86/87 200X CAMSHAFT VS TR200 FATCAT TRX200SX difference??

[Dirtcrasher]

Anyone know why the camshaft has a different part number on the 200X versus the Fatcat and quad??

I believe those have a manual decompression but that normally holds a valve open and isn't on the cam, later Honda models have a mechanism on the cam itself.

I always thought the top ends were identical aside from that decompression lever. I never though the cam had a different profile...

[Shep1970]

Damn steve your right! Profile is slightly different.... Holding them in my hand they look identical, i always assumed they were the same. Dont tell my son he has the trx200sx in his or he'll have me swapping it out :rolleyes:
Now who has the Fatcat or trx200d quad book? The trx200d has the same looking cam.
266178

shep

[11GalleryATV]

The cam heights are slightly different ...

86-87 200x IN = 34.683 mm | EX = 34.557 mm
86-88 200sx IN = 34.371 mm | EX = 34.242 mm

The rocker arms, valves, valve springs, and valve seats are the exact same in both. The only top end difference seems to be the camshaft.

[jasong_10]

I'll try to remember to ask my father-in-law if he has the book for his Fatcat, pretty sure it's going to be the next resto project anyways.

[11GalleryATV]

The FatCat camshaft is the same as the TRX200SX and so is the complete top end ...

FatCat Service Manual:
IN = 34.371 mm | EX = 34.242 mm

[jasong_10]

The FatCat camshaft is the same as the TRX200SX and so is the complete top end ...

FatCat Service Manual:
IN = 34.371 mm | EX = 34.242 mm

Cool, thanks for the info.

[11GalleryATV]

No problem ... here are the respective pages from each of the service manuals ...

http://11galleryatv.com/img/1986-1987-Honda-ATC-200x-Service-Manual-6-1-Cylinder-Head-Valves_header.jpg
http://11galleryatv.com/img/1986-1987-Honda-FatCat-Service-Manual-6-1-Cylinder-Head-Valves_header.jpg
http://11galleryatv.com/img/1986-1988-Honda-TRX200SX-Service-Manual-6-1-Cylinder-Head-Valves_header.jpg

[jasong_10]

Been a while since I've played around with cam numbers, am I right to assume the 200x cam is more aggressive?

[11GalleryATV]

Yessir! The FatCat and TRX200SX are basically just the detuned (by cam lobe height) 200x top end ... I have no idea why Honda would do this as it seems pretty expensive to make something have slightly less power :wondering ... maybe to increase gas mileage?

[Dirtcrasher]

Good stuff guys, thanks for sharing!!

I recently found a Fat Cat connecting rod, but I have a feeling it is slightly different than the 86/87 200X crankshaft rod.

Crazy how Honda played with stuff with such tiny differences in order to achieve perfection!!

[11GalleryATV]

Yes, the 200x and FatCat connecting rod are different and are NOT interchangeable. I spent many hours researching this when building my 200x motor (I really wanted electric start). I came to the conclusion that the only connecting rod that fits the 1986-1987 Honda ATC 200x is the 1986-1987 HONDA ATC 200X and that's it!

I do believe the 1986-1987 Honda FatCat and the 1986-1988 TRX200SX motors are completely identical ... top and bottom.

Here is the 1986 200x connecting rod from Partzilla: https://www.partzilla.com/product/honda/13201-HB5-300
Here is the 1986 FatCat connecting rod from Partzilla: https://www.partzilla.com/product/honda/13201-HB3-300

You can see in the fitment sections the compatible machines with each of these parts ...

It fits both the FatCat and the TRX200SX

200x OEM Parts: https://www.partzilla.com/catalog/honda/atv/1986/atc200x-a
FatCat OEM Parts: https://www.partzilla.com/catalog/honda/motorcycle/1986/tr200-a-fatcat
TRX200SX OEM Parts: https://www.partzilla.com/catalog/honda/atv/1986/trx200sx-a-fourtrax-200sx

[dirtwheels]

I found a lot of this out when building my e-start 86 200x a few years ago. Ended up having a custom crank done up.

More info in this thread on what parts I used in case anyone is interested:

http://www.3wheelerworld.com/showthread.php/184747-86-200X-now-with-e-start