Hello (Project300ex)

[Project300EX]

Hi guys. I've loved atvs for a long time and decided to build up my own, so I guess this is my project thread. It's going to be a frame up build starting with an oem '02 300EX frame. It's also going to be a budget build. I'm doing all the fab work. I just won the frame on Ebay last night and hopefully will have it next week. The first thing I'll do is gussett the frame up nicely, since I'll be running plenty of power through this, by means of a CCBR600F4i motor. I'm not sure how much you guys like the Frankenstein bikes, but I'm wanting plenty of power and it's just for pure fun and hobby riding. Since I'll be fabbing up a lot of stuff on the frame I'm going to use either 250R, 400EX, or Z400 front suspension. Out back I'll be extending the oem swingarm and a Z400 rear shock. Aesthetics will include 250R or 400EX race cut plastics.

Now onto the question. What are some specific points I need to gussett to handle that kind of power? I don't have any experience with 300EXs, since most of my riding has been on a modified Warrior, 400EX, and 660 Raptor.

Thanks and I'm sure I'll be flamed by someone, but please refrain. If you feel the need to just try your best to give constructive criticism instead.

[2muchquad]

Theres nothing wrong with being different,go for it.You will have to do some frame gusseting though.I have never done a conversion with a 300ex frame so i would imagine you'll just have to look it over for possible stress points,like the swingarm pivot area.You may have to modify the frame anyhow as im sure the 600 wont just "drop in".I have seen pics of a mojave with a zx600 ninja motor online before more than once so it can be done.A 250 ninja twin motor has been put into a 300ex before also.Good luck and take your time with it,dont rush;)

[Project300EX]

Thanks. The first thing I'll be doing once ups drops the frame off is cleaning it up and gussetting it. I think I can make the CBR motor set in the frame, but I'll have to modify the front A-arm bracing. I want to at all costs keep the frame geometry the same. So if I find out that the frame will have to be stretched then I may be forced to go with a different motor though. I'm optamistic about it. I saw a 300EX with a GSXR-600 motor and I don't think it had to be stretched. I just wish someone on here had done a hybrid 300, that way I would atleast have some sort of direction. I know I won't be rushed though, since this is a drawn out project that I'm working on as I get money.

Edit: 2muchquad I see you have 400EX arms. Are they oem and have you had any problems with them? Also how much do they extend past the 300ex ones? I've heard so many good and bad things about them.

[2muchquad]

Also how much do they extend past the 300ex ones? I've heard so many good and bad things about them.

I havent had them side by side but i guess they are like plus 2 compared to stock.I havent had a problem with mine as far as not being meant for the 300 etc.In fact i will probably go with some plus 2 a arms for a 250r or 400ex if i see a deal on them.They work great for the riding i do.I almost did a ex500 conversion a few yrs back,its the kawasaki 500cc twin in their streetbike ex500.That wouldnt have been too bad because i only had 2 exhausts pipes to worry about.Heres my blaster i stretched

[Project300EX]

Originally posted by 2muchquad
I havent had them side by side but i guess they are like plus 2 compared to stock.I havent had a problem with mine as far as not being meant for the 300 etc.In fact i will probably go with some plus 2 a arms for a 250r or 400ex if i see a deal on them.They work great for the riding i do.I almost did a ex500 conversion a few yrs back,its the kawasaki 500cc twin in their streetbike ex500.That wouldnt have been too bad because i only had 2 exhausts pipes to worry about.Heres my blaster i stretched


Thanks. I've been researhing the a-arms like crazy and it seems like for every good feedback there's bad. I think it will be fine for me though since this will just be for hobby riding. As for the frame stretching I just want to keep it the same length for the sake of plastic mounting and getting everything to fit together after modifying the frame geometry. Looks like you did a good job on that blaster though.

[Dan229]

Here is the thread about gusseting for the 300 http://www.exriders.com/vbb/showthread.php?s=&threadid=194880&highlight=gusset