Honda TRX ATV Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
I have a 400ex I’m building the year is from 99 to 03. The output shaft has play in it I can move it in and out is that normal? Also are all 400ex engines the same size? (From 99 to 08) Only asking because I’m building a go kart buggy and I’m using my unbuilt engine as a template which is a different year then the same engine I’m putting in it (the one I’m putting in has reverse) after I’m done doing motor mounts I will take the built engine from my running 400ex and mount it up so I’m wondering if everything will line up. That’s why I’m asking if they’re all the same length width and size.
4452
,
0AF5586E-3F97-4C1F-AAC5-68491ED40F78.png
4454
 

·
Super Moderator
Joined
·
3,915 Posts
You might be the one to tell us!

Everything changed in 05 - the engine cases were redesigned and widened and a reverse gear was added to the transmission. The output bearing on the output shaft was increased 3 mm on the OD, but the ID and width of the bearing remained the same - additionally, the bearing of the 99-04 matched the dimensions of a common 6205 (25x52x15), but the bearing (part number 91003-KCY-671 is 25x52x13) - in 05 the bearing measured 25x55x13 (part number 91003-HN1-003). So in 05 the bearing became a more special bearing than the 04 as a 6205 can be machined to a 13 mm width, but the 25x55x13 was a special dimension bearing not matching anything "on the shelf". The swing arm bolt is the same length for 99 to 12, so it will fit the rear mount of the engine, but you will have to measure the rear of the 05 to see if it's the same as the 04 at 80.5 mm.

As to the end play in the transmission shaft: it is not specified in the service literature, but 1/2 to 1 mm is not abnormal - there has to be some lateral movement for proper operation - it's vertical and horizontal movement that is not good - that indicates a worn bearing.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #3
You might be the one to tell us!

Everything changed in 05 - the engine cases were redesigned and widened and a reverse gear was added to the transmission. The output bearing on the output shaft was increased 3 mm on the OD, but the ID and width of the bearing remained the same - additionally, the bearing of the 99-04 matched the dimensions of a common 6205 (25x52x15), but the bearing (part number 91003-KCY-671 is 25x52x13) - in 05 the bearing measured 25x55x13 (part number 91003-HN1-003). So in 05 the bearing became a more special bearing than the 04 as a 6205 can be machined to a 13 mm width, but the 25x55x13 was a special dimension bearing not matching anything "on the shelf". The swing arm bolt is the same length for 99 to 12, so it will fit the rear mount of the engine, but you will have to measure the rear of the 05 to see if it's the same as the 04 at 80.5 mm.

As to the end play in the transmission shaft: it is not specified in the service literature, but 1/2 to 1 mm is not abnormal - there has to be some lateral movement for proper operation - it's vertical and horizontal movement that is not good - that indicates a worn bearing.
Hey thanks for the reply, I’m aware that they changed output shafts because I kept ordering the “wrong” bearing til I called the parts guy and he explained to me that they changed them. id rather not take the chance haha, so I will just take out the built engine and redo my mounts with that before I go too far.

So my output shaft play is not normal? I have the seal out because I accidentally tore it trying to take out the old crunchy bearing. Getting a new seal and I ordered a used bearing from eBay because the only one I can find was $120 which I can’t do right now. I Still didn’t Install the used bearing I ordered, so if the play is not normal what can my issue be? Before I put it back together
 

·
Super Moderator
Joined
·
3,915 Posts
I don't follow the question. In and out play is normal as long as it is not excessive - up and down or forward to back play requires bearing replacement.

The output shaft bearing for an 04 (25x52x13 91003- KCY-671) was $24 when last available - I have 3 in stock
The bearing for the 05 (25x55x13 91003-HN1-003) is $18.50 and I have 3 in stock
A new seal (25x35x3 91203-KCY-671) used in many models from 1996 to 2021 (400's, 650's, 680's and 700's both motorcycles and quads) is only $6.50 - I don't have any in stock

The bad news is the engine has to be completely disassembled to install the bearing and the 04 engine case gasket is no longer available - has to be purchased with a complete engine gasket set or from a custom gasket vendor.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #5
I don't follow the question. In and out play is normal as long as it is not excessive - up and down or forward to back play requires bearing replacement.

The output shaft bearing for an 04 (25x52x13 91003- KCY-671) was $24 when last available - I have 3 in stock
The bearing for the 05 (25x55x13 91003-HN1-003) is $18.50 and I have 3 in stock
A new seal (25x35x3 91203-KCY-671) used in many models from 1996 to 2021 (400's, 650's, 680's and 700's both motorcycles and quads) is only $6.50 - I don't have any in stock

The bad news is the engine has to be completely disassembled to install the bearing and the 04 engine case gasket is no longer available - has to be purchased with a complete engine gasket set or from a custom gasket vendor.
Ok so is forward to back play the same as in and out play?

Also where can I buy your bearing? Is it new? I would rather buy from you so if you can send me a link or something and do they still make the seals for the 04? Taken it apart isn’t the problem I have the whole top end off like seen in the pictures, I bought a gasket kit from an aftermarket vendor so I have that already. Just need the seal and bearing. The bearing I need is 91003 kcy 671
 

·
Super Moderator
Joined
·
3,915 Posts
Ok so is forward to back play the same as in and out play?
In and out play is is just that - pulling on the shaft and pushing it back in to the engine - play that way is normal and necessary

Front to back or up and down is bad - if you can detect movement by standing in front of the shaft and moving it from left to right or up and down, it's bad.

I have 3 of the 91003-KCY-671 bearings at $28 each. And to be perfectly honest, they are not OEM Honda, but Chinese manufactured replacements (the French made SKF is $120).

The seal is available, but I have zero on hand - takes me at least a week to get one from Honda $6.50.

I sent you a PM
 
1 - 6 of 6 Posts
Top