what should I re-enforce or re-weld on my 86 quadracer frame? I think it needs a little sprucing up and it may have some cracks... The welds on there are HORRIBLE, I think they're factory suzuki, but they suck! I'm putting a non-counterbalanced RM 250 engine in there so I'm pretty worried...

 

If you already think you have cracks then you will have to weld them anyway. You really need to strip the machine down to the frame and check it out throughly. The RM motor should work fine as long as it is mounted securly. The counter balencer is there mainly for rider comfort.

 

I heard that the engine will cobble up the frame, destroy the mounts... etc.


The paint is thick, and there are two layers, the original and this other stuff... The paint hides any kind of damage I suspect... I see a dent near the motor mounts I don't like. I think I will get the frame sand blasted soon.

 

You definitly need to sandblast the frame to check it for cracks. It will also allow you to weld in gussets without catching the paint on fire. Why would the RM motor "cobble" the frame? I could see where you might need to worry if it was a CR 500 engine you were installing but the MX motor is not that much different from what you already have. The bike uses this motor and its frame isn't much different than your Quadracers. Just make some sturdy mounts out of thick aluminum plate and try it out. I assume you must have gotten a good deal on the RM motor rather than just using a Quadracer engine. What year is the RM motor? The new it is the more different it will be from the Quad motor and will require addition fab work to install it.

 

Why not just use a Lt250 engine? Even a lt500 could work and it would be counterbalanced so you wouldn't have to worry about vibration.

 

The engine is an 89. Why the dirtbike engine? It was cheap, and has more power.

 

you have to remember that the gears in the rm motor is set to move A dirt bike 150lbs and a rider175 lbs. so a 325 lbs quad and a 175 lbs rider is not what the tranny is made for. so you might have to try diffrent gearing on motor and axel to get it to fly
good luck

 

good point. The gearing would be different, but I think the front sprocket were similar in teeth and I'm still using the stock rear sprocket, so I'm not overly concerned about gearing.


However, the jetting on the carb may need adjusting after I use a custom pipe (if I do)...


EDIT: The trannies had similar gears I think, and the dirtbike weighed maybe less than 250 and the quad weighs 293 from the factory, minus all the crap that's been removed on the quad... 280 something pounds... not that much to worry about I think.