rear swing arm extension?

[Pismo Girl]

Has anybody seen (or done) an extended swing arm in the rear? My husband does not like the handling of my bike. He tried spinning a donut on my bike and it wheelied out from under him. My husband and I are industrial engineers and he is getting ready to perform surgery on the rear swing arm of my 250ex. Has anybody seen this done before? We are torn between a 4" and a 6" extension. We weighed the bike today with me on it and after running some numbers we think we can transfer 40lbs from the rear tires to the front tires with a 6" extension.

Would anybody be interested in this conversion for thier bikes? If there is some interest my husband will build a jig so he can build more of these without having to weld the entire bike to his jig table.

[hondariderdylan]

i was thinking about this because all it is is just a little driveshaft in the swingarm

i dont think it would be too hard
but im no fabricator so i really wouldnt know where to start

[Pismo Girl]

The driveshaft shaft is only $60 so we ordered an additional shaft and are planning to combine 2 into 1 to length it to 6" longer. We have to make a custom shock mount also. The hardest thing seems to be how to length the brake cables. Any suggestions? We will post some pics as we get farther into it. We are looking into shocks - a banshee shock seems to be the way to go but we have to find a single.

[hondariderdylan]

as far as brake lines go, i would say hunt down a company that makes them and get a set made, or measure how long they need to be and see if any other quads lines are that long
they strech they swingarms on other quads and they have to have extended lines so i dont think it would be too hard

shock mounts: i would say make a new crossmember a little farther down on the swing arm so you could mount a longer shock, maybe 450R or raptor 700 shocks?
not sure
look at lengths of shocks and see what you could make into the swingarm

[86250rrider]

if you lengthen the swinger,it will need a longer shock if the mount moves back. if you dont move the mount ,you will need a firmer shock due to the leverage on it. just things to think about. if you keep the mount in the same location the rock hard stocker may work better. let me know about the works as im going to get a set irregardless.

I would only go +4" swingarm and try running a 300ex rear shock. Moving the a-arms up 1" would be a good mod too.

[Pismo Girl]

We finished the 6" extension on the rear swing arm and it works awesome. The rear shock still needs help because we had to reuse the stock lower mount. This setup is temporary because the rear end is super rigid and the shock is rubbing the battery box. It lowered the bike about 2" and looks great. We will post some photos soon.

It rides much more like a real sport quad. It actually spins donuts without constantly trying to high side. Rejetting helped the throttle reaction time, regardless of gear.

[hondariderdylan]

Originally posted by Pismo Girl
We finished the 6" extension on the rear swing arm and it works awesome. The rear shock still needs help because we had to reuse the stock lower mount. This setup is temporary because the rear end is super rigid and the shock is rubbing the battery box. It lowered the bike about 2" and looks great. We will post some photos soon.

It rides much more like a real sport quad. It actually spins donuts without constantly trying to high side. Rejetting helped the throttle reaction time, regardless of gear.

Good Deal!
waitin for the pics:)

[Pismo Girl]

these photos are not the best because the bike is still wedged in the back of our toy hauler. We will post more pics when the bike is outside in the sunshine again. We didn't take pics of the drive shaft extension but I can give instructions to anyone wanting to follow our lead.

[Pismo Girl]

having trouble posting

[Pismo Girl]

more pics

[Pismo Girl]

more pics

[Pismo Girl]

shock is rubbing the battery box, Doh!

[Pismo Girl]

still capture from video

[Pismo Girl]

more stills

[Pismo Girl]

donuts are cool!!!!!!!!

[HONDASALESMAN]

looks good! How is the ride now compared to before?

[hondariderdylan]

thats great!

it looks like a dirt drag quad now
all it needs is a different shock to det the rear end up a little

now all we need are some different gears to go along with that swingarm
can ya do that??:D

[ryanh250ex]

Very interesting. Any problems with vibrations due to extending the driveshaft?

