4Strokes.com Honda Technical: XR650L Smog System Removal

I used info from 4Strokes.com and instructions from an IMS Smog Block-Off Kit to remove the smog equipment and oil separator from my '95 XR650L. I took the following pictures and made notes. Hope it helps you!

Note: Removing the oil separator is optional. If removed you may see oil in the airbox, and a fair amount depending on how hard the bike is ridden. See procedure 24 for details.

Colored text corresponds to that color text in the photo.

1995 Honda XR650L smog system

1) Remove smog pump and oil separator. Two 10mm nuts allow removal of smog pump. Smog pump. Oil separator.

XR650L with smog system removed

2) This is the goal. The finished product.

Front view of smog pump

3) Remove these 5mm bolts then install the IMS block-off plates in there place. Front view of smog pump.

Smog block-off plate location

4) Remove allen bolts and pull tubing from each side of head. Install 2 blockoff plates reusing hardware. I put liquid gasket on plates before installing them.

Right-side smog block-off plate location

5) Right smog block off plate. Remove 2 bolts and install blockoff plates reusing hardware. Left smog blockoff plate.

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) Remove metal smog tubes from front of head. Left side shown. 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 head. Both sides must be unbolted to remove 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) Smog tubes and air pump removed. Remove 4 allen 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 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) Removal of the oil separator. Smog pump hose will be shortened and attached to trany case.

Removal of the charcoal canister

16) To remove the oil separator, slide it up and off the metal mounting strap.

This is the transmission vent connection

17) Pull hose from oil separator and smog pump, cut to length, reattach, and run between trany vent and airbox.

Airbox vent hose connections

18) Pull top airbox vent hose. Pull air box vent connector. Insert large rubber plug in hole just created.

Large rubber plug inserted

19) Large rubber plug inserted.

Evaporative charcoal canister and hoses

20) The oil separator and all of its hoses detached.

Carb vent hoses

21) Carb vents may differ per year. Remove hose & plug 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. For option of leaving oil separator see pic 1, pic 2 and pic 3.

Vent hose connected at transmission

25) Close-up of vent hose connected at trany.

Removed smog equipment

26) Smog equipment and oil separator removed.

Smog equipment laid out

27) Smog equipment and oil separator laid out as it was on the bike.

XR650L with smog equipment removed

28) 1995 Honda XR650L with smog equipment and oil separator 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, oil vent filter housing, and/or possibly a fuel vapor canister. The smog block-off kit instructions said the diaphragm and oil separator can also be removed.

Credits: Article written and submitted by Gary Crawford. Thanks to Dave Closs for taking the time to notify us of incorrect use of terms: "charcoal canister" and "evaporative canister" were replaced with "oil separator" in addition to Oil Separator Removal being optional. Final article, image edit and published by 4Strokes.com.

Disclaimer: The instructions above are for informational purposes only. There is no guarantee that you or your bike will not endure damage or injury by using the above information. As with any modification, proceed at your own risk.

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