Author Topic: Advancing too far (Read 8990 times)

dave500 · « **Reply #25 on:** January 06, 2014, 02:19:52 PM »

bosch distributor springs can be used,they have heavy and light etc to choose from.

andrewk · « **Reply #26 on:** January 06, 2014, 03:24:10 PM »

You're correct that the springs aren't too easy. I think most people that modify these end up cutting the spring and bending a new loop on the end. Not the most scientific approach, but it solves the problem.

Dave, any idea what model Bosch distributor uses similar springs?

fendersrule · « **Reply #27 on:** January 06, 2014, 03:45:00 PM »

This is some good information.

There are obviously a couple ways to skin the cat so I'm seeing.

Dave's method sounds to me like the "for sure" method when setting the ignition that's "unknown" to make sure it's advancing when it should be.

If you set it statically, it "should" be set perfectly in advance as long as the ignition is working 100%.

I set my '78s timing a couple weeks ago.

1) Set point gap with dwell meter (24.5-25 on a V8 scale)
2) Set the dynamic timing at idle using a timing light.
3) Rev the motor to 2400 on both positions to make sure that it's inbetween the advancing marks. Both sets of cylinders were in-between the advancing marks with the timing dynamically set at idle....my stuff must be working properly.
4) Recheck point gap with feeler gauge.

Doing the above worked for me.

HondaMan · « **Reply #28 on:** January 06, 2014, 08:41:34 PM »

Quote from: Maurice on January 06, 2014, 10:19:43 AM

I see, I'll take a look tonight.

I did come across a gem from HondaMan which seems to describe my symptoms: http://forums.sohc4.net/index.php?topic=59886.0

Result 1 or 2 in google when you search for "daiichi points".

This place looks decent for OEM stuff: http://www.partzilla.com/parts/search/Honda/Motorcycle/1977/CB550K+A/POINTS+%2B+ADVANCER/parts.html

If I understand correctly TOYO == TEC.

I still think my springs may be acting up also. I'm assuming there is no easy source for just those? Are these special springs that you can't find at, say, McMaster Carr?

Yep, TOYO = Tokyo Electric Corporation, aka TEC. You'll see this logo on many Japanese car electrics (and some Fords as well!).

Maurice · « **Reply #29 on:** January 07, 2014, 05:38:47 AM »

Quote from: HondaMan on January 06, 2014, 08:41:34 PM

Yep, TOYO = Tokyo Electric Corporation, aka TEC. You'll see this logo on many Japanese car electrics (and some Fords as well!).

Not sure this is good news...

Well F me... I ventured to the garage to check on the brand of points, and it turns out plate and points at least are TEC, don't know about the condensers but the whole thing looks brand new actually (sorry, crappy pics, winter is here):

Timing is spot on for both sets with the plates here

but gap is on the lower end of the scale. I need to get a dwell meter then I'll know for sure.

This leaves the springs as potentially causing issues. They feel a bit on the loose side so I looked around and saw this (this a member here anyway?). Are these the same size as 550/750? $5 a pair shipped looks fair to me, I'll give them a try. The interesting thing is the website of the spring manufacturer, you can search for many different springs based on different specs. These are specc'ed at 1lbs. and the Honda manual calls for 1.43 to 1.87, but seem a tad shorter so we'll see...

Bru-tom · « **Reply #30 on:** January 07, 2014, 06:00:26 AM »

If you run your bike and shine a torch in the timing hole in the plate, you can see the advancer move when the revs are increased when you tech 2,5 to. 3k rpm. It's what I used to see it my advancer was actually operating.

Maurice · « **Reply #31 on:** January 07, 2014, 07:09:59 AM »

Bru-tom, you are right and I do see the weights moving. Now do they do it as they should? Don't know...

Still does not explain the over-advancing, I'll re-check with the timing light as soon as I get a chance, possibly with old/new springs.

Thanks

Bru-tom · « **Reply #32 on:** January 07, 2014, 07:22:56 AM »

i statically timed mine as the manual says, mine seems fine.

are your points contacts clean and clear of any foreign substances? no oil or grease from lubing the cam and the advancers pivots through the timing plate hole?

did you do as the guys above mentioned with ignoring idle timing and setting it up on the advance marks at the higher rpm? Maybe now that you see the advancer moving, note the rpm and do your timing again and set the revs to a little above where you saw he advancer advancing and set it there at the full advance marks... woah, thats a mouthfull

Maurice · « **Reply #33 on:** January 07, 2014, 07:59:12 AM »

Right now it's:

- took an ignition file to the points, made sure they were clean
- points gap set, 'bout .012" so I don't have to set the base plate too far retarted for the "F" mark (this is important)
- static timed spot on now

Now I need to see how far it goes with the timing light, ran out of time and it was really cold last time.

