Topic: Carb tune or timing tune, which comes first?

[drumstyx]

I'm just talking about a simple balance when it comes to carbs...Should I make sure they're balanced before dynamic timing?

Edit: and on that note, where the heck do I get vacuum nipples for the carbs? I've never had a bike that didn't just have them built right in ('78 750k)

[PeWe]

Carbs enough so it can idle. Bench sync can be done very close. I did that all the time for many years ago.
Points? Set them static first. Points gap.
Then with a stroboboscopic timing light to get 1-4, 2-3 correct
Fine tune points with a dwell meter and set both points to same degree. This is done when engine idles around 1500 rpm.
recheck with timing light again. 2-3 might differ a little..

How to do dwell check on points... http://forums.sohc4.net/index.php?topic=147444.0

[drumstyx]

Carbs enough so it can idle. Bench sync can be done very close. I did that all the time for many years ago.
Points? Set them static first. Points gap.
Then with a stroboboscopic timing light to get 1-4, 2-3 correct
Fine tune points with a dwell meter and set both points to same degree. This is done when engine idles around 1500 rpm.
recheck with timing light again. 2-3 might differ a little..

How to do dwell check on points... http://forums.sohc4.net/index.php?topic=147444.0

Just bought a nice multimeter with a dwell angle setting, so I plan to get timing *perfect*

Edit: disregard the nipple search...I finally sprang for a Morgan carbtune

[BomberMann650]

+1 what PeWe said.

I tried using a dwell meter once.  It led me in the wrong direction.  A strobe will help you determine if your advancer unit is working right.  But I find that to be a pita as well.

A nice, clean, and lubricated auto advancer is a solid starting point for timing a bike.  Tec/oem points plate a must have as well. 
Static timing with dead on accurate firing between 1/4 & 2/3 is the bees knees.

[PeWe]

Dwell meter is really easy to use when knowing how to do.  I had one in my cheap Auto multimeter.

Thanks to Mike in that thread I tried it and got really good result. I added photos to visualize. Mike is otherwise a great fan of technical development and improve the CB. Like newer tech for ignition as a Dyna 2000.... (plus all mechanical goodies... thanks Mike..)
Even Mike was gladly surprised of the result in that thread

[Deltarider]

This I wrote many years ago and is still valid. For a start you can use a feeler gauge. Points gap should be set between 0,3 and 0,4 mm (0.012-0.016). Or you can use a dwellmeter that shows the degrees the crank rotates while the breaker points remain closed. So, the higher the dwellmeter reading, the smaller the point gap and the shorter the dwell, the wider the point gap. I prefer the meter over the feeler gauge. Some DMMs have this function and nowadays they're affordable. A meter is easier, more precise and you're able to check for irregularities at different rpms. On 500/550s breakerpoint dwell should be in between 98^o-92^o or 49^o-46^o or 24,5^o-23^o depending on what cylinder scale your meter reads. If you have a dwellmeter that reads duty cycle, it's even easier as they registrate in % no matter how many cylinders. Then 98^o-92^o or 49^o-46^o or 24,5^o-23^o translates in simply 54,4-51,1% and there's no need to select a cylinder scale anymore. Like Pewe I prefer to start with the widest gap (= lowest dwell) as contactbreakers tend to decrease their gap (= increasing the dwell) over time.
Setting the dwell should precede the timing. Once you have set the timing correctly, you can - later on - correct the timing, if necessary, by simply bringing the contactbreakers to their correct dwell again and you don't have to bother to loosen the plates anymore. Less screws to work on. BTW, that's how all mechanics at Honda dealers it.
For those of you that prefer, like me, the dynamic procedure and use a dwellmeter, here is a tip.
Years ago I have attached two ‘blind’ extra wires on my coils (12V-) both with a female connector at their end. Once you have set your timing correctly, these wires allow quick diagnoses later on. Write down the dwell for future reference. Almost all changes in timing originate at the contactbreakers. When the dwell changes, so does the timing. When you suspect the timing is off, simply connect the dwellmeter to the extra lead 1&4 or 2&3 and you can verify if dwellangle is still the same or has changed. It’s important that those female connectors are well shielded to avoid groundcontact.
I have had these wires attached for years now. What I like is that I can check really quick without even to remove the ignitioncover. O, and another thing: I'm always impressed how many miles I can ride without having to readjust the ignition. Just keep that little felt lubed.

[PeWe]

... more  tricks with good old points
Guys with dyna and similar will replace it with points if reading this thread! no joke...
I have tec points on my CB750 K6, I have NOS TEC points for my other CB750 K2 project...

[drumstyx]

Dammit, I had this thing running with the old points, now I replaced them with new OEM and I swear the timing is perfect (checked with a timing light while cranking the starter...is that ok, or does a timing light only work properly once the engine is running?) but it won't catch! Figured maybe it's flooded, so I turned off the fuel, and I'm charging the battery to try again tomorrow. It catches for a few revs then stops at this point. It's possible my idle stop is too open/close I guess.

As a side question, on #1 the light only works every few revolutions, while on 2-3 it flashes just about every time. This is my first time using a timing light.

[Deltarider]

As a side question, on #1 the light only works every few revolutions, while on 2-3 it flashes just about every time. This is my first time using a timing light.

