I just thought I'd let some of you know what I've done to my Falcon 250 to upgrade it's performance. I've sent some of you a setup guide that I've written to help you out with your ATV's. I've done different mods to different ATV's I've owned over the years and decided to try them on this ATV. After I got it running well (with exception of a blowby and oil burning issue which I've been waiting for parts for from USA ATV's for about 2 weeks now). I then cleaned out something that was stuffed in the muffler (that I believe shouldn't be there as it was blocking the outlet hole, kind of looked like a rag or sorts). This improved performance somewhat so I decided to mod the muffler even more. I cut the curve off the exhuast tip and drilled the tube out using a 1 1/2 hole saw that just fit over the pipe. I noticed a sizeable improvement and decided to go through the next plate with the hole saw. More improvement. I also drilled a 1/8 inch hole in each end of the muffler at the bottom to allow any condensation from the exhaust to drain. I've noticed it has been working. Then I parked it and started more serious modifications. First were 2 inch extensions on the rear wheels and 1 inch on the front wheels to improve it's handling. This worked fine but I wasn't happy with the tires so I ordered a set of new rims and Carlisle Turf Tamer AT 20 x 11 x 8 tires for the rear. I ended up ordering a set of rims with a 3 x 100 & 4 x 100 bolt pattern and drilling the correct bolt pattern in them using one of the hubs I removed and centered in the rim. The rims were 1.5 inches wider than the originals and the tires have more ground contact than the original 19 x 9.5 x 8 tires that would roll over and grab causing the atv to handle erratically on high speed turns. The new tires let loose when I need them to so I can pitch the rear end around corners using body position and throttle. They work great. The next mod I did was to lower the quad by about 1.5 inches in the front and the rear. The bottom of the rear shock is moved back about 2.5 inches with the use of a 2023 aluminum adapter I milled out in my shop. The bottom of the front shock was moved out towards the tire about 2 inches by using new mounts I welded and clamped to the front lower a arms. These two mods changed the ride of the quad from a slight kidney buster to a cadillac. I may have to add some tension to the springs and upgrade it to an escalade. It seems a bit too soft at the moment. The greater angle on the shocks is like having a longer lever or prybar so the springs are compressing more and more easily than before the modification. My last issue was to tackle the carburetion issue. The stock carb is a constant velocity Keihin which basically uses vacuum to open and close the throttle slide. These came on some Hondas (even scooters), Kawasaki's and even Harley Davidson's. Usually when someone bought a Harley the first of the improvements they made to it was to replace the carb with a replacement carb. Most often they were replaced with Mikuni's. So I bought a Mikuni carb for my ATV. I searched Dennis Kirk and they have several carbs listed. I looked at the more expensive keihin replacement/upgrade carbs and a 34mm was recommended for replacement of a Honda 250cc 4 stoke carb. So I went with the 34mm flat slide carb for $150. The round slide 34mm carb is only about $95. I put it on last night and "Holy Cr&%" what a difference. It wasn't perfect just taking it out of the box and bolting it on the starting was flawless, the response from the engine was immediate (no waiting for it to warm up fully before the throttle could be touched) and the power was, to be honest, unbelievable. A slight touch of the throttle and the rear tires lit up. I have several spinout marks on my concrete garage floor to prove it. This was in forward and reverse, with and without the front brakes on. It's running a little rich so I adjusted the jet needle. It improved throught the throttle range up to about 3/4 to 7/8 throttle so I still have to adjust the size of the main jet. This bike now lifts the front tires off the ground, especially after/while going around a sharp corner and pulling the throttle to about 3/4. Any higher and the bike misses due to the main jet being too big. The original Keihin main jet is/was 170 and I know that was way too small due to the lack of performance and pinging/knocking at mid to high throttle. The new Mikuni main jet is 280 which I know is way too big. I ordered a set of jets that goes from 200 to 270 and will power tune the bike when they come. Till then I'm going to solder the main jet shut and drill the equivalent of what I believe is a 250 main jet and see how it runs. Had I had more information available I would have ordered the jets ahead of time or just gone smaller with the 32mm carb which comes with a 250 main jet. This is what I would recommend to anyone planning on upgrading their Falcon 250 carb. If you don't know how to tune a carb and don't want to make a lot of jet adjustments go with the 32mm and order a couple of smaller main jets with it. Or wait to find out what my final jet sizes and adjustments are and copy what I've done. The original Keihin carb is 30mm by my measurements but runs the engine way too lean. This is verified by the exhaust temp, the factor that the idle mixture screw is almost all the way out and the idle screw is almost all the way in. Not to mention the pinging and knocking at mid to high speed. I'm hoping I get my engine parts pretty soon so I can finish the mods with a good running engine. I'm hoping that USA-ATV's not responding to my last 5 or 6 emails is not on purpose. I was setting up a deal with them to write setup guides for their entire line of ATV's. I'm also hoping they didn't use me to get a free setup guide for the Falcon 250. If so I'll have to offer my services to other dealers. They sent a replacement rear fender section instantly to replace the banged up one that arrived on the new ATV but, as of lateley, have been ignoring me with regards to my oil burning/smoking engine problem. I'm sure once I get that issue fixed the ATV will be a real great runner. I even called one of their customers long distance and helped them resolve an overheating problem after the bike was left outside to freeze the day it arrived at the owners house. Supposedly they gave me a $30 credit on my card but I have yet to receive my statement to verify that it is actually true. Screw me once, shame on you, screw me twice, shame on me is all I have to say right now. If I don't get some satisfaction I'll just order the parts myself and go elsewhere with my setup manuals, parts orders and customer help. I hope this information helps some of you with your Redcat/Kazuma ATV's

