Yes Megadan I'm running a 40 tooth on the rear. I'm currently running a 16 tooth on the front because I have been doing a lot of mixed off and on road riding. If I know I'll be doing mostly highway I'll swap to the 17. When I go strictly off road and know i'll be climbing hills and going threw soft mud I'll swap to the 15. The 15/40 is very close to the same ratio as the 17/45 combo which work perfect for off road and city driving but gets real buzzy when over 55mph. 16/40 works great for trail riding and highway up till about 60-65 mph before it gets buzzy. The 17/40 is perfect for 60-65 highway cruising and have got up to 74mph and not be screaming. 74 seems to be the top speed on al three combos. Don't expect to get that on the stock bike and don't be disappointed if you can't hit 60 brand new. Once these engine get some hours on them, broke in and loosen up they will start to perform. Unplug the stock exhaust or get one of the ebay exhaust will wake it up. Rejet the stock carb or pick up the mikuni vm26 and jets will help a lot. I'm a cheap bastard :hehe: so I just modified the stock exhaust and carb and accomplished the same results for little or no cost. Main thing to do when you assemble is to replace all fluids such as oil, brake fluid and fork oil. Next is to grease and lube every moving component including the chain. After 2000 miles I'm still running the stock chain with very little stretch and well within spec. It was one of the 1st things I pulled off and put in a can of 90w synthetic gear oil to soak. Spraying chain lube on the out side of the chain doesn't lube the most important part of the chain. That where chain stretch starts and is caused by the wearing of the internal components. Okay enough of my rambling lol.

I probably go you way once or twice a month for work. Do they have any campground/ATV parks in your area? I've been looking for other places to go. We go the Bonnet Carre Spillyway on a regular basic and spent a few weekends up at Tower Traxs in Fluker and Silversprings up in Mount Herman. Tower Trax is about the best place I've been. Miles of trails to ride.

So a 16/40 seems to be the best of both worlds as far as gearing. Keeping street at 60mph max and off road grunt. My old bike i had to regearand dont want it screaming while doing 60

Yes it's been working perfect for me. Most of the highway riding I've been doing lately has been 50-60 mph. The 17 is good if your on flat land and light trail riding but the 16 seem to be better for both worlds.

The main roads around me are 50-55mph but i also go 5 over. The thing with the trails where i am is there all hilly so id want some low end grunt to get up them.

How many rpms is motor turning with the 16/40 at 60mph for curiosity

I just put the 16 on a couple of weeks ago and didn't really pay attention to the actual rpms. But I would say around 6000. I'll check over the weekend if the rains hold off. You will still have some good low end with the 16.

Well, one of the reasons the Hawk (and others that use the same engine) works so well is because of the great torque curve of the engine. It has plenty of low end grunt, especially after the engine is broken in. Carburetor tuning is required to get the most out of it, all the way from idle on up. No matter which gearing you choose, it is going to be a compromise. But 16-40 works pretty well....ARH

Yes, the 16/40 is a great combination, which is why I went to a 17/43. It's nearly the same ratio :tup: 16/40 is a 2.5:1 ratio. 17:43 is a 2.53:1

The advantage of the 17/43 combo is a minor one, but one I happen to like, which is sprocket and chain wear. These two sprockets cause an almost perfect roller hunting scenario, so combined with proper chain care and chain alignment it should theoretically make for the longest sprocket and chain life.

In my opinion the 17/43 (16/40 or 15/38) is the best all rounder gear ratio for a modified bike. The only downside is that it will lack some punch on more technical stuff, which is why swapping the front sprocket is a great way to get relatively easy gear ratio changes. I have swapped back to a 15 front with my 43 rear, and have found it just about perfect for any sort of off roading, but it loses some of it's highway cruising capabilities.

The front sprocket is so quick and easy to swap too.

Yes it is, and it requires minimal tools, and can be done just about anywhere in 10 minutes. That's why I decided on the 17/43 setup, because with just a tiny bit of work I can gear down for off-roading fun, have fun, then gear back up for the ride home.

This is advantageous for me, because I live at least 40 minutes to an hour from any sort of true off-road trails, and Nebraska state highways are all 60-65mph. It makes having good road gearing a necessity if I don't want to ride wide open at redline for long periods of time, but also means that I won't have the best gearing for the trails when I get there. Swapping front sprockets is the best and easiest solution to this.

I agree. The "Hunting Tooth" principal is imprtant to chain and sprocket life. It evens out the wear on both the chain and the sprocket, so giving the longest life to both components, assuming adequate chain lubrication....ARH

My chains are bone dry after 10 minutes.. i think the eviroment has more to
do with chain & sprocket life than a hunting tooth ever could on a dirt bike..


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That problem is why I went from oiling a chain to a hot bath of canning wax mixed with graphite.....ARH

I have wondered how natures wonder lubrcant would work...
Bees wax...