The only problem I see with this kind of mod, is it would shift the center of gravity forward. I can't imagine that even with the right rear suspension setup that you hit many jumps, as you have now created a situation where the bike is extremely nose-heavy. A smaller - 2 or 3" at most- extension would be ideal, as I believe it would allow for a long(er)-travel shock, without shifting the CG to the point where the bike could not be used for MX/XC use. With the lack of forward offset A-arms, unless you're drag racing I think it is best to stick to the stock swingarm.

[hondariderdylan]

Originally posted by ryanh250ex
Very interesting. Any problems with vibrations due to extending the driveshaft?

The only problem I see with this kind of mod, is it would shift the center of gravity forward. I can't imagine that even with the right rear suspension setup that you hit many jumps, as you have now created a situation where the bike is extremely nose-heavy. A smaller - 2 or 3" at most- extension would be ideal, as I believe it would allow for a long(er)-travel shock, without shifting the CG to the point where the bike could not be used for MX/XC use. With the lack of forward offset A-arms, unless you're drag racing I think it is best to stick to the stock swingarm.

i agree with the 2 or 3 inch longer swinger
but still and awsome mod you guys made:)

[Pismo Girl]

ryan,

Have you ever ridden a 250ex???? the weight bais stock is worse than a wheel chair! Even a super light weight rider will have trouble shifting enough weight forward to the front wheels to break the rear tires loose. How many times have you dumped the clutch only to have the bike dump you on your tail bone???

Before we modified the swing arm we spent some quality time with a scale and calculator. The stock weight bias of the stock bike with rider was 42% front and 58% rear with a 44" wheel base. Now after the swing arm extension the weight bias is 49% front 51% rear with a 50 inch wheel base. The wheel base and weight distribution is now very similar to a Yamaha Raptor or Suzuki 400 sport bike.

I dont know why you think that the bike is now suddenly "extremely nose heavy" or setup for drag racing only. once we re-mount the rear shock, this bike will continue to see plenty of air time at our local MX track and at pismo.




Dylan, sorry no big ideas on re-gearing the rear end, I think we are all stuck with the stock ratio. Any idea what the stock ratio is? I switched to holeshots (20X11X10) and I kind of wish we had gone even shorter.

No problems with vibration on the drive shaft but I spent considerable time jigging and tig welding it so it doesn't have much run out.

[ryanh250ex]

Originally posted by Pismo Girl
ryan,

Have you ever ridden a 250ex???? the weight bais stock is worse than a wheel chair! Even a super light weight rider will have trouble shifting enough weight forward to the front wheels to break the rear tires loose. How many times have you dumped the clutch only to have the bike dump you on your tail bone???

Before we modified the swing arm we spent some quality time with a scale and calculator. The stock weight bias of the stock bike with rider was 42% front and 58% rear with a 44" wheel base. Now after the swing arm extension the weight bias is 49% front 51% rear with a 50 inch wheel base. The wheel base and weight distribution is now very similar to a Yamaha Raptor or Suzuki 400 sport bike.

I dont know why you think that the bike is now suddenly "extremely nose heavy" or setup for drag racing only. once we re-mount the rear shock, this bike will continue to see plenty of air time at our local MX track and at pismo.




Dylan, sorry no big ideas on re-gearing the rear end, I think we are all stuck with the stock ratio. Any idea what the stock ratio is? I switched to holeshots (20X11X10) and I kind of wish we had gone even shorter.

No problems with vibration on the drive shaft but I spent considerable time jigging and tig welding it so it doesn't have much run out.

Pismo Girl,

I am hardly a newbie when it comes to the 250- the FAQ at the top of the page contains mostly info I have compiled over the years myself.

I can honestly say I've NEVER had an issue with weight transfer. I have had an issue with 3 wheeling during aggressive cornering, but that seems to be more related to greater offset in the rear than the front, not necessarily CG-related.

Is your bike a sportclutch model? My '02 is an autoclutch, so that might also be why I dont see the same issues you do.

