Need some advice on conversion

[vwcamper74]

Hi everyone,
I am currently toying with the idea of putting my 500 motor in a newer frame.  I have read all of the past posts regarding conversions but still don't know which the best option will be.
What is the handling like when you put the 500 motor in a 04 or new chassis.  I will be mostly doing high speed desert riding and I want something that is stable at high speeds.  Reading up on the kx250 frames has me a bit confused as the 04 kx 250 had a 27degree rake and the 05 and later went to 26 degrees.  Are the 250 frames good for high speed and would the reduction in rake in 05 reduce stability.  The trail on these frames are less than on my 500 but I honestly don't know how trail affects handling.

Would a 250f frame offer better handling than a kx250 frame and thus be a better conversion?

Lastly, assuming I picked one of the above options to do a conversion, how would the handling compare to a 500af conversion-again high speed stabilitly is important to me?

Sorry about all the questions but if i'm going to go down this route, I want to make sure that I start with the right chassis.

Thanks - Mark

[kxpegger]

I have an "08" KX500AF from Service Honda. I ride Nevada Desert (high speed). The front does get a little squirrley from time to time but I haven't really played with the suspension settings or adjusted the sag yet for my weight. It's not so bad that I'm worried about it or that it slows me down but it is noticeable compared to my other bikes. It's not enough for me to even consider a steering stabilizer either. I may put just a little more preload on the steering bearing nut and that should probably take care of it.

[vwcamper74]

Thanks kxpegger,
What kind of speeds are you doing when it starts to get squirrely and is it doing it on rough ground or at a certain speed.
Probably a hard one for you to answer unless you have ridden a kx250/500 conversion but do you think the handling would be similar to your AF with a kx250/500 conversion?  The reason I ask is that I can get a 250 chassis a lot cheaper than a 450 chassis and I would be able to do most of the conversion myself.

[kxpegger]

It handles the big stuff fine. Usually when I start to notice is 4th and 5th gear. Smaller repeated high frequency hard pack (concrete) bumps mostly when on the gas. I can't really blame the bike as I'm still tuning the suspension. It's getting better everytime I go out. Most of my adjustments have been to turn the rebound down front and rear. I've left the compression alone for now and will try different tire pressures when I think I'm getting close. With the stock front D742 tire it had a tendency to really push the front end in the deep tight sand wash turns. I put a D745 on front and it made a world of difference. After I think I've got the suspension dialed in I'm going to play with the fork height and find the best setting for turning and stability at high and low speed. I'll figure it all out someday. Took me 6 months to get my RMZ450 dialed in for best overall offroad performance for the type of riding I do.

What I can say for sure is the AF is head and shoulders above the KX500 steel frame handling. One of my riding buddies has a 97 KX500 and we traded bikes for about a 1/2 hour. He was amazed at the difference and didn't want to give my bike back.

Don't know what to say about the 250 conversion. Do you mean AF or steel? Service Honda is now using the 250F chassis unless you ask for the 450F. Either way I have no experience with the 250 conversions.

Hope this helps!

[The Flyin Hawaiian]

Im building a 04 KX250/500. Its been pretty easy to do so far. Im at a stand still right now because I need to save some money up for the exhaust. I have alot of time on 03, 04, and more recently the 07 KX250s. The 04 that I am using was bought new by me and raced in enduros. Its a very stable chassis and turns well also. I raced a 02 YZ250 before switching back to KXs and the KX is as stable as the YZ and turns better. I dont think you would be disappointed in using a 03/04 style chassis. The 05-07 chassis is changed quite abit. At first glance it looks identical to the 03/04s. Upon closer inspection, you start to see the changes. Ride them back to back and you will immediately feel the difference. The 07 feels 125ish, very nimble and narrower at the footpegs. A problem that yu will have with the conversion is that an IMS or Clarke will not fit, not even close! I will be using the stock tank for now until I can possibly have a carbon fiber or aluminum tank made for it. It will be pretty spendy though. The stock tank fits perfect! 

[vwcamper74]

Thanks a lot for your help kxpegger and flyin hawaiian, you guys have helped me out a lot with my questions - it's very much appreciated.
Just a couple more quick questions:
Flyin Hawaiian, you mentioned that the 05 250 and later is a different bike altogether.  Do you think a 500 motor will still fit in fairly well compared to an 04 or earlier conversion? You also mentioned that the later bikes feel different to ride and are more like a 125.  Do you think some of this has to do with the reduction in rake and do these bikes feel less stable compared to your 04 at higher speeds?
Are the big tanks hitting on the plug or somewhere else? 

Sorry for all the questions - just want to get it worked out before I spend the cash!

[BullKaw]

What are all the Pro desert riders riding, the ones on Kawasakis?
If the answer is KX450f or KLX450F then the debate should be over....06-09 AF wins. 

[The Flyin Hawaiian]

I havent noticed much of a difference in stability between the 03/04 and the 05-07. Both bikes have WER steering dampers, which helps the stability some. They seem to turn about the same. The older 03/04 chassis just feels a little bigger, although its not a hindrance at all as far as handling and rideability goes. Im not sure if the 500 engine would fit the 05 up frame. Someone on here put a 05 up KX250 engine in a 03/04 KX250 frame and it was a pretty easy conversion. The 05 up KX250 engine is completely different from the 04 and below. So, I would think the 500 would go into the newer frame.
 I have both the IMS and Clarke tanks for the 04 KX250. Due to the height of the 500 cylinder and the amount the tank drops, there is just no way, with out considerable reshaping and maybe cutting and modifying, that either tank will fit. Ill try to snap a pic this weekend.
 As far as the aluminum frame goes, I dont have the fabricating skills required to mod the al frame. I also had the 250 already. I also prefer the steel frame. After riding a few aluminum frame CRs and YZs, I found that even with the suspension revalved for woods riding, there seems to be a noticeable amount of harshness transferred to the rider with the aluminum frame bike over the steel frame bikes. The al frames are pretty rigid. The steel frame has a little bit of flex and has a little bit more of a comfortable ride over the course of a 6 hour, rocky enduro. If I had the money though, there would be a KX500AFX sitting in the garage!
 Why are the pro desert riders riding KX450s and KLXs, because that is all thats available to them. Im sure if Kawasaki made a steel perimeter framed 500, they would be on them instead.   

[vwcamper74]

I also don't have the necessary skills to work with alu.  I would be relying on a fabricator who can work with alu but would never have done a conversion before.  The job might look nice but I won't know what to look for to tell if it has been done properly and will withstand the stresses of the bike.  I don't doub't that a conversion done by someone with experience doing them would be stong but I will be relying on someone doing one for the first time.
I'm sure you guys have probably seen the pictures from the cr500 site

http://cr500riders.com/cgi/yabb/YaBB.pl?num=1239428868

but I must admit that it made me a bit more cautious

with a steel frame I could do the work myself and be comfortable that it has been done properly

I'm sure the AF would be a beast of a machine and would love to have one

[kxpegger]

Welding aluminum is a little tricky especially for high stress. I was a certified stick welder back in the late 70's but I wouldn't try welding anything but steel today.

http://lincolnelectric.com/knowledge/articles/content/alum.asp