Timing Gurus,

1998 FXSTC. On startup I get one pop through the pipes (not sure if it is both or just one) and then she will fire. Bike runs fine otherwise, but starting has been quite hard for a while now and I have noticed an increase in vibration under acceleration. This got me thinking that maybe my ignition was retarded. My pipes are also blackish which would indicate a rich condition. However, maybe this colour could also be caused by incomplete combustion due to the ignition being retarded.Here's my theory. Ignition somehow got retarded which means that combustion occurs later in the compression cycle. This would potentially allow some of the air/fuel mix to escape into the pipes. As soon as the engine fires off the pipes heat up rapidly which causes the escaped mixture in the pipes to explode.
So, I decided to have a play with the timing (without a timing gun). I advanced the timing 1.5 degrees after allowing the bike to fully warm up. I then shut her down and tried starting her again. She fired on the first (or second) compression without the after firing. Took her for a short run and gave her a fair bit of throttle and she seemed to run really well (no detonation or pre-ignition sounds). Shut her off and tried starting her again - no problems. Left her for about 1.5 hours outside in the cold and then went to start her again (in the past this type of exercise would cause her to start really hard and I would definitely need the enrichener). Jugs had the slightest amount of heat leftin them but she fired right up with no after firing and idled beautifully.

I plan on getting a timing light to see exactly where the timing is set. I'm also going to take her for a run and gradually increase engine speed and loadand listen for any nasty sounds,but in the meantimewhat do people think of my theory and reasoning? What are the chances of doing engine damage with only (potentially) 1.5 degrees of advance?

Cheers, Bill.

 

I am amazed that a tiny change in timing like 1.5 degrees would make a difference but if it worked, ya can't argue with success. I hope it runs smoother for you.

 

Other than a timing light if you know any body that has an electronic ign (preferably a dyna 2000 ) I use one of these to time all evos It's the static method and it's the cats ***

 

sqdealgeorge is right as I just installed a Dyna 2000 dual/single fire on my bike. We went single fire, installed the single fire coil and selected curve #3 as the engine top end is new.

to help answer your question, Dyna states in their directions that in some cases the timing needs of the engine will fall between the selectable programmed curves. In these cases Dyna recommends shifting the timing at the adjustment plate on the cam timing sensor by a degree or two in small increments either way (advanced or retarded), until you get where you need to be. They also advise you that this then shifts the entire selected programmed curve by the same amount.

Seems like you are on the right track into solving your problem. Long as you do not advance too much to start detonating your solution is looking good so far.

 

So, I guess your timing was right on the cusp of being in the sweet spot. That's great man. I will file this info away in the wood-fired computer I call my brain.
Did you get it to run smoother as well?

 

Guys,

I've got my hands on an inductive pick up timing light and I will be having a look at where the timing is tomorrow. Once I take her for a test ride, I'll let you all know the outcome.

Cheers.

 

Have fun, you are in for a messy surprise.

 

Well guys, I put the plastic timing hole plug in and proceeded to check the timing. By crikey it was difficult to see the 2 dimples (they really are quite small). However, the dimples were in the centre of the hole (as far as I could tell)which is the correct position according to the manual. How does it now run? Starts very easy, has lost the flat spot as you slam the throttle open and has noticeably less vibration under load. I took her up to 100kph at varying loads and got no detonation or pre-ignition indications. All in allmy after firing problem has dissappeared and she is running beautifully.

 

Good to hear, I have aquestion how could you see the mark with the plastic cover. I tried using one once and could not see the mark so I to this day just use the old fashioned messy way to set my timing.

Seriosly you could see the mark through the plastic?

 

89,

I moved the timing light around to the side of the timing plug (ever so slightly). This stopped the light being reflected back into my eyes. I also had the daughter stand the bike upright with a slight lean to the right in order to minimise the effect of oil splash on the plug. Yes it was difficult to see but I could definitely make out the dots (although they did seem to blend into one dot).