.

So do me a favour and try this:
clean the spark plug as good as you can (ideally get a new one in)
then start it up (I know.. please once more!)
then rev it up as high as you can (gently... do not rip that throttle but caress it to the highest rpm you can get to)
as soon as it died, remove the spark plug and take a pic of it to show us.

I'd expect it to be wet (dripping wet even)
My thinking is.. since that thing now has ~30 years of abuse on it's saddle and likely little to no maintenance,
the piston rings or even the cylinder walls are completely worn out..
causing a severe lack of compression and thus making it terribly hard to start..
Since as it got harder and harder the inexperienced rider might think adding fuel can solve that..
now with no noteworthy compression all that uel is just spoiling the spark plug making it even harder to start.

Solution: rehoning the cylinder wall and fitting oversized pistonrings (or piston where due)
don't worry.. it sounds worse than it actually is.. a honing kit costs a few bucks true (50-70ish) and while psitonrings aren't expensive, sometimes pistons can be (IDK about the Tomos.. but I'd say it might be again in the 30ies dollarwise for a new piston)

Chances are you (well.. your friend) got really lucky and the spark plug ends up one dry.
in which case a carb clean (NO replacement just yet..)
disassemble it, boil in lemon juice, blow every nuck and cranny with shop air and repeat twice until you checked every ever so tiny air passage to be free of debris.

reassemble and it'll be as good as new and you havent spend more than a few pennies for it.
maybe new gaskets.. and the lemon juice that's usually all it takes)

Most airfilters can be cleaned.. some need to be replaced.. I can't tell w/o pics of course.
So *shrugs*

But to me that sounds like a worn out cylinder wall.

While at it, cleaning everything on the engine is a good idea,
and if you have to remove the cylinder it's also good to check the ports
(or does it have a reed valve.. it doesn't, does it?)
if it does.. make sure the valve is still in good shape
(no broken flaps, no crusty fins, and closing properly)
maybe do that BEFORE you remove the cylinder since a broken flap can be the culprit as well

what else?

Oh right: those two strokes need a matching exhaust.. sooo
if someone drilled holes in yours or cut a part off or installed a nice looking four stroke exhaust instead (to get rid of that nasty pineapple shape [which is the needed expansion chamber])
then you should fix that as well..

'sid
__________________
Jokes about german sausage are the wurst.
Reply With Quote
The Following User Says Thank You to itsid For This Useful Post:
Sticky_Molasses (02-11-2019)
  #3  
Old 02-11-2019, 04:49 AM
Sticky_Molasses Sticky_Molasses is offline
Member
 
Join Date: Apr 2018
Location: Florida
Posts: 32
Thanks: 16
Thanked 3 Times in 3 Posts
Default

Thanks Sid! Iím going to try all that as soon as I can! And yes, to start it you have to pedal backwards to get going and it isnít too hard to do but takes 5-10 minutes of pedaling to get it started.
I appreciate all the help with such little information on my end, thank you again.
Reply With Quote
  #4  
Old 02-11-2019, 08:50 PM
ghost civic ghost civic is offline
Senior Member
 
Join Date: Mar 2015
Location: maine
Posts: 229
Thanks: 0
Thanked 13 Times in 11 Posts
Default

Quote:
Originally Posted by Sticky_Molasses View Post
Thanks Sid! Iím going to try all that as soon as I can! And yes, to start it you have to pedal backwards to get going and it isnít too hard to do but takes 5-10 minutes of pedaling to get it started.
I appreciate all the help with such little information on my end, thank you again.
I have a tomos targa lx myself.

are you applying the choke?

It should have a dellorto carb like in this pic (unless it is a newer a55 motor) and that lever you push down is the choke. To remove the choke once the bike is started, you simply give it a quick full throttle snap...the throttle cable going WOT releases the choke mechanism.

Other than that, you could have a partly clogged jet (only one in there) or if the original air box/filter is missing then it could be getting too much air for the amount of fuel the carb can supply.

If yours has a dellorto 14:12P carb, then a new one from amazon is like $16.

Another possibility is that you have the A35 motor which has reed valve on the intake and the reed valve is worn out.

Moped army has a ton of info on tomos bikes. Can help you figure out the year, motor variant and such.

I got mine not running for $80 and have since put $200 into it, new tires, rear shocks, carb, paint, kickstand ect.
Attached Thumbnails
61Y2MCPEHZL._SY355_.jpg   0209191645.jpg  

Reply With Quote
The Following 2 Users Say Thank You to ghost civic For This Useful Post:
landuse (02-11-2019), Sticky_Molasses (02-18-2019)
  #5  
Old 02-15-2019, 12:29 AM
Denny Denny is offline
Canned Monster
 
Join Date: Sep 2014
Location: Mayberry, Indiana
Posts: 1,454
Thanks: 86
Thanked 666 Times in 497 Posts
Default

Another common 2 stroke problem is a plugged up exhaust. Loosen the bolts or nuts holding the exhaust to the head and see if it runs better. If it does you found the problem.


Denny
Reply With Quote
The Following User Says Thank You to Denny For This Useful Post:
Sticky_Molasses (02-18-2019)
  #6  
Old 02-18-2019, 05:46 PM
Sticky_Molasses Sticky_Molasses is offline
Member
 
Join Date: Apr 2018
Location: Florida
Posts: 32
Thanks: 16
Thanked 3 Times in 3 Posts
Default

Thanks for the advice guys. Unfortunately my friend has been really flakey the past couple weeks and hasn’t brought it to get worked on
I’ll keep you all posted.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 09:44 AM.