yerf dog flips too easy

[yerf_dogger]

I am looking at ways to fix this issue.

After upgrading the motor it has a lot more power and constantly flips on two wheels or completely over.

I have already wrecked my knee once when it flipped on top of me. Another issue needing addressed is the steering.

I know ackerman but I cant figure out what I need to do to make it steer rather than skid on the front wheels.

Thinking knobby tires on the front maybe?

If I widen the rear axle with a 48" axle will this make a substantial difference?

What about new shocks? any suggestions?

 

[Nodroz]

Are you making wheelies? If so, you could add some weight at the front. Maybe move the engine slightly forward, so the center of gravity moves forward aswell.

Could you post up a pic of 2 of your steering setup?

 

[yerf_dogger]

no it doesnt do wheelies, that would be sweet.

I cut donuts or turn into a sharp corner and gun it...

and it flips sideways. I get it on two wheels alot.

I really screwed my knee up and now it scares me to haul !ssa
I cant drive it to its full potential with fear I will flip doing forty around a corner or while burning out in the gravel and yard.

I can try and post pics soon but dont have a charger on my digital camera.

Ill ask my gf to take pics on her phone and upload them a little later.

 

[Nodroz]

Ah, I understand now.
Widening your back axle would work. How's it with the center of gravity? Keep it as low as possible. Is it possible to mount your engine closer to the ground?

 

[Doc Sprocket]

It seems to me that there was a model that had an inherent defect in the steering system that could cause such mishaps. Unfortunately, I'm not 100% sure you have that model. PM Blazkoweiz. He will have all the info, including the fix. Until then, don't kill yourself!

 

[yerf_dogger]

I dont think its the engine placement.

It has 20x10x8 inch tires on the back and a 37" axle as of now.

I'd like to add some 4 wheeler shocks to the back end and widen the axle 5-6 inches on both sides.

Once I get more clearance I was thinking some 22x12x8 tires.

this is going to make the kart higher but much wider.

still not sure if this will fix the issue.

maybe once I install the 4-point harnesses my body weight may stay a little more centered and not lean towards the outside so much.

I am just at a loss for keeping it as an off road buggy and lowering its center of gravity.

I dont wanna lower it because I changed gearing by adding a larger sprocket on the axle

 

[yerf_dogger]

It seems to me that there was a model that had an inherent defect in the steering system that could cause such mishaps. Unfortunately, I'm not 100% sure you have that model. PM Blazkoweiz. He will have all the info, including the fix. Until then, don't kill yourself!

I own model number 3203 and I dont think this is the one with the defect.

I also know that these karts werent made with 12-13 hp motors revving at 6-7 thousand rpms. it sucks and needs improvement.

I will post pics shortly and maybe everyone could shoot me ideas on fixing this major issue.

 

[OzFab]

Here's what it comes down to: Roll angle (the angle at which an object flips from it's base to it's side) is determined by the centre of gravity; the higher the COG, the lower the roll angle (which means, the lower the angle needs to be before it flips). Obviously, the roll angle is also reduced by a gain in velocity.

As for the steering issue, there's a few factors in there too:
1. Badly designed steering geometry
2. Excessive power, reducing weight at the front

First thing you need to address is the dodgy steering; get out your tape measure, a set square & a ball of string & get some measurements. Then we can help you sort out what needs to be modified

 

[KartFab]

lean your body hard into the turns

 

[yerf_dogger]

As for the steering issue, there's a few factors in there too:
1. Badly designed steering geometry
2. Excessive power, reducing weight at the front

First thing you need to address is the dodgy steering; get out your tape measure, a set square & a ball of string & get some measurements. Then we can help you sort out what needs to be modified

what should i measure with these devices?

 

[okenadie]

I have a Yerf with the same problem. It seems that it comes from the front end. You can't really steer the thing. It will just slide around a corner. I am in the process of redoing the steering on mine. The front wheels are way to small. And the A frames don't let you make a tight turn.

 

[gixxerkart]

Really simple. Ackerman/toe out is what you need. Drill to the inside of every tie rod connection hole. This gives you poor mans Ackerman. It won't completely solve the issue but it will give the kart better stability at high speed and better counter steering radius. To completely dial out the roll over factor you MUST design independent rear suspension. The swing arm rear suspension is why old vw beetles and quads flip so easily. It's cheap to manufacture. Have fun, I sold mine because of this.

 

[trekklee]

I have a Yerf and is has the same problem too my model is 32001 when i take corners is like a tower falling down and my front wheels can't turn with it.

 

[yerf_dogger]

ok so I have been readin ackerman geometry and see what i need to do.

this case gixxer stated I need ackerman toe out... which would mean the top of my tires should be slightly facing out.

Is there a way to adjust this?

I was thinking a longer stiffer shock would raise the front end lifting my front end up and causing a "toe out" effect.

I was also thinking this may produce more friction between the tire and ground surface, thus causing better steering.

Please correct me with better suggestions and further ingenuity to eliminate this slip angle of the front tires

 

[yerf_dogger]

well this kart is actually for my son. then I ended up building the motor and loving it so much that I bought me a vanguard V-twin 16hp.

I am in the works of finding a good frame to put that on while tinkering with this and learning what to look for.

I figure with a flywheel, rod, cam and new valve springs that baby ought to put out pretty good with the governor removed.

I am looking for some sort of exhaust and intake now and saving for the flywheel and other upgrades.. They are way more pricey for the V-twin rather than the clones.

hopefully I will be able to find a nice buggy to put the motor in.

 

[yerf_dogger]

I was gonna use a 40 series with a jack shaft.

Why would it be dog slow?

I figure with over 28 ft/lbs of torque and revs of 5-6k this thing ought to put out plenty.

I am not looking to make an all ought dune jumping sand rail.

just something to take to the creek or land and tear it up with my boy.

I have a buddy with a golf cart that has the same engine and it hauls a$$, has loads of torque and all he did was remove the governor. it has a CVT simlar to a comet 44 series.

and on another note...

This is the same engine that they used in the older kawasaki mules, if geared properly they haul tail too

 

[yerf_dogger]

www.youtube.com/watch?v=Eanmrn_w0DI

just look at this

or this

www.youtube.com/watch?v=pAeZaOKLE6U

www.youtube.com/watch?v=pmFsYEcYqIE

www.youtube.com/watch?v=_wxoIHxuIos

 

[yerf_dogger]

heck no the 40 or 44 series both handle way more than 8-10 hp.

they are 1 to 1 1/8 diamter.

http://www.ebay.com/itm/230821415644?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

here is the 44 series

http://www.ebay.com/itm/Comet-44-Ma...Parts_Accessories&hash=item5d36a9e769&vxp=mtr

and if it gets too powerful you could mock up a snowmobile clutch (also a cvt) but thats a lot more work involved

 

[OzFab]

what should i measure with these devices?

Ackermann, caster, camber. Adjusting any or all of these will improve your steering

The common theme among those v twim powered karts you featured is they're all karts, not buggies. The difference: buggies have suspension, karts do not, making them harder to flip. Keep that in mind...

 

[Grimace]

I can tell you for a fact that widening the rear axle will make it steer worse. The narrower the rear, the easier it will steer. I went from a 48" rear axle to a 54" rear axle and my steering went to crap. I am now working on fabricating a yerf dog style front end, which will widen the front stance to an inch wider on both sides. This should also help with the rollover I am getting in a sharp turn at 40+ mph.