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Well stated analysis... but wrong. The kit distributes the suspension load across both sides of the frame, actually REDUCING stress on the individual a-arm mounting points. Extended a-arms, however, DO increase the stresses on these mounting points.

I have two DJ kits, one on one of my 400ex's the other on my Raptor. I also have a 400ex with extended a-arms, so I am very familiar with the characteristics of both. A-arms are better overall, but the kits make a hell of a difference for a whole lot less money. I am very happy with the handling improvements due to my kits. They are well designed and very strong. Althought the a-arms do exhibit slightly better handling, I really have little to complain about with the kits. Geometries are changed so little from stock or extended arms that I dare you to notice a difference. All in all, the kit is a great improvement over stock especially considering the low cost.

The only real issue is the kit's addition of 10lbs or so to the front suspension... I haven't noticed much impact from it myself, and i am a wheelie nut. Of course, just adding a full tank of gas adds 15lbs or so, but not so far forward (but a LOT higher!).

If you have patience, you can camp on the daily eBay auctions (even tho they state a particular bike, they will deliver any kit if you win) and get a kit for around $100 or less. I bought my first for $89 my second for $102.

Bottom line, if you want the better handling of a wider front track but can't afford extended arms, the DJ kit is an affordable way to get you most (but not all) of the way there.

Good Luck with your choice!</end quote></div>

Well,...... I didn't say it wasn't a fine product. I answered the questions presented. I tried not to sway by opinion at all. I may have gone too far with that avoidance.

I've spent a lot of time in engineering, and I took a quick point analysis direction and I'll stand by this due to my basic approach. Anytime you add length, width, distance, or what have you to a levered or non-levered assembly, you increase the stresses it will have to handle. Leverage is always greater with a longer "arm". Since the frame has not been changed, but another piece was added to gain the width(read this as length) there are added stresses. No two ways about it. The approach taken by the disigner/engineer of the DJ kits is outstanding adaptation with a minimum of stress induced. This is a great achievement, no doubt. I'd give it a try on my older bike without flinching. It appears to be a decent product.

I agree with the "bottom line" of the quoted post. But I must defend my analysis as correct. My analysis is not opinion. It's analysis based on engineering principles. It appears as though your experience with this product is great. I expect nothing less.

For some reason Yamaha(and Honda, and Polaris, and the rest of 'em) and many moons of engineering, didn't arrive at this simple solution to a very common problem. It may be they didn't care, or that they already tried similar options, or their engineers are just not very good. I don't know. But I bet they know about the product and if they haven't already considered this mod as production, they likely have some people looking at it.

The designs of almost any production machines are not typically thrown down without some thought. My point in the original analysis was to expect some differences. It was not to point out fatal flaws.

But since we have to tell someone they are wrong, I'll have to return the favor. My opinion of the product is obviously Favorable. But since the question I answered was "what possible damage could it do?". I kept it to those <u>possibilities</u>. Not to my opinion.

In direct response to the criticism, There will definitely be a change in stresses on the A-Arm mounts. It will reduce one type of stress while inducing a different one, and possibly a third due to twisting since the lever arms will be increased. I see this as a trade. Not a reduction. It definitely appears to strengthen the points the suspension parts are mounted to, since the pieces added are, in fact, thicker heavier material than the original frame parts, without increasing the actual needed strength of the frame's mounting points or materials. The added leverage will be pulling more against the welds of those original factory mounts, and the strength of the actual material. The likelihood of stretched mounting holes(original ones) and broken welds would not be reduced. Nor would the twisting of the frame.

All that plus, the adding of more parts also drives up the maintenance a bit, and the increased possibilities of loose bolts. I think, by not having owned the kit or used it, I'd still think it was worth it.

But I must interject once again, I like the product.

I don't like the insinuation that I don't have a clue what i am discussing.

Thanks though.

 

If you simply stated that ANY modification of kind will increase lever arm, i would agree... however, your statement was about the kit, not about increasing the track width in general. As stated, extended a-arms DO increase the stresses you described, in particular: a-arm bushing mounts and individual frame member loads, while the kit actually reduces them.


I AM an engineer, have been for 30 years, and had analyzed this system thoroughly before purchase, for my own safety. I went so far as to generate a rudimentary Solid Works model and then performed a Cosmos finite element analysis to look at stress loading on the pertinent components. Results from the model were pretty close to what I've seen in real life (and on other forums). If, for instance, you hook a tree at high speed, an incident that would severely damage at least one a-arm and likely tear an a-arm bushing mount or two in the process, with the kit (and this is documented with pictures at Raptorforum.com) two of the extender bars bent... that's IT! Of course there are some causal modes that will see more or less damage, but in most cases, extended a-arms will cause MORE. So the CHANGE that you are describing is for the good, in the case of the kit. And extended a-arms are what we're comparing to here, not stock. The poster wants to widen his ride, and these are the only two safe options.

Sorry, but the statement about the manufacturers not having done this so it must not be a good idea (and I am paraphrasing your comment here) doesn't wash. Adding extended a-arms is one of the most prevalent modifications for improved handling yet the manufacurers (except for Can-am and one or so other) don't offer these either. Are you also suggesting, through the same logic, that these are unsafe or somehow untenable? The design of any production system is always a compromise, based upon requirements generated during the development. In many cases, individual users may want to improve upon this design by adding aftermarket components. The manufacturer can't possibly meet everyone's desires, just the average. This is why the aftermarket industries are HUGE.

As to "answering the questions that were presented"... compared to the original post, "worth it, or just a waste, can find the same ones on ebay cheaper from same source", leaves me asking - what was answered?

And please understand, the "the insinuation that I don't have a clue what i am discussing" is not that. It is simply a point by point analysis of where your logic is incorrect, primarily due to infamiliarity with the system.


Anyway, enough of this. I think that the original poster now has enough information to make up his or her own mind.

Good Riding!

 

ENGINEERS!!!!!! My god, you don't need to show off how smart you are!!!!! Don't take it so personal.

 

I wouldn't put this kit on mine. There was a guy on here recently that had one of these kits and he said he flipped his quad once and the kit got mangled up real bad where he couldn't even make it back home. Nothing else on the front got bent. I have flipped a lot of 4-wheelers in my day, and never have I broken anything off of the front to the point where I couldn't at least limp home.

 

I'd worry about the (threaded ) tie rod extensions