New Hawk, new adventures.

[Megadan]

So, after much tinkering around....

Of all of the CDI boxes I have tried, the Purple unit is the one I keep going back to. I actually gave a more pricey CRF230F ProCom box a try (40 bucks), and it did perform decently in the middle and upper RPM ranges for sure, but not any better than the purple unit when adjusted to add more advance up top, but without any low RPM benefit. The Red one is just about the same as the stock one, and the blue one was total crap.

I haven't had a chance to really ride my Hawk too much the last week and a half, but I finally got around to getting my jetting figured out. 38 pilot, needle 2nd notch, 155 main. Mixture about 2 1/2 turns out on the air screw. I did try a 160 main and it pulls very strong, but I do get a surge transitioning back to the needle. Either I need to drop the needle another notch, or the 160 is just a hair too rich. It doesn't cut out and bog wide open, so if it is too rich it is just barely. I might have to go pick up a 157 main to try. Either that, or I need to start looking into finding a needle profile with a shallower taper and/or larger diameter.

The 155 pulls cleanly and strong, and the plug chop shows just the lightest hint of tan in low 80/high 70 temps, so it is not bad by any means.

I kept bouncing back and forth with the pilot jet, but I finally settled on the 38. I am not a big fan of having the mixture screw that far out, but the bike is strongest at idle with that jet and it can pull my fat butt along at idle in first gear without stalling. The 35 also would occasionally have lean fits at light throttle when the air temps dropped into the 70's.

All of this jetting is with a foam pod filter. Now that I know where the jetting limit is for the foam pod filter I am curious to go back to the other filter and see if there is any performance difference seeing that with that filter even a 145 main jet was causing a WOT bog/stall. I have a feeling it needs a 135 or 140 main to be happy.

My experiment with the 1.5" spark arrestor was successful, but not without minor faults. It does restrict exhaust flow, at least on my bike, just enough to slightly throw off the jetting and make it all just a tad richer. It does make the exhaust quieter though. Not whisper quiet, but it takes it from LOUD to *loud* and gives the exhaust note a bit more of a sharp edge/growl thanks to the increased outlet pressure.

Still waiting on my 31 tooth sprocket to arrive. The one downside to having to order it from Europe... shipping takes forever.

[China Rider 27]

Appreciate this thorough analysis as we all work toward better tuning and performance! CG tough, ride hard!

[duck9191]

My storm went lean when I pulled the arrestor. Minor change but it was noticeable.

[Megadan]

Originally Posted by China Rider 27

Appreciate this thorough analysis as we all work toward better tuning and performance! CG tough, ride hard!

The whole purpose of me sharing all of the details and my own thoughts is to help others with troubleshooting ideas as well as help from others with any issues I may be having with their own insights. I have no problem admitting when I was wrong and then correcting myself here, done it a few times already lol.

[Megadan]

Originally Posted by duck9191

My storm went lean when I pulled the arrestor. Minor change but it was noticeable.

That's pretty much what I experience as well. It didn't entirely alter the performance of the bike enough to be detrimental, but I could tell that everything was just a bit richer than before. I have a feeling that to be ideal I would simply need to step down half a step on the main jet (ie. 152 from a 155) and it would be fine.

[Megadan]

So, thanks to a member on the Hawk 250 facebook page I am now waiting on something new for the engine of my Hawk. You know I can't leave well enough alone.

Basically, he managed to find the 70mm cylinder jug for the air cooled CG300 along with the piston and rings. If they will work or not is the only unknown. Everything looks to be that way, but until I have them in my hands it is just speculation. It would be nice to match up another 21cc to the cam and 30mm carb. So far I am only in it $36, but I still have to pay the shipping from China to here which could easily be just as much.

I am hoping it works out because that is honestly the one thing I have wanted to do for a while.

[Deckard_Cain]

Originally Posted by Megadan

So, thanks to a member on the Hawk 250 facebook page I am now waiting on something new for the engine of my Hawk. You know I can't leave well enough alone.

