Author Topic: CB350F Ignition timing marks. (Read 939 times)

Gibbon · « **on:** February 06, 2023, 09:50:10 PM »

Hello Folks.

I'm attempting to set the ignition on my '350F. If I align the 'F' mark with the engine casting indicator mark I do not have enough adjustment range to set the points.
When I look closer I can see a much fainter mark that is a few degrees anti-clockwise of the casting mark.

I've indicated the casting mark with a red arrow in the photo and the fainter mark with a green arrow. Should I be using the fainter mark to set the points ?

Thanks,
G

bryanj · « **Reply #1 on:** February 07, 2023, 12:18:07 AM »

You dont set the gap at the F mark, you set the gap when the fibre heal of the points is on the highest part of the cam, you then set the timing at the F mark, usualy using a bulb across the points

Gibbon · « **Reply #2 on:** February 07, 2023, 12:58:40 AM »

Hi.

Sorry I used the wrong terminology.
I'm trying to set the ignition timing. If I align the 'F' with the casting mark I cannot adjust the plate far enough to get the points to operate.
This is after setting the points gap to 0.4mm on the peak of the cam.

Regards.
G

Bodi · « **Reply #3 on:** February 07, 2023, 05:52:34 AM »

No. The "green" mark is a casting defect or was done by a PO.
I take the gap spec as a suggestion. Not a commandment. Dwell angle is not critical.

bryanj · « **Reply #4 on:** February 07, 2023, 03:21:07 PM »

Gap should be 0.35 or 14 thou

scottly · « **Reply #5 on:** February 07, 2023, 06:33:48 PM »

Quote from: Gibbon on February 07, 2023, 12:58:40 AM

Hi.

Sorry I used the wrong terminology.
I'm trying to set the ignition timing. If I align the 'F' with the casting mark I cannot adjust the plate far enough to get the points to operate.
This is after setting the points gap to 0.4mm on the peak of the cam.

Regards.
G

Which direction do you have the plate rotated at it's max travel? Does the advance mechanism move freely, and return under spring tension?

HondaMan · « **Reply #6 on:** February 07, 2023, 06:51:51 PM »

If you have a new ignition plate, especially one made by Daiichi, the timing marks will not align with the points in the 0.012"-0.016" total gap range allowed. The geometry of the Daiichi points is "off" by a little bit.

The easiest workaround for this problem is to widen the slots on the timing baseplate. Another method is to realign (as in, carefully bend) the ground arms of the points sets. They must be bent inward toward the moving contact about 0.020"-0.024" or so, and then re-bent to provide a parallel, flat face-to-face contact between the 2 contacts, by making the right-angle bend at their base a little bit closer to the moving point. In other words, the Ground contact must move closer to the Moving contact by about 0.008"-0.010", but in the end the faces of those contacts must end up parallel to each other. It's not all that easy to do!

I do this routinely with the Daiichi points in order to make them reach their timing marks. You need them to align with the "F" marks: the easiest way to do it, IMHO, is with a timing strobe light while the engine is idling. Set them to about 0.014" gap to get it running, then use the strobe light for final setting.

If the contacts hit each other on an edge (which has sometimes been done by frustrated home mechanics, by just bending the ground arms inward) then they will quickly wear, but it will run. A few folks (including me, circa 2008 or so when these miserable points first appeared) just left them tilted like that so as to meet the timing marks, then installed my Transistor Ignition to stop the points wear. I ran my 750 for 4 seasons like that until I figured out the the ground pads are just made too far away from the points' pivot in these points, and with patience and re-bending they can be made to work correctly.

Gibbon · « **Reply #7 on:** February 09, 2023, 12:28:34 AM »

Hello.

Thanks for the advise.
The advance mechanism seems to move correctly.
The plate is original as far as I can tell.
After much messing about and not getting very far I changed method from what is recommended in the manual. Aligned the timing marks, set the plate to about mid position and then adjusted the points to be just open. Checking the point gap after setting things this way gives me about 0.011' gap.

After contending with a flat battery the bike is running again.
The points are quite literally spitting sparks. I think it's time for new condensers and points.

Are aftermarket points and condensers any good ? Should I try to find OEM parts ?

Deltarider · « **Reply #8 on:** February 09, 2023, 03:10:46 AM »

Quote from: Gibbon on February 09, 2023, 12:28:34 AM

The points are quite literally spitting sparks. I think it's time for new condensers and points.

Depends. Check if the connectors are not mistakingly contacting the plates. Especially the 2+3 breaker has a crosshead dangerously nearby. Isolate the breakers by inserting a piece of plastic between the points and then check there's NO continuity to ground. If there is continuity, the inner tiny isolating ring is misaligned causing the bolt to make ground. Are the condensers firmly attached?

