Doing Hawk things.

[Megadan]

I decided to revisit the exhaust I bought almost a year ago and try to make it work just to see if there is any loss from it having a catalyst compared to the normal "ebay" exhaust 99% of Hawk owners run.

It's not available at the moment, but this is a link to it if you decide that you too want something that doesn't fit and needs fabrication. https://www.amazon.com/exec/obidos/A...im/refuge08-20

Before I delve into things too much, you may notice my plain jane carb and filter setup. I already did an experiment with carburetors on the Motocult head and big bore setup with the 292 cam. One for curiosity sake, and the other just to prove a point to people that obsess over having the biggest carb they can manage to fit on the Hawk. Yep, that's a "Mikuni VM26 30mm" It took me 5 minutes to setup, and one main jet adjustment to get running right. I haven't lost a thing in terms of power and speed, and if anything it runs the best it ever has and the mileage is incredible for a larger bore, ported head, big duration cam engine. I will never stop loving the Fake Mikuni carbs. It's staying there forever.

Anyway, on to the real reason we are here. Redneck Engineering! A bit of steel strap for a muffler hanger and a pair of vice grips to hold the mid pipe in place.
(as always, if you want larger pictures, all of the images are linked)


The first problem with this particular exhaust is the mid pipe mounting bracket on the pipe itself. It sits too far away from the pipe, at the wrong angle, and does not center with the mount point on the Hawk at all.

My solution involves 2 heat shield mounts/clamps and a hinge reinforcing bracket from the hardware store (because it was $2 and weirdly perfect for this). Now I could mark my center and drill a hole. If you are curious about the stability of this mid pipe mount solution, it is incredibly solid. Surprisingly so.

This is the original bracket that comes on the mid pipe. If you are so inclined and can weld stainless steel, it would be entirely possible to simply cut off this mount, shorten the legs, and weld it back on in a better position.


I don't have a welder capable of thin stainless, so this is the hardware store solution.




Once I had the hole drilled, just a simple bolt and nut on the back side to hold it, and a large fender washer to help clamp the rubber isolator in the frame better. My last one got chewed up pretty bad because of the heat and probably my own over tightening the bolt and squeezing the rubber too tightly.

I will say this, the exhaust fits way better than the ebay system across the board. Plenty of clutch arm and engine case clearance. If my airbox was still intact it would completely clear the bottom with an inch of air gap. With my home brew md pipe bracket I was able to get the muffler alignment perfectly straight, where before it was putting most of the muffler over the tire.

The head pipe does't protrude out as far and stays tighter to the engine.


Look at all of that room.

[JerryHawk250]

What? No video or sound clip! lol That's definitely different. Looks good.

I picked up a new flux core welder a while back for just under $100. They do make a flux core stainless wire. I'm ordering a spool to test out. I have a huge lump in my exhaust on the Lycan I need to remove. lol I'm sure the welds won't be pretty but I have a huge heat shield that will cover it.

[Megadan]

Originally Posted by JerryHawk250

What? No video or sound clip! lol That's definitely different. Looks good.

I picked up a new flux core welder a while back for just under $100. They do make a flux core stainless wire. I'm ordering a spool to test out. I have a huge lump in my exhaust on the Lycan I need to remove. lol I'm sure the welds won't be pretty but I have a huge heat shield that will cover it.

I had considered a cheap small welder. I still might. Since this is an experiment at this point I don't really mind. Plus, I'm not kidding when I say that mount system is solid. It's not going anywhere anytime soon.

As for a sound clip. 2 things preventing that. I decided to re-do some wiring and eliminated the fuse block I installed, which required a re-do of some wiring and I don't have the right size ring terminal for my new fuse holder. Need to get one today.

The other reason is the weather. We are getting some spring time severe weather. Tornado threat and a chance for large hail, etc.

