ATC vs TRX 250r motors

[mineralgrey01gt]

Are there any differences between an 86 ATC 250r motor and an 86 TRX250r motor? I found an engine and its for an 86 ATC 250r.

[04blasterkid]

from what iv read i understand 86and back are the same stroke and everything, but idk if the motor mounts would lighn right up, might need some fab

[MossboysRacing]

the 86 atc motor is identical to a 86 trx motor. I currently run an 85 ATC motor in my 88 250r. As long as you have your stock motor mounts for your trx, it will bolt right in.

[mineralgrey01gt]

awesome thanks!

[my88r]

i beleave there the same. i dont know if those had a counter balencer.

[TheFontMaster]

The ATC engines are the same exact thing as the 86 TRX engines. They are the short stroke version of the 250r engines. The only difference is that the ATC head gaskets were a little thinner, giving them a little more compression.

[daman02]

the motors are the same and it will bolt in with factory mounts for whatever frame you are running.

[mineralgrey01gt]

thanks again yall. I picked up an 86 ATC 250r motor for $550. The only things that are wrong with it is the front motor mount bolt is stuck in the motor, which isnt anything to get out, and the clutch cover is cracked by one of the bolts, which could be from over tighening it? Im replacing that clutch cover anyways so its no problem for me on that. I couldnt pass up that price though.

[86 Quad R]

they are the same. i've got an '85 atc in mine and my sons quad has an "86. the only differences that may exist is the head gasket as mentioned and possibly the fly wheel weight and timing timing.

[beobe99]

Yes $550 is a very solid deal man.. Hows your project coing along anyway? I saw you were building an R from scratch like myself. Always like to hear about others projects you know..


Later

[fireburns99]

Just be careful prdering pistons, and such for it. The piston for the 85-86 is different from the 87-89. It has an extra notch cut out for the intake port. It also has a shorter rod. I found this out the hard way.

[zedicus00]

the mount the same, there are lots of internal differences though.

85
light flywheel

85-86
short rod
timing and electrical
long gear tranny

87 is a mut
long rod
but had long geared tranny

88-89
long rod
close gear tranny
timing advance

89
clutch update

all pieces are interchangeable but its best to keep electrical stuff together, if using 88 flywheel then use an 88 cdi. stuff like that.

[zedicus00]

spacer plate mod

long rod engine with 85-86 piston. this gains some crankcase volume but the biggest thing is it lets u overbore the jug past .80 over. 85-86 pistons are available in up to 120 over.

also there is some small differences in the porting in each year but nothing major.

seriaoulsy it amazes me how many R owners dont hav all this stuff engraved into their memory.

[Cr85rRida]

Mineralgrey01gt your pm box is full but I got the money order today and your parts will be shipped out today as well. thanks.

[mineralgrey01gt]

sorry about the box being full, its cleaned and thanks for the heads up on the parts!

The project is coming along great. Its a full roller now, with a motor obviously lol. Ill get pics up at the beginning of next week since my camera and my R is at my parents house right now.

Thanks about all the info yall are posting up. This is helping a lot. My wiring harness is from a 86 trx 250r so im sure its gonna work just fine. I have to get me a kill switch for it but it still has the key so I may just use that for a little while.

here is a few pics from a few months ago:

http://img2.putfile.com/thumb/7/18513530218.jpg (http://www.putfile.com/pic.php?img=5895384)

http://img2.putfile.com/thumb/7/18513530284.jpg (http://www.putfile.com/pic.php?img=5895383)

http://img2.putfile.com/thumb/7/18513530245.jpg (http://www.putfile.com/pic.php?img=5895382)

http://img2.putfile.com/thumb/7/18513530248.jpg (http://www.putfile.com/pic.php?img=5895381)

http://img2.putfile.com/thumb/7/18513530295.jpg (http://www.putfile.com/pic.php?img=5895380)

http://img2.putfile.com/thumb/7/18513530185.jpg (http://www.putfile.com/pic.php?img=5895379)

[Cr85rRida]

Looking good!! if you sell the key set up i may be intrested!! Parts are shipped aswel!!

[mineralgrey01gt]

thanks for the update again! Ill let you know if I sell it which I may but then again I may enjoy having it on the bike lol. Also thanks for the compliments. The bike looks way different now. It has all the brake systems, a-arms, frame was painted black, a-arms are painted aluminum color. All hubs are painted red. It came out pretty decent looking.

[racerx573]

Originally posted by zedicus00

seriaoulsy it amazes me how many R owners dont hav all this stuff engraved into their memory. [/B]

I am gonna have to agree.. but hey a lotta guys are still just getting their first R :eek:

[RichM1983]

The 88 and 89's had bridged intakes. One more slight motor difference.

[GOTFEAR]

atc tranny is geard more so for mx thats what the old guys say

[86 Quad R]

actually i think the 88-89 tranny was geared better for mx-ing. they shortened the gear ratio in 5th and 6th if not mistaken.

[TheFontMaster]

Originally posted by 86 Quad R
actually i think the 88-89 tranny was geared better for mx-ing. they shortened the gear ratio in 5th and 6th if not mistaken.


Nope, you aren't mistaken.:)