Well I finally got my RWR kit on. What a pain in the ***, that was the hardest kit I ever installed. First no instructions, 2nd hard to remove old manifold, and lastly that head pipe was absolute hell to get on. But aside from that all the parts were quality items. After testing in my yard in first gear (yard to small to open up) I am definitely impressed. It sounds like a four stroke now. The low end is awesome! No more rev-limiter. I think my jetting is off a little, but not that much-unlike ScoobyDFW's. I will be testing all out friday afternoon at my track. I will let you know the results. One thing though you really have to twist the throttle that spring on the carb is tough. Also I installed an inline filter, Puralator Pro-Fuel 5/16 glass filter. I got it at Pep Boys for $10 i highly recomend it. If anybody needs some info on installing the race kit let me know I will try to help.

 

LUBA, Yeah it was hell installing. I bought the kit for use with the thumb throttle. Ron had a cable for it. Yeah the throttle return spring is tight as hell. Try using the thumb throttle with that spring - ouch! I have spent hours working on that carb, loosening the initial loaded tension by trimming a SMALL portion of the spring so that it isn't so hard on my thumb. I don't recommend doing this (See the forum "performance mods & mechanical" for my post on thumb throttle resistance). The downside of doing this is that in the rest position, the throttle does not have much force holding it down. I'll have to see how it works now, it might need some adjustments if it is too loose. With the spring mod, I was able to loosen the tension by about half - still slighly stiffer than the stock carb. One other thing I did was remove the spring for the accelerator pump rod.

My jets are here and I have new spark plugs so now I can try to tune that thing. What filter did you order - the stock replacement or the racing filter that mounts directly to the carb?

 

I ordered the filter for the stock airbox, we run into a lot of wet mud in Michigan. Unfortunately my K&N didn't come with my kit, they are on backorder and Ron will send it as soon as he gets it. Right now I am running the stock setup with the lid off. Where did you mount the choke lever? I have mine just zip tyed to the throttle cable. I don't think the U-shaped exhaust piece had a big enough bend, that's why it took so long to install. I will tune mine today.

 

Does anyone know if the Wood Rotax pipe can be fitted with a spark arrester? Ron said they didn;t offer one, but something about using a Supertrap one some how. Any ideas?

 

I share most of the complaints all you guys ha ve. The carb is nowhere near right. The throttle return spring must be off a Holley 750 double pumper. I have already raised the needle clip one position with no help so I will be needing more jets and more jetting time. Right now if I nail it wide open from idle the engine will stall if I dont let off.

I am pleased with the look of the products however and can definitely agree with RWR in the fact they used every available milimeter of space available for that pipe. I found the pipe easier to install using allen head bolts that I got from a sea doo and I used a ball end allen wrench to tighten them up.

I haven't taken the main or pilot jet out of my carb yet so if anyone knows the numbers please share them.

 

JD,
Even with the 440 kit, your still down 200 CC's compared to the DS. I have just seen the DS for the first time, and it is one trick and well put together machine.. Forget the 400ex, get a ds...

RoostKing... 99 BAnshee 85 LT 250R, now its hanging on the wall...

 

Concerning the tension of the throttle spring you guys are not so happy with. You actually have a couple of things you can do. In the tech connection (I read just about every single post in there when I was first getting into ATV's) it said that if you SHORTEN the spring, you'll actually make it stiffer. to make it softer, you need to use a grinding device or file of some sort to reduce the diameter of the wire itself. when you grind away at that, you're then making the spring a little weaker, which is exactly what you want. (I hope that made sense) basically, you'r griding the side of the spring not the end. The other thing that you can do if you have a thumb throttle, is buy a ThumbSaver from a company Called CDS. 2%3Ak for their ad in DW or 4WA, I dunno if they are on ATVing.com yet) I just installed a couple of them, and they really do make a huge difference. (It's basically a plastic thing that is about 3" longer than your thumb throttle.) So try that, it'll help, plus it's cheap and easy to install.

 

I switched from the #155 main jet to a #145 main jet to go from black plugs to clean plugs. I have been playing around with he pilot jet as well. It came with a #40. I have tried a 37.5 and now a 30. I have switched jet needles too and the needle positions. No matter what I do, I can't get rid of the hesitation in the motor when you are idling and tap the throttle real fast. I have a feeling that this is going to be a side effect of using a very large flatside carb with this motor & pipe. In the Sudco Mikuni Tuning Manual, it says tht it can be difficult to get a smooth response out of this carb with a high flowing exhuast system. On the other hand, the accelerator pump is supossed to give instant throttle response, so I'm not convinced that disabling it was the right thing to do. I might try to get the accelerator pump working and see if it helps. When I run the stock carb with the ron woods pipe, there is no hesitation. With the new carb though, I think I'm getting more low end. The top end still doesn't seem right to me and may be related to the pipe or maybe more tuning is required as well as a high flowing air filter.

 

Well I finally took mine to my track. Man that thing is insane now. It really flys. I too still have the slight hesisation at idle blipping the throttle, and after running hard and shuting down I get an occasional backfire. But I am running just the carb Wood sent me with the stock filter no lid. I will pull the plugs and take a reading monday. I will also call Ron and ask him for a jet kit for their carb and my K&N filter. I went with the twist throotle and I'm not sure that the way to go. Landing after a jump it too easy to accidently twist the throotle send the tires skyward-that can be scary. Maybe I'm just not use to it. Did you guys put new grips on? The stock grips are weird, and the bar ends are notched-are you supposed to cut the old bar ends when putting new grips on?

 

I took the DS out this weekend for more testing. It's not running too bad now. I still have the hesitation problem though. I'm pretty sure that the pilot circuit is not correct. According to Mikuni, the idle RPM should go from low to high to low as you turn the pilot air screw from around 1 1/2 or 2 turns out to around 3 turns out. The pilot screw does not behave this way. Instead, the idle RPM goes from low to high and remains there with more turns beyond 3. According to Mikuni this means that the pilot jet is too big - with the air screw all the way out there is still not enough air. The carb came with a #40 pilot jet in it which is huge. I have tried as low as 30 but that isn't low enough. I think I need a #25 or #20. I'll have to go back to the harley dealership and pick those pilot jets up and try them. Hopefully the off idle hesitation will then be solved. I haven't fine tuned the jet needle and main jet yet because of the pilot jet problem. Aside from the off idle hesitation, the lowend and start-of-midrange power & acceleration are noticably better than stock. At the moment, the DS seems a little off in the end-of-midrange and topend power & acceleration. It actually seems a little bit less than stock. I need to fine tune the jetting and get a high flow air filter, so maybe that will take care of it. Overall, the DS is definitely accelerating faster, but feels a little flat at high RPM at times.