×
Pictures Posting Not Working (12 Jun 2023)
Picture uploads is again unavailable. We are working on the problem. Thanks for your patience.
Makotosun
carb issues
- Dogboy
-
Topic Author
- Away
- Junior Member
-
- Posts: 26
- Likes received: 9
Replied by Dogboy on topic carb issues
Plugs are at .22, clip is raised up 1 position, air jet screw is 3.5 turns out and idle jet is a 20, down from a 25. and i will try to get another audio. probably 2.
01 Jul 2026 14:07
#21
Please Log in or Create an account to join the conversation.
- Dogboy
-
Topic Author
- Away
- Junior Member
-
- Posts: 26
- Likes received: 9
Replied by Dogboy on topic carb issues
01 Jul 2026 14:44
#22
Please Log in or Create an account to join the conversation.
- RT325
-
- Offline
- Platinum Member
-
- Posts: 11039
- Likes received: 4855
Replied by RT325 on topic carb issues
If it's running well then that's the main thing but often having to go lean on the pilot jet & air screw can point to a very worn needle jet & needle combo, so it's trying to draw fuel up there at idle when should only be the pilot. That wear/ware causes rich running up where the needle does its main job too. Don't panic, if she's running well.
Please Log in or Create an account to join the conversation.
- MarkT
-
- Offline
- Site Supporter
-
- Posts: 14901
- Likes received: 11208
Replied by MarkT on topic carb issues
I'd put the jetting back to stock.
Sounds good in last video. When a bike gets "loaded up", you need to ride it. It's not something you can tune to fix or clear up by running the engine in the driveway. And it's possible to foul several plugs in a row until you ride it enough to clear it out.
I learned that from experience. Chased my tail for over a week once years ago. Finally just put a new plug in it and rode the darn thing.
Sounds good in last video. When a bike gets "loaded up", you need to ride it. It's not something you can tune to fix or clear up by running the engine in the driveway. And it's possible to foul several plugs in a row until you ride it enough to clear it out.
I learned that from experience. Chased my tail for over a week once years ago. Finally just put a new plug in it and rode the darn thing.
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
The following user(s) Liked this Post: Ht1kid
01 Jul 2026 17:25
#24
Please Log in or Create an account to join the conversation.
- Dogboy
-
Topic Author
- Away
- Junior Member
-
- Posts: 26
- Likes received: 9
Replied by Dogboy on topic carb issues
thank you very much guys.
MarkT - when you back to stock do you mean pilot jet and needle clip or just one of them? Idle screw must be out that far to get it to idle reliably.
MarkT - when you back to stock do you mean pilot jet and needle clip or just one of them? Idle screw must be out that far to get it to idle reliably.
01 Jul 2026 17:29
#25
Please Log in or Create an account to join the conversation.
- SKYDANCER46
-
- Offline
- Site Supporter
-
- Posts: 550
- Likes received: 718
Replied by SKYDANCER46 on topic carb issues
You can also remove the head & cylinder and get all the excess oil and gas out of the crank area if necessary. I had to do that on 2 of the 4 bikes i just bought a few months ago. They were loaded. One was full of gas. Glad i never tried to start it first. I take the cylinders off on every bike i buy and check for this.
As Mark said i would also put all the jetting and carb settings back to stock and leave it alone. 3 1/2 turns out on the air screw is Way way to much.
As Mark said i would also put all the jetting and carb settings back to stock and leave it alone. 3 1/2 turns out on the air screw is Way way to much.
1968 DT1 250, 1969 AT1 125, 1969 CT1 175, 1970 RT1 360
The following user(s) Liked this Post: swm, Ht1kid
01 Jul 2026 17:35
#26
Please Log in or Create an account to join the conversation.
- Dogboy
-
Topic Author
- Away
- Junior Member
-
- Posts: 26
- Likes received: 9
Replied by Dogboy on topic carb issues
so besides a keyster kit where would I get the proper needle jet & needle combo?
02 Jul 2026 16:08
#27
Please Log in or Create an account to join the conversation.
- SKYDANCER46
-
- Offline
- Site Supporter
-
- Posts: 550
- Likes received: 718
Replied by SKYDANCER46 on topic carb issues
I would not use any keyster or aftermarket kit.
Speedandsports.com and CMSNL both show the needle & nozzle in stock.
Speedandsports.com and CMSNL both show the needle & nozzle in stock.
1968 DT1 250, 1969 AT1 125, 1969 CT1 175, 1970 RT1 360
02 Jul 2026 16:54
#28
Please Log in or Create an account to join the conversation.
- MarkT
-
- Offline
- Site Supporter
-
- Posts: 14901
- Likes received: 11208
Replied by MarkT on topic carb issues
Yes, back to stock jets. Mikuni, not Keyster. Keyster jets on these models have been known to create issues. They are not the same calibration no matter what numbers they stamp on them.
There is a Mikuni tuning manual in the tech library or online. It explains the operation of the circuits. You must jet the correct circuit based on throttle slide opening. Idle mixture is only controlled by pilot jet and air screw. Leaning out other jets to correct an idle issue not only won't work, it can lead to an engine seizure.
Check your float level. Sometimes manual specs are wrong. Float arms should be parallel to bowl gasket surface when float needle closes.
There is a Mikuni tuning manual in the tech library or online. It explains the operation of the circuits. You must jet the correct circuit based on throttle slide opening. Idle mixture is only controlled by pilot jet and air screw. Leaning out other jets to correct an idle issue not only won't work, it can lead to an engine seizure.
Check your float level. Sometimes manual specs are wrong. Float arms should be parallel to bowl gasket surface when float needle closes.
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
The following user(s) Liked this Post: Ht1kid
03 Jul 2026 08:44
#29
Please Log in or Create an account to join the conversation.
Moderators: yamadmin, Makotosun, DEET, Vinnie, James Hart
