A bit of dust on this thread.
Ha! Is there a prize for pointing out the obvious? or least input? or wasted thread space?
Don't get angry, just don't do it...
Ya ya, I know grave digging
Was wondering if over time you had any problems? What would you do different? Have you started the 300/380 Blaster yet? I:I
Still riding her!
Problems:
Broke lower motor mount. Suspect due to frame flex and bending by sliding over rocks and logs. Chrome moly does not take to standard welding very well. It gets brittle and breaks just outside the weld. My mounts were spotted onto the tube and sure enough, broke as predicted once stressed. Have used a larger plate under the motor and spot welded it in more locations to spread out the stress. Brazed overlapped joints would have been a better idea.
Broken pipe mounts. More or less the same idea as above. Re-MIG'ed with larger area pads and seem to be working.
Lengthened pipe. Increased torque massively but decreased rpm range. Will be running a stock length pipe in the future.
Swingarm length. With this much power on tap hill climbing can be a biatch with the stock swingarm. The 2" extension is a massive improvement and still keeps excellent traction on the flat, but the hills need even more length to keep the front end down and from flipping over. I have been slow to agree, but 3"-4" is needed for the hills with this much power. Another answer I haven't tried yet may be lowering the pegs since flip over is a function of how high CG is. If I lower my pegs my weight is at that point when I am standing, like on a hill climb. A 4" swingarm really compromises flat traction and getting over logs on slippery surfaces.
Cylinder erosion from poor intake/filter sealing. I was using a paper filter with its edges sealed with grease. Not good enough. Cost me a cylinder plating due to the sand and water I run in. Now have a stock style foam filter and even better intake/airbox sealing.
Cracked stock swingarm. "X" crack on central body. Welded and cracked again. Due to twisting flex. Would be even worse with an widened axle. Welded it again and watching it. Gives lots of warning but a stronger swingarm is a good idea with over 40hp.
Limited transmission range. MX engines have close range gearboxes, not really suited for quads. These swaps will always be a bit limited for that reason. Even the KTM enduro gearboxes have less than half the range of a Blaster gearbox. While this is a kick a$$ quad that will blow away most of the competition in acceleration, I have to pick top speed or rock crawling sprockets ahead of time because of the limited transmission range.
300/380 mods. The KTM 250 motor will spin or wheelie at pretty much any speed until revved out. On hill climbs there is no problem with bogging out, flipping or spinning are the problems. So far I don't feel any need for more displacement, but if I did... the older (pre2003) motors will not fit the frame without major alterations. This rules out the 380. The 2003SX/2004EXC-up motors are more upright and compact. The 300 is just a jug change and I actually have one to do it, but it takes a different pipe, so more work needed. As mentioned about pipe above, I am planning on building a new stock length pipe and will probably make it to fit the 300, just to try it.
What would I do different?
Build up a stock blaster rather than a hybrid, mainly due to transmission.
From what I have learned with Triplecrown's Blaster, it is easy enough to build nearly 40hp. 10 more hp just goes to wheelspin mainly.
Rather than all the work trying to make odd parts fit, as much fun could be had with a built up stocker.
And no rad needed...
Steve