[JerryHawk250]

I'm really impressed with this little welder. So much better and lighter than my old mig welder. You can use it for Tig and Stick welding too. I see the price went up. If you have Prime, you get $30 off. https://amzn.to/4aCuMXK

[Megadan]

Originally Posted by JerryHawk250

I'm really impressed with this little welder. So much better and lighter than my old mig welder. You can use it for Tig and Stick welding too. I see the price went up. If you have Prime, you get $30 off. https://amzn.to/4aCuMXK

For that price I may just give it a try. Good enough to stick a bracket back on an exhaust after cutting it down to size. I saved that to my wishlist.

As for the muffler I likely won't be using this one for too long. The look is different, and in it's own way kind of cool, but I used it because I had it on hand from my last exhaust experiments. I am probably going to order one of these guys in the 440mm length, assuming I don't find my bike losing power with this exhaust.
https://www.aliexpress.us/item/32568...yAdapt=glo2usa

Or this Round bodied Yoshimura knock off (450mm).
https://www.aliexpress.us/item/32568...Cquery_from%3A

Or I can go silly and use one of these 570mm giants. With this set of pipes I can! That's the part I love, options.
https://www.aliexpress.us/item/32568...Cquery_from%3A

[JerryHawk250]

I was going to order one of the Yoshimura Knock offs for my Vulcan S. Now that I have the ST, I put the Vulcan S up for sale. I have a guy coming tomorrow to pick it up.

[XLsior]

Originally Posted by JerryHawk250

What? No video or sound clip! lol That's definitely different. Looks good.

I picked up a new flux core welder a while back for just under $100. They do make a flux core stainless wire. I'm ordering a spool to test out. I have a huge lump in my exhaust on the Lycan I need to remove. lol I'm sure the welds won't be pretty but I have a huge heat shield that will cover it.

Having used the Blue Demon branded stainless fluxcore wire during my 3" custom exhaust for my van. on much the same type of budget welder 140am 240v...


My only advice is get the thinnest stainless wire gauge. My welder needed to be cranked to 11... and I believe what is .9 wire settled up with a heavy bead though managed to penetrate...


pre heating the job would probably help...


But yes it will do the work it just wont look like a TIG fusion finish.

[XLsior]

Hmmm...


https://www.aliexpress.com/item/1005...80160.html?spm

[Megadan]

So, first of all, it is not a cat. I believe Thumper is right and it was some attempt to make a resonator or built in dB killer. I was purposefully a tad rich, and after over 30 miles of riding around town doing everything short of WOT (ok, I did it once in 4th gear lol) as I am technically still within "break in" for my new rings and cylinder. The "cat" never got any hotter than the rest.of the system. Not even slightly.

My Action camera batteries are all dead. Seems they don't like sitting at 0 percent for a few months, go figure. (Oops) so all I have is this clip from warming it up after the first start. The camera doesn't translate how loud this.is, even at idle. I ended up using both baffles I mention in the video to make it tame enough to not feel horrible conspicuous, and go deaf.

Short Video:
https://youtube.com/shorts/g9ODyDyC_...ueIznQsRZu-Dyo

[Megadan]

So, my opinion on this exhaust. Other than the minor fitment issues, it's a good pipe. If it is a cat, it doesn't seem to hamper the performance at all, even on my big bore, ported, cammed CG250. The larger pipe volume after the "cat" likely helps with that a little bit. What you gain is a better fitting exhaust system, with engine, frame, and airbox clearance as well as the ability to fit any 51mm inlet muffler your heart desires.

As for me, I just ordered this guy iin the 440mm length because it was less than 40 bucks with a "coupon" deal: https://www.aliexpress.us/item/32568...yAdapt=glo2usa

I also ordered this inlet baffle. I may not need it, but I really like the design of tit, and it as $5, so why not. https://www.aliexpress.us/item/32568...yAdapt=glo2usa

It lookslike it will do the job without being as restrictive as the other one I have. My main goal is to have the performance of an exhaust system, but without as much noise as the normal ebay system. I want to be a little less conspicuous... or I am just getting old.

[Megadan]

I did manage to find 2 of these exhausts for sale on ebay, if anybody has an interest. Obviously, some minor fab work required.

https://www.ebay.com/itm/224730570293

[Megadan]

I am reminded why the PZ30 and VM26 can be annoying to tune as I have to play with the idle mixture screw. I went ahead and ordered these to make my life a bit easier. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Should work, but I won't know for sure until I get them in. At the very least the idle speed knob will definitely work, and I prefer that to be a thumb screw.

