* Special note: Some of you may have noticed in various threads (not just mine) the "blurring" or deletion of Photobucket linked pics. Well, we all know as of late that Photobucket's policy changes and strong-arming subscribers into "upgrading" their account is causing internet catastrophe as it relates to our sharing visual information. I have been going through many of my older posts and changing pic links so I can be done with PB once and for all. They will not get a dime more of my money. In any event, please let me know if you see any issues with my pics and links. *
How-To: 4° Advance Timing and Clutch Spring Upgrade
Well, after the catastrophe of getting my clutch springs over-nighted ...
Okay, short story to preface the process: I spent the additional $$$ to overnight my EBC Clutch Springs from Jake Wilson (.com). That was Thursday and JW did their part flawlessly and I even helped them realize that the CSK028 kit DOES fit more models including mine ('03 ACE 750). Anyway, they were due Friday by 10:30, but delayed by weather in Louisville KY. UPS wouldn't deliver them on Saturday, so I waited until Monday @ 10:30 ... 11 ... 12 ... 1 ... um yeah, 2 frikkin 30 is when I got 'em. Ugh. Whatever. :roll:
Obviously and as always, any modifications you do to your bike are your responsibility and solely yours alone. I cannot be held liable for any errors, omissions or or damage done to your bike as a result of the following procedure. You assume any and all risk by choosing to follow this procedure. Capisce? Good. If any one notices an error, please chime in and let's get this thing modified. Thanks!
Now, why do you want to do this?
By advancing the ignition process by 4 degrees the piston receives the flame front 4 degrees sooner. Combustion happens while the piston is traveling upward. The time it takes for the 'spark' at spark plug to expand to the top and sides of the chamber allows the piston to pass top dead center before it receives the flame.
The expansion of the gasses during the period from ignition point ( before top dead center) to the flame front reception (after top dead center) increases the volume in the chamber and actually creates higher compression. This is why when the timing is advanced the higher position of the piston increases the effective compression and gives more power on the downward stroke. That equals more torque.
Keep in mind that the ideal compression for most gasoline engines is 10.5:1 for 93 octane fuel. Our VT750's are 9.0:1. That being said ... no you will not see that kind of difference in compression nor gobs of torque being handed to you on a platter. But, any HP or TQ gains no matter how small can be noticeable on a vehicle that weighs in just over 500 pounds. So bang-for-the-buck just oozes from this process if you have the time and patience.
Now you're thinking, "You don't gain power by advancing timing!" and "My engine will run hotter, won't it?" ... Technically no, and no. Tweaking your timing will not directly cause your engine to gain more power, but rather to run cooler (yes, cooler), improve gas mileage, make the motor burn cleaner and give you a better throttle response. The throttle response is where you are 'feeling' this torque gain.
I will mention too that higher-octane fuel can be good insurance when you have advanced your timing. This is because you may experience the dreaded pinging/knocking (a bad thing). But let's consider something first. The VT750's timing on these bikes have deliberately been retarded for emissions in the U.S. So advancing the timing upwards of 4°, even 6° is only putting the VT750 back to it's optimal running point (basically pissing off the Al Gore society). :mrgreen:
While I have no immediate plans to dyno-test these results, it's an old-school hot-rodding trick that pre-dates my birth, that's for sure. Plus, the math adds up and it's been tried and true.
Let's get to work now.
Advancing the timing on our beloved VT750's is a pretty simple process. There are some tutorials on the net, but this is my contribution and all of my own pics. Note, your process may slightly differ since I have aftermarket Cobra exhaust, a modified rear brake rod and forward controls. And this is being done to a 2003 Honda Shadow ACE VT750.
Parts needed:
Not everything is shown in the pic …
1. Begin by placing the oil catch pan under the bike and removing the oil drain plug using the 17mm wrench/socket.
2. Place oil container aside if reusing oil, or properly dispose of. Reinstall the drain plug so you don’t forget later!
3. Next, remove your exhaust pipes using the 12mm socket on an extension where each pipe connects to the head. On my Cobras, the 13mm wrench and socket was used to remove the pipes from the frame bracket. Set the pipes aside out of the way. If they did not fall out or stick to the exhaust pipe, look for the copper crush gaskets inside the exhaust port of the heads. They’re there; just use a flat head screw driver to gently pry them out.
4. Here’s the old copper gasket (left) compared to the new. Notice how they flatten when you torque down the exhaust.
5. Now drop down your rear brake bracket by unscrewing the frame pivot bolt with the 5/16” Allen wrench.
6. If you have stock pegs and controls, you may have to drop those down as well (not shown as I have forward controls and they were not in the way of the casing bolts.
7. Continue by disconnecting the clutch cable from the clutch lifter arm on top of the case. I used a piece of wood to push forward the lifter arm while grabbing the cable with the pliers and pulling outward to free it. This way you don’t have to mess with adjusting the clutch cable at the hand lever.
