facebook1 youtube1 twitter1 instagram google plus linkedin1 pinterest1

logosmallNOTICE:  If you are not a free registered member of the site, you will not see the photos in the forum, and you won't be able to access our premium member content. Please consider joining our community!

Welcome, Guest
Username: Password: Remember me
  • Page:
  • 1

TOPIC: Started! Almost....

Started! Almost.... 17 May 2019 20:26 #1

  • StukaGruppen13
  • StukaGruppen13's Avatar Topic Author
  • Offline
  • Sportsman
  • Sportsman
  • Posts: 50
  • Likes received: 8
Hello gentlemen! Finally, my DT125B started...but only when gas was put directly down the spark plug hole. It started, then died when that fuel ran out. So it HAS to be fuel delivery. I'm checking the reeds out tomorrow, but do any of you have any other suggestions?
- perfectly clean (ultrasonic cleaned) proper Mikuni carb
-new fuel line
-clean tank and petcock
Thanks!

Please Log in or Create an account to join the conversation.

Started! Almost.... 18 May 2019 05:49 #2

  • RT325
  • RT325's Avatar
  • Offline
  • Collector
  • Collector
  • Posts: 3798
  • Likes received: 1214
Is the fuel actually getting into the carb. Pretty easy to fit the float upside down & stop fuel flow. If it 'has' fuel in the bowl it should get to the motor unless something very unusual is happening. Even if all jets were blocked it'd still start on choke with a closed throttle providing that jet is clean but sounds like you given it the ultimate clean [ultrasonic clean]. There's a very slight chance but highly unlikely that one of the crank seals has escaped & putting fuel down the plug hole is igniting it just because the fuel is right where its needed if the piston is above ports closed. Reeds never do anything to stop it running unless the stops have been folded closed or one reed is broken & missing. If it sat for 20 years i suppose they could stick shut with fuel residue. I've run out of ideas sorry.

Please Log in or Create an account to join the conversation.

Started! Almost.... 18 May 2019 06:46 #3

  • MarkT
  • MarkT's Avatar
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 5386
  • Likes received: 2650
If reeds stuck shut somehow I doubt it would get enough air to run?

Problem is likely in carb or fuel supply to carb... I've had to clean carbs more than once and all it takes is a little bit of debris in a fuel line to plug up the pilot jet.

Please Log in or Create an account to join the conversation.

1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250

Started! Almost.... 18 May 2019 08:09 #4

  • DaveR
  • DaveR's Avatar
  • Offline
  • Mini Enduro
  • Mini Enduro
  • Posts: 26
  • Likes received: 43
Make sure the carb slide is not in backwards !

Slide has narrow slot for guide pin, full length of slide.
Notch on other side for idle adjustment screw and only at bottom.
The following user(s) Liked this Post: MarkT, StukaGruppen13

Please Log in or Create an account to join the conversation.

Started! Almost.... 18 May 2019 12:22 #5

  • StukaGruppen13
  • StukaGruppen13's Avatar Topic Author
  • Offline
  • Sportsman
  • Sportsman
  • Posts: 50
  • Likes received: 8
Update: Thanks everyone for your suggestions, but I think we've found the issue; vacuum leak. We started the bike and it runs well, except when the choke is off, then the RPMs skyrocket. As well, it takes a while for it to even start. Anything you can image that has to do with starting (spark, timing, fuel supply, carburetor) we've checked, cleaned, and checked again (took the carb to an expert, found nothing wrong) so all that rules out if being something else. Also, we were told that if an excess of smoke pours out of the primary side of the case (where the dynamo is) it is a sign of a leak.

Please Log in or Create an account to join the conversation.

Started! Almost.... 18 May 2019 15:45 #6

  • RT325
  • RT325's Avatar
  • Offline
  • Collector
  • Collector
  • Posts: 3798
  • Likes received: 1214
first thought 'now' is--is the slide hitting the bottom when shut off. Should here it click down when flicking the throttle plus back the speed screw right off so slide is hitting right down. Choke won't work if the throttle is open, well won't like working at kick speed anyway. Major air leak but no major smoke sounds like left crank seal behind mag. But FIRST i'd go looking in the carb & eyeball each jet. Pilot is super small & i use my acupuncture needle to clean it. Remove the needle jet that hold the main jet & look through. Lift the slide needle, put clip on groove 5--the lowest groove, then go try it. Oh, & check the float level to see if its in the ball park. Otherwise yes, a major air leak.
The following user(s) Liked this Post: Snglsmkr, StukaGruppen13

Please Log in or Create an account to join the conversation.

Started! Almost.... 19 May 2019 10:17 #7

  • StukaGruppen13
  • StukaGruppen13's Avatar Topic Author
  • Offline
  • Sportsman
  • Sportsman
  • Posts: 50
  • Likes received: 8
We removed the engine (before I saw this ;) ), removed the dynamo and the armature, and lo and behold, massive gap between oil seal and crank shaft. So it was a giant air leak, I'm surprised we even got it started! Thanks for the suggestions and help, I'll have to get a new one, pop it in and reassemble it.

Please Log in or Create an account to join the conversation.

  • Page:
  • 1
Moderators: VinnieDEETyamadminDmanEnduronutMakotosunDevinJames Hart