I also bought a new oil cooler. My current silver unit is taking a bit of a beating now that it's not mostly protected by the front fender, and I have had to straighten quite a few fins, so I ordered a black cooler of the same size with a protective screen on it. That should help it blend in better and protect it. They also claim it holds 150ml, but I don't know how accurate that is.
Link: https://www.amazon.com/dp/B08P2YF26Q...roduct_details

I will say this, without the fender in the way the cooler is almost too effective when the temps drop below 60. With the screen on this one I can at least devise some sort of insert to block air when it gets colder and help the engine get up to temp and stay there better.

[Megadan]

Follow up on the previous post items. Oil cooler came in, and it's just a black version of the silver one I have, but with said screen and slightly thicker/better mounting brackets. That was a nice discovery. I will wait to swap it out until I am at the end of the break in period for the new rings, which is a few hundred more miles. Good chance to really flush out the system, and if there is any metal particles in the cooler they will disappear with the old cooler.

The idle speed knob I ordered out of the first link is perfect. The mixture screw doesn't work. The threads are right, it's the tip that was wrong. I ordered a different one with the right shaped tip... to find that the threads are entirely incorrect. What I need is the tip shape of one and the threads of the other. I love these cheap knock off carbs lol



I did a little more searching and I think I found the hybrid of the two for just a few bucks, but I could only find it on ebay, not amazon, and it ships from China, so I have a couple of weeks to wait.

I may not even need it because I know my mixture is pretty close to perfect after I made a jetting adjustment. How it was behaving had me question if I was too rich at idle, so I cranked that idle mixture down to 1 turn out and it was still having a rich idle issue. So I changed to a pilot jet size I know was too lean on my first Hawk with an exhaust and pod filter - a 25 - an I set the idle mixture at 1 3/4 out because I remember that being just slightly lean on the other hawk. It's perfect now. It's not even too lean at light throttle like I used to experience on said first Hawk.

With that adjustment I bumped my main jet size up one size on a hunch, and now it idles rock solid (as a 292 duration cam can at least) and pulls strong on the clutch, which means the fueling is just about perfect. My brief pull at WOT was also the cleanest and strongest pull I have experienced yet with this whole setup. I'm avoiding getting on it as I am still within break in on the new rings, so as I said it was brief. I wll explore main jet fueling more once I am out of break in.

That all left me with my next adjustment I am going to test, which is the needle. It has an extremely slight sluggishness at part throttle, with the occasional hicuup when getting back on the throttle like you tend to get with lean spots. I have left the needle in the middle notch, but it is now going to be located to the fourth notch from the top (one down) to richen up my part throttle and I do believe I have my carb tuned in at least 90%.

It's quite incredible how strong the draw on the jets is that with a bigger bore, a fairly large cam, a ported head from Motocult, a basic pod filter, and an exhaust. Roughly 22hp at the crank and I am running a 25 pilot, 120 main, needle 4th notch.

My first Hawk, a stock motor with an exhaust and pod filter 27.5, needle third notch, 115 main for an engine making maybe 17hp at the crank.

Let me tell you, the power is definitely more. quite a lot more. Up to 55mph I am maybe at half throttle, tops. It can climb a decently steep hill with my fat butt in 5th gear at 40mph/4500rpm with an ease you would never expect from a CG250.

[Megadan]

Got a nice little heat shield for my head pipe from aliexpress. about $9 with shipping charges. It's a pretty sturdy little unit, and it even comes with a gasket-like set of washers to isolate the plastic from the metal and keep it from melting/burning.



I suspect this thing is going to melt since it just feels like regular plastic, but I will give it a go.

I've also been considering giving this larger fender a try for the front of my bike. The little one I have on there now looks ok, but doesn't offer a whole lot in rock and splash protection.
https://www.aliexpress.us/item/32568...Cquery_from%3A

[Aussie_in_MO]

That new heat shield looks like a prime candidate for doing some backyard sand casting to make one out of Aluminum!