8. Start loosening and removing the bolts that connect the crankcase cover to the engine block using the 8mm socket. You may find yourself needing to use an 8mm wrench on the bottom bolts. A 5/16” works too, as I found out because I could not locate my 8mm wrench.
9. Remove the oil dipstick if you haven’t already. The case may stick to the block as mine did. There are two tabs on the back side of the crankcase cover that you can use to pry off the case (first pic, case upside down as if pulled directly off bike towards you and flipped over towards you). I used a crowbar between the frame and the rear tab to gently break the case loose. Just put a rag on the frame where you are applying force (second pic).
10. When the case breaks free, remove it and set it aside.
11. If you have an earlier model VT750, you may have a gasket around the case either stuck to the case, or the block, or torn between them. Discard it regardless and get a new one. Or, you can seal it up later using the Permatex Ultra Black gasket maker. Later VT750’s use this as opposed to the gasket anyway. Shockingly, if you’re as lucky as me I found this inside as an extremely rare factory bonus! And no time too soon!!!
12. Moving on … Now you’re ready to dig in. If you’re NOT swapping out the clutch springs, skip step (B) that follows.
13. Step (A) – Timing Modification:
Looking at the engine you will see your clutch assembly in its cradle (the large drum to the left), and your and ignition pulse generator rotor and the ignition pulse generator (IPG) itself (gear and black box to the right). Using the feeler gauges, insert the largest gauge between the small rectangle magnet on the bottom of the IPG and the gear tooth it is nearest. It should measure somewhere between .030” - .050”. Keep this in mind as when you reinstall the modified magneto, you need to stay within this parameter.
14. Remove the two bolts holding the IPG using the 12mm socket. Holding the IPG, gently free the wire and two rubber grommets from the block.
15. So you don’t have to actually trace down the wire and remove things from the top part of your bike, just to disconnect the IPG and bring it to your work bench, you can simply cover the open engine area and surroundings to prevent any grinding dust and metal particles from intruding on these surfaces. I set my “work area” up as follows, using some cardboard, a trash bag, a paint can and a scrap piece of wood for a table top.
16. Holding/securing the IPG, use the Dremel tool with grinder stone to grind down the centering lips of the bolt holes. Grind them completely flat. The IPG is a magnet, so you will see debris sticking to it and gradually building.
How-To: 4° Advance Timing and Clutch Spring Upgrade
Well, after the catastrophe of getting my clutch springs over-nighted ...
Okay, short story to preface the process: I spent the additional $$$ to overnight my EBC Clutch Springs from Jake Wilson (.com). That was Thursday and JW did their part flawlessly and I even helped them realize that the CSK028 kit DOES fit more models including mine ('03 ACE 750). Anyway, they were due Friday by 10:30, but delayed by weather in Louisville KY. UPS wouldn't deliver them on Saturday, so I waited until Monday @ 10:30 ... 11 ... 12 ... 1 ... um yeah, 2 frikkin 30 is when I got 'em. Ugh. Whatever. :roll:
Obviously and as always, any modifications you do to your bike are your responsibility and solely yours alone. I cannot be held liable for any errors, omissions or or damage done to your bike as a result of the following procedure. You assume any and all risk by choosing to follow this procedure. Capisce? Good. If any one notices an error, please chime in and let's get this thing modified. Thanks!
Now, why do you want to do this?
By advancing the ignition process by 4 degrees the piston receives the flame front 4 degrees sooner. Combustion happens while the piston is traveling upward. The time it takes for the 'spark' at spark plug to expand to the top and sides of the chamber allows the piston to pass top dead center before it receives the flame.
The expansion of the gasses during the period from ignition point ( before top dead center) to the flame front reception (after top dead center) increases the volume in the chamber and actually creates higher compression. This is why when the timing is advanced the higher position of the piston increases the effective compression and gives more power on the downward stroke. That equals more torque.
Keep in mind that the ideal compression for most gasoline engines is 10.5:1 for 93 octane fuel. Our VT750's are 9.0:1. That being said ... no you will not see that kind of difference in compression nor gobs of torque being handed to you on a platter. But, any HP or TQ gains no matter how small can be noticeable on a vehicle that weighs in just over 500 pounds. So bang-for-the-buck just oozes from this process if you have the time and patience.
Now you're thinking, "You don't gain power by advancing timing!" and "My engine will run hotter, won't it?" ... Technically no, and no. Tweaking your timing will not directly cause your engine to gain more power, but rather to run cooler (yes, cooler), improve gas mileage, make the motor burn cleaner and give you a better throttle response. The throttle response is where you are 'feeling' this torque gain.
I will mention too that higher-octane fuel can be good insurance when you have advanced your timing. This is because you may experience the dreaded pinging/knocking (a bad thing). But let's consider something first. The VT750's timing on these bikes have deliberately been retarded for emissions in the U.S. So advancing the timing upwards of 4°, even 6° is only putting the VT750 back to it's optimal running point (basically pissing off the Al Gore society). :mrgreen:
While I have no immediate plans to dyno-test these results, it's an old-school hot-rodding trick that pre-dates my birth, that's for sure. Plus, the math adds up and it's been tried and true.
