Hawk locking up

[JerryHawk250]

You could try TXPowersport.com. Even though the parts are not listed they should be able to get them for you. Worth a try.

[letsride]

If everything checks out, then yeah you could in theory swap everything into a new set of cases. But who knows what kind of carnage happened when the case busted, and why did all this start happening to begin with? Could be a laundry list of problems with the internals of that motor. If it were me, I would cut my losses and get a new mill. But thats just me.

[Lit Hawk]

Got it torn down and waiting on a new engine block, I only needed the left side. $67 w/shipping from rps. Only 1 gear was damaged ordered from csc. So just waiting on my parts so I can put it back together. I was thinking of porting the head while it’s down but I have no idea how. I’m a sheet metal fabricator and started off with polishing and grinding stainless steel, my father taught me and his father taught him. In 18 yrs ive been in this line of work have never seen anyone else that can polish as good as us. So I know how to polish and grind and have the tools too. I searched YouTube a bit to see if someone showed how to do it and came up with nothing. Can anyone point me in the right direction or have links to show me how it’s done? Thanks

[Megadan]

Search headbytes on youtube and watch some of his videos. He goes into a lot of theory and shows how he does some his work. That would be a good start.

The real question is, how serious of a port job are you wanting. Of the 4 ported heads that I know of mine and Jerry's are the most aggressive in terms of reshaping and material removal, and mostly on the exhaust port. Silva did a good straightforward port job with some sanding rolls and he reported a decent performance boost.

[Lit Hawk]

Awesome link MegaDan, definitely subscribed. Id like to do the most aggressive for most hp but safest. Don’t want to have to put more money on new cylinder head because I screwed it up. . I’m pretty impatient to get my bike back on the road it’s hard for me to let her be. I’m gonna study vids and hopefully learn before my parts come in so I can get it done. Last time my hawk was down I gutted the cat and grinded the lip inside my exhaust going into engine. It was a lot and I think that’s what porting is but on engine side. I just don’t understand the measurements and compression test. I just replaced my rear bearings also like 2 days before I cracked the engine. Luckily I wasn’t going that fast and had just left work my rear wheel was wobbling. Had to walk it to my dads house. good thing wasn’t that far. Houston bearings & supply I got 1 timkin and 1 Japanese bearing don’t remember the name but like $6 compared to the $14 timkin. Sux but waiting was not an option. It was pretty scary when that bearing went out. I was just about to jump on the freeway after work and all of a sudden that rear wheel wobble.

[Megadan]

Well, the most power without affecting reliability. Given a lack of experience, I would suggest trying to keep the port work simple. Using sanding rolls is the safest way to do port work. You won't be able to go super crazy with reshaping around the valve guides, but it will allow you to smooth the ports out, and with enough effort, reduce the pinch point created by the excessive amount of material around the valve guide.

This is a before and semi-after look at the exhaust port on the head I ported for my Hawk (if you haven't already seen it). Most of the focus with my port work involved opening up the roof of the exhaust port around the guide, and trying to smooth the flow around the guide along the roof of the bowl. With exhaust ports, this is where you want to focus most of your efforts. The short side radius just needs a good smoothing out, but keep material removal to a minimum.
http://chinariders.net/showpost.php?...&postcount=113

Finished product looking in from the chamber. http://chinariders.net/showpost.php?...&postcount=129

That change in the exhaust port took me several hours, going little bits at a time, until I got what I was after. This is where a big portion of the top end power gains is going to come from. The intake port is a little restrictive, but already fairly big for the size of the engine, so focusing more on smoothing out the port and bowl transitions, and removing material around the sides of the valve guide at the roof where it transitions into the bowl will make the biggest difference.

Another area where you can gain a little bit more from the head with a little work would be to smooth out the combustion chamber. Get rid of the machinists ridges around the valves, and smooth the edges in the center of the chamber formed by said ridges. This will allow the intake and exhaust charges a much more direct and smooth path in and out of the chamber as well as eliminate potential hot spots. I did almost all of this to my head by hand with sand paper.
Before: (Second picture) http://chinariders.net/showthread.php?t=19200
After: http://chinariders.net/showpost.php?...&postcount=133

As far as reliability goes. At this point you could call it good and skip decking the head. If you want to gain a little more compression, then have the head milled half a mm. This will keep the compression ratio well within the mid 9:1 range, which won't affect reliability. I decked my head almost a full 1mm, which, thanks to the non-factory head I used, put me in the low 10:1 range for compression. (10.27 to be exact).

[Megadan]

If you haven't run into the other Hawk owners threads and their port jobs...

JerryHawk250's exceptional work that makes mine look like doo doo in comparison. http://chinariders.net/showthread.php?t=20410

Silva's thread. This is a great look at a basic sanding roll port job that almost anybody could do. http://www.chinariders.net/showthread.php?t=20362

Between the three different approaches, you will notice many shared elements in where the port work was focused. That should give you a good idea of what direction to take.

[franque]

Hey, for the cases,

Originally Posted by franque

You have to get them as a set (they're machined as a set).

Basically, if you don't get a matched set, the crank could easily be so tight that it would bind, or too loose, so that you would get side to side endplay, which you could only fix by shimming, if you could even find said shims, not to mention the jug might not center in the cases. Again, you really should just get a set, it'll probably save you from owning a set of paperweights.

[Lit Hawk]

Yes ive read everyone’s threads, a lot of great info. Thanks for the help MegaDan Franque I do remember reading your post about getting them as a set. They transferred me to the mechanic at RPS and I asked him if it would be ok to just replace the left side. He assured me it would be fine but now You haveme doubting it. Damn I really didn’t want to switch that side out but you make a good point. Anybody have any experience with just replacing one side?

[franque]

I'm a certified, Honda-trained motorcycle and atv mechanic. I wouldn't trust a certified bolt screwer working with RPS. SOP for anything that needed a crankcase half with Honda single cylinders was that it needed a crankcase, due to the aforementioned reasons. Additionally, with CB's, there are small differences between brands (not sure if that means that say, a loncin and zongshen wouldn't be compatible, but I wouldn't really assume anything), and according to humanbeing, there are three different shift drum types, which makes me think that unless you're lucky, you might be chasing parts trying to make the transmission work.

[Lit Hawk]

So I just got off the phone with RPS and he told me they don’t come in pairs that they ship them from the factory separate. He can sell me a right side but he has no idea if they were machined together. So we’ll see hopefully by this weekend. Hope I’m not building a death trap.

[JerryHawk250]

I agree with franque on this. It should be sold as a set. Hopefully you won't have any issues. Just check during assembly for tolerances. Everything should move freely but don't want to much play either. I'm certified, just not as a mechanic

[Lit Hawk]

got my new case today and guess what. It doesn’t match, looks like I might have to throw in a new engine after all. It must be a newer model I’m guessing cause my bikes 2017. Can y’all tell the differences. @$#%!!!!

[Megadan]

Originally Posted by Lit Hawk

got my new case today and guess what. It doesn’t match, looks like I might have to throw in a new engine after all. It must be a newer model I’m guessing cause my bikes 2017. Can y’all tell the differences. @$#%!!!!

I would send them back these pictures. They sent you the wrong item.

[JerryHawk250]

Definitely not the same.