i8amm

 

You seem very knowlegable with the Falcon 250 I was wondering if you could help me with adjusting the valves on the 250? Thanks in advance.

 

I have a setup guide that I wrote for USA-ATV's. It is in MS Word format with pictures and explanations on valve adjustments, carb adjustments and a ton of other things that should/can be done. You can either reply with your email or send me a private message with it. I'd be happy to send it to you. You can then email me with any questions the setup guide doesn't cover. I had my 250 out today riding with a Honda 125 dirt bike, Honda 400 Quad and Honda 450 Quad and held my own on the trails. I couldn't keep up with the quads running down a long straightaway in a field but they didn't get too far ahead. I can't expect too much since I was outgunned in displacement. That is with my new carb that I finished installing last night and have yet to fine tune. I am very surprised at the power that I have been able to get out of this quad. Better than I expected.

i8amm

 

yes please email me this it is greatly appreciated
legrand@franklinvt.net

 

Well USA ATV's came through and my parts are on their way. Turns out the rep I was emailing was in Texas and his emails were getting lost on the server down there. I have to give him the benefit of the doubt because he said my parts are on the way. Other than the email issue/misunderstanding he hasn't steered me wrong yet. I can't wait to get them and stop my engine from smoking. I'm hoping I see a little performance improvement as well.

i8amm

 

Great information. I have a Falcon 110 for my son and I will show this to my brother-in-law who just got a Baja250 and see how much we can implement on our stuff. I would love to switch out the carb, but the lack of specs is holding me back. Hard to believe how difficult they make it for somebody like me to shop for aftermarket parts/upgrades. I'll pass along any info I get our stuff. When I go to a parts shop (Motorcyle, Auto or ATV) and mention my brand, they just look down on me and brush me off. If it isn't one of the major brands (Honda, Polaris, Yamaha, etc) they won't even try to help. So any info I get here is deeply appreciated. I want to make my son's ATV perform the best it can within my means.

 