Let's get to work now.
Advancing the timing on our beloved VT750's is a pretty simple process. There are some tutorials on the net, but this is my contribution and all of my own pics. Note, your process may slightly differ since I have aftermarket Cobra exhaust, a modified rear brake rod and forward controls. And this is being done to a 2003 Honda Shadow ACE VT750.
Parts needed:
- New Honda exhaust pipe copper crush gaskets
- New clutch springs (EBC CSK-028 or Barnett #501-75-04005) … if you’re doing this as well
- Torque wrench
- 17mm wrench/socket
- 13mm wrench/socket
- 8mm wrench (or 5/16”)
- Socket wrench
- Socket wrench extensions/adapters
- 13mm socket
- 12mm socket
- 10mm socket
- 8mm socket
- Pliers
- 5/16” Allen wrench
- Flathead screwdriver
- Crowbar
- Feeler gauges
- Razor blade and/or sand paper
- Magnetic pick up tool (optional)
- Permatex Ultra Black gasket maker (or new gasket pre 2002 I believe)
- Loc-Tite (use blue, even though I show red)
- A couple lock washers (to fit 12mm bolt; unsure of washer size)
- Clean-up rags/paper towels
- Nylon/latex gloves (if you want to still be able to touch your lady later)
- Oil catch pan (clean if you’re reusing the same oil)
- Safety goggles
- Dremel tool with metal grinder bit
Not everything is shown in the pic …
1. Begin by placing the oil catch pan under the bike and removing the oil drain plug using the 17mm wrench/socket.
2. Place oil container aside if reusing oil, or properly dispose of. Reinstall the drain plug so you don’t forget later!
3. Next, remove your exhaust pipes using the 12mm socket on an extension where each pipe connects to the head. On my Cobras, the 13mm wrench and socket was used to remove the pipes from the frame bracket. Set the pipes aside out of the way. If they did not fall out or stick to the exhaust pipe, look for the copper crush gaskets inside the exhaust port of the heads. They’re there; just use a flat head screw driver to gently pry them out.
4. Here’s the old copper gasket (left) compared to the new. Notice how they flatten when you torque down the exhaust.
5. Now drop down your rear brake bracket by unscrewing the frame pivot bolt with the 5/16” Allen wrench.
6. If you have stock pegs and controls, you may have to drop those down as well (not shown as I have forward controls and they were not in the way of the casing bolts.
7. Continue by disconnecting the clutch cable from the clutch lifter arm on top of the case. I used a piece of wood to push forward the lifter arm while grabbing the cable with the pliers and pulling outward to free it. This way you don’t have to mess with adjusting the clutch cable at the hand lever.
8. Start loosening and removing the bolts that connect the crankcase cover to the engine block using the 8mm socket. You may find yourself needing to use an 8mm wrench on the bottom bolts. A 5/16” works too, as I found out because I could not locate my 8mm wrench.
9. Remove the oil dipstick if you haven’t already. The case may stick to the block as mine did. There are two tabs on the back side of the crankcase cover that you can use to pry off the case (first pic, case upside down as if pulled directly off bike towards you and flipped over towards you). I used a crowbar between the frame and the rear tab to gently break the case loose. Just put a rag on the frame where you are applying force (second pic).
10. When the case breaks free, remove it and set it aside.
11. If you have an earlier model VT750, you may have a gasket around the case either stuck to the case, or the block, or torn between them. Discard it regardless and get a new one. Or, you can seal it up later using the Permatex Ultra Black gasket maker. Later VT750’s use this as opposed to the gasket anyway. Shockingly, if you’re as lucky as me I found this inside as an extremely rare factory bonus! And no time too soon!!!
12. Moving on … Now you’re ready to dig in. If you’re NOT swapping out the clutch springs, skip step (B) that follows.
13. Step (A) – Timing Modification:
Looking at the engine you will see your clutch assembly in its cradle (the large drum to the left), and your and ignition pulse generator rotor and the ignition pulse generator (IPG) itself (gear and black box to the right). Using the feeler gauges, insert the largest gauge between the small rectangle magnet on the bottom of the IPG and the gear tooth it is nearest. It should measure somewhere between .030” - .050”. Keep this in mind as when you reinstall the modified magneto, you need to stay within this parameter.
14. Remove the two bolts holding the IPG using the 12mm socket. Holding the IPG, gently free the wire and two rubber grommets from the block.
15. So you don’t have to actually trace down the wire and remove things from the top part of your bike, just to disconnect the IPG and bring it to your work bench, you can simply cover the open engine area and surroundings to prevent any grinding dust and metal particles from intruding on these surfaces. I set my “work area” up as follows, using some cardboard, a trash bag, a paint can and a scrap piece of wood for a table top.
16. Holding/securing the IPG, use the Dremel tool with grinder stone to grind down the centering lips of the bolt holes. Grind them completely flat. The IPG is a magnet, so you will see debris sticking to it and gradually building.