I do not understand why you would opt to make the rear hook up less than the stock setup. I have done my share of drag racing both on the dirt and the tarmac (in other apps) and unless you're running into such a weight and balance issue that the front end is coming up uncontrollably in 2nd and 3rd gear, I dont see it necessary to bring it back by 6 inches.

What have you done regarding the shock mounts to maintain proper geometry and to prevent binding?

[hondariderdylan]

well that sucks, i really hate the stock gear ratios
its like the top end just hits a wall and fifth gear is nothing
i feel it could pull a sixth very easy

but oh well
and whitch holeshot did you get?

[Pismo Girl]

ryan,

yes the bike is a sport clutch and gets ridden pretty aggresively. you mention that you have had problems with three wheeling on aggresive turns, what happens when you feed in more power? the bike hooks harder and pitches up onto three wheels even more. If the these bikes had more power, grabbing a handful of throttle would simply break the rear end loose, BUT THAT DOESNT WORK!!!! I am soooo sick of this bike trying to pitch me off during aggresive riding or flipping upside down anytime I try to spin a donut. I am an expert rider and if I can't manhandle the bike into submission, my wife doesnt have a chance.

These are the reasons for shifting some weight onto the front tires. Our goal was not to make the bike more like a dragster or exagerate the balance forward. Our goal was simply to make this bike handle more like a sport machine. Our time weighing each corner of the bike proves this, we simply brought the weight balance more in line with a proven sport machine.

The rear shock is still mounted incorrectly and it is boud up againstg the battery box. I am working on a progressive link setup (or at least a better mounting point) because right now the rear end is way too stiff AND the shock is trying to break the battery box.

[ryanh250ex]

Originally posted by hondariderdylan
well that sucks, i really hate the stock gear ratios
its like the top end just hits a wall and fifth gear is nothing
i feel it could pull a sixth very easy


Get a aftermarket rev box, If you really need that extra few mph in mph. on 22" or so tires an extra 1250 rpm should net about a 60 mph top speed.

Pismo,

I suppose I see your point. Question- did you factor in the weight bias with you or your wife actually on the bike? I have a feeling that depending on your and your wife's riding stance , the "dynamic" bias might be different, thus potentially skewing your results.

I think it should be noted that while you are correct that wheelbase is a function of manueverability, it is still important that the bike be widened to have stablity both during aggressive turns and high-speed manuevering. the wheelbase is 44 inches, while the width is about 42. So essentially if you were to widen the bike by 2 inches on stock wheelbase, you'd have a square footpoint. Go wider, like some have, and you may end up with some interesting handling dynamics (essentially the bike feeling squirrely). Your swingarm extension would allow people to go wider and retain optimum handling.

I still do not agree with +6 on the swingarm extension. I still think +2-+3 would be ideal. But, it should be noted that I'm not trying to put you down for your efforts- your ingenuity is admirable and you and your wife should be commended for your efforts.


Would it be possible to produce a kit that would sleeve the swingarm enough to extend it by 2-3 inches, and in addition, a shock linkage set up for the change in geometry? I would imagine that lengthening the driveshaft would be as simple as taking it to your local driveshaft shop and having them weld some extra tubing to it, then balancing it.

Please PM me for more details- if this would enable us to run a longer travel shock, I would be very, very interested.

[tri5ron]

Pismo,
did you ever decide on how to move the shock forward, and away from hitting the plastic?

also, I am VERY interested in a 2" to 3" extension for my wifes 250ex. We occaisionally ride with rear racks and cargo bags attached to our quads, for riding trails. may have 40 to 45 lbs hanging off the rear.

I'm sure you can imagine what that does to the CG, especially with it all aft of the rear axle to boot!

my wife is a very novice rider, who is quite happy in 2nd to 3rd gear riding. she does not ride fast. She has NO intrest in jumps, donuts, sliding, etc.
the 250ex is a great bike for her, and she will, in all probability, NEVER "graduate" to a larger, faster, sportier quad.