There's polarity to observe, so either flip the pick-up sensor on #1 or use it on #4 like you had it on #1. Also the HTleads need to be clean and not greasy. If necessary clean wit a little bit of alcohol.

[flybox1]

Dammit, I had this thing running with the old points, now I replaced them with new OEM and I swear the timing is perfect (checked with a timing light while cranking the starter...is that ok, or does a timing light only work properly once the engine is running?) but it won't catch! Figured maybe it's flooded, so I turned off the fuel, and I'm charging the battery to try again tomorrow. It catches for a few revs then stops at this point. It's possible my idle stop is too open/close I guess.

As a side question, on #1 the light only works every few revolutions, while on 2-3 it flashes just about every time. This is my first time using a timing light.

Once you put in new points,  you have to revisit setting the gap.  Start there.
..and the bike should then be running so you can fine tune the firing of each set, and also check when full advance kicks in, adjust if needed.

A digital multimeter with dwell is significantly better than that actron analog unit.
Vacuum sync always comes last.

[Deltarider]

A digital multimeter with dwell is significantly better than that actron analog unit

My experience is contrary. I used to have an old analogue d'Arsonval meter. Much easier to work with than digital because you could see from the corner of your eye what the needle was doing. Tach is also easier to check/adjust with an analogue meter and for measuring volts on a running engine I prefer one as well.

[drumstyx]

Dammit, I had this thing running with the old points, now I replaced them with new OEM and I swear the timing is perfect (checked with a timing light while cranking the starter...is that ok, or does a timing light only work properly once the engine is running?) but it won't catch! Figured maybe it's flooded, so I turned off the fuel, and I'm charging the battery to try again tomorrow. It catches for a few revs then stops at this point. It's possible my idle stop is too open/close I guess.

As a side question, on #1 the light only works every few revolutions, while on 2-3 it flashes just about every time. This is my first time using a timing light.

Once you put in new points,  you have to revisit setting the gap.  Start there.
..and the bike should then be running so you can fine tune the firing of each set, and also check when full advance kicks in, adjust if needed.

A digital multimeter with dwell is significantly better than that actron analog unit.
Vacuum sync always comes last.

I've got a digital multimeter with dwell I just picked up. It was a little pricy for a multimeter IMO, but I had a gift card, so whatever.

I fixed the issue with the timing light (flipping the pickup did the trick), but I've seen some old school guys suggest that the timing light shouldn't be used for idle timing, only advanced timing. Reasoning being that the advancer could start opening around idle speed. My thought is that, at a true 1100RPM (multimeter will tell me), I'd want the timing to be dead on the F mark, regardless of the advancer's status, correct?

I've noticed a problem with the points adjustment though -- the whole plate fits very snugly in place, so 1-4 adjustment is just fine (for the most part, there might be 1 thou of wiggle) but the 2-3 adjuster plate has loads of lateral play aside from the radial adjustment, so that any movement of that plate will screw with the dwell/gap.

[Deltarider]

I've noticed a problem with the points adjustment though -- the whole plate fits very snugly in place, so 1-4 adjustment is just fine (for the most part, there might be 1 thou of wiggle) but the 2-3 adjuster plate has loads of lateral play aside from the radial adjustment, so that any movement of that plate will screw with the dwell/gap.

Has to be fixed first.

My thought is that, at a true 1100RPM (multimeter will tell me), I'd want the timing to be dead on the F mark, regardless of the advancer's status, correct?

With a timing light it's very easy to check the advancer. Look up in the manual at what rpm advance should begin. You should not aim at a dead on timing at idle. Check timing at full advance is correct and accept the timing at idle it results in. 99% of the time you ride with the ignition fully advanced, that's why.

[flybox1]

I was only making the comparison to the Actron units, which are widely available here in the US, but cheaply made.
There is no way to calibrate them other than shipping them back to Actron at your expense, per Actron.
If you dropped it, or it was dropped during shipment, there is no way to determine if it is accurate.
The unit I purchased was unusable.  If I had to do it all over again, i would have purchased a digital mm with dwell function.

[drumstyx]

I've noticed a problem with the points adjustment though -- the whole plate fits very snugly in place, so 1-4 adjustment is just fine (for the most part, there might be 1 thou of wiggle) but the 2-3 adjuster plate has loads of lateral play aside from the radial adjustment, so that any movement of that plate will screw with the dwell/gap.

Has to be fixed first.

My thought is that, at a true 1100RPM (multimeter will tell me), I'd want the timing to be dead on the F mark, regardless of the advancer's status, correct?

With a timing light it's very easy to check the advancer. Look up in the manual at what rpm advance should begin. You should not aim at a dead on timing at idle. Check timing at full advance is correct and accept the timing at idle it results in. 99% of the time you ride with the ignition fully advanced, that's why.

How would I fix the 2-3 plate? You can shim the 1-4 main plate, but the 2-3 plate indexes on the screws it seems

[Deltarider]

For the record, is yours genuine Honda (TEC or Hitachi?) or imitation like Daiichi?
First check and if necessary adjust gap and then timing of 1+4 before you go to 2+3.
Do you have all little spring washers in place. Some manuals do not show all in their pics! Below a correct pic.