HondaMan · « **Reply #9 on:** February 09, 2023, 04:42:49 PM »

Quote from: Gibbon on February 09, 2023, 12:28:34 AM

Hello.

Thanks for the advise.
The advance mechanism seems to move correctly.
The plate is original as far as I can tell.
After much messing about and not getting very far I changed method from what is recommended in the manual. Aligned the timing marks, set the plate to about mid position and then adjusted the points to be just open. Checking the point gap after setting things this way gives me about 0.011' gap.

After contending with a flat battery the bike is running again.
The points are quite literally spitting sparks. I think it's time for new condensers and points.

Are aftermarket points and condensers any good ? Should I try to find OEM parts ?

Look on the plate, points, and condensors for the letters "TEC". or a circle-like emblem with another circle inside of it, and a tiny "H" in the center of them. These will be the HOnda OEM points plate sets.

If yours have no ID of any kind, or has the "Daiichi" mark on them, they are the counterfeit type.
You may be able to get an OEM points plate assembly directly from Honda. Beware of counterfeits and the Daiichi brand: neither will work, ESPECIALLY the condensors. Their condensors can cause the points to spark greatly, even spitting sparks out well past the points.

If you cannot find a proper set of points and condensors, your 350F can use my Transistor Ignition, which was designed expressly for these bikes. It uses just the points, without condensors at all, in situations where the rider cannot get good condensors. It will also work with the narrow gap you now have: if running normally with this small gap, the points life will be very short from the arcing without this addition.

Gibbon · « **Reply #10 on:** February 10, 2023, 12:23:04 PM »

Hi.

The plate is marked 333 and has an ND in a circle mark. I'd assume the ND is Nippon Denso so likely it's original. I would not be surprised if the points and condensers are also original. On close examination the points are very worn, blackened and pitted. they are probably well beyond the use by date and the reason I'm having so much trouble setting the gap and timing correctly. Probably also explains the poor running at high rev's.

I'll go to the local Honda dealer today and see if they have new points and condensers. I don't think there is much of a chance they will but it's the first place to start.
Can someone recommend a reputable supplier of OEM parts?

Thanks.

bryanj · « **Reply #11 on:** February 10, 2023, 11:43:35 PM »

Dave Silver but if you want both sets of points and condensers its cheaper to buy a complete plate assembly, part number will be different as 750,550,500,400 and 350 are all the same

dave500 · « **Reply #12 on:** February 10, 2023, 11:57:42 PM »

you can fit an electronic sytem for way cheaper and be done with points,like 500 billion cars cant be wrong?

HondaMan · « **Reply #13 on:** February 11, 2023, 07:57:27 PM »

Quote from: dave500 on February 10, 2023, 11:57:42 PM

you can fit an electronic sytem for way cheaper and be done with points,like 500 billion cars cant be wrong?

The only electronic system that will work in the CB350F is my Transistor Ignition. It was built for the 500/550 and 350F bikes because of their small alternator outputs. It just got popular in the other bikes (and Yamahas and Suzys, even the Kawi 900-4) because it makes the points last forever and stops their wear. There might be a Boyer unit that would also work, but I haven't seen one actually installed in the 350F.

HondaMan · « **Reply #14 on:** February 11, 2023, 08:01:58 PM »

If your existing points are ND (and condensors) then the arcing is likely due to oxidation from sitting for a long time. With a new points file they can usually be restored to working condition again. There will be small peaks on one contact (and corresponding valley(s) on the opposing one) from this arcing. You file those peaks off and reset the gap. This also restores the shiny appearance of the contacts, if they are genuine ND points, as those were 100% tungsten and last for many tens of thousands of miles.

dave500 · « **Reply #15 on:** February 11, 2023, 08:54:11 PM »

boyer and tyronic will have units to suit.

Gibbon · « **Reply #16 on:** February 24, 2023, 10:18:15 PM »

Hi Folks.

Got the replacement points and condensers earlier this week and fitted them today.
The old points were aftermarket Daiichi parts. Badly burnt and pitted. The condensers were OEM as far as I can tell but were both well off the 0.22 uF specification.
Once the point gap and timing was set the adjustments were about mid-position. I'm going to count that as a win.
The engine runs much more smoothly now and the high rev performance is much better.

Thanks for the advise about getting OEM parts, I would have ended up with Daiichi replacements as they are the only parts available locally.
G.

Trevor from Warragul · « **Reply #17 on:** February 25, 2023, 12:18:40 AM »

Quote

The only electronic system that will work in the CB350F is my Transistor Ignition.

Well, that depends. If you have a CB350F with a headlight switch, you can run a Dyna for years with no problems (with the headlight switched off).

newday777 · « **Reply #18 on:** February 25, 2023, 03:48:27 AM »

Quote from: Trevor from Warragul on February 25, 2023, 12:18:40 AM

Quote
The only electronic system that will work in the CB350F is my Transistor Ignition.

