Installing Barnett Clutch Springs
Installing Barnett Clutch Springs
  This is a simple and inexpensive upgrade for the ACE. While not necessary for stock bikes, it is a recommended modification if you have changed to a smaller rear sprocket and/or have done some power increasing modifications. The Barnett cutch springs are quite a bit stronger and therefore they prevent any clutch slippage due to the changes I just mentioned. And even a stock bike can benefit from these springs since the clutch action becomes much smoother with the upgraded springs. The springs themselves are a breeze to change, but since you have to open up the right side engine case and remove the exhaust, I would estimate about 3 hours to complete this task. If you plan on doing the 4 Degree Timing Mod, then now would be a good time, since you will have the engine opened up already. And, finally, it's also a good idea to plan your oil change for this time as well... since you have to drain it anyhow.

Materials & Tools Needed
  1. Bike Lift (optional);
  2. Barnett Clutch Spring Kit - Barnett P/N 501-75-04005. About $15.00;
  3. Oil Pan (Clean one if you plan on reusing the oil!);
  4. 17mm Wrench (drain plug);
  5. 12mm Socket and Wrench (exhaust nuts and mounting bolts);
  6. 8mm Socket (engine case);
  7. Two new exhaust gaskets - Honda P/N 18291-MM5-860. (I paid only $2.50 each for them);
  8. New Right Side Gasket (Honda P/N 11394-MV1-850, about $12.00) or a tube of gasket maker. Buy the Honda stuff or Permatex brand;
  9. Three quarts oil and Filter (If doing oil change)

Step 1:

  It's best to use a bike lift, which raises the bike up to a good level so you can just sit in a chair and do the work, but it is possible to do this with the bike on the ground as well. First thing to do is remove the exhaust pipe(s). Then remove the brake pedal assembly. You can remove it completely or, what I did, was just undo the two mounting bolts on the forward peg bracket, then I pulled the lever away a bit and undid the brake switch spring and undo the brake lever return spring further back and lay the whole thing down on some padding. It's out of the way still but you don't need to take all the pivot points apart. Just be careful of the long thin brake rod at the back. It's easy to bend so make sure it's not stressed when you lay the forward stuff down.

Step 2:

*** DRAIN THE OIL! ***

Forget to do this step and you'll be taking a bath when you pull off the side cover! I'd recommend pulling the filter at the same time and letting the engine drain for 20 minutes or so before taking the engine cover off. Once the oil is drained then loosen the clutch adjuster (on the engine case) until it is totally slack and then remove the bolt holding the clutch cable to the case. Remove the clutch cable from the clutch arm. Then go around the engine side cover and remove all the 8mm head bolts.

If your ACE is a 2001 or newer, then you don't have a gasket, instead they used a gasket sealing material somewhat like silicone. All ACE's before 2001 had a paper gasket. In either case, the cover will likely be stuck on pretty good after several years so care must be taken to get it off. The aluminum is VERY soft, so DO NOT attempt to pry the side cover off in any way. Your best bet is to gently tap araound the edges of the cover with a soft faced hanmmer or, something I did, was to remove the oil filler cap and then put the wooden handle of a hammer in the hole and gently pulled on that to break the seal. The cover has to come straight out for 1/4" to clear the locating dowels.

Once the side cover is off, take it to a workbench and remove all the old gasket material from the mating surface of the cover. If you have a newer ACE with the sealant, it should just come off by rubbing your finger or a cloth over it. Make sure to clean the mating surface on the engine side as well. Also, take note of the two locating dowel pins (see arrows on right picture). It's best to put the dowels back in their holes on the cover and not the engine, so you don't accidently knock them out while working on the clutch.

Step 3:

  Remove the four clutch lifter plate bolts. Turn them out a little at a time in a criss-cross pattern. The bolts are very long and the plate will come out far enough to take all tension off the springs. Remove the lifter plate, bearing and clutch springs. Be careful as the bearing just falls out loose.

Step 4:

  Here's one of the old clutch springs beside the new Barnett spring. The Barnet spring is about 0.11" longer then stock and also thicker and stronger wound. If you are curious, you can also measure the length of the stock springs to see if they were within service limits. Honda says they should be at least 1.73"(43.9mm) long. Anything shorter then that and they are scrap. I found mine to be 1.75" long after 21,000km.

Step 5:

  Put the four new springs in place and then place the lifter plate on top, making sure the open side is facing out (side that the bearing drops into). Hand thread the four bolts back in and start tightening them, again in a criss-cross pattern until they bottom out. Final torque is just 9 Ft Lbs. Slip the bearing back into place.

Next, either place a new paper gasket on the engine or use an approved gasket material to run a new seal around the mating surface (Only on the engine side). I used Permatex Blue on mine. Don't glop on too much and smooth it out while removing the excess. Let the gasket material set up for a few minutes, then slip the cover on and hand thread all the bolts in, except the one holding the clutch cable. (make sure the dowel pins are in). Now tighten the bolts in a criss cross pattern in several steps. There is no official final torque, but these are very thin bolts so you should just do them "snug" and even all around. I used a 1/4" drive rachet as well, not some 2 foot long monster, lol. Once the cover is secured, install the clutch cable and final case bolt to the bracket. Now's a good time to take a damp rag and wipe off any excess sealant that you squeezed out.

Step 6:

  Install the brake lever back on. I had some difficulty with the brake switch spring until I loosened the adjuster on the switch all the way and also put the spring on while I had the lever assembly off and in my hand. That way I was able to bend and move the whole thing until the spring could just be slipped on by hand, then when you put the lever back on the bracket, the tension returns. Also, make sure the brake return spring (near the pivot at the swing arm) is put back into it's proper place. The spring hooked end actually goes around the FORWARD part of the little bracket, not in the hole. If you put it in the hole, you will find the spring lacks tension and the brake lever won't return properly... causing problems with the brake light remaining on, etc.

Once you have the brake lever assembly back on, make sure you adjust the rear brake and brake switch properly. Here are the links to those instructions...

Task #04 - Brake System Inspection

Task #05 - Brake Light Switch Adjustment

Once that is done, then inspect and adjust the clutch arm properly...

Task #07 - Clutch Adjustment
Step 7:

  Before reinstalling the exhaust, make sure you have new crush gaskets for them (you can NOT reuse the old ones!). Also, you will probably need a pick to pry out the old gaskets as they get wedged inside the exhaust port pretty tight. With the new gaskets in place, reinstall the exhaust.

If you were changing the oil at this time, make sure you have the new filter in place and the drain plug in and then fill up the oil.

Task #20 - Engine Oil & Filter Change

Now just take it for a test drive! I found the clutch lever quite a bit stiffer and this might be a problem with riders who have small hands but it didn't take long for me to get used to it. And the action of the clutch is amazing now! I find it goes into gear much more smoothly now. I also tried lugging the bike up some steep hills in a high gear and not once did I detect any slippage so far. A great mod for a small price!


  The articles in the "Modifications" section of this website and those that may be posted in the forums are meant for information purposes only. These modifications are not manufacturer approved changes and they may not be legal in some municipalities. is furnishing this information "as is". does not provide any warranty of these articles whatsoever, whether express, implied, or statutory, including, but not limited to, any warranty of performance or fitness for a particular purpose or any warranty that the contents of the articles will be error-free.

  We do welcome, however, any feedback from our visitors about anything they may have found here to be inaccurate or untrue. You can contact the webmaster to report any problems HERE.