Couple of timing questions.

jbswear · Post by **jbswear** » Fri Jul 02, 2010 2:24 pm

'74 GT380

One: I set my timing last night by means of a dial indicator and my multimeter last night. I set all the gaps to .014", then I set the Left, Right, and then Center cylinders to open at 2.4mm BTDC. I used my multimeter to know when each points breaker opened, by measuring voltage across the points--when the points were closed, no voltage. Right when they opened, it jumped to just about 9v, engine off, key on (battery hadn't been charged in a while).

Question is this: On each of the points, the timing mark is WAAAAY off. In the little window below the breaker plate, the timing mark is about 20 degrees to the right of the stationary mark at the point where the points start to open. Is this a problem? Two years ago I opened up the right side of the engine case to inspect the clutch plates. When I put the rotating plate back on, I don't remember if I lined it up perfectly.

Next question: What oil do I put on the fiber oiler on the points cam? It's dry and there's a bit of rust on the point cam.

Thanks!

Coyote · Post by **Coyote** » Fri Jul 02, 2010 4:39 pm

Is it possible this is a transition motor? Try setting one cylinder to the J/K spec (2.99, 2.93, 2.99) and see if it comes in at that. It won't run at 20 degrees out. Also it is important to set the timing in the direction of rotation. Never 'back up' to your mark. if you back up you must go a couple mm's further and come back forward to your mark (on the indicator). This compensates for any lash in the gears.
I doubt seriously that you got the timing plate out of whack as it is located by a pin on the shaft. Remember?
You can get cam lube at any automotine store if you are so inclined. I just used a couple of drops of Marvel Mystery Oil on mine.
POLISH THE CAM!! If it is rough, your point setting will go away fast as it eats away at the rubbing blocks.

jbswear · Post by **jbswear** » Fri Jul 02, 2010 5:07 pm

I'll try it at 2.99.

jbswear · Post by **jbswear** » Fri Jul 02, 2010 5:28 pm

The VIN is GT380-63511. Can that be used to find out which one it is?

jbswear · Post by **jbswear** » Fri Jul 02, 2010 6:05 pm

2.99 is still 10-15 degrees to the right of the fixed timing mark.

I think I remember it not lining up completely when I put it back on. Back then I didn't know too much about these things; I don't remember there being any kind of key that would lock it into the correct place. I do vaguely remember somebody saying that one must be careful when putting it back in.

So...now that I've moved it just less than a millimeter further from TDC and it still isn't lined up...which one do I go with?

Buffalo-guy · Post by **Buffalo-guy** » Fri Jul 02, 2010 11:19 pm

The 380 is the only one of the triples that has the ignition cam indexed by a plastic gear, that must be properly positioned when putting the clutch side cover back on. It sounds to me like you have the points cam out of position by one tooth. The drive gear on the end of the crank has a dot that must line up with the pointer that is there, and the points timing marks for the left cylinder must line up at the time you slide the cover into position. This should fix your timing marks issue. Unfortunately, it means pulling the engine cover off, but it needs to be corrected. It has been my experience that the factory timing marks are very close to requirements, certainly close enough to make the bike run quite well. The dial guage test is a good way of verifying the marks. Coyote is absolutely right in saying the points cam needs to be cleaned of rust. Any good motor or gear oil should work fine on the cotton swab. Charge the battery as well. The charging system will be much more happy. Hope this helps. Cheers.
Fred

Suzukidave · Post by **Suzukidave** » Sat Jul 03, 2010 4:07 am

http://www.3cyl.com/mraxl/gt/manuals/gt380man/index.htm

Barry S. · Post by **Barry S.** » Sat Jul 03, 2010 6:54 am

Do not turn the motor with the points cam bolt, it may break the plastic gear.

