Need help on timing with dial gauge.

[pearljam724]

I finally got my 750 running pretty descent consistently. It drops no cylinders now. However, I live around fairly inclined terrains. The bike runs good for long periods, if I don't attempt to climb a long incline. If I do, it loses all power. But, I gain that power back once the bike idles for 4 to 5 seconds. I've addressed every mechanical issue under the sun to correct this. Including many different fuel screw adjustments. At this point, I'm 1000% positive that my timing is still ever so slightly out of wack. Reason it runs fine until I need more power, because the timing is not allowing it to make enough power. I looked at the timing most recently through the window and verified that is in fact off time ever so slightly on 2 cylinders. It's been difficult trying to static time my bike being that I can't tell exactly where the high point of the lobe is in reference to setting the left cylinder. I pretty much try to stand on my head, because the high point of the cam is at the bottom of the crank when trying to determine it.
I scored a deal on Ebay today for a Suzuki dial gauge still in the box for $39. According to the video posted below. What would be the exact readings on that gauge for the Buffalo that I would need to shoot for after I find top dead center as he does ? I realize the btdc right/left cylinders would need to be at 3.63 mm and center 3.42 mm. For example, he finds top dead center on his bike. Sets dial at 0 to indicate it. Then sets his points to open at 2 mm before top dead center. Which he converted to .078. What does 3.63 mm and 3.42 convert to in thousandths ? My last question. What is the max suggested advance without fear of putting a hole in a piston for a street bike ? Just to be sure I'm never too far advanced. But, I do want to time it slightly advanced. https://www.youtube.com/watch?v=yjvc491 ... 89&index=3" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[pearljam724]

I apologize for my lack of mathematical skills. But, I believe I found the conversion thanks to Google. 3.63 mm = 143 thousands and 3.42 mm = 134 thousandths. So what would those thousandths indicate on his dial ? 14.5 and 13.5 ?

[tz375]

3.42mm = 0.134" and 3.63=0.142" according to the manual.

Those equate to 24 degrees BTDC on all 3 pots.

Set the points gap with the points sitting on or around the highest lift point.

Then set the timing to where the points just crack open - use a radio off channel or a timing light or buzzer to determine the exact point of opening.

If your Dial Test Indicator goes from zero to some number, in both directions, turn the motor back about 4-6mm and bring it forward again slowly and watch for the light. Adjust as required.

Some DTI's go from 0 to to 10 over 1 complete revolution and those require and extra step on the calculator. Yours probably goes through 0.100" per complete revolution, so it would go through one complete revolution plus another third of a revolution roughly speaking.

[pearljam724]

Thank you, Richard. The original Suzuki dial gauge I bought is identical in numerical value as to the video I posted. Under that circumstance. His gauge travels 21 1/2 numerals to succeed roughly 2 mm. Am I way off base in thinking that I wouldn't need complete rotation or more ? It seems to me that every 10 numerals equals roughly a mm ? Generally speaking. http://www.ebay.com/itm/171347787667?_t ... EBIDX%3AIT" onclick="window.open(this.href);return false;

[tz375]

That dial gauge says .01 -5mm so that means each small graduation is .01mm and one full rotation is 100 graduations or 1.0mm. The gauge will go around 5 full rotations for a full range of 5mm.

My Inch type dial gauge has each graduation is .001" and it is 0.1" per revolution and has 10 revolution range.

If you want timing at "3.something"mm then the motor has to be rotated so that the gauge rotates almost 4 full rotations. 2mm is about right on a small Yamaha twin.

In inches that's 1 and 1/3rd revolutions roughly speaking on my DTI

[Vintageman]

What about measuring direct or indirect?

Direct = the measurement is taken in the same axis as piston movement.
Indirect = Since the plug hole may be at an angle to piston movement and then if your gauge is attached in line with plug threads the measurement is indirect with piston movement (longer distance for same crankshaft degree versus direct. you need to know angle of plug to piston movement to compensate if the spec is direct an dyou measure indirectly).

For example, Rotax would tell you if the distance published was indirect or direct and depended if plug was straight or at an angle to piston movement.

I have always assumed Suz specs were direct even though plug hole may be at an angle to piston movement. I never verified this for example taking crank stroke, rod length etc and calculate or use a degree wheel to set. It seems every time I assume direct it is very close agreement to marks provided by Suz near points and good enough... I may be wrong?

[pearljam724]

Thanks, guys. That helps. I think I understand it now based on what you told me about my gauge. That original Suzuki dial gauge that I bought comes with 2 different length stems as you can see in the Ebay posting I added. Does it matter which length stem I use ? If so, any idea which one is proper ? Based on the Suzuki dial gauge I bought. To set the timing for the left and right cylinders at 3.64 mm after finding TDC. The gauge would be rotated 3 complete revolutions to equal 3mm. 100 minus 64 equals 36. So that last revolution beyond the third. The reading should read 36. Does this sound right ?

[pull the wire]

Hi Justin,

It appears the dial indicator he is using reads in .001 (1 one-thousandth of 1 inch) increments per every mark. When the needle rotates one complete revolution the total movement of the tool moves .100 or 100 thousandth's. To convert millimeters to inches is easy. Simply multiply the mm measurement times .0394. Your answer will be in thousands of an inch. So 3.42 times .0394 equals .135 or 135 thousandths'. After setting your point gap on all three sets of points, you can now use the dial indicator method shown in the video. To be safe, your indicator needs to travel at least 2 revolutions to make sure you do not run out of travel. Set up the indicator as shown and find TDC. Zero the indicator. Slowly and carefully rotate the engine backwards (clockwise points side for a GT750) a little less than 2 complete revolutions of the dial and then slowly rotate the engine counter clockwise until you reach .135 on your dial. Zero the indicator there and that will be your target timing setting. Remember that is going to be 1 full revolution (.100) plus another .035 or 35 lines on your dial. Now you adjust your center cylinder points so that it just breaks open, no continuity, right at that point. Repeat for the other cylinders with the different measurement and it will be as close as it's gonna get until the points wear, again.

