Hawk 250 - Thinking about another sprocket

[Bill1]

I swapped out my stock 15/50 sprockets for 17/45 a while back and was very happy with the improvement. I use my bike for mostly (95%) commuting, but still want to be able to run through some loose sand and stuff and to take on some trails.
I was thinking about swapping the rear sprocket to 39t, but was afraid that I would lose any low-end power in 1st. If I did go to 39t and knew I was headed out, I could always swap the front back to 15t and be about where I am now.

Has anyone gone as tall as 17/39 and taken the Hawk offroad?

I'm in mostly flat country and only weigh about 160# so I'm thinking it might be OK on the road. I'm just worried about bogging down in 1st offroad.

[Megadan]

Originally Posted by Bill1

I swapped out my stock 15/50 sprockets for 17/45 a while back and was very happy with the improvement. I use my bike for mostly (95%) commuting, but still want to be able to run through some loose sand and stuff and to take on some trails.
I was thinking about swapping the rear sprocket to 39t, but was afraid that I would lose any low-end power in 1st. If I did go to 39t and knew I was headed out, I could always swap the front back to 15t and be about where I am now.

Has anyone gone as tall as 17/39 and taken the Hawk offroad?

I'm in mostly flat country and only weigh about 160# so I'm thinking it might be OK on the road. I'm just worried about bogging down in 1st offroad.

I do believe Jerryhawk would have the best opinion on this. He ran a 17/40 for a while and has currently switched back to a 16 tooth front sprocket because the 17/40 while great for road use, wasn't very off-road friendly.

His 16/40 combination is the same basic ratio as the 17/43 gears I currently have, and I ran those on the stock Hawk tires (currently have a slightly smaller rear with the same gears) and I found that combination to be a good mix for a bike that still sees a lot of road use, but doesn't sacrifice too much off-road.

Oh, and if you are worried about losing grunt in first gear, don't be. With basic mods to the exhaust and intake, and a properly tuned carb, I was never disappointed in my bikes get up and go in first gear with the 43 tooth on the road. Off-road MAY be a bit of a different matter, but even for light trails I really never had a problem.

So my opinion is, go for it. What Jerry and Myself both kind of decided on our own bikes was that if necessary we can change out the front sprocket. The front is a really quick and easy change, and going between a 17 and 15 tooth (or even 16) means we can still use the same chain with zero issues.I would say maybe try a 41 tooth instead of a 39, but I am also a bigger rider. If you weigh sub 200lbs the 39 might work out ok for you. In any case, if you decide it's a bit too tall for your liking, as you said you can go back to a 15 tooth front. If you decide to take a longer ride though, you can easily swap that 17 back on for good highway revs.

[JerryHawk250]

The 17/40 is a good for the highway and light off road riding. Not so good in soft sand and mud. I only weight 180. 16/40 is perfect for off and on road which is what i'm currently running because while out riding i'll take little detours through the cane fields. Like you south Louisiana is mostly flat but when I do go up to north Louisiana where there are steep hills and do some heavy off road riding I swap out to the 15/40 which is about the same ratio as your 17/45. The 17/39 will be good for highway but may be alright for light trail and on hard ground. Front sprockets are quick and easy to change out. Here's a sprocket calculator I used to figure out what rear sprocket was for me. http://woodsware.aciwebs.com/gears/ Type "Hawk" in the filter to bring up the 2016 Hawk in the list.

[Ariel Red Hunter]

Originally Posted by Bill1

I swapped out my stock 15/50 sprockets for 17/45 a while back and was very happy with the improvement. I use my bike for mostly (95%) commuting, but still want to be able to run through some loose sand and stuff and to take on some trails.
I was thinking about swapping the rear sprocket to 39t, but was afraid that I would lose any low-end power in 1st. If I did go to 39t and knew I was headed out, I could always swap the front back to 15t and be about where I am now.

Has anyone gone as tall as 17/39 and taken the Hawk offroad?

I'm in mostly flat country and only weigh about 160# so I'm thinking it might be OK on the road. I'm just worried about bogging down in 1st offroad.

Actually, I think the 39 tooth rear is a good idea. For one thing, it reduces gear changes in the twisties. The Hawk has a magnificent torque curve. By gearing up, you take advantage of it. Of course you will have to have your carb spot on, both pilot jet and main jet. Or you will be fanning the clutch all the time, which overheats both the clutch, and the engine oil. So get that carb spot on. If after jetting it, it is still a little doggy coming off idle with the clutch fully engaged, raise the float level a hair at a time until it will pull right from idle. Changing the float height is the last step, don't do it to compensate for the wrong pilot jet. You will spend a lot of time in second gear this way, with first available for steep hills and such....ARH

[Fodarr]

If I go to a 17/43 combo is it possible to use the stock chain still?

[JerryHawk250]

Originally Posted by Fodarr

If I go to a 17/43 combo is it possible to use the stock chain still?

Yes, you may have to remove a couple of links.

[Megadan]

A 130 link chain does work with the 17/43, but as Jerry said removing one set of links down to 128 is better. With 130 links, I found my axle sitting to the rear of the adjustment range and leaving very little room to adjust for any chain stretch. With 128 links the axle sits close to the center of the adjustment slots in the swing arm.

[Rejekt]

Originally Posted by Fodarr

If I go to a 17/43 combo is it possible to use the stock chain still?

I've got about 40 miles on stock chain 17/43 right now. I just did the swap the other day. Have no issues and didn't remove any links. Cruise 55 no problem and hit 62. And I'm a bigger guy at 250.