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77 Dt 250 set timing on a bike that wont start.
- MrDrSirMan
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77 Dt 250 set timing on a bike that wont start. was created by MrDrSirMan
I just rebuilt my 77 dt250. I suspect that it had some timing issues before. I snapped 2 kickers from it kicking back so hard and went to the hospital once. Anyway at least it would start. After assembling I matched the marks left by the previous screws and figured I would adjust the timing after I started it. Now the kickback problem seems to be even worse. The bike has great compression and the spark seems just fine. So I was just wondering how to set the timing on a bike that wont run. My manual says nothing about it.
16 Apr 2024 20:46
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- MarkT
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Replied by MarkT on topic 77 Dt 250 set timing on a bike that wont start.
What you did is the first step of the best practice... put the stator back as close as possible to where it was.
To set the timing you use a dial indicator to locate the piston BTDC and then adjust the points so they just open with the piston the specified distance BTDC. If you don't have the tools, if you're lucky the timing tab that lines up with a mark on the flywheel might be unmolested and you can get close using that.
The factory service manual in the tech library has the timing procedure in Chapter 2 page 13... or there are many posts on timing here if you search
To set the timing you use a dial indicator to locate the piston BTDC and then adjust the points so they just open with the piston the specified distance BTDC. If you don't have the tools, if you're lucky the timing tab that lines up with a mark on the flywheel might be unmolested and you can get close using that.
The factory service manual in the tech library has the timing procedure in Chapter 2 page 13... or there are many posts on timing here if you search
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
16 Apr 2024 22:24
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- RT325
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Replied by RT325 on topic 77 Dt 250 set timing on a bike that wont start.
Ok an essay or sermon below but i'll leave it now i've typed it. If you can wade through just pick out what's useful--if anything.
Wow, i'd be surprised if you could get the timing far enough out to kick back hard enough to break the kickstart let alone two kick starts & a trip to hospital.
My thoughts are with you but hope ya all healed up now for another try. But first get the timing close to 3.2mm btdc.
That said my first thought is crank key is missing? & by shear luck you're getting the timing in the ball park albeit a very big ball park when fitting the flywheel.
Ok maybe i'm overstating things but you also say you'll adjust the timing after starting it which i don't quite understand as isn't possible while running.
Just a random thought though.
Has it got points or has someone fitted a CDI mag of a "79 DT250 or a 400 because if that had a faulty pulser coil or something haywire then maybe time for a re-think.
If none of that applies then are you kicking it from the top & also kicking from against compression so your first movement of the kick is going through 'that compression' & it should strike the next compression near the bottom of the kick stroke so you got through the first one then catch the second one at speed--good kick speed--& it should start as it goes through that second compression near the bottom of kick stroke.
If you do it wrong & move past comp with lever then start kicking, you'll arrive at compression halfway down on the lever & it just doesnt work or will bite back.
So find compression with the lever, then bring it back to the top so you then kick 'through' that comp right from the top.
If you accidentaly push through compression getting ready to kick the then go through the process again so you're doing it right from the top with compression.
Wow, i'd be surprised if you could get the timing far enough out to kick back hard enough to break the kickstart let alone two kick starts & a trip to hospital.
My thoughts are with you but hope ya all healed up now for another try. But first get the timing close to 3.2mm btdc.
That said my first thought is crank key is missing? & by shear luck you're getting the timing in the ball park albeit a very big ball park when fitting the flywheel.
Ok maybe i'm overstating things but you also say you'll adjust the timing after starting it which i don't quite understand as isn't possible while running.
Just a random thought though.
Has it got points or has someone fitted a CDI mag of a "79 DT250 or a 400 because if that had a faulty pulser coil or something haywire then maybe time for a re-think.
If none of that applies then are you kicking it from the top & also kicking from against compression so your first movement of the kick is going through 'that compression' & it should strike the next compression near the bottom of the kick stroke so you got through the first one then catch the second one at speed--good kick speed--& it should start as it goes through that second compression near the bottom of kick stroke.
If you do it wrong & move past comp with lever then start kicking, you'll arrive at compression halfway down on the lever & it just doesnt work or will bite back.
So find compression with the lever, then bring it back to the top so you then kick 'through' that comp right from the top.
If you accidentaly push through compression getting ready to kick the then go through the process again so you're doing it right from the top with compression.
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- RT325
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Replied by RT325 on topic 77 Dt 250 set timing on a bike that wont start.
I was starting to doubt my own advice so i just went out in the dark & fell over everything in my messy shed & tried the 360 then 250 by hand & pushing through the first comp at the top of the kick stroke it finds the second one about 3/4 of the way down so you have good kick speed going on by the time you go through the second one.
17 Apr 2024 00:26
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