[glamisdunin]

what is the difference in the 85 atc engine watercooled if any from the 87-89 engine ??? will it bolt right up without problem and would anyone recomend it if i need cases and possibly some drivetrain?? what are all the differences thanks to anytone who knows

 

[mstohner]

the 85 atc engine is the same engine in the 86trx. correct me if i am wrong but here it goes 85-87 same trany. 85-86 short rod motor. 87-89 long rod motor. 88-89 they droped one tooth of the primary trans shaft. 89 did the clutch up date. on a stock motor they uped the compression in 88 i believe. but the cases are the same 85-89 atc/trx. i know there is more i just cant think right know.

 

[Michael88R]

Aren't the 85 trannys a little weaker and a wider ratio? Bigger jump between gears?

 

[glamisdunin]

the 85 atc engine is the same engine in the 86trx. correct me if i am wrong but here it goes 85-87 same trany. 85-86 short rod motor. 87-89 long rod motor. 88-89 they droped one tooth of the primary trans shaft. 89 did the clutch up date. on a stock motor they uped the compression in 88 i believe. but the cases are the same 85-89 atc/trx. i know there is more i just cant think right know.

do you know what dropping one tooth on the primary transhaft does alsoit should be no problem to drop my 88 internals into an 85 case right?

 

[mstohner]

Aren't the 85 trannys a little weaker and a wider ratio? Bigger jump between gears?

the 85 and 86 motor are the same. all honda did was take the atc motor and puy it in a quad frame in 86.

 

[mstohner]

do you know what dropping one tooth on the primary transhaft does alsoit should be no problem to drop my 88 internals into an 85 case right?

if you motor a and motor b everything is the same except one has a 86 trany in it and one has a 89 trany the 86 will have a little high top speed. but in 88 they uped the compression and droped the weight of the machine. yes you can put 88 internals in a 85 case. you just can't mix match trany shafts.

 

[deathman53]

I wonder how come when I ordered a 85 countershaft, it came as the 88/89 part? I called and I was told that the part number superceded. Also, 85 and 86 had different kickers gears, the 86 gears being stronger. I had to replace 3 sets of 85 kicker gears, they tend to slip when compression is raised and used alot. The whole thing about the copression is wrong, 85 and 86 atc's had the highest compression(they used thinner head gaskets). 86-88 were the same compression and 89 had even lower compression(to ease the starting).

 

[glamisdunin]

alright guys thanks alot this is gonna save me alot of money cause now i can get cases and internals for the same price as trying to get just the cases new from esr or on ebay

 

[hondatrx250r]

i belive the 85 three wheeler motors had a little more radical port timeing then the 86s

 

[2R's]

the 85 atc engine is the same engine in the 86trx. correct me if i am wrong but here it goes 85-87 same trany. 85-86 short rod motor. 87-89 long rod motor. 88-89 they droped one tooth of the primary trans shaft. 89 did the clutch up date. on a stock motor they uped the compression in 88 i believe. but the cases are the same 85-89 atc/trx. i know there is more i just cant think right know.

most here sounds correct .. but the cases are different ,altho you can interchange parts inside of cases (complete gear sets etc) & mis match (most of time )

 

[glamisdunin]

yea i just need to make sure i can install all of my 88 internals into an 85 case if thoughs become available cheap because i damaged my cases

most here sounds correct .. but the cases are different ,altho you can interchange parts inside of cases (complete gear sets etc) & mis match (most of time )

 

[warreng250r]

I wonder how come when I ordered a 85 countershaft, it came as the 88/89 part? I called and I was told that the part number superceded. Also, 85 and 86 had different kickers gears, the 86 gears being stronger. I had to replace 3 sets of 85 kicker gears, they tend to slip when compression is raised and used alot. The whole thing about the copression is wrong, 85 and 86 atc's had the highest compression(they used thinner head gaskets). 86-88 were the same compression and 89 had even lower compression(to ease the starting).

The 85-86 did have the higher compression ratios because of the thinner head gaskets but, it was only for the ATCs the 86-89 ATVs used the thicker head gasket to some what tone down the engine. the compression ratio was raised in 1988 but then lowered again in 1989 because that year was meant to run on premium unleaded instead of the premium leaded that the previous R's were meant to run on.

 

[86 Quad R]

the 85 and 86 ATC had 8.0/1 compression and the 86 TRX had 7.5/1, the 87-89 TRX had 7.7/1 compression

 

[2R's]

yea i just need to make sure i can install all of my 88 internals into an 85 case if thoughs become available cheap because i damaged my cases quote]


if your ony switching cases alone ..then yes you can ...