She is quite content with the power of her 250ex, as She is certainly NOT an "Adrenalin Junkie". LOL !

BUT... she HAS Flipped the quad, and is a little spooked even on the medium trails. it is very tippy especially with the rear rack/bags, trying to go uphill, and then hitting a 6" or 8" rock.
(See pic)
http://i111.photobucket.com/albums/n148/tri5ron/Pinnacles%20ride%207-04-09/IMG_9924.jpg

She was NOT happy at this moment, a little scared, and this is not condusive to having a good time, and enjoying the sport.
Granted, She does need to learn how to better shift her weight forward, and this will come in time with more practice.

a 3" extension would greatly reduce the tendency of this happening.

She is a Putt-putt trail rider, happy when all 4 wheels are on the ground, and her butt is on the seat. I doubt that she will ever master whoops, or standing on the pegs with knees bent.

She will NEVER try to jump her quad.

She does enjoy riding. But she enjoys riding slowly, cruising around with the wheels on the ground at all times, or at least as much as possible.

The 250ex IS a tippy feeling quad, and does have a tendency to lift a wheel in a slightly aggresive turn, or when on uneven ground.
To help reduce this, (and since she is NOT an aggresive rider), I have flipped the front rims, I will also be installing a steering stabilizer to reduce the feedback thru the bars when hitting a rock, And I am even looking for some softer front springs, (Since she will NEVER even come close to bottoming the stockers).

But I would also consider a 3" swinger extension, to be helpfull for her riding abilities.
I'm very interested in what you think. let me know.
Thanks,
Ron

[hondariderdylan]

Originally posted by tri5ron
Pismo,
did you ever decide on how to move the shock forward, and away from hitting the plastic?

also, I am VERY interested in a 2" to 3" extension for my wifes 250ex. We occaisionally ride with rear racks and cargo bags attached to our quads, for riding trails. may have 40 to 45 lbs hanging off the rear.

I'm sure you can imagine what that does to the CG, especially with it all aft of the rear axle to boot!

my wife is a very novice rider, who is quite happy in 2nd to 3rd gear riding. she does not ride fast. She has NO intrest in jumps, donuts, sliding, etc.
the 250ex is a great bike for her, and she will, in all probability, NEVER "graduate" to a larger, faster, sportier quad.

She is quite content with the power of her 250ex, as She is certainly NOT an "Adrenalin Junkie". LOL !

BUT... she HAS Flipped the quad, and is a little spooked even on the medium trails. it is very tippy especially with the rear rack/bags, trying to go uphill, and then hitting a 6" or 8" rock.
(See pic)
http://i111.photobucket.com/albums/n148/tri5ron/Pinnacles%20ride%207-04-09/IMG_9924.jpg

She was NOT happy at this moment, a little scared, and this is not condusive to having a good time, and enjoying the sport.
Granted, She does need to learn how to better shift her weight forward, and this will come in time with more practice.

a 3" extension would greatly reduce the tendency of this happening.

She is a Putt-putt trail rider, happy when all 4 wheels are on the ground, and her butt is on the seat. I doubt that she will ever master whoops, or standing on the pegs with knees bent.

She will NEVER try to jump her quad.

She does enjoy riding. But she enjoys riding slowly, cruising around with the wheels on the ground at all times, or at least as much as possible.

The 250ex IS a tippy feeling quad, and does have a tendency to lift a wheel in a slightly aggresive turn, or when on uneven ground.
To help reduce this, (and since she is NOT an aggresive rider), I have flipped the front rims, I will also be installing a steering stabilizer to reduce the feedback thru the bars when hitting a rock, And I am even looking for some softer front springs, (Since she will NEVER even come close to bottoming the stockers).

But I would also consider a 3" swinger extension, to be helpfull for her riding abilities.
I'm very interested in what you think. let me know.
Thanks,
Ron

pismo hasent been on in probably 2-3 months:(