Why 17/45 Sprockets on Hawk 250?

[JerryHawk250]

I got the sprocket and jets in today. I installed the 110 jet first then swapped out the 50t with the 40t. It all went pretty good. I had to take off 2 links of chain. The results are great. Before with stock sprocket and jet 63 MPh at best now 74 MPh. It's perfect. Cruise 60 MPh with ease.

[Republic]

I'd been running 17/45 for awhile but changed to 15/45 this afternoon. Once I can give it a whirl I'll report my findings.

The 17/45 makes first gear just a little too fast for my uses, and it maxes out at 63ish mph at 6500 rpms which according to the specs is below the 7000 rpm max HP. Maybe 15/45 will be better on both fronts?

[JerryHawk250]

Originally Posted by Republic

I'd been running 17/45 for awhile but changed to 15/45 this afternoon. Once I can give it a whirl I'll report my findings.

The 17/45 makes first gear just a little too fast for my uses, and it maxes out at 63ish mph at 6500 rpms which according to the specs is below the 7000 rpm max HP. Maybe 15/45 will be better on both fronts?

Have you done anything with the carbrerator? Jetting? I was getting 63 mph with the stock 15/50.

[Jmcgee]

Is that speedo 63? or GPS confirmed?

[Republic]

GPS confirmed, and that is even with carb re-jetting. At stock gearing I was afraid to go past 50 due to the high rpm's on a fresh engine, so I'm not sure what I could have gotten.

My problem is wind. With a tailwind I can do 65+ but with any headwind I'm at 60.

This weekend I'll see how the 15/45 does, if I can get into the power band without my hands going numb.

[JerryHawk250]

I'm heading out tomorrow for the weekend of camping and trail riding. Going to see how the 15/40 works out. It still has good low-end power. Can still pull a wheelie in 1st. Lol. The 63 and 74 mph are both GPS confirm

[JerryHawk250]

Originally Posted by Republic

GPS confirmed, and that is even with carb re-jetting. At stock gearing I was afraid to go past 50 due to the high rpm's on a fresh engine, so I'm not sure what I could have gotten.

My problem is wind. With a tailwind I can do 65+ but with any headwind I'm at 60.

This weekend I'll see how the 15/45 does, if I can get into the power band without my hands going numb.

Were are you located? What elevation? I'm almost at sea level in south Louisiana. I know years ago I took a trip up in the mountains in Tennessee on a my Yamaha I had and I lost a lot of power at the higher elevations.

[Republic]

I am pretty much sea level Oklahoma. With 17/45 I can get to 60 easily and can even climb a moderate hill at 60, but it just has nothing left above 6000 rpm's. Maybe my exhaust has some bad welds and is extra restrictive.

I'll know more this weekend when I try a speed run with the 15/45

[JerryHawk250]

Originally Posted by Republic

I am pretty much sea level Oklahoma. With 17/45 I can get to 60 easily and can even climb a moderate hill at 60, but it just has nothing left above 6000 rpm's. Maybe my exhaust has some bad welds and is extra restrictive.

I'll know more this weekend when I try a speed run with the 15/45

Oklahoma sea level? Aren't you about 800-1000 ft above sea level? lol South La. 6-10' above lol. I removed the end cap on the spark arrestor. It helped some.

[Republic]

Map says I'm 471 ft above sea level. I removed the endcap but didn't really notice a difference. I've seen some images of the inside of some exhausts and they looked horribly restrictive, maybe mine is.

[chuck]

My hawk been running very good with 17t-39t.Today I hit 72 mph @7000rpm with a fair amount of wind hitting my chest.Next week I'm going with 17t-42t and I think it will be the best combination for my weight and street riding.
80-20 tires
115-30 jets
k and a filter
ngk spark plug
Pro-circuit t-4 exhaust
168 lbs.
Mystef's accurate cluster.
Side note:The Ducati s2r1000 has taken the back seat since I purchased the Hawk,it's a ton of fun for an affordable price.

[JerryHawk250]

Originally Posted by Republic

Map says I'm 471 ft above sea level. I removed the endcap but didn't really notice a difference. I've seen some images of the inside of some exhausts and they looked horribly restrictive, maybe mine is.

I never really paid attention to what it looked like on the inside. It was dark when I took the spark arrestor off and took off the end cap. Maybe take a long 1" rotary drill and bore a hole right through the center. I know sounds crazy but who will be the first to try it.

[Republic]

Tried the 15/45 today and RPM's at 60 aren't something I'm comfortable with for any sort of distance. Went back to 17/45. I think 16/45 might be the sweet spot for me.

[Ariel Red Hunter]

Originally Posted by JerryHawk250

I never really paid attention to what it looked like on the inside. It was dark when I took the spark arrestor off and took off the end cap. Maybe take a long 1" rotary drill and bore a hole right through the center. I know sounds crazy but who will be the first to try it.

I don't know how bad the muffler is. What I do know is that the head pipe is terrible, and the exhaust gasket is awful on the Hawk.

[JerryHawk250]

Got back from my weekend camping /off road trip. 212 mile over the weekend through trails and steep hills. The 15/40 combo worked perfect to me. The 110 jet really helped out. I'm 5'11" 180 pounds so not a lot of weight to carry around. There were a few hills that look like there was no way I can make that but went right up. I wish I would of had a helmet cam. We rode past midnight on Friday night, all day Saturday and night and Sunday. Don't know why my butts so sore lol. I'm not changing anything. it runs to good. I'm glad I mounted some bright LED's on my daughters side by side to light up the trails. Next on list are some LED's for the Hawk.