Hawk is here, yay!

[Megadan]

Originally Posted by BlackBike

See, if you would have bought from a reputable dealer all these things would have been professionally taken care of be fore you received the bike ( yea right)

Yeah, like my buddies brand new R6 that had the rear banjo fitting on the rear master cylinder back out after 200 miles lol.

[Megadan]

Originally Posted by Trey

having the same problem with loud vibration of front pad rotor. will give this a try.

I wont say that it will fix your particular problem, but it may help you find it.

[Megadan]

So since I discovered that with my new rear tire my current effective gearing with a 120/80-18 tire with a 17/43 sprocket setup is more or less the same as a 17/45 on a 110/100-18 tire, in order to get back to the same basic overall drive ratio I would need to run a 41 tooth rear sprocket, which does exist in the JTR269 rear sprocket but it is not offered by any vendors here since it came on a bike we never received and would have to be ordered in from Europe.

So, instead of ordering that sprocket right away I am going to go ahead and experiment with going just a bit taller and see how it copes with my mass on the bike. I went ahead and ordered a 39 tooth rear sprocket with some of my work points through Amazon... I have nothing better to use them on lol.

A part of the reason I am doing this is because I plan on converting to a 520 chain, and while I already have the 13 tooth front sprocket and chain I need for this, I want to go ahead and figure out what rear sprocket to run before I order. Mainly because I want to figure out if I want to stick to the 17/43 and stock tire final drive i had before, or maybe go a bit taller since my bike is mainly used on road. If the 39 proves to be too much of a dog, then I will likely order a 32 rear as this will give me the closest match to my previous goal of having the ability to swap between off-road an on-road capable gears with a 17/43 changed to a 15/43, just a tiny bit shorter on the road side, and a tiny bit taller on the off-road side - within a couple percent.

If I find that I like the taller gearing then I will likely order a 30 tooth, and if I feel I want something inbetween I can always get a 31 tooth...but that has to come from Europe.

Don't worry, I know that the 520 chain is overkill for this bike...by a long shot. I just feel that 428 chains are mildly under rated for their duty/abuse behind the type of torque and weight this bike demands of it. This is especially true of taller gearing which puts more tensile stress on the chain links.

Yes, it is a bit heavier than 428 chain, but not by a whole lot, usually an extra .15lbs per foot. There are also a lot less teeth options when it comes to rear sprockets compared to the 428 chain. It also means that front sprocket swapping to give an easy ratio swap is more limited as well, so careful planning and more compromises are in order... Hence the experimenting.

[Emerikol]

Dan, check the collar where the speedo drive/pickup goes on the side of the front tire. Is it possible that something has come adrift in that assembly? As far as the headshake goes, I think that you're experiencing the same thing I mentioned a few posts back. I don't think the steering stem nut would have backed off, at least, mine has always been tight. I wonder if the headshake could be a combination of the lightness of the motorcycle, and some small imbalance of the rim? Perhaps one of the spokes has loosened up a bit and is creating the oscillation? I have to admit, I haven't checked my own spokes, so I'm really just spitballing here, trying to drum up some ideas while I have a midnight feeding with Nugget. Please keep us posted as this unfolds.

[Emerikol]

So I guess I should pay more attention to the thread before I reply. Glad you got it worked out. Back to feeding Nugget... Any update on the headshake?

[Megadan]

Originally Posted by Emerikol

So I guess I should pay more attention to the thread before I reply. Glad you got it worked out. Back to feeding Nugget... Any update on the headshake?

I think mine is a combination of things. My stem nut did back off a little. I marked the nut and threads with a grease crayon when I last greased the bearings during assembly and they were about an 8th of a turn off. I tightened it back up with some thread locker this time. Most of the shake went away, but its still faint aroung 60+ I am planning on checking my rim for trueness tomorrow..

[Emerikol]

So between packing up the house and doing all the new baby routine stuff, I managed to dig up a bit of time for a ride today. I had the Hawk up to around 65mph, and got the worst headshake on it I've ever had. It was so bad I thought I was going to dump the bike. I pulled out of the throttle and pushed forward on both ends of the bar and got it back under control, but just barely. Seriously scary moments there. When I got back to the house, I checked the tire pressures, and they were WAY low. Like 24 pounds in the rear, and about 15 pounds in the front. I usually run 32 and 28. Once I got the tires back up to scratch, I went back out and everything seemed to be good. I hate to bring up something so basic, but have you put a good gauge on your tires as part of running down these symptoms? Just something that occurred to me after today's near miss.

