Triumphrat

Caulky · 08-08-2009, 12:09 PM

In order to strobe the ignition timing, I need to rev the engine to 5000rpm.
Just about everything is new in the engine.
Is it wise to run it at that speed now?
It seems to be behaving itself on static timing, but with some qualifications.
I`ve been tweaking the carbs, but I`m unable to get the tick-over revs below 1000 rpm.
If I snap the throttle open, it hesitates or dies.
How long does it take to get the engine hot enough to make adjustments?
How long is too hot...I mean, this is air cooled in a shed

One good thing is there`s no smoke, yippee

...been dogged with that since I`ve had it.
Carb settings:
Main jet 180
Needle jet 105
Slider 3 1/2
Float heights set at about .070"
Needle has 2 rings...in centre groove.
After the first start-up for around a couple of minutes, I pulled the plugs
Left was fairly clean with a little oil.
Right was similar with a bit more oil.
I put this slight oiling down to it being new and not run-in.
No blackness or whitening.
Tickover was quite steady...but a bit fast.
If I could get the tickover revs down a bit,I`d be happy.

panda · 08-08-2009, 04:26 PM

1,000rpm really isn't too fast. they are better off having sufficient oil pressure.

GrandPaulZ · 08-08-2009, 07:24 PM

You need to use a large fan to keep the engine cool while strobe timing.

5,000 RPM is for FULL advance; you can keep the timing revs to 3,500 before break-in, and note the indicator swing as the engine revs, then compensate SLIGHTLY for full advance which you shouldn't be needing for at least one full tank of gas.

Does this make sense? Have a helper slowly build the revs up to 3,500, calling out every 500 RPM increase so you can watch the strobe track the moving timing marks. From this, you should be able to estimate if the progression would find the marks aligning at about 5,000 RPM based on the track the marks were closing in on each other as the engine hit 3,500 RPM. If they were well short, bump up the timing a bit advanced and re-check to see if it's closer. Just a fraction of rotation on the stator plate is all that's required.

henryanthony · 08-08-2009, 08:04 PM

Hi

I'll need to strobe time my Bonnie at some point - when it finally gets running

- and have read in my service manual that full advance is 2,000 rpm. I don't doubt GrandPaulZ but, that's quite a difference. I have also heard that those service manuals are not always correct. What's the red line for an older Bonnie, say 1970?

Regards,

Henry

jimballard · 08-08-2009, 08:39 PM

With the standard points setup, my '70 is at full advance at around 2,500 but I usually go to 3,000 briefly to check the marks.

Just a quick "blip", that's all: Jim

thirdbike · 08-08-2009, 10:25 PM

Henry, your manual references a bike with stock points and a mechanical advance. In other words, the flyweights are already fully extended somewhere around 25000 to 3000 RPM whereas the above bike has an electronic ignition where the entire ignition function including advance is more precisely controlled electronically.

Caulky · 08-09-2009, 07:40 AM

Thanks for the replies

Good ideas GrandPaulZ.
There`s a graph of the advance with increase in rpm.
I can estimate the advance with marks, but keeping the revs down.
For the moment I`ll leave everything until its run a few times.
Its going to change anyway, I suppose.
I`ll keep an eye on the plugs.

GrandPaulZ · 08-09-2009, 12:55 PM

thirbike has it correct. modern electronics time max advance at 5,000 RPM. In stock trim, you can see that the engine will continue to rev out to 7,000 RPM, but power delivery tapers off after 5,000; unless you alter cams and intake (porting & carbs) there are no major gains other than numerical speed (at a reduced rate of increase).

henryanthony · 08-09-2009, 11:01 PM

thirdbike and GPZ,

Thanks for the clarification. I think it's a good thing I did not try strobing with mechanical points at 5K. I do have a proper fan though. A good lesson for all learners here - make sure what you are reading applies to your particular bike and set up.

Henry