cdavilajr


I'll add how I selected and researched some of the upgrades I have done. I was told that my ATV was a Honda clone. Not that it really mattered when I was selecting some of my parts. I went on DennisKirk.com and selected all the carbs. If you look at the Keihin carbs they will tell you what engines/makes/models they fit. In my case the Keihin 34mm carb would fit the Honda 250sx. Then I looked at the varoius models of Mikuni carbs which are great stock and aftermarket carbs and cheaper than all the other aftermarket carbs. You can select a carb on Dennis Kirk and look at the specs to see if it will fit. If you are going to use an aftermarket air filter than the filter side doesn't matter. I had to make a rubber adapter/sock so I could use my original airbox/filter till my new one came. I then ordered the 34mm Mikuni flatslide carb. The intake side of the carb is slightly bigger than the original but it fits snug and there aren't any problems with it. I probably could have just gone with the 32mm Mikuni as I have to detune the carb a bit. It's a little bit rich but even with that and a slight oil burning/smoking issue I have a real significant improvement in power. I would say it is close to twice the power I had with the stock carb and an extra 10 to 15mph. I just recieved and installed a foam air uni air filter and the extra air flow is making the carb run even richer so I know I have increased my air/fuel flow through the carb. I just ordered it according to the diameter of the airbox side of the carb, 2 1/4. One problem I ran into with putting the new carb on is that the cable doesn't adapt from the old carb to the new one because mine mounts on the outside of the carb to the butterfly shaft and my slide is pulled up by vacuum. If your cable goes into the top of the carb to directly pull the slide up and down there shouldn't be any issue. I ended up having to install a twist throttle to get the full range out of the new carb too. I had forseen this and it was actually around the same price to order a twist throttle with a cable as it was to just guess and just order a calble that might not fit. I actually like the twist throttle better, I have a greater range of throttle choices and it's more comfortable on long rides. Last night I installed a set of used front springs from a Honda 400ex (ebay, $50 w/shipping) because the originals were soft but still elbow killers. This along with lowering the front end about 1/5 inches and moving the shocks outward on the lower control arm has made an incredible difference in the ride and eliminated the bump steer to about 10% of what it was. I think bringing the front wheels in about 1 to 1/2 inch will fix the rest of it. I currently have 2 inch spacers installed on each side. I lowered the rear end by moving the shock back and installed 3 inch spacers on each side in the rear. The atv is almost un-flippable now. I made my own but they can be purchased from many places. Raceway has solid aluminum ones that are 3 inches for the Kazuma/Redcats with the 3 hole bolt pattern. I made mine out of Stainless steel. It adds more weight than the aluminum but I already had it so it didn't cost me anything. I installed two new rims and carlisle turf tamer tires to the rear which also made a gread difference in the handling, especially around corners. The rims were about $27 each from Dennis Kirk and I had to drill the right bolt pattern on which was easy since you can take a hub off and set it on the tire backwards so it self centers in the hole in the rim. Just make sure the 2 half moon spaces between the hub and rim are about even and start to drill each hole just to mark the pattern. You can also drill one at a time and drop a bolt down through each hole after you drill it to hold the hub centered. You can even go on ebay and look for a carb for a 100 or 125 45 stroke bike and ask them to measure the intake and filter diameters on the carb and compare them to your own. If it will fit you can order the used one or take the bike information down and use that for purchasing your new/aftermarket carb. Just purchase a replacement for the year/make/model of carb for sale on ebay. Just looking quick a 20mm Keihin carb is the replacement for a 80cc quad. The 110 would probably be something this size or a little larger. If you go to ronniesmailorder.com you can look up and order stock parts for miscellaneous atv's and dirt bikes too. This is a good research area but takes a bit of time to find what you're looking for. I found the new carb I bought was installed on several years of Suzuki 250 quadracers. If you need any help looking for parts let me know, I'll see what kind of information I can dig up.

i8amm

 

I did the same mod to the muffler on my son's 110 and he says that it runs better (i'll have to check the max speed with the GPS - last time max speed was 31mph). But he loves even more the new sound the muffler produces. I'll keep playing and tweaking as I get more info on the carb. A mechanic friend of mine saw it and immediately recognized it as a Honda and is looking up a compatible one for it.

 

cdavilajr,


Glad to hear my muffler mod helped you out. Keep me posted on the speed improvement when you find out. I just got my new jets and other components for the aftermarket carb I put on my 250. I ordered them from Ronnies Mail Order, Microfiche (stock/oem parts). The parts are/were for a 1988 stock Suzuki Quadracer 250. I am still a little higher than the stock jet because the stock Suzuki carb was probably only a 30 or 32mm model. I'm working with a 34mm Mikuni so I have to equal the amount of fuel with the amount of air coming through the carb. I learned yesterday that I may be getting a whole new engine to replace my smoking/blowby one since they can't get all the parts I requested at the moment. This kind of worries me about getting parts later on. I may come up with a parts list of things that will eventually need replacement in the event that prices may/will eventually rise and parts will become unavailable. Right now I am planning on getting a CDI (spark) unit, cam, head, cylinder, valves, clutch, drive belt, piston, rings, coil, radiator, water pump and some other things I haven't thought of yet.

i8amm

 

Can you post some pictures of all your upgrades?? I would love to see some.