[BlackBike]

Originally Posted by Emerikol

So between packing up the house and doing all the new baby routine stuff, I managed to dig up a bit of time for a ride today. I had the Hawk up to around 65mph, and got the worst headshake on it I've ever had. It was so bad I thought I was going to dump the bike. I pulled out of the throttle and pushed forward on both ends of the bar and got it back under control, but just barely. Seriously scary moments there. When I got back to the house, I checked the tire pressures, and they were WAY low. Like 24 pounds in the rear, and about 15 pounds in the front. I usually run 32 and 28. Once I got the tires back up to scratch, I went back out and everything seemed to be good. I hate to bring up something so basic, but have you put a good gauge on your tires as part of running down these symptoms? Just something that occurred to me after today's near miss.

topped mine up before I took off today.

God trying to get your attention

[timcosby]

the rake and trail on these buggers is for dirt bike riding i believe. i get a small shake when hitting any small bump at 45 or above. if the trail is close to the minimum it will get a high speed wobble if its below minimum you could get a high speed wobble that is unrecoverable. i think the hawks are just close to minimum. your low pressure let the front go down changing the trail.

got 4" of trail on this one.

[Megadan]

I check my pressure every day. I have a small compressor and a gauge/filler valve i used to use when I did SCCA stuff. Makes it quick and easy to do.

[pete]

Originally Posted by timcosby

the rake and trail on these buggers is for dirt bike riding i believe. i get a small shake when hitting any small bump at 45 or above. if the trail is close to the minimum it will get a high speed wobble if its below minimum you could get a high speed wobble that is unrecoverable. i think the hawks are just close to minimum. your low pressure let the front go down changing the trail.

got 4" of trail on this one.

minimum = ?

4" of trail is less that most dirt bikes have...
If that chopper thing dose have 4" of trail it is less than a
Yamaha XT660R that has 4.21" of trail & 27.25* of rake standad...
And the XT660X motard version has 3.70" & 26*

the Hawk will be somewhere around the 4" plus area.... But if the front
is as soft as some complain that it is.... that will reduce the trail & steepen
the rake of the forks.... the heaveyer the rider the worse it can be...

the thing with a wobble is you are always reacting to something that has already happened..
IE... if the left side handle bar jerks forward so you pull it back.... but by the time you react to that the bar is already about to move rearwards.... so your action is only going to make
it worse... so put even pressure on both sides & move your weight forward to make the trail
do what it was designed for.. "self centreing"


...

[Megadan]

Suspension compression on its own will not change the rake and trail in any major or permanent manner unless the attitude of the bike has changed. Example: I never had a head shake problem until I added more preload to the forks. In doing so, when I put my weight on the bike the rear end compresses more relative to the forks than it did before, thus making the rear of the bike effectively lower at "ride" height. While this will technically increase the rake and resulting trail figure, it also makes an already light front end even lighter. So while the hard numbers and facts say I should have heavier steering and a more stable front wheel, the physics behind the change also work against me.

A big reason many cruisers tend to suffer from head shake is for the same reason. The weight distribution is further back, so even though they generally have high rake and trail fugures, they can still be prone to a little wobble at certain speeds and conditions.

When I say my bike has a very faint head shake, it's the ever so slightest of wobble, and not enough to be unstable. I've (bravely) let go of my bars as much as I can at 65mph without losing throttle, and they barely wiggle. It also doesn't worsen with bumps in the road or other outside conditions. I have had worse wiggle from a cruiser.

Likely what I am feeling is my wheel being laterally out of true just a tiny bit. I never had a chance to check it, but I suspect this to be the case.

In an experiment to my lighter front end theory, I attempted to basically sit on the fuel tank and lean forward at around 60...which yes I probably looked ridiculous...and let go of the bars as much as I could, and no wiggle. If the wheel has just a tiny bit too much lateral runout it can sometimes be masked by extra front end weight. Sounds kind of counter-intuitive, but it wouldn't be the first time I had this issue lol.

[Megadan]

Okay... so revisiting the whole gearing combination thing.