The issue last time is that it was already maxed out on the retard setting, so I couldn't move it back further to align the advanced marks... Dilemma, huh?

In any case, next steps are to see where full advance lies now, then firmer springs and see what it does, then

New points maybe? Measure dwell? We'll see, one thing at a time.

Given that these points/plate are TEC as I was not suspecting, the only retard in the story is probably just the one behind the screwdriver...

Bru-tom · « **Reply #34 on:** January 07, 2014, 08:08:32 AM »

damn, this is where i take the back seat and wait for the gurus. I did see however that your top mounting screw is around 4-5mm further towards the end of the slot at the left than mine is. probably insignificant, but i can see where you are coming from when running out of adjustment.

why not do as hondaman recommends and remove half a coil of one spring and see if that changes anything? im sure that in your case, this will help a lot. because your points contacts dont look very worn down in physical size from the side profile in your pics.

Have you adjusted the 2-3 points plate on the main assembly plate to be matched spot on with 1-4?

Maurice · « **Reply #35 on:** January 07, 2014, 08:11:15 AM »

Yep, springs is the next step indeed.

And yes, 2-3 plate is same gap as 1-4 and spot onto the "F" mark. Its own mark that is

Bru-tom · « **Reply #36 on:** January 07, 2014, 08:16:19 AM »

kudos brother, well, thats all i can aid in all this, just running stuff past you to confirm you've done it already

hope to hear that the spring mod was a success

good luck

Maurice · « **Reply #37 on:** January 07, 2014, 08:23:31 AM »

Yeah I'll be sure to report. Nothing like reading a thread, thinking "goddamn that's EXACTLY what I'm seeing here!", only to get to the end without any resolution...

Maurice · « **Reply #38 on:** January 09, 2014, 03:19:23 PM »

Not a whole lot of time to do anything, and it's still freezing here.

I went to the garage and pulled the points cover on the 750 engine. Points look new, TEC so there's hope that will be good for a while. Pulled the advancer to check the springs, and they're noticeably snappier than the 550's. Then my fingers were stiff and my nose running too much. I know, I'm a wuss.

HondaMan · « **Reply #39 on:** January 10, 2014, 05:04:18 PM »

Those are the 'new' TEC points, which appeared about 3 years ago. I have a set in my 750 just like them.

Here's one more thing to check that I forgot to mention, but takes some equipment: if the shaft that holds the advancer to the crankshaft is bent, it has 3 symptoms, depending on which way it is bent:
1. The 2-3 points timing "jitters" under a timing light's view.
2. The 1-4 points may not be able to slide into the correct timing marks, while the 2-3 side seems to be closer.
3. Opposite #2, above.

The most common cause of the bent shaft is: someone pulling the crankshaft backward (CCW) with that big nut, with the sparkplugs in, on a tight engine. Usually, it bends with the dowel applying the fulcrum angle, which makes the #2 scenario above the most common. But, if the dowel's hole is nice and snug, it can bend the shaft 180 degrees away from that angle, and then #3 scenario appears.

The end of the shaft should wander no more than .003" out-of-true as the engine is turned over. To test it, I remove the sparkplugs and the points plate and advancer, set a dial indicator against the smooth part just inside of the threads, and turn the engine slowly with the kickstarter. To true it, install a nut on the threads and tap it in the right direction with a small hammer and 'snug' taps, a little at a time.

Maurice · « **Reply #40 on:** January 10, 2014, 07:07:14 PM »

HondaMan,

I see exactly what you mean. On the 550 it's actually a bolt, as opposed to a shaft on the 750. Same method for checking trueness will apply, though. Seems like a flimsy approach by Honda, it's a 6mm bolt/shaft if I remember correctly.

Maurice · « **Reply #41 on:** January 11, 2014, 09:27:28 AM »

Got some time to work on the bike, and after fiddling to the point the engine wouldn't start, I started over:

- gap both sets of points
- static time, needed adjustment 2-3 was way off
- started up the bike, ran much better
- with the timing light 2-3 was still not ok, re-gapped and re-static timed
- bike now starts and idles much smoother, and timing light shows things where they should be

Another thing that compounded was the carbs needed a touch richer mix screws. 2 turns out and it responds well.

Still waiting on newer springs, these are weak. Runs well enough in the garage though.

The bottom line is that things do seem in spec. Once I took the time to adjust, check and re-check, marks are where they should be. Maybe I was gapping wrong? I did notice that an incorrect gap had a big impact.

