Topic: Timing maxed out

[Jon_murph]

I am the recent new owner of a 76 honda cb550. I bought the bike non running, I went through the basic tune ups but after getting it running I decided to adjust point gap. It was in time before I did the gap procidure according to my manual but now I can not get it to the f mark ( the plate maxes out at half way between f and the marks that are advanced). I have set timing with my light before but on an electronic ignition so I know the light works. Am I missing something? I tryed setting gap at min and max still cant get it there.

[Jon_murph]

I did stumble across the faq on shimming the plate however ther is no gap between the plat and the bosses.

[flybox1]

Points, and points plate brand matters. 
Daiichi(3leaf flower logo) is the most common aftermarket brand, and is poor quality.
ND(Nippon Denso) and TEC are OEM, and preferred.

[Jon_murph]

Tec is the brand that is in it, I have a new points set on there way believe it is daiici though.

[madmtnmotors]

Tighten up on the points gap. Set the points gap to the small side of the range.

[Jon_murph]

I have tryed min and max point gap .012 to .016 if memory serves, I imagine there something simple I am missing just not sure what. Timing gets close if i turn the idle down but still doesnt get quite there. I trust my timing light but not sure about my harbor freight rpm gauge (stock tach is broke).

[Deltarider]

Set the points gap to the small side of the range.

Why do you advice this? His timing seems already retarded. I'd advice the contrary, to set the gap at 0,4 mm. Make sure cam is rotated until gap is at it's widest before you measure with the feeler gauge. Did you had the advancer removed by any chance? Not that you have to, but we must know.
Another tip: concentrate on having the timing right when fully advanced, say at 2500 rpm. The timing at idle doesn't matter much: the 'F' mark is OK, but the standing vertical leg of that letter F too. But try to have both 1&4 and 2&3 to have the same.

[madmtnmotors]

Set the points gap to the small side of the range.

Why do you advice this? His seems already retarded.

I can not get it to the f mark ( the plate maxes out at half way between f and the marks that are advanced).

This describes an advanced condition. The points should fire at the "F" mark at idle. His are firing halfway between the "F" and full advance...

At times, I have given what appears to be retarded advice though!     

[Deltarider]

This describes an advanced condition. The points should fire at the "F" mark at idle. His are firing halfway between the "F" and full advance...

Ah... sorry, maybe I am mistaken, but I interpreted his post that he couldn't get to the full advance marks doing the timing dynamically with a strobe. I myself don't ever use the strobe to do the timing at idle.

[madmtnmotors]

This describes an advanced condition. The points should fire at the "F" mark at idle. His are firing halfway between the "F" and full advance...

Ah... sorry, maybe I am mistaken, but I interpreted his post that he couldn't get to the full advance marks doing the timing dynamically with a strobe. I myself don't ever use the strobe to do the timing at idle.

The description is kind of vague, but Jon says "I can not get it to the f mark" which implies timing at idle. I, too, static time my points before breaking out the light. I'll use the light to double check my static timing, which usually proves the static timing to be spot on. 

[Deltarider]

Jon, can you try to set the timing statically? If you've managed, check with the strobe. If then the strobe shows timing is already advanced at around 1100 RPM, it would indicate there's something wrong with the advancer springs.

[madmtnmotors]

+1

Delta's suggestion is a good way to determine whether there might be issues with the advance springs. Check the movement of the advancer an make sure it's not sticking as well. A link to static timing procedures can be found in my signature below.

[BomberMann650]

Delta said it before I did.

Can't use strobes to time these bikes.

[Jon_murph]

To clear up the questions, yes timing is stuck advanced not retarded, I did time staticly and believe I did it correctly and got it timed, however it is my first time doing timing staticly. Is there a good walkthrough on checking the advance mechanism I cant find anything in my clymer.

Thanks for all the help so far.

[Deltarider]

 

but not sure about my harbor freight rpm gauge (stock tach is broke).

