Easy
15-30 minutes
This genuine item is supplied directly from the original equipment manufacturer for use with Honda engines commonly installed on a variety of lawn and garden equipment. It is the main cover for the cylinder assembly. The part helps to protect the internal components from dust and other contaminants. If your cover is damaged or is missing, this will provide an identical replacement for the original component that was installed on a new unit. This high-quality head cover is made of durable metal and is sold individually. Note, the hardware to secure it is sold separately. You will need a wrench to perform this repair.
Head Cover 12310-Z8A-000
OEM part for: Honda, Briggs and Stratton, Toro
Part Number: 12310-Z8A-000
$36.75
In Stock
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Compatibility
This Head Cover will fit the following 305 machines. Confirm this part works with your model, and view the detailed model diagrams and repair help we have to offer.
Briggs and Stratton
Honda
Toro
Show More Compatible ModelsThis item works with the following types of products:
- Engine Parts
- Lawn Mower Parts
- Snowblower Parts
This part replaces obsolete part #: 12311-ZL8-D00 (Serial# (1000001-9999999)), 12310-Z0J-000 (Serial# (1212617-9999999)), 12311-ZL8-000 (Serial# (1000001-1468766)), 12310-Z8B-000, 12310-Z0J-000, 12311-ZL8-000, 12311-ZL8-D00
Customer Part Reviews ?
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Honda parts ordered.
Everything I ordered arrived on time and your website is easy to navigate.
Guest -
March 13, 2023
Verified Purchase
Perfect Fit
The part was original part at a great price. Speedy delivery
Guest -
July 5, 2022
Verified Purchase
Easy fix
Wasn’t sure why my lawnmower just died and wouldn’t restart. I didn’t realize that I dented the valve cover while mowing around a fire hydrant. Once I figured it out, I ordered a new one from ereplacementparts. Arrived fast and perfect condition as always. First place to check when you need a part.
Guest -
April 30, 2022
Verified Purchase
Easy repair
Was in great condition
Guest -
November 18, 2020
Verified Purchase
Arrived quickly, identical to original part, quick fix.
The parts arrived quickly and the quality was excellent. The head cover is not designed to use a pre-made gasket. This is true for the original part too.You will need to get a tube of “Permatex” and follow the directions on the tube. Be sure to use the high heat type. You put a line of permatex on the lip of the new head cover and let set per tube instructions. Works perfectly. Be sure to tighten the 4 screws evenly to insure the permatex is pressed down and seals evenly. Torque screws per instructions to insure the screws stay tight.
Charles -
August 4, 2020
Verified Purchase
Easy part and install
Ok original packing.
Guest -
June 22, 2020
Verified Purchase
Original Part
Ordered this part for my Honda engine pressure washer. Part arrived very quickly and fit perfectly. Installation was quick and easy.
Guest -
July 15, 2019
Verified Purchase
Quality and fit
Good quality and price delivered in timely manner.
James -
May 27, 2019
Verified Purchase
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Customer Repair Instructions ?
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part.
Valve cover was leaking due to damage.