jbswear · Post by **jbswear** » Sat Jul 03, 2010 7:11 am

Buffalo-guy wrote:The 380 is the only one of the triples that has the ignition cam indexed by a plastic gear, that must be properly positioned when putting the clutch side cover back on. It sounds to me like you have the points cam out of position by one tooth. The drive gear on the end of the crank has a dot that must line up with the pointer that is there, and the points timing marks for the left cylinder must line up at the time you slide the cover into position. This should fix your timing marks issue. Unfortunately, it means pulling the engine cover off, but it needs to be corrected. It has been my experience that the factory timing marks are very close to requirements, certainly close enough to make the bike run quite well. The dial guage test is a good way of verifying the marks. Coyote is absolutely right in saying the points cam needs to be cleaned of rust. Any good motor or gear oil should work fine on the cotton swab. Charge the battery as well. The charging system will be much more happy. Hope this helps. Cheers.
Fred

So if the rotating indicator is off the mark, does that mean engine problems if it's run that way? If so, I'll take the cover and all off, but I'd rather not if I don't have to. If I can run it as it is, I'd prefer that.

Barry S. wrote:Do not turn the motor with the points cam bolt, it may break the plastic gear.

Oh yeah. Bike is in sixth gear and I'm using the rear wheel to turn the crank.

gt-keith · Post by **gt-keith** » Sat Jul 03, 2010 9:03 am

Why did Suzuki alter the ignition timing over the years?
Did they alter the port timing in the barrels them selves? Or just change the ignition timing to suit the emission issues of the day?

gt-keith

Here's a photo of the 380's timing gears prior to assembly

Points timing plate should look like this.

jbswear · Post by **jbswear** » Sat Jul 03, 2010 12:30 pm

Yeah, I'll be taking apart the right side this afternoon so I can set it straight.

Man, I just wanna ride this dang thing! So close, I can almost taste the two-stroke smoke!

jbswear · Post by **jbswear** » Sat Jul 03, 2010 1:31 pm

Alright, so I pulled off the tranny cover to line it up. Using the stamped mark on the gear, I lined up the gear with the indicator like the picture above.

When I now put on the cover, with the "L" marking on the timing plate lined up with the mark in the window, it won't line up perfectly. When I slide on the cover, the timing mark aligns itself about a millimeter to the right of the mark as you're looking at it.

Is this close enough? Should I be concerned with it?

jbswear · Post by **jbswear** » Sat Jul 03, 2010 2:34 pm

Here are the steps I've followed to set the timing:

Recharged the battery.

Removed the spark plugs.

Set the mark on the driving gear to match the arrow under the right engine cover. The left mark on the timing plate is almost perfectly aligned with the mark in the window.

Set the gaps on all the points to .014" when fully open.

Digital dial indicator in the LEFT plug hole. Found TDC and then 2.4mm BTDC.

Rotate the breaker plate until the LEFT points JUST open. I verified open/close position with a multimeter--0v when closed, 9.8v when open.

I did this for ALL three cylinders.

Now when I look at the timing plate, AT THE POINT WHERE THE POINTS JUST OPEN, the timing mark is still about 20 degrees to the RIGHT of the set mark in the window.

I'm following the directions just as Coyote sent them on the PDF he sent me, which, by the way, are a perfect match for the directions in the 1981 Chilton's motorcycle maintenance manual.

Am I doing something wrong?

Suzukidave · Post by **Suzukidave** » Sat Jul 03, 2010 4:02 pm

Are these new or used points ? Suzuki or after market ? as if the rubbing blocks are worn it will change where they open . I have seen the need to narrow the gap on points sets some to get the timing marks to line up .

jbswear · Post by **jbswear** » Sat Jul 03, 2010 4:12 pm

Suzukidave wrote:Are these new or used points ? Suzuki or after market ? as if the rubbing blocks are worn it will change where they open . I have seen the need to narrow the gap on points sets some to get the timing marks to line up .

The points are about two years old, but are basically unused. They're Suzuki points. What do you mean by narrowing the gap? The gap when they're at their widest?

I just put the carbs back together after syncing them fairly closely. It will start and run no problem, with that nice outboard boat motor sound. All three pipes are hot, so I know all three are firing.

I have lots of smoke coming from the right cylinder, but hardly any from the other two. I'm gonna check the oil lines next; I just refilled the oil tank.

I'm having trouble getting it to idle. In other words, it won't without stalling. I'll work on that after I know that I have oil going to all cylinders.