Seriously considering using transistors in place of the condensers... This is fun but I can see how they'll need some constant attention.

Need to deal with the stuck clutch now.

Thanks all!

HondaMan · « **Reply #42 on:** January 11, 2014, 09:19:21 PM »

Quote from: Maurice on January 10, 2014, 07:07:14 PM

HondaMan,

I see exactly what you mean. On the 550 it's actually a bolt, as opposed to a shaft on the 750. Same method for checking trueness will apply, though. Seems like a flimsy approach by Honda, it's a 6mm bolt/shaft if I remember correctly.

Oops, yeah. Sorry about that: I'm so used to describing the 750...

Maurice · « **Reply #43 on:** January 14, 2014, 07:19:55 AM »

Got new springs in the mail, so I went and tried them out.

Visual inspection and manual feel tells me it's too tight.

Old on the left, new on the right:

I went ahead and installed them, they fit fine but there seems to be too much force required to lift the weights.

Installed on the engine, pulled choke, ignition and it started first kick. Let it idle a bit to warm up, but I could tell already it had trouble revving up. Once I was able to idle without choke it would sputter out the carbs when giving it gas (you can feel it through the throttle too). If you insist then eventually the revs pick up and it goes well.

Sure enough what is happening is that the advance is on/off: looking at the weights through the window in the points plate shows that clearly. So now I have 2 sets of springs: ones too weak that will go full advance almost as soon as the engine picks up any revs, and another one that does not advance soon enough.

Did not have time but next thing I'll do is use 1 old and 1 new spring. Will report.

cougar · « **Reply #44 on:** January 15, 2014, 07:42:29 AM »

The title of this thread is "Advancing too far" . IMHO, everyone is overlooking the simplest solution ! I read about it here, http://www.motorcycleproject.com/motorcycle/text/sohcign.html (7th paragraph,8th line down) about something that hasn't been mentioned (that I've seen yet) !!! If your timing is "Advancing Too Far" there is only 1 Easy fix !!! The stops on your advance that stop your advance from going to far have become worn or bent ! It explains what to do ! Hope this helps ! ...cougar...

Deltarider · « **Reply #45 on:** January 15, 2014, 08:44:19 AM »

I find it hard to believe the stops get worn, bent maybe, that is if you really tried.
Advancing too far can be caused by an incorrect dwell.

PeWe · « **Reply #46 on:** January 15, 2014, 12:04:36 PM »

...... Once I was able to idle without choke it would sputter out the carbs .....
Exactly as my CB750 behaved when it got full advance at 1500rpm. Maybe even earlier too.... spring fix solved that.
Timing light will show how advanced it is and when. Not possible without.

Maurice · « **Reply #47 on:** January 16, 2014, 07:46:26 AM »

Very interesting information. The issue I have with bending the tabs back is that the f*ers will snap off very easily. maybe more effective to build up the back of the weight arms with some JB weld IMO.

At any rate, timing seems much better now after careful adjustment. It wasn't so much over-advancing as I was adjusting wrong (I think...) since after re-gapping and re-timing the strobe shows things moving where they should, does not go past the rightmost full advance mark now and idles right at F. Weird...

Thanks all

Bru-tom · « **Reply #48 on:** January 16, 2014, 09:12:12 AM »

progress is sweet!

well done Sir.

HondaMan · « **Reply #49 on:** January 16, 2014, 10:40:32 PM »

Quote from: Maurice on January 14, 2014, 07:19:55 AM

Got new springs in the mail, so I went and tried them out.

Visual inspection and manual feel tells me it's too tight.

Old on the left, new on the right:

I went ahead and installed them, they fit fine but there seems to be too much force required to lift the weights.

Installed on the engine, pulled choke, ignition and it started first kick. Let it idle a bit to warm up, but I could tell already it had trouble revving up. Once I was able to idle without choke it would sputter out the carbs when giving it gas (you can feel it through the throttle too). If you insist then eventually the revs pick up and it goes well.

Sure enough what is happening is that the advance is on/off: looking at the weights through the window in the points plate shows that clearly. So now I have 2 sets of springs: ones too weak that will go full advance almost as soon as the engine picks up any revs, and another one that does not advance soon enough.

Did not have time but next thing I'll do is use 1 old and 1 new spring. Will report.

I'd suggest turning the air mix screws inward a little bit with the slower advance rate. I think I have something about this in the old "Thoughts of Hondaman" forum that SteveD put together. When the springs advance too soon, the idle mix needs to be richer to prevent stumble: when slower advance, the mix needs to be leaner to let it rev sooner.

News:

Author Topic: Advancing too far (Read 8990 times)

fendersrule