This could be it, you mistakenly interpreting a factual higher rpm for an idle. So before anything, are you sure that when you think engine idles, it really does say 1100 rpm. What I am saying is that when your engine does say 1500 rpm, please realise that there's already a partial advance in play. So if you mistake that 1500 for idle rpm (by having your meter set in the wrong range for example), you will never be at the static F mark. If you're 100% sure you have tried at a real idle rpm (around 1100 rpm), then the following would be my next step.
Unless you've set the gap not right (measure when the cam has opened breakerpoints at it's widest!) it could be you have to service the advancer which is not very difficult to do btw. Before you remove the ign plate, it's a good idea to mark its actual position with a scratch (cardboardknife) just for a reference.

[Jon_murph]

Thanks for all the advice i am going to give static timing another go tmrw and if i get it set staticly but still have the same issue i will try rpm and then check the advance mechanism. I will keep you updated.

[Garage_guy_chris]

I have tryed min and max point gap .012 to .016 if memory serves, I imagine there something simple I am missing just not sure what. Timing gets close if i turn the idle down but still doesnt get quite there. I trust my timing light but not sure about my harbor freight rpm gauge (stock tach is broke).

This right here is suggesting the advancer springs are worn and stretched and advancing too early (at idle), I would remove the advancer and the advancer springs and just shorten the hook ends by .020" to 0.040" so it will stay at base timing at idle. Then you should be able to set your base timing with the light and then as you blip the throttle you can watch the timing advance and retard with engine speed. A common problem is hanging idle, this can be caused by the timing not retarding back to base timing and getting stuck or fluttering somewhere between the F and advance marks

Also keep in mind if your using a electronic tach that these engines use a wasted spark system and will spark every TDC using the 4stroke setting will read double your actual rpm,  for these bikes use the 2 stroke setting

[Deltarider]

So start with the easiest and verify that what you think is an idle rpm, really is 1100 rpm.

[PeWe]

My bike had sloppy adv springs and full advance way too early. I cut each spring 1/2 wound and bent the cut side to look good. Good advice from Hondaman that worked and still work fine. Full advance now at around 2600-2700 rpm and 'F' where it should at idle.
My idle is 1200, not less since my CB750 must have ensured lubrication of the cam and all stuff up there. 1400 rpm idle OK too, especially with a hotter cam.

[tennesseebreeze]

My bike had sloppy adv springs and full advance way too early. I cut each spring 1/2 wound and bent the cut side to look good. Good advice from Hondaman that worked and still work fine. Full advance now at around 2600-2700 rpm and 'F' where it should at idle.
My idle is 1200, not less since my CB750 must have ensured lubrication of the cam and all stuff up there. 1400 rpm idle OK too, especially with a hotter cam.

This is something I was thinking of trying. Though cutting into the springs that are so rare to find gives me pause. Using a strobe at 1100 idle, my spark is advanced to somewhere between the F and T marks. The springs can fatigue over time and allow it to advance early. If I remember correctly, Hondaman suggested this to correct the "flat spot" in acceleration between 3000 and 3500 RPM that these bikes have from the factory.

[flybox1]

Cutting springs is really an easy task.  I did it both with my 750 and the 550 im working on.  Makes a huge difference.
Snip off the existing 'hook' and form a new one.  Done.
There are plenty of advance mechs (w springs) on ebay, and new springs at Yamiya 

[tennesseebreeze]

Cutting springs is really an easy task.  I did it both with my 750 and the 550 im working on.  Makes a huge difference.
Snip off the existing 'hook' and form a new one.  Done.
There are plenty of advance mechs (w springs) on ebay, and new springs at Yamiya 

Cool. You've given me the confidence to go ahead with it. Thanks Fly.

[Deltarider]

I just wonder why I never had to cut mine??? Would be interesting to know what brand advancer suffers most from sloppy springs: TEC or Hitachi?

[tennesseebreeze]

I just wonder why I never had to cut mine???

I don't think it's a matter of having to as a necessity. The springs may not fatique to a point that it makes an apprieciable difference. My bike is running strongly, despite the timing being slightly advanced at idle. Hondaman's suggestion was framed more as an improvement over stock. I'm willing to try it, along with some other things he suggested.

[b52bombardier1]

Does anybody have a reference for buying advancer springs from Yamiya?  I know a few folks with 90 cc Honda engines that could use a few.

For Flybox1 - do you have a URL for those springs?

Rick

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