Theory

[rustyATV]

Would someone help me test a theory?

With a tape measure, measure the distance from the swing arm bolt to the lower rear a-arm mount on a '86/'87 250R, and then on the '88/'89 250R.

I have a theory that the early R's are about one inch shorter, based on old magazine specs I've read.

I'll tell you why I want to know this later.

Thanks!

[Rich250RRacer]

Originally posted by rustyATV
Would someone help me test a theory?

With a tape measure, measure the distance from the swing arm bolt to the lower rear a-arm mount on a '86/'87 250R, and then on the '88/'89 250R.

I have a theory that the early R's are about one inch shorter, based on old magazine specs I've read.

I'll tell you why I want to know this later.

Thanks!

I've already done this, they are the same.

[mxduner]

the 86/7 i believe have a 1 in. longer swinger but i thought they were longer overall as well:confused:

anywho my 88 measures about 28 1/4 from c2c

cannot wait to hear your theory:devil:

[All250R]

Originally posted by rustyATV
Would someone help me test a theory?

With a tape measure, measure the distance from the swing arm bolt to the lower rear a-arm mount on a '86/'87 250R, and then on the '88/'89 250R.

I have a theory that the early R's are about one inch shorter, based on old magazine specs I've read.

I'll tell you why I want to know this later.

Thanks!

For the 88 I got 27.25" from pivot bolt center to the rear part of the a-arm mount - where the flange bolt mates with the frame.

[zedicus00]

86/87 swinger is 2" longer then 88/89.
88/89 a-arms are 1" forward. (not the mounting location, the A-arm shape itself)

this gets 1" difference in wheelbase BUT moves the center of balance and that was the goal.

[250r_86]

I always thought the 86 swinger was 1" longer than the 87-89 swingers?

[mxduner]

hers the dimensions from my manual:
overall length 86/7 71.9"
88/9 72.4"
that should be with the grab bar and bumper.

wheelbase: 86/7 51.0"
88/9 49.8"

according to my service manual, that makes the late models 1.2" shorter. but overall .5" longer.

[All250R]

The way I heard it from an a-arm fabricator is the 86-7 had a +1 swingarm. So people then sell and buy +1 a-arms to move the center of gravity rearward whcih is closer to what the -1 rear of the 88-9 accomplishes. His recommendation for the 88-9 was +0 forward arms. If the a-arms were different on the 86-7 he failed to mention it.

[zedicus00]

Originally posted by mxduner
hers the dimensions from my manual:
overall length 86/7 71.9"
88/9 72.4"
that should be with the grab bar and bumper.

wheelbase: 86/7 51.0"
88/9 49.8"
thats all correct

according to my service manual, that makes the late models 1.2" shorter. but overall .5" longer.

the 86-87 swingarm is actually + ALMOST 2. so close that is just said to be plus 2.

the A-arm guys are dependent on manufacturer. most brands did not even sale a +0 for the 86-87, the SAME set of arms would be sold as +1 for the 86-87 and +0 for the 88-89. also some manufactures just called it a +1 even though if you mounted it on a 88-89 you was really just getting standard forward.

you would see a rating on the a-arms like +2+1 this meant the front would be 2" wider and 1" forward over a stock 86 model. (normally) but with out calling the manufacturer you will just be assuming.

the frames technically measure the same BUT the 86-87 swingarms mount a bit different then the 88-89 swingers. so measuring to a mounting point of one or the other doesnt get you a true comparison of what you are wanting.

while we are making comparisons of years we might as well do it all

85-86 had very similar engines, head gaskets are different, 85 had a lighter flywheel. other then that, the same.

87 had long rod but same tranny as 85-86 with taller 5th and 6th ratios.

88 was the highest horse rated stock engine, more minor port adjustments, higher compression, close ratio tranny, timing set 3 degrees advanced, and long rod.

89 had slightly lower compression due to complaints in 88 about it being hard to start, seriously. identical other then that.

really this is all covered on here about 15 million times. someone should make a sticky about differences if there isnt)

[mxduner]

lmao zed i agree:D

[All250R]

Your knowledge is very impressive. You forgot paint color though.

[matt250r21]

All OEM TRX250R a arms are the same dimensions. The +1 forward is an aftermarket only option.

[Rich250RRacer]

Originally posted by matt250r21
All OEM TRX250R a arms are the same dimensions. The +1 forward is an aftermarket only option.

This is something I always believed, but I didn't want to argue with anybody on here. I have always thought the swinger was what made the difference in wheelbase. I do have both stock 86-87 arms and 88-89 arms sitting in my attic, but I'm to lazy to dig them out and make a comparison.:D

As far as specs in the factory service manual, it wouldn't treat them as gospel, I've seen quite a few mistakes in it.

[86 Quad R]

Originally posted by matt250r21
All OEM TRX250R a arms are the same dimensions. The +1 forward is an aftermarket only option.

i'd tend to agree as i have an R that has 86 lowers and 88-89 uppers. and there doesnt seem to be a bit of difference in them.

although after reading this thread i'll find myself later doing a comparison. :cool:

went out en took some pics
http://i793.photobucket.com/albums/yy213/86-Quad-R/IM000786.jpg
http://i793.photobucket.com/albums/yy213/86-Quad-R/IM000787.jpg

[All250R]

Originally posted by 86 Quad R
i'd tend to agree as i have an R that has 86 lowers and 88-89 uppers. and there doesnt seem to be a bit of difference in them.

although after reading this thread i'll find myself later doing a comparison. :cool:

went out en took some pics
http://i793.photobucket.com/albums/yy213/86-Quad-R/IM000786.jpg
http://i793.photobucket.com/albums/yy213/86-Quad-R/IM000787.jpg
That's the only benefit to misinformation that I can think of... it may inspire people to go out and disprove it.

[zedicus00]

you can mix uppers and lowers, the difference is almost totally unnoticeable.

look ive got a stock 86 next to a stock 88. you will HUNT for where the difference is for days. it is there but. over the distance of the a-arm you not going to notice an inch at the end.

you would have to mount them on the same quad, 86 on on side, 88 on the other, and then measure to a fixed frame point, and only then will you be able to account for the "magic inch" give up now, or keep hashing about it. doesnt matter since everyone runs aftermarket and aftermarket has no standard.

btw, stacking them and taking a pic is about as accurate as measuring with your fingers. especially since the shape of the arms is so close and 1 inch over the entire length of the arm is all but going to disappear.

see what im sayin yet???

[86 Quad R]

Originally posted by zedicus00
you can mix uppers and lowers, the difference is almost totally unnoticeable.

look ive got a stock 86 next to a stock 88. you will HUNT for where the difference is for days. it is there but. over the distance of the a-arm you not going to notice an inch at the end.

you would have to mount them on the same quad, 86 on on side, 88 on the other, and then measure to a fixed frame point, and only then will you be able to account for the "magic inch" give up now, or keep hashing about it. doesnt matter since everyone runs aftermarket and aftermarket has no standard.

btw, stacking them and taking a pic is about as accurate as measuring with your fingers. especially since the shape of the arms is so close and 1 inch over the entire length of the arm is all but going to disappear.

see what im sayin yet???

i dont doubt what your saying. as a matter of fact i just so happen to have a bare frame hanging on the wall and have a complete set of each year arms that i'm going to mount........ you've got my Curiosity going now. :D interesting!