Good luck and I hope this helps bro

[pull the wire]

OOPS . I should have looked at the photo first. The gage you purchased is in MM. Pretty much the same technique. 1 full revolution of that tool equals 1 millimeter. So you need to make sure your dial range is 4 revolutions, 4mm. It's all the same after that. The stem length you need will be up to your trial. Get the cylinder as close TDC as you can first and then select the short stem and set it up so the dial moves 4 revolutions. if you can't get 4 revolutions of travel, try the next longer stem. Lock it down there and you should be good to go. Once you get it set and zeroed at TDC, rotate clockwise for almost 4 revolutions of the dial. then slowly rotate the engine counter clockwise until you are at .42 mm mark. Remember this is 3 revolutions plus .42 that the tool will be extended into the cylinder. Zero it at that point and adjust.

[pearljam724]

Thanks, guys. That gauge was the best tool I ever bought ! ! ! ! The bike is running like a champ now. Ran it for a few hours. Climbed the steepest of hills with plenty of power. In fact, I deliberately sought after the steepest and longest inclines around. Previously, I had to avoid them. Once Richard, explained it to me so I better understood. It was a breeze. pull the wire, where were you yesterday when I needed that information ? That's exactly what I learned today. No exaggeration, I static timed the bike at least 50 times. Nothing, I ever did ever made it quite right. With the dial gauge, it only took one attempt and she was golden. I compared the previous static timing after I set it with the dial. The left cylinder was a mile off. Regardless, of where I timed it through the window. Believe it or not. I had the propeller timed dead nuts on all cylinders many times and it never timed it quite right. I will never static time again. Worthless. I changed every part on the bike, even though they were all new. Reevaluated, all the wiring. Nothing ever completely fixed the issue. I checked over everything at least several times and nothing worked over a couple month period. Let this be a lesson to a lot of people. Don't rely on static timing ! ! ! I never will again. I could get the bike to easily start and run. But, that's about all of what static timing is worth. Through my long going experience. This was how it idled a couple days prior to the dial gauge. It started, idled and ran fine. As long as I didn't make her climb. Hold your ears, Richard. I know you don't like the popcorn. https://www.youtube.com/watch?v=H5zHi7fh6F0" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[pull the wire]

Sorry PearlJam. I'm glad you got it right!!!! That's great

[pearljam724]

Thanks, Doug. Yep, finally. No need to apologize. I was just poking you. I appreciate all the help you provided.

[Vintageman]

Are not the gt750 plugs on an angle with respect to piston motion ( I all ready forget and just finished my gt750 less than acouple weeks ago. Well some of the Suz plugs are on an angle so still a good point

If so you set timing using distance "indirectly" and if that distance was to used :directly" you are not quite as advance as it should be.

Guys go back a read my first reply to this post

I timed my engine when on the bench. On all these old girls I used the tail off the bottom of my calipers and the caliper was set in direct alignment with piston motion when I set timing distance. Not the angle of the plug hole

Maybe the plug angle is so small the error will be small if you measuring instrument is aligned to plug hole and not piston motion?

Actually those chambers really don't Pop Corn (Clap...Clap...Clap) that bad at all. Very nice! I would like to here it when you ride it. I'll have to do the same with my 75 and Jemco's.

Again sweet bike!

[pearljam724]

The sound of the Higgspeed pipes popping and crackling are dependent on the timing. Some guys I've noticed in videos leave the full thickness of fiberglass that comes with them. I tore mine in half, making it thinner. If you time the cylinders advanced the bike revs faster of course, reflecting on the sound of the pipes. I think if you time it somewhere in between you get a lot of crackling, pinging and popping. If you listen to my left cylinder pipe. If I remember correctly, it was probably timed a little retard. While the other 2 cylinders were revving faster without as much popping and pinging. Just crackling at that speed. My understanding, that if a motor is too far advanced the motor itself will ping. It seems to me just the opposite with the Higgspeed pipes. If the cylinder is retard, the pipe itself pings a little because it's revving slower and the spark's detonation is slower. I could be wrong. But, that's what I gather. Personally, I love all the different sounds they make. Thanks, for the compliments and all of your help. I'm a happy camper now.

Vintageman, the part I found to be critical is finding TDC. Because TDC gives you a precise starting point to meet your BTDC measurement. It's hard to determine TDC when static timing or accurately finding the exact BTDC point when your points just begin to open and that distance to TDC being accurate. It leaves for some room for error without taking accurate measurements. Finding it with the dial gauge made the world of a difference for me. If you have a problem, I'll lend you mine.

[Craig380]

I have always assumed Suz specs were direct even though plug hole may be at an angle to piston movement. I never verified this for example taking crank stroke, rod length etc and calculate or use a degree wheel to set. It seems every time I assume direct it is very close agreement to marks provided by Suz near points and good enough... I may be wrong?

As I understand it, the Suzi specs are INDIRECT. On the 380s, this is why the centre cylinder has a different (slightly retarded) timing spec to the outer two cylinders. The plug hole in the centre cylinder is much less offset than the plug holes in the outer two, so the BTDC timing measurement for the centre cylinder is slightly less than for the outers.

The actual firing point when measured DIRECTLY (that is, in degrees BTDC) is the same for all 3 cylinders on the 380. But when measured by dial gauge in the spark plug holes, it's slightly different because of the different offsets.

On the 550 and 750 triples, maybe the offsets of the 3 spark plug holes are not so different to each other, so the measured difference is smaller.