Basically, he managed to find the 70mm cylinder jug for the air cooled CG300 along with the piston and rings. If they will work or not is the only unknown. Everything looks to be that way, but until I have them in my hands it is just speculation. It would be nice to match up another 21cc to the cam and 30mm carb. So far I am only in it $36, but I still have to pay the shipping from China to here which could easily be just as much.

I am hoping it works out because that is honestly the one thing I have wanted to do for a while.

Looking forward to seeing how that goes!

[duck9191]

So the cg300 is a true 250cc? Gotta love China lol.

[Deckard_Cain]

Originally Posted by duck9191

So the cg300 is a true 250cc? Gotta love China lol.

Ah, a fellow Michigan Hawker.

Personally, I'd love the Hawk with a 400, thumper or preferably a parallel twin.

Ok so basically a clone of the DRZ400 I guess. Lol.

[duck9191]

Originally Posted by Deckard_Cain

Ah, a fellow Michigan Hawker.

Personally, I'd love the Hawk with a 400, thumper or preferably a parallel twin.

Ok so basically a clone of the DRZ400 I guess. Lol.

I wish they would make a reasonably price drz400 knock off lol. Been eyeing a drz, been a few S's for 3500. Want a sm but they hold their value to well.

[Megadan]

Originally Posted by duck9191

So the cg300 is a true 250cc? Gotta love China lol.

No, the 300 has a slightly bigger stroke to go with it's 70mm bore, but yeah, it is still nowhere near 300cc. The 70mm bore will make the CG250 250.15cc, so it will actually be true to name.

[duck9191]

Originally Posted by Megadan

No, the 300 has a slightly bigger stroke to go with it's 70mm bore, but yeah, it is still nowhere near 300cc. The 70mm bore will make the CG250 250.15cc, so it will actually be true to name.

Do they share the same case?

[Megadan]

Originally Posted by duck9191

Do they share the same case?

not 100% sure. I know that the OD of the cylinder sleeve is supposedly the same, the height of the cylinder block is the same, and the total height is only .5mm longer. So in dimensions the cylinder should work. I won't know for sure until I get one in.

[Megadan]

Since I have been away a little while I could update this. I haven't actually really done much while I have been away.

Put the 31 tooth sprocket on the back, but decided to go back to the 33. It does pull very well in the lower gears, but it is just enough of a change that I don't like how it pulls up steeper hills in 5th with me on board. The difference is slight, but the 33 just feels better. Since I don't care about top speed so much, I am going to leave well enough alone.

I had to wait 3 months for it, but I ordered in a TT250 seat and it finally arrived a couple of days ago.

For starters, the TT250 seat construction is just better, period. The plastic frame of the seat is made of a better plastic, and thicker. It fits much tighter to the bike as well. The Vinyl cover on the seat is thicker and a better texture as well. The foam while still a bit on the soft side, is a lot firmer than the Hawk seat, and the shape of the foam is actually a bit different, with the hump being much less pronounced. Overall the seat is much more comfortable, and was well worth the money.


As far as the CG300 parts go. Still waiting on them. No update as of yet.

[grumpyunk]

I have seen zero about roller tipped rockers for the CG250. You installed a pair. How well do they work? You mentioned different push rods. Are they necessary to use the roller rockers?
How do you set the cam timing on the CG. I can't see the timing marks on the SG250 that I am working on. What is the trick to see the timing marks?
I have never split one before, so am in murky waters as far as I am concerned. Don't know if I have to remove the cluch basket etc to gain access to the gears inside the case. I just need to remove some bits of a HeliCoil that broke off and hopefully put it back together. I got the roller rockers on a whim figuring they'd cut friction. New cam too, just because it was a low cost option. From the same ali source I think you used. Any pointers on installing the rockers & cam? I have not taken the case apart yet, but will soonly and then put in the cam & rockers. Just no doc to work from...
tom

Added: Have you gotten the bigger cylinder yet? I understand a different crankshaft is necessary. Could be wrist pin diameter, or the actual piston weight imbalance normally incurred with BBKs.
tom