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The 2-Stroke Garage => Turning Wrenches => Topic started by: rodneya on May 12, 2019, 12:17:13 PM

Title: checking timing with timing light
Post by: rodneya on May 12, 2019, 12:17:13 PM
If I want to check my RD350 timing with a light do need to set to 1.8mm advanced with a dial gauge and make a new mark above the viewing window? my timing light does not have any advance / retard setting
Title: Re: checking timing with timing light
Post by: bracket maker on May 12, 2019, 06:00:27 PM
when the cylinder is ready to fire the timing marks line up. there is a mark at 1.8mm ahead of tdc. you can't see the marks without the strobe light when the engine is spinning. marking the line helps to see it when you flash the strobe. I remove the spark plug on the side I'm checking and run on one cylinder when I'm timing.

there is no advance/retard on any timing light. better ones work on induction, cheap ones work with the ignition voltage. I have the cheap one so I have to remove sparkplugs to time.
Title: Re: checking timing with timing light
Post by: Redbird on May 12, 2019, 06:53:21 PM
Quote from: bracket maker on May 12, 2019, 06:00:27 PM
there is no advance/retard on any timing light.
Several manufacturers sell timing lights that you can pre-set ignition advance.
I have a Craftsman model in my box as we speak.
Title: Re: checking timing with timing light
Post by: m in sc on May 12, 2019, 08:01:16 PM
yes set to 1.8. if you use a dial back, the chart is in the tech library (mm to degrees)

Title: Re: checking timing with timing light
Post by: bracket maker on May 13, 2019, 06:55:37 AM
Quote from: rodneya on May 12, 2019, 12:17:13 PM
If I want to check my RD350 timing with a light do need to set to 1.8mm advanced with a dial gauge and make a new mark above the viewing window? my timing light does not have any advance / retard setting

why do you think the marks in the timing window are not already set at 1.8mm atdc?
why do you think advance in timing has anything to do with the light and not the points adjustment?
Title: Re: checking timing with timing light
Post by: m in sc on May 13, 2019, 07:53:08 AM
rd350s factory timing marks are set to 2.0mm btdc from the factory.  :twocents:
Title: Re: checking timing with timing light
Post by: rodneya on May 13, 2019, 10:40:06 AM
Quote from: bracket maker on May 13, 2019, 06:55:37 AM
Quote from: rodneya on May 12, 2019, 12:17:13 PM
If I want to check my RD350 timing with a light do need to set to 1.8mm advanced with a dial gauge and make a new mark above the viewing window? my timing light does not have any advance / retard setting

why do you think the marks in the timing window are not already set at 1.8mm atdc?
why do you think advance in timing has anything to do with the light and not the points adjustment?

I know for a fact that the mark  on the rotor is not 1.8mm
I never said advance timing has anything to do with the timing light, but if you have that feature on the timing light you can set it and it will flash at TDC
Title: Re: checking timing with timing light
Post by: rodneya on May 13, 2019, 10:42:41 AM
Quote from: m in sc on May 13, 2019, 07:53:08 AM
rd350s factory timing marks are set to 2.0mm btdc from the factory.  :twocents:

Thanks M in SC.


Title: Re: checking timing with timing light
Post by: rodneya on May 13, 2019, 10:42:57 AM
Wow, the complete lack of correct or helpful info posted in the answers is amazing.
Title: Re: checking timing with timing light
Post by: m in sc on May 13, 2019, 10:45:56 AM
to be more on point, yes. verify your marks are at 2.0. use chart, set dialback light where you need it (1.8) and time with a light.  :cheerleader:
Title: Re: checking timing with timing light
Post by: bracket maker on May 13, 2019, 10:46:35 AM
Quote from: m in sc on May 13, 2019, 07:53:08 AM
rd350s factory timing marks are set to 2.0mm btdc from the factory.  :twocents:


that's not the point. why does the op feel he needs an advance on the timing light to set the timing?
why does the op feel the timing marks set at the factory are wrong?
the timing light strobe does not adjust timing it only allows you to see the timing marks in real time when the engine is running. why would a timing light have adv/retard built in? how would this even be possible, mm to degrees is a complicated formula dependent on stroke and rod legnth. how could you even enter this info into a light?
Title: Re: checking timing with timing light
Post by: m in sc on May 13, 2019, 10:54:39 AM
because you can use tdc timing marks with a dialback timing light to set it where you want to. I set my cars using the tdc mark and change the offset in the light to reflect initial advance, then total advance when i rev it out to.  I also set up my cdis in the bikes with programmable curves using one mark as well that way, OP is on the right track. so, you can throw a timing light on the rd at tdc mark (you have to make that). then set the dial back to where you need it ( i linked the chart) .

but  to the ops post, yes, make new marks if you dont have a dialback. easy as pie.
Title: Re: checking timing with timing light
Post by: bitzz on May 13, 2019, 11:02:21 AM
Quote from: rodneya on May 13, 2019, 10:42:57 AM
Wow, the complete lack of correct or helpful info posted in the answers is amazing.

Welcome to the internet.
New here?
Title: Re: checking timing with timing light
Post by: bracket maker on May 13, 2019, 11:16:05 AM
Quote from: rodneya on May 13, 2019, 10:42:57 AM
Wow, the complete lack of correct or helpful info posted in the answers is amazing.

dialback timing light, man I'm fucking old. mine is neon to boot. I just do it live and make my own marks when I need.
Title: Re: checking timing with timing light
Post by: m in sc on May 13, 2019, 11:20:01 AM
i have a self powered neon one as well. theres a bunch of ways to skin a cat, the dialback is not expensive and a real time saver if oyu work on a lot of vehicles.
Title: Re: checking timing with timing light
Post by: SoCal250 on October 17, 2021, 01:19:58 PM
Decided to double check my RD125 timing with an actual light. I'm using a standard Craftsman inductive timing gun.
Static timing was initially set with a dial gauge and quadruple verified. It's right on 1.8mm BTDC on both cylinders and I made sure the factory pointer was aligned.

With the light and engine at idle (or revved up to about 3K) the mark on the rotor seems to bounce around a little. It's not perfectly steady, moving erratically a little plus and minus from the pointer, and happens on both sides. Is that normal? I thought I recall seeing in Chuck's videos that the pointer and rotor mark were always steady/stable.
Title: Re: checking timing with timing light
Post by: Striker1423 on October 17, 2021, 09:31:56 PM
My guess is that jumping is either point dwell, or a temporary flicker in the induction pickup on the light. They aren't always aperfect when reading pulses.