Well, that depends. If you have a CB350F with a headlight switch, you can run a Dyna for years with no problems (with the headlight switched off).

Get home before sunset......

newday777 · « **Reply #19 on:** February 25, 2023, 03:51:39 AM »

Quote from: Gibbon on February 24, 2023, 10:18:15 PM

Hi Folks.

Got the replacement points and condensers earlier this week and fitted them today.
The old points were aftermarket Daiichi parts. Badly burnt and pitted. The condensers were OEM as far as I can tell but were both well off the 0.22 uF specification.
Once the point gap and timing was set the adjustments were about mid-position. I'm going to count that as a win.
The engine runs much more smoothly now and the high rev performance is much better.

Thanks for the advise about getting OEM parts, I would have ended up with Daiichi replacements as they are the only parts available locally.
G.

Good to hear it's running better. So you found TEC points and condensers or a whole plate assembly?

Get Hondaman's transitor ignition (used in conjunction with the points) to make your points last.
http://forums.sohc4.net/index.php/topic,67543.0.html

Actual link to buy
http://sohc4shop.com/catalog/product_info.php?products_id=32&osCsid=738fe85c48cb08ad0529cdd578dd1b58

Gibbon · « **Reply #20 on:** February 25, 2023, 03:53:20 PM »

Good to hear it's running better. So you found TEC points and condensers or a whole plate assembly?

Get Hondaman's transitor ignition (used in conjunction with the points) to make your points last.
http://forums.sohc4.net/index.php/topic,67543.0.html

Actual link to buy
http://sohc4shop.com/catalog/product_info.php?products_id=32&osCsid=738fe85c48cb08ad0529cdd578dd1b58

[/quote]

I got replacement points and condensers, I could not find a complete plate OEM replacement.
I'm planning to De-cafe the bike over winter and likely will include a Hondaman ignition with the re-build. I probably could build my own transistorised ignition but why re-invent the wheel ?

G.

HondaMan · « **Reply #21 on:** February 27, 2023, 11:53:37 AM »

Quote from: Gibbon on February 25, 2023, 03:53:20 PM

I probably could build my own transistorised ignition but why re-invent the wheel ?
G.

There are several old schematics out there if you want to build one from scratch. The old Velleman kits work (but are physically big in size: Delta has shrunk them to fit his SOHC4) too, if you can scare one up somwhere? They were based on the old Citroen car ignitions, which were points with an electronic 'amp' that kept the points from wearing out (some of old 1970s Mercedes had this, too). While mine has a couple extra 'tricks' thrown in (from doing electronics designs since the 1960s) that are expressly for the bikes, it will run without those changes equally well with the Velleman or Mercedes units. All of these designs use about 80-100mA (0.1 amp) extra power as compared to points-coils alone: this is where the other commercial units cause issues with the USA bikes, due to us having to keep the headlight on all the time (thanks to the Carter Administration's DOT...). The DYNA units hold both coils fully ON all the time except for the moment when the magnet(s) trigger the sensors, drawing too much power from the system that wasn't designed for that. The Tytronics comes 2 ways: the older original version triggered OFF following the sensor for a short (but fixed) duration, then back ON, while the current version is reported to provide a 180-degree ON time limit, making it closer to the power used by points alone.

However...neither the Boyer/Branson, Dyna, nor Tytronics units provide any 'backup': if you use the points-assist approach with your electronic choice, and it fails when lightning hits the bike (or an EMP weapon takes out your electronic unit?), or it just breaks, you can still ride home with the points by swapping the 4 wires at the back-right side of the engine where the points' wires meets the coils' wires, to get back to running on points again. For me, living where it is 100 miles to anywhere once you leave the city limits, this has always been important.

C317414 · « **Reply #22 on:** February 27, 2023, 01:31:44 PM »

Quote from: HondaMan on February 27, 2023, 11:53:37 AM

However...neither the Boyer/Branson, Dyna, nor Tytronics units provide any 'backup': if you use the points-assist approach with your electronic choice, and it fails when lightning hits the bike (or an EMP weapon takes out your electronic unit?), or it just breaks, you can still ride home with the points by swapping the 4 wires at the back-right side of the engine where the points' wires meets the coils' wires, to get back to running on points again. For me, living where it is 100 miles to anywhere once you leave the city limits, this has always been important.

I've installed many Boyer Bransden ignitions on bikes at the shop I worked at, as well as my personal bikes. In 40+ years I've never seen one fail, so I'm comfortable riding a Boyer equipped bike anywhere, with no backup. One of the reasons I like Boyer is that they eliminate the advance mechanism. The ignition curve is electronically controlled, and not subject to wear. Having said that, all of these installations were on British bikes, but many of these probably had a charging system that was weaker than the one on early Honda fours.

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Author Topic: CB350F Ignition timing marks. (Read 939 times)