Ignition time setting with current octanes

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LC Cnd
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Ignition time setting with current octanes

#1 Post by LC Cnd » Mon Jun 12, 2017 1:39 am

Newbie at time setting but willing to give it a shot. Note on previous threats that current fuels can throw off the manual setting of 2mm BTDC but its suggested to be 1.6 mm or 1.8 mm BTDC on the 350LC engine at 2000 rpm. Using 230 mains on Microns and 22.5 pilots with stock Minukis on 94 octane with a 32:1 premix. Note some debate degree wheel vs. dial gauge also. Built a dial gauge with an old spark plug as suggest. So, 1.8 or 2 mm setting and how long should the probe stem be for the gauge to get a proper reading?
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hondaror
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Re: Ignition time setting with current octanes

#2 Post by hondaror » Mon Jun 12, 2017 2:34 am

Holy crap. What oil are you running at 32:1? 230 mains? You should be way leaner than that at sea level. You need to get that thing on a dyno, to see what it's really doing. I know you are not close to one, but make it a priority.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

LC Cnd
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Re: Ignition time setting with current octanes

#3 Post by LC Cnd » Mon Jun 12, 2017 12:05 pm

The priority is to get the bike running with some modicum of decent preformance then consider a fine tuning. You got to work with what's available. In my case its the following: a shop manual, whats left after paying the bills for replacement bits, wrenches, seek advise and tenacity to get the job done. I'm currently using Ipone and switching to Amsoil. Any advice on a local fix for the settings?

Bare
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Re: Ignition time setting with current octanes

#4 Post by Bare » Mon Jun 12, 2017 12:29 pm

IMO Even a dial gauge is inexact (piston dwell)
Print out a degree wheel.
Glue stick it to your flywheel and use it and a Strobe to set it to 20 degrees.
32:1 on premix will Not make for a long and happy engine life.
Even with that Amway oil.
I use Chevron 94 as it has zero Ethanol Which far more than octane rating.. messes 2 strokes.
Shell may be similar.. So I've been told.

LC Cnd
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Re: Ignition time setting with current octanes

#5 Post by LC Cnd » Mon Jun 12, 2017 3:00 pm

Found a printable one here for those interested in printing their own:
http://www.swarfrat.com/DegreeWheelDownload.htm" onclick="window.open(this.href);return false;
What do I line up to glue it proper to set it at 20 degrees.

logierob
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Location: Victoria B.C. Canada

Re: Ignition time setting with current octanes

#6 Post by logierob » Tue Jun 13, 2017 7:57 pm

If you want to use your degree wheel make a pointer (I used a sharpened cloths hanger with a loop for the screw to go through) and attach it by using one of the screws that hold the crankcase cover on that side. In your picture that would be the top one just to the left of your stator wiring bundle. Then with your dial guage find tdc and line up pointer with tdc mark on your degree wheel. From there you can check what 1.8 or 2mm will be and make a paint pen mark on the rotor that lines up with the stator mark.
From 1993 To 2008 my 81 lc was on 32:1 premix with 230 mains and 25 pilots and ran great at sea level. I am now back on the pump and running PWK 28.

logierob
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Re: Ignition time setting with current octanes

#7 Post by logierob » Tue Jun 13, 2017 8:26 pm

I should add that for years i never used a dyno. Never saw a need on the bone stock set up of an LC. I now have a zeel and the PWK carbs and did the seat of the pants tune and plug chops. Last month i paid for some time on the dyno after a long drive to get to where one is 600KM away just to check my feuling and all we ended up doing was lifting the needle after some new ignition curves. Maybe just lucky. But dyno is a relatively new thing to do in the home tuning world.

hondaror
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Re: Ignition time setting with current octanes

#8 Post by hondaror » Tue Jun 13, 2017 10:24 pm

With 2 hours of dyno time, you can do a full days worth of jetting work. Without the dyno, one change at a time. The dyno read out shows you where you are rich or lean. If you know what you're doing, you can have it running great with minimal attempts at changing things.
32:1 is old school thinking. Oils are really good now. They have been for 30 years if you ante'd up back then. MC-1 Bel-Ray is what I ran my moto crossers at 60:1. Never seized a premixed engine.
Last Sunday I showed up at our local event. A guy hunted me down and asked me why my bike was not smoking. All his 2 strokes smoked. I told him, jetting and ride them hard. Don't err on the side of rich. Check your plugs when you are jetting. Chops are only for the main jet. If you are dangerously lean, your plug will be white, very hot looking. The bike should sound crisp and dry, if that makes any sense. Throttle response should be very responsive and quick to rev. There should be no runny oil coming out of your pipes at either end. If so, you are way too rich, and have no idea how a good running engine pulls, because you have not felt it yet. If you stick your finger in the end of a pipe from a good running engine, your finger will come out brown and dusty dry. The sound at idle, distinct popping of both cylinders firing one after the other, with pipes. Stock pipes are muddled sounding.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

Hooligan
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Re: Ignition time setting with current octanes

#9 Post by Hooligan » Wed Jun 14, 2017 2:21 am

I use a dial gauge for setting my timing. It is after all, exactly how the manual describes setting the timing. I had to use a fairly long reach gauge to hit the piston top and even then it doesn't follow the piston through its entire stroke.