Gary - August 26, 2016
👍 4 of 5 people found this instruction helpful
Tool Type
Engine
Difficulty
Easy
Time
15-30 minutes
Tools Used
Screwdriver, Pliers
Parts Used
1. Unscrewed valve cover.
2. Used pliers to pull valve cover off which damaged.
3. Cleaned off all sealant from head portion that valve cover mounts on.
4. Put grey sealant on the new valve cover which was recommended by others. (There was no gasket.)
5. Installed new valve cover and hand tightened screws per instructions.
2. Used pliers to pull valve cover off which damaged.
3. Cleaned off all sealant from head portion that valve cover mounts on.
4. Put grey sealant on the new valve cover which was recommended by others. (There was no gasket.)
5. Installed new valve cover and hand tightened screws per instructions.
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Rings wore out
Janet - June 16, 2016
👍 3 of 3 people found this instruction helpful
Tool Type
Lawn Mower
Difficulty
Medium
Time
1-2 hours
Tools Used
Screwdriver, Wrench Set, Nutdriver, Electrical screwdriver
1. Prep engine for work. (drain oil, remove trim, remove from mow deck, etc)
2. Remove valve cover
3. Open crankcase
4. Remove flywheel with puller (try to mark locations on timing belt)
5. Remove crankshaft and piston (lose markings on timing belt)
6. Remove valve rockers and Springs then valves
7. Order new parts and wait for them to come
8. Install new valves and Springs and rockers (using online diagrams for exact part locations)
9. Install new rings on piston.
10. Install piston using recently purchased ring compressor
11. Install crankshaft
12. Refer to Internet for timing (quite simple)
13. Reinstall flywheel
14. Put rest if motor back together as best I can.
15. Try to figure why choke isn't working like should, no luck
16. Put in oil and gasoline and celebrate when it fires up and runs.
2. Remove valve cover
3. Open crankcase
4. Remove flywheel with puller (try to mark locations on timing belt)
5. Remove crankshaft and piston (lose markings on timing belt)
6. Remove valve rockers and Springs then valves
7. Order new parts and wait for them to come
8. Install new valves and Springs and rockers (using online diagrams for exact part locations)
9. Install new rings on piston.
10. Install piston using recently purchased ring compressor
11. Install crankshaft
12. Refer to Internet for timing (quite simple)
13. Reinstall flywheel
14. Put rest if motor back together as best I can.
15. Try to figure why choke isn't working like should, no luck
16. Put in oil and gasoline and celebrate when it fires up and runs.
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My cover had a puncture hole so I needed to replace it.
Corey - May 2, 2017
👍 1 of 1 people found this instruction helpful
Tool Type
Lawn Mower
Difficulty
Easy
Time
30-60 minutes
Tools Used
Socket set
Parts Used
1. Drained what left of the oil.
2. Removed the old cover.
3. Applied a gasket maker compound.
4. Placed my new cover on.
5. Hand tightened the bolts but not fully.
6. Allowed gasket compound to dry for a bit.
7. Came back and tightened all the way for a good seal.
2. Removed the old cover.
3. Applied a gasket maker compound.
4. Placed my new cover on.
5. Hand tightened the bolts but not fully.
6. Allowed gasket compound to dry for a bit.
7. Came back and tightened all the way for a good seal.
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Valve cover was leaking oil!
Zachary - July 23, 2016
👍 1 of 1 people found this instruction helpful
Tool Type
Lawn Mower
Difficulty
Easy
Time
15-30 minutes
Tools Used
Socket set, Wrench Set
Removed valve cover. Cleaned off old gasket material. Applied new gasket rtv and installed new valve cover
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Valve cover bent during removal. Honda recommends replacement on this OHC emgine.
Charles - January 21, 2023
Tool Type
Engine
Difficulty
Easy
Time
30-60 minutes
Tools Used
Screwdriver, Pliers, Socket set, putty knife to clean Silicone
Parts Used
Removed 4 bolts on valve cover. It was glued on and was quite bent before I got it off! I checked the valve adjustment and put the new one on with fresh sealant. It was a perfect replacement part.
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I somehow punched a small hole in the aluminum valve cover. So it was releasing minute oil smoke
James - July 11, 2022
Tool Type
Lawn Mower
Difficulty
Medium
Time
15-30 minutes
Tools Used
Screwdriver, Socket set
Parts Used
Took the 4 bolts out an thought I could just remove the cover. Wrong... it is sealed with liquid gasket material. So you will likely bend and make useless the one you're removing. For me it was no problem as I was replacing it anyway. Be sure to note the instructions for the gasket material. Mine said do not use for 24 hours to allow a full cure.
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Valve cover was bent preventing the valves from working
Paul - July 28, 2021
Tool Type
Lawn Mower
Difficulty
Easy
Time
15-30 minutes
Tools Used
Socket set, form a gasket
Parts Used
removed. And replaced valve cover
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Timing belt kept jumping off the pulley.
Brent - November 17, 2019
Tool Type
Engine
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
Nutdriver
Parts Used
Removed the rocker arm cover.
Removed the rope starter assembly.
Move the flywheel to the magnets meet the magneto.
Move the cam sprocket so the timing marks line up.
Re-install the belt onto the cam sprocket.
Put the new rocker arm cover on. (Has a retainer to keep the belt from jumping.)
Re-install the rope starter assembly.
Log Splitter started on second pull.
Removed the rope starter assembly.
Move the flywheel to the magnets meet the magneto.
Move the cam sprocket so the timing marks line up.
Re-install the belt onto the cam sprocket.
Put the new rocker arm cover on. (Has a retainer to keep the belt from jumping.)
Re-install the rope starter assembly.
Log Splitter started on second pull.
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Our customer service team are at the ready daily to answer your part and product questions. We have a dedicated staff with decades of collective experience in helping customers just like you purchase parts to repair their products.
All our part reviews are solicited directly from other customers who have purchased this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
Based on data from past customer purchasing behaviors, these parts are most commonly purchased together along with the part you are viewing. These parts may be necessary or helpful to replace to complete your current repair.
All our installation videos are created and produced in collaboration with our in-house repair technician, Mark Sodja, who has helped millions of eReplacementParts customers over the last 13 years repair their products. Mark has years of experience in selling and repairing both commercial and residential products with a specialty in gas-powered equipment.
This data is collected from customers who submitted a repair instruction after replacing this exact part. Customers can rate how easy the repair was to complete and how long it took. We aggregate this data to provide a repair rating that allows customers to quickly determine the difficulty and time needed to perform their own repair.
