[trapp250r]

I just got back from pismo and I busted my swingarm. It cracked up by the swingarm bolt on both sides. What would cause this? I will post pics later. The bike is a 87 but the previous owner put a 88-89 swingarm on it. I am thinking about going back to stock style swingarm because I dont motocross and the extra inch will help in the dunes to keep the front end down. If I switch back what will I have to buy besides the swingarm and motor mounts. Will the swingarm bolt work? will my carrier work with a older one? It is a aftermarket carrier not sure on the brand. Axle work? Thanks matt

Also anyone have a 86-87 swingarm they want to get rid of? or 86-87 motor mounts?

 

[bushwesl]

What would cause this?
The 88/89 swingarm is made of aluminum, whereas the 86/87 are made of steel which makes them stronger. Also, if you go with an aftermarket swingarm it's most likely going to be made out of chromoly, which is even stronger yet.

If I switch back what will I have to buy besides the swingarm and motor mounts?
That should be it as far as I know.

Will the swingarm bolt work?
Yes.

Will my carrier work with a older one? It is a aftermarket carrier not sure on the brand.
Yes

Axle work?
Yes.

 

[2R's]

heis ^ correct all you have to do now is figure out what year the "dogbone" is
86/87 was longer than 88/89 styles you'll need to use the longer 86 /87 styles if going to the early swingarm


btw you can use the atc swingarm pivot motor mount also from a 3 wheeler

 

[trapp250r]

How would I know what year dogbone I have? I would assume its a 88-89 because that is what swinger is on it but who knows. Is there a diff in its look or just a measurement? It has a adjustable strut on it if that makes a diff. What companys out there make aftermarket 86-87 swingers that are reasonable priced I looked at the lonestar and dont want to spend that type of cash right know any other cheaper? I am going out to the garage I will take some pics and post them in a couple mins of the dogbone and the damage. Thanks for all the help guys.

 

[2R's]

It has a adjustable strut on it if that makes a diff. .

makes a difference ,...the shock was built work corectly with the right length linkage & dog bone ..hopefully its still a 86/87 shock & not 88/89 or ya might consider getting the right shock for it too
I beleive the 86 was 6 5/8 ,,,,& the 88 /89 was around 6 or so ....but not positive these measurements ...I have a spare 86 I can recheck sometime

 

[trapp250r]

The dogbone measures 7 inches from bolt center to center. And the strut is set at 6 inches currently. Here are some pics. The crack on the swingarm would not show with the camera but it is right below the motormount bolt in the pic below on both sides. Its like the inside insert that is not there on a 86 swinger busted off.

 

[2R's]

you post is confusing ...
it hasnt got a dogbone ,the adjustable strut replaced it,,& its bolts to the swingarm forward of the axle carrier

...the part bolted to the frame is called the link

btw that quad sits high in the pic ... so I am gonna ask does it have a 250R rear shock ?'......is the spring over compressed ?...something is "off" about the stance IMO

 

[trapp250r]

you post is confusing ...
it hasnt got a dogbone ,the adjustable strut replaced it,,& its bolts to the swingarm forward of the axle carrier

...the part bolted to the frame is called the link

btw that quad sits high in the pic ... so I am gonna ask does it have a 250R rear shock ?'......is the spring over compressed ?...something is "off" about the stance IMO

Im stupid the adjustable strut lol is 6 inches currently and the link is 7 inches bolt center to center. Thanks for clearing that up for me. So the link never changes year to year for the trx just the dogbone? Sence I have a adjustable strut I can just make it longer or shorter depending on what shock swingarm combo I have? Is there a minus about having the adj strut vs the dogbone? is it weaker? I also thought that my r's rear sat to high I guess it could be the rear shock but I am pretty sure it is the stocker here are some pics. Maybe running the shorter swingarm with a older shock makes it sit up higher I dont know.

The number on the rezzy for the rear shock says Showa HB9-671 dont know if that means anything or not.

 

[deathman53]

actually the dogbone for 87-89 is the same and 85/86 are the longer ones. If I recall correctly 86 had the longest shock and dogbone, 87 shorter dogbone and slighlty shorter shock, 88/89 had yet shorter shocks. All linkege pieces from the frame are the same except for 85(for some reason, later year collars don't fit in 85 linkeges). But, yes, parts need to be matched up to work right.

 

[2R's]

thanx for the correction Chris ..I seem to always make that mistake about dogbones LOL..anyways the point is he has a mix of stuff that could be wrong ..
& now seeing the shock ..this is another twist I know the 86 had a blue spring & I always thought the 87 did too .. but some body else should confirm that :lol:

I've never heard of a stock dogbone breaking ..but I know of the strut breaking for some ,..it was primarily designed for changing ride stance /heighth on flat track quads I beleive ..so riding hard with one could be risky ...just depends how hard you push it I guess ...not sure if it contributed to breaking the swingarm or not but I would certainly would try to get all the correct peices if going to by another swingarm to fix the quad

 

[Michael88R]

My couzins dad, the guy you bought that quad from, should still have a the stock swingarm laying around for that thing. Probably the stock dogbone too. I know he did something to that shock when he rebuilt the quad. Either got a different one or had it rebuilt or both. Try asking Tyson about it if you still have his number.