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Honda XR650L Smog System Removal by Gary Crawford on 4Strokes.com
4Strokes.com Honda Technical: XR650L Smog System Removal by Gary Crawford
I used information from 4Strokes.com and instructions from an IMS Smog Block-Off Kit to remove the smog equipment from my 1995 Honda XR650L. I took the following pictures and made notes. Hope it helps you. Click pictures to enlarge.
1995 Honda XR650L smog system
1. Left side. We'll remove the smog pump and evaporative charcoal canister. Green: These two 10mm nuts allow removal of the smog pump. Red: Smog pump Blue: Evaporative charcoal canister
XR650L with smog system removed
2. This is the goal. The finished product.
Front view of smog pump
3. Red: Remove these 5mm bolts then install the IMS block-off plates in there place. Blue: Front view of smog pump.
Smog block-off plate location
4. Remove the 5mm allen-head bolts and pull off the steel tubing from each side of head. Install the two block-off plates reusing hardware. I put liquid gasket on the plates before installing them.
Right-side smog block-off plate location
5. Red: Right side smog block-off plate location. Remove the two bolts and install the block-off plates re-using original hardware. Blue: Left-side smog block-off plate location.
Right-front smog block-off plate location
6. Right-front smog block-off plate location. Photo taken from behind front wheel.
IMS Smog Block-Off Kit
7. IMS Smog Block-Off Kit.
Left-side smog tube
8. First step is to remove the metal smog tubes from the front of the cylinder head. Left side shown. A T-handle allen wrench or socket is needed here.
Both bolts removed from left side of cylinder head
9. Both bolts removed from left side of cylinder head. Both sides must be unbolted to remove the smog tubes.
The four allen-head bolts are removed
10. The four allen-head bolts are removed and the smog tubes are free from the head.
Smog tubes and air pump removed
11. The smog tubes and air pump have been removed as one unit. Remove four allen-head bolts and two 10mm nuts for the assembly.
Installation of the left-side smog block-off plate
12. Install the left-side smog block-off plate. I used hi-temp liquid gasket maker to seal it all up.
Smog pump bracket
13. This is the smog pump bracket located under the pump itself. Remove it by removing the two 10mm bolts.
Right side smog block-off plate installed
14. Right side smog block-off plate installed.
Next is the removal of the charcoal canister
15. Next is the removal of the charcoal canister. The smog pump hose will be shortened and attached to the trany case.
Removal of the charcoal canister
16. To remove the charcoal canister, slide it up and off the metal mounting strap.
This is the transmission vent connection
17. The trany vent is located just under the carb on top of the trany. Pull off the hose from the charcoal canister and smog pump, cut to length, and reattach. The hose will run between the trany vent and airbox.
Airbox vent hose connections
18. Red: Pull off the top airbox vent hose. Blue: Pull off the airbox vent hose connector. Green: Insert the large rubber plug into the hole that you just created.
Large rubber plug inserted
19. Large rubber plug inserted.
Evaporative charcoal canister and hoses
20. The evaporative charcoal canister and all of its hoses detached.
Carb vent hoses
21. The last step is the carb vent hoses, which may differ per model year. Remove hose and plug the T-connector. Remove smog pump from bike.
Close-up of hose at the T-connector
22. Close-up of other end of hose at the T-connector.
Cap from smog block-off kit installed
23. Rubber cap from smog block-off kit installed.
Vent hose routing
24. Vent hose routing.
Vent hose connected at transmission
25. Close-up of vent hose connected at trany.
Removed smog equipment
26. All smog equipment that was removed.
Smog equipment laid out
27. Smog equipment laid out as it was bolted on the bike.
XR650L with smog equipment removed
28. '95 XR650L with smog equipment removed.

What an improvement! Looks like a engine now! I noticed less popping on deceleration but it has not gone away. I also notice the power seems to come on smoother now. There is obviously some weight savings as well. I would also think the engine may run a little cooler due to the increased airflow around the head with all the tubes, hoses and pump removed.

Other Models: This is what worked on my 1995 Honda XR650L. Yours may differ slightly with respect to the carb vent hoses. Some models have four vent hoses, a diaphragm mounted to the frame on the left side, and a fuel vapor canister. The smog block-off kit instructions said the diaphragm and canister can also be removed.

Disclaimer: The instructions above are for informational purposes only and there is no guarantee that you or your bike will not endure damage or injury by using the above information. Proceed at your own risk.

Credits: Article written and submitted by Gary Crawford and edited by 4Strokes.com

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