HarleyTechTalk

Quote from: Scotty on March 17, 2022, 05:50:31 PMYou can get it at Bunnings
WD40 Silicon Spray

     good stuff for lots of things   

Quote from: Adam76 on March 17, 2022, 05:22:46 PM

Quote from: billbuilds on March 17, 2022, 10:37:46 AMBe sure to use some spray silicon on your manifold seals so that they seat properly.

Thanks Bill, what is spray silicone?

Will a bit of red rubber grease do the same thing?

     No, I would not advise it. I'd go with what Scotty suggested. Other brands out there too but WD''s pretty common.

Quote from: FSG on March 17, 2022, 06:05:14 PM

Quote from: Scotty on March 17, 2022, 05:50:31 PMYou can get it at Bunnings
WD40 Silicon Spray

     good stuff for lots of things   

Ah, thanks FSG. I actually have a can of that stuff for lubricating the rollers on the sliding doors of my house. 

 Vaseline works

Quote from: Scotty on March 16, 2022, 10:30:19 PMIs it spitting back out through the carb or the exhaust?
If through the carb a 46 and a 195 it should be close and sounds like it is leaking through the manifold to head seals and running lean. Putting a 48 in will just mask the problem and not fix the issue.

Thanks Scotty, I pulled everything off and put new seals in the intake manifold, and tightened it up the correct way a per the video and it seemed to do the trick.

I took it for a short run and it ran smooth with only a kinda burble through the exhaust on deceleration..... I think I'm pretty close tuning wise. I'll check the plugs after the next ride.

Thanks for everyone's input regarding the intake leak, I never would have thought it was the problem. 

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That is great to hear! Getting close now

Thanks.

One thing that is confusing me is how to set the DTT ignition.

The instructions for setting initial timing and advance slope are really vague and only cover 3 scenarios.

1. Stock motors = 5 and 5
2. Stock and mildly modified engines = 5 and 7
3. High compression engines start = 2 and 2....

Where do I fit?
96" big bore
10-1 compression / 190ccp
83cc stock heads unmodified.
570 lift cams

Haven't even broken the engine in yet, so looking for a good starting point.

Thanks for any tips.

It's one of those things you make an initial setting and run it in whilst listening for any detonation (ping).
I would start at 5 and 5 and adjust from there.
What you are looking for is to have as much timing as you can with no pinging.
Initial timing is for low RPM and and other one is for high rpm.
Switches are easy to adjust 1 click at a time.
Number goes down to take out timing and up to add timing.

As mentioned, you can start at 5 and 5, but don't be surprised if you end up at the 2's when you start riding it hard. Mine is similar to yours, I think I'm at 1 and 2. Spark setting at multi, 1 I think on that dial.

I made it out for a half hour ride,  took it easy as per break in procedure.

When I got home I pulled the plugs to see what they look like, the front plug looks possibly too lean and the rear plug looks OK??

I'm no expert at reading plugs, so do you think I should change any settings / jets on the carb? The AF mixture screw is about 2.5 turns out.

Thanks.
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Take a photo straight on to the bottom of the plug.
They look good to me in those photos though.

Quote from: Scotty on March 24, 2022, 10:05:38 PMTake a photo straight on to the bottom of the plug.
They look good to me in those photos though.

You mean like this?
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I would run it like that no problems as they look good to me.
Unleaded fuel does not give you the same colour as leaded fuel used to and it's a air cooled motor not a water cooled car motor. One plug looks slightly better than the other but it's a Harley and it's quite normal.

look good to me as well ....

prolly NGK but what plugs are they and what gap?

Quote from: FSG on March 25, 2022, 01:23:27 AMlook good to me as well ....

prolly NGK but what plugs are they and what gap?

NGK DCPR7E  3932

I left the gaps as they were manufactured.

Thanks

I always double check the gaps, often inconsistent from the box. If dropped during any part of the shipping process they can get out of whack.
I also prefer to run mine at 35 thousandth, rather than up to the allowed 43 thousandth. I'd read years ago it takes less energy to jump the smaller gap, the fuel doesn't care if it fires with a shorter gap.
Again, it's all about the details.
For your plugs, I would clean them up a little with a brass brush, check gaps, and throw them back in with just a touch of anti size on the threads.

Kevin Baxter has a video on reading spark plugs that goes into detail.

You might want to check it out.

Clean them up a little, check gap, put on some miles.
Run a tank of gas and check your mileage. That will give you an indication if you're close on jetting.

My 95" twin cam Heritage with Mik 42 gets about low 40's on mileage.
Cam is a Andrews 26 with DTT ignition module. Stage 1 I guess.
You can tell how the engine health is by "road manners".
Does the bike start,idle,run, with no hesitation, flat spots, pops, drama, etc?

JMHO
 

BTW, do use a torque value when installing the plugs?
 

I try not to use any metal brush on a sparkplug, simply because dragging metal across the ceramic can deposit traces of the metal, which can induce a misfire. No problem with cleaning the threads, and I use anti-seize on any reinstallation of plugs (or O2 sensors). Gap @ .035"-.038", and make sure the accelerator pump is spraying directly on the needle.

I agree about the metal brush, especially soft brass for tracking.  Stainless bristles will make scratches and a perfect set up for permanent carbon tracking.  Even the old Champion spark plug cleaning machines used an abrasive blast not a brush.

With respect to the plug gap, I have used down to .022" gap in a high compression engine.  The spark is hotter due to the close gap and holds for a longer duration before it collapses.

The timing cut line is indicating too much advance especially front cylinder. I usually recommend setting the DTT at 2,5 on a high compression (yes yours is this) motor. No sign of detonation because you have octane in AU. Run single fire, not multiple spark.

I'm curious on the single fire verses multi. Is the multi a multiple spark for one cylinder on compressoon, or is it a single spark per cylinder per revolution, like the original ignitions with a spark on the exhaust cycle on the second cylinder at the same time as the spark on the compression cylinder, the wasted spark system?

Quote from: HogMike on March 25, 2022, 05:47:38 AMBTW, do use a torque value when installing the plugs?
 

Thanks HogMike.
No, just finger tight plus 1/4 turn with wrench.

Quote from: rigidthumper on March 25, 2022, 06:01:37 AMI try not to use any metal brush on a sparkplug, simply because dragging metal across the ceramic can deposit traces of the metal, which can induce a misfire. No problem with cleaning the threads, and I use anti-seize on any reinstallation of plugs (or O2 sensors). Gap @ .035"-.038", and make sure the accelerator pump is spraying directly on the needle.

Thanks, I'll re check the gaps and make sure the pump is spraying directly onto the needle.

Cheers

Quote from: HD Street Performance on March 25, 2022, 06:51:04 AMThe timing cut line is indicating too much advance especially front cylinder. I usually recommend setting the DTT at 2,5 on a high compression (yes yours is this) motor. No sign of detonation because you have octane in AU. Run single fire, not multiple spark.

Thanks, I will try this.

What's the theory behind running single fire vs multi spark? I'm curious because I'm sure everything I've read so far says / suggests running multi ?

Thanks