I have a few questions about my 89 cbr600 engine thats going into my sandrail. first, does it hurt to have the oil level a little high? since its not in the bike, a cant lean into the turns so all of the oil will go to one side and i dont want it to be starved of oil when i turn. Im not really familiar with the carburetors and i think the engine is running rich since i put new plugs in about a month ago, i havent ran the engine for more than 20 hours and the plugs were covered with carbon and its backfiring during deacceleration ever now and then. What is the outside diameter of the stock rear wheel? trying to figure out what size sprockets i need and whether or not i need a jackshaft.

 

 

I believe the stock rear is 130/90/17 so that would make the outside dia 117 mm + 17 inches (432mm) outside dia = 549mm or a little over 21 and a half inches.

 

Man, I love those things! Just nowhere to drive one, other than on ice in winter... Even had a pug 205 engine once to put in one of those, but let it go cause nowhere to store the thing and no time to build one... A 600cc engine is enough to one of those? Always thought it would need more torque.

I don't think the oil thing will be an issue, normally every service manual says never to overfill the engine, I have understood it's worse than too little since it will try to get to the cylinders and cause other problems. I'd reckon the engine is going to run pretty hot on that kind of use, so I would recommend using mineral oil. I have full synths in my f2, and have slight gear issues, which i'm told can come from the oil going too lean when hot.

 

And the sprockets, not sure about an f1, but f2 has 15/43, so I would imagine the teething would be somewhat the same in the earlier model...

 

i think it will have enough torque as long as i gear it good, plus its not that big so it shouldn't weigh over 500lbs or so.

 

I got halfway through making the frame when i realized a few tunes werent exactly straight. found out that my garage floor isnt level, and i didnt tack the tubes in place first so they warped. started over, now i have the back of the frame done, tacked it all together first, then welded. next step is mounting the engine in the frame. i was looking at sprockets so i could figure out how far back the engine could go, and the biggest sprocket i can fit in it is 55 tooth. with a 14 tooth front sprocket and a 55 tooth rear sprocket, and the smallest i can for for wheels in the back is 22 inch. that gives me a top speed of 34.884 in 1st gear, 50.414 in 2nd, 62.698 in 3rd, 75.117 in 4th, 88.582 in 5th, and 99.713 in 6th. do you think that ill have enough torque and acceleration for off road with a 600(ish)lb dune buggy?

 

I think the shorter gearing & torque increase from that would easily make up for a couple hundred pounds in extra weight. I don't have any personal experience with a sandrail, but that's a big difference in top speed which should yield a very large amount of increased torque and acceleration.

 

R u planning to put paddle tires under it that I've seen in youtube, or normal ones? one would think those paddle things could require more torque, but +10 in the back should give lots of more of that... Even so that you're propably going through the gears in a hurry, possibly a little smaller one would work good too, but that's a matter of trial and error... About the oils: I learned the hard way not to use full synths, it won't stay in and causes a variety of other problems, mineral based Castrol Act>evo 20w50 works great on my bike and if you're worried about the leaning thing, it's pretty stiff so I'd think it would work good in yours too.

 

im planning on using some knobby 4 wheeler tires on it for off road, and if i can get it street legal, just some compact tires should do for that. i plan on taking this thing through lots of mud which is why i want to gear it down and get some more torque out of it, dont want to just be digging ruts the whole time.