I tossed on the 39 tooth rear sprocket and spent a solid day riding around on the bike getting a feel for it. Before I begin, let me reiterate that with the 120/80-18 rear tire my bike acts like it is 2 teeth larger than it would on a stock bike, so a 39 tooth for me is like a stock tire with a 41.

On flat ground it was amazing, and around town it definitely is good road gearing. Much less shifting between gears, able to hold gears for corners, and you will never go beyond 4th gear on any in town main roads. It's not a big difference to when I had the 43 tooth on the stock tire, but enough of one to notice.

My problem is hills. Now most people imagine Nebraska as flat, but in truth a majority of my state is big steep rolling hills and remants of mountaints (Bluffs), so the ability to hold highway speed on a hill matters to me. I think this gearing is just a bit too much if you have to climb anything decently steep for any length of time. I often found myself having to downshift to fourth in order to hold my speed on these hills, then winding out the engine more than I ever had to with the 43 tooth on the stock rear tire.

My conclusion. With a 17 tooth front sprocket - If you live somewhere with less inclines and/or only ever use your Hawk around town, then the 41 and 39 tooth sprockets are a great option. If you live somewhere like I do, where big hills are a constant, then stick with the 45 or 43 tooth gears. Unless you aren't a 260+lb 6 and a half foot tall sasquatch, then I am sure they will work much better for you.

Me, I want that little extra bit of pulling power to heft me up and over without fighting too hard and straining the motor. So I decided to order a 31 tooth rear sprocket for my 520 chain conversion. That will bring me back close to the same final drive as a 17/43 did on the stock tire, being only 1.6% taller overall, which is the closest I can get to having that same final drive.

[goat67]

Originally Posted by Megadan

Okay... so revisiting the whole gearing combination thing.

Me, I want that little extra bit of pulling power to heft me up and over without fighting too hard and straining the motor. So I decided to order a 31 tooth rear sprocket for my 520 chain conversion. That will bring me back close to the same final drive as a 17/43 did on the stock tire, being only 1.6% taller overall, which is the closest I can get to having that same final drive.

Typo I think 41 not 31

[Megadan]

It was covered in a previous post by another member - jimwildman, but if you are interested in doing a 520 chain, the sprockets needed are as follows.

Front: JT sprockets part number JTF328 with the options of 12, 13, or 14 teeth.
- Note: According to the other member that has done this conversion, the
14 tooth will likely be too large.
Rear: JT Sprockets part number JTR279 with options for 30, 32, 33, 35, 38, 39,
and 40 available in the U.S. Market.
- Other tooth counts such as the 31 that I ordered are not sold in the
U.S., and I had to order mine from the UK. It was only a few more
dollars though, mainly due to shipping.

If you are unsure of what sprockets to order, then you can always use a sprocket chart to compare ratios. For quick reference, here are a couple of the more popular combinations.

Stock 15/50 =12/40 (exact match)
17/50 = 12/35 or 13/38
17/45 = 12/32 or 13/35
17/43 = 12/30 or 13/33
17/41 = 13/31

As far as chain links. He stated he removed 5 links from a 112 link chain for his 13/38 setup, which I think was a typo since chains are even numbered in links. Based on chain pitch, a 102 or 104 link chain is close to the same length as a 128 link 428 chain. I would personally buy a longer chain and remove the links needed - as usually most lengths are usually close to the same price anyway. I will obviously post up my results when I get around to this.

The only downside to this conversion is the loss of being able to swap the front sprocket for 2 teeth down or up for a drastic change in gearing. Being able to swap between a 15 and 17 tooth front makes it far easier to switch between more road friendly gearing and more off-road friendly gearing. So I won't be able to achieve as drastic of a jump.

If this is something that appeals to you, then stick to the 428 chain and sprockets. There is nothing wrong with this chain setup. My reasons for the 520 chain is mainly my penchant for overkill.

To me, the 428 chain is not ideally suited for hard use on a 200-250cc class bike, be it pushing a heavier bike/Rider with tall gearing or lots of heavy handed off-road use in lower gears. Both of these scenarios put a lot of load on a chain, and it's close to the limits of what a 428 chain is meant to handle, even a Heavy Duty version. However, for the average person, the 428 chain is likely more than fine. Keep in mind, this is my personal opinion and should not be treated as fact in any way.