Need help Identifying A/R Units

[Guest]

Long story short. I have fitted 650 pistons, cylinders, head and carbs to a 550 bottom end. I have been running the 550 advance/retard unit with Dyna S ignition. The motor has been pinging coming out of corners, or going up a grade, usually at lower revs and reasonably wide throttle openings.

I am trying to fit the 650 advance/retard unit which is a bit longer than the 550 unit. I purchased one 650 unit on Ebay, but the springs were a bit stretched. So I purchased another one. But they appear to be different.

I don't know whether the 650 unit changed partway through the run (only 3 years). Or whether one of the units is off another model, 750, 850, etc.



It can be seen in the picture above that the distance between the TDC mark and the initial firing mark (T and F) is different, closer together in the left unit.

The distance between the initial timing firing mark and the total advance mark is further apart on the LH unit. And the overall total from T to the total advance mark is also different on both units.

I don't see why this would be. Changing the ignition timing on the same engine.

There are numbers stamped on each unit, 342 on the LH unit and 49 on the RH unit.

Does anyone have any idea which each of these units are off? Are there any 650 owners out there that can give me the number off the unit mounted to their motors.

P.S. The reason for changing from the 550 unit to the 650 unit is because there could be a difference in the weight of the bob weights and the strength of the springs and this will hopefully rid me of the pinging in my motor under initial acceleration. The pinging does not happen going through the gears, but only when opening the throttle in 6th or 5th coming out of a turn or going up a grade.

More pics below for reference.






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[tom203]

Both my spares look like unit on left- #342 on it ! I wonder whether other unit was off a 450 automatic tranny model.

[Suzuki_Don]

Thanks Tom. Good update. Good to get some relevant information. I am starting to think the other unit is off a 650 Katana. I seem to remember now that I got it off a bloke selling Katana parts. But I don't know why the ign timing on a Katana would be different. I thought all the 650 motors had the same state of tune.

[hjfisk]

Also I don't know if they are the same or not but a 650E has a roller crank and a 650G has a insert crank, so I am not sure if that would make a differance or not.I just did a cross referance on the parts and a 650E has a different # than a 650G

[tom203]

The different timing makes no sense- unless it was for a big single.

[chef1366]

Have you looked into a Dyna 2000 where you can set the advance curve?

[Suzuki_Don]

Have you looked into a Dyna 2000 where you can set the advance curve?

Bill, can you explain how the 2000 works? How do you set the advance curve and are there any extra modules, black boxes to be mounted on the bike?

Thanks for your reply.

[boontonmike]

You would run the dyna crank trigger with electronic pickups. It removes the mechanical advance. You set up your baseline advance and time the 2 sensors using dynas methods. Then the dyna 2000 box does the rest and set the advance through the iginition box. there are mutiple settings you can run with preset timing curves.

You would be getting rid of the entire stock ignition set up pretty much. you need different ohm coils to run the dyna2000 too. I beleive 3.0 or 2.2 depending on application.

http://www.ebay.com/itm/Dyna-2000-CDI-Ignition-Coils-Wires-Suzuki-GS-1150-/250856717226?item=250856717226&vxp=mtr

You can see it has a blue box, crank trigger with pickups on a plate, coil packs, and wires. Im going to be running this setup.

It also has an iginition kill leg for WOT shifts , or an extra secutriy switch to turn off the ignition as well as tach outputs.

Most people will tell you to just go with the dyna S which is alot simpler and cheaper tho.

[Suzuki_Don]

Thanks Mike, I know this would be my best option, but I don't have the dollars for that type of upgrade at the present time. I will persevere with the mechanical advance/retard unit.

[Suzuki_Don]

I think I might have struck gold and worked out why the difference between the two advance/retard units.

These units have a unique number stamped on them from the factory. In the top picture above the numbers on the two units are 342 (LH) and 49 (RH). I looked on Ebay at a number of GS650 units that were up for sale and they all had the 342 number stamped on them.

So now to find out what the other RH unit above is off with the number 49 stamped on it. Well a bit more searching on Ebay and I found an advance/retard unit with the 49 stamped on it and guess what, it was off a GS1100E motor. No wonder the timing marks were a bit different.



The timing on the 650 is 10 deg initial and 40 deg total advance.

The timing on the 1100 is 12 deg initial and 32 deg total advance.

So this would pretty well account for the differences in the timing marks on each of the units in the top photo.

I am happier now. At least I know why it was pinging, although performance never suffered. It always had plenty of oomph.

Thanks for the interest of those who contributed.

P.S. Seeing as each of the advance/retard units have a unique number stamped on them from the factory it might be worth putting a list together for reference in the future. I will start.

GS650 -- 342
GS1100E - 49


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[tom203]

Good detective work! But can you tell me why camshaft timing on 650 shafties is slightly different than chain drive E- more valve overlap????