1 / 7AUTOKAY TRX400EX Top-End Rebuild Kit, 85 mm
AUTOKAY’s TRX400EX top-end rebuild kit is listed for Honda Sportrax 400 TRX400EX models from 1999–2008. The description lists a cylinder, piston and related engine components, while the title gives an 85 mm size. Confirm the exact fit and bore before ordering.
At a glance
- Listing title specifies an 85 mm size, but the description does not independently detail the bore.
- The listed fitment is Honda Sportrax 400 TRX400EX, model years 1999–2008.
- Description lists cylinder, piston, piston rings and pin, piston clips, head and base gaskets, and an NGK spark plug.
Pros and cons
Pros
- The stated kit contents cover several core cylinder and piston components along with two gaskets and a spark plug.
- The listing names a specific TRX400EX model-year range and interchange part numbers for fitment research.
Technical specifications
7 specifications| Brand | AUTOKAY |
|---|
| Listed fitment | Fit for Honda Sportrax 400 TRX400EX 1999-2008. |
|---|---|
| Interchange part numbers | 12100-KCY-670, 12191-KCY-672, 13011-KCY-670. |
| Additional interchange part numbers | 12100-KCY-670 , 12191-KCY-672 , 13011-KCY-670 13101-KCY-670 , 90601-KA5-000 , 13111-KCY-670 12251-HN1-003 , 12391-KCY-671 , 14560-KCW-851 |
| Weight listed | 8.97 pounds |
|---|---|
| Package dimensions | 16.06 x 12.4 x 7.28 inches |
| Manufacturer part number | 12100-KCY-670 |
|---|
What to know before buying
Listing details to confirm
The listing details are inconsistent: the title states an 85 mm size, but the description gives no bore measurement. The title and feature list provide only three interchange numbers, while the longer description lists additional numbers. Confirm bore, part-number compatibility and fitment for the specific ATV before purchase.
Who is it for?
A good fit for
- Owners of a Honda Sportrax 400 TRX400EX from the listed 1999–2008 range researching a top-end cylinder and piston rebuild kit.
- Buyers comparing kit contents and interchange numbers against their existing parts.
Less suited to
- Buyers who need confirmed compatibility with models or years outside the stated range.
- Anyone who requires a verified bore measurement or confirmed interchange-number match before buying.
Customer reviews on Amazon
- 5 stars
52% 52% - 4 stars
0% 0% - 3 stars
0% 0% - 2 stars
0% 0% - 1 star
48% 48%
The supplied aggregate ratings are sharply divided between five-star and one-star categories, with only a very small number of ratings overall. They do not explain the reasons for either view, so they offer little basis for judging fit or durability. For a rebuild, the stated model-year fitment and kit contents are more actionable, but the listed bore and part-number details still need confirmation.
Frequently asked questions
Which ATV models does the listing say this kit fits?
It lists Honda Sportrax 400 TRX400EX models from 1999–2008. Check the specific model and part numbers before ordering.
What components does the description list?
It lists one cylinder, piston, piston rings, piston pin, two piston clips, head gasket, base gasket and NGK spark plug.
Is the 85 mm bore confirmed in the description?
No. The title states 85 mm, but the description does not provide a bore measurement. Confirm the required bore before purchase.
Alternative options
NICHE Cylinder Head for Honda 12200-KCY-670 12200-HN1-A70 12310-HN1-010 | For Honda, Fits 1996-2004 XR400R, 1999-2008 Sportrax 400 TRX400EX, 2009, 2012-2014 TRX400X 2x4, Replaces 12310-HN1-A70
$219.95
NICHE Big Bore Cylinder Wiseco Piston Gasket Kit for Honda 12100-KCY-670 | For Honda, Fits 1999-2008 SporTrax 400 EX 2X4, 2009-2014 TRX400 X 2X4, 1996-2004 XR400R, Replaces 12100-HN1-A70 13101-KCY-670
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NICHE 440cc Big Bore Cylinder Piston Kit for Honda 13111-KCY-670 | For Honda, Fits 1996-2004 XR400R, 1999-2008 Sportrax TRX400EX, 2009, 2012-2014 TRX400X, Replaces 12100-HN1-A70 12191-KCY-672
$99.95
Top End Gasket Kit Set Replacement for Honda TRX 400EX | Replacement for Honda TRX 400EX 1999-2014 Trx400ex 400 Head Gaskets
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NICHE Cylinder Head Piston Gasket Kit for Honda 12100-HN5-670 98069-57916 | For Honda, Fits 2000-2006 Rancher TRX350, Replaces 12200-HN5-M00 12251-HN5-671 13010-HN5-671 13111-HC0-000 13112-HN5-670
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