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Makotosun
Smoke under the DT 400B tank
- Wessi
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Smoke under the DT 400B tank was created by Wessi
New to me DT400 is in really bad condition, everything stripped to a pure dirt bike, but was announced as "running".
In deed, I started the bike and motor in idle run fine without bad noises. But then smoke appeared under the front of the gas tank, so I stopped the engine.
Didn't find the source, nothing visible on the wiring loom or surroundings. And bike don't have spark, now.
My question now is, can I try to start this CDI bike also just by connecting the black wire with the coil,,as it is possible with the points bike DT250?
I know the CDI is not reliable and I will convert the ignition later. For time being, I just want to find out in a short ride, how engine is running and shifting, before a possible rebuild starts.
Mabe just top end rebuild and new seals or enough?
Thank you in advance for your help.
In deed, I started the bike and motor in idle run fine without bad noises. But then smoke appeared under the front of the gas tank, so I stopped the engine.
Didn't find the source, nothing visible on the wiring loom or surroundings. And bike don't have spark, now.
My question now is, can I try to start this CDI bike also just by connecting the black wire with the coil,,as it is possible with the points bike DT250?
I know the CDI is not reliable and I will convert the ignition later. For time being, I just want to find out in a short ride, how engine is running and shifting, before a possible rebuild starts.
Mabe just top end rebuild and new seals or enough?
Thank you in advance for your help.
04 Jul 2024 07:42
#1
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- MarkT
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Replied by MarkT on topic Smoke under the DT 400B tank
Not possible to do that on a CDI bike.
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
04 Jul 2024 07:55
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- RT325
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Replied by RT325 on topic Smoke under the DT 400B tank
Smoke aint good but an easy way to find the short. But is the smoke coming from a worn decompressor & smoke is wafting up there under the tank. Ok not that. Nothing is battery powered in the cdi but i guess a short to ground or short together could melt the wire casing. Have a close look.
04 Jul 2024 20:51
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- Wessi
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Replied by Wessi on topic Smoke under the DT 400B tank
The smike must come out of the wiring loom.
It appeared after motor was running for 1-2 minutes..I think you are,right, must be a short
But where? I will have a closer look..Thank you both
It appeared after motor was running for 1-2 minutes..I think you are,right, must be a short
But where? I will have a closer look..Thank you both
05 Jul 2024 13:03
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- MarkT
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Replied by MarkT on topic Smoke under the DT 400B tank
Most common "smoke under the tank" cause I've seen is the rectifier and/or the rectifier wires (white and red)... generally caused by a shorted battery or no battery and the red touched ground.
Technically, that won't make it stop running on its own... but what can happen is adjacent CDI wires get melted/shorted in the harness.
Technically, that won't make it stop running on its own... but what can happen is adjacent CDI wires get melted/shorted in the harness.
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: RT325
05 Jul 2024 13:15
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