The manual describes exactly how the crank is to be manipulated in order to perform the measurement. Its all in making sure the piston is moving in the correct direction, which would minimize any piston dwell.
'82 RD350LC in '81 colours, OEM pipes, UNI filters
'85 FZ750

Bare
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Re: Ignition time setting with current octanes

#10 Post by Bare » Wed Jun 14, 2017 7:52 pm

Find TDC By using a piston stop Or fooling with a dial gauge 'til you think you have found TDC at the centre of the piston's dwell.
Set the Degree wheel Zero to TDC with 20 degrees on the F mark on the flywheel
Use the strobe at ~2000 rpm to check and see if it lands on it. Adjust as wanted by rotating the stator.
A couple of degrees on the Timing wheel is a Small number on a Dial gauge.
Tough to set with Any confidence
LC Cdi has No ignition curve, any that exists is purely electronics lag. It's important to get it right as the Goofy factory CDI is a Performance bottleneck

Also Mikunis are now 35+ years old and Likely worn right out.. no longer overly reliable.
So mixtures can be sketchy even when carefully worked with.
Brown to light brown plugs are 'good'
Lean is for trying/wanting to win your race.. at all costs.

Personally I use More rather than Less oil.
Tried Klotz when it was the hyped New technology and it's Reduced oil content claims.
A mistake I won't be revisiting

But yer welcome to :-)

LC Cnd
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Re: Ignition time setting with current octanes

#11 Post by LC Cnd » Thu Jun 15, 2017 4:06 am

Thx to all who advised. Going to try both methods. Been playing with the dial gauge and still trying to figure which is the intake or out port rotation going to TDC. With the degree wheel, paper in my case, Bare which type of adhesive did you use to adhere the wheel to the flywheel?

seahorse
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Re: Ignition time setting with current octanes

#12 Post by seahorse » Mon Jun 26, 2017 7:42 am

Check your squish if your not below .9 mm then Set your firing point with a dial guage at 1.8 before TDC. Period. Check with a timing light when your done.
81 RD 250 LC Hybrid .Widened frame with Aprilia RS250 Back end & Front end, strokd RZ 421, Kennys TSA's, 31KVM26SS Carbs M-360 P-25 ALBA Ndl Pos 3, Air 1.3/4
81Rd350lc resto 2016
81 Rd250lc resto 2017
1999 ZRX 1100

LC Cnd
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Re: Ignition time setting with current octanes

#13 Post by LC Cnd » Tue Jun 27, 2017 2:09 am

The orifices in the pilot jets were restricted (abeit a bit gummed up). Replaced them - fired up 1st kick. Cut back on the oil 40:1. The ignition does not sound tinnie enough in the pipes and the acceleration feels retarded. I'm thinking the timing is out a few degrees as the right cylinder feels like its not getting fuel or firing proper. Timing next finally.

LC Cnd
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Re: Ignition time setting with current octanes

#14 Post by LC Cnd » Tue Jun 27, 2017 9:14 pm

Obtained these items today for timing. I was told you set the plate's zero mark on the crack case split, set it at 4 degrees +. Newbie at this and I'm enquiring what else is needed to set the timing apart from tools (got that covered).
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2smoke
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Re: Ignition time setting with current octanes

#15 Post by 2smoke » Sun Jul 16, 2017 9:00 pm

So how did you make out with the timing?

I was bored today so I played about with the base timing on mine.
5 adjustments, 5 rides
Ended up back at the stock setting for best results with our gas and my engine.
Go figure.
91 octane
less than 1.9 mm made the bike groggy taking away from a stop and sleepy between 4000-6000. Didn't want to try wide open.
Over 2mm seemed to run thru the RPM range same as 2mm but "noisier" between 4000-6000.(less smooth?)
Anyways my bike has to stick between 1.9mm-2mm to be in the zone.
Been wanting to experiment with this for a while now.
Which leaves me wondering why there is such a wide adjustment slot?
Colin
79 RD400F Daytona Special
81 RD350LC
89 TDR250
75 Kawasaki H1 500
77 Can-am Tnt250

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