CSC TT250 stock carb upgrade follow up.

[GatorBootz]

I made this post on the closed TT250 facebook group and since I have been lurking around here since I purchased my bike (ty whoever made the rear rack from a cutting board GREAT mod) I figured I would post it here also to help anyone looking to do this or have any questions.

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Changed out the jets in my stock carb the other day. I bought the kit directly from CSC for $12 which includes 112 Main Jet, 115 Main Jet, 40 Idle Jet, and Air Mixture Screw. The stock main jet in mine was a 102. ( I thought they shipped with a 108ish). I opt to do the 112. I also changed out the idle jet stock was 38 and I installed the air mixture screw.

I tried moving the main needle up ( so the clip down one) and it seemed to not fully correct my bogging down and hesitation issue at WOT. Putting the needle back in its stock position surprisingly was the best for me. As I mentioned I changed out the air mixture screw. The stock mixture screw seems to be cut and capped off ( see photo). I used a small electric grinder to slot this in order to unscrew it to replace with a new one. Surprisingly I did not have to adjust it from its fully seated position even tho I just added more fuel I did not seem to need much more air..Also the dam air mixture screw is almost impossible to adjust while its on the bike let alone while its hot and running!

After going for a test ride with everything in play I decided to simply reverse my snorkel on my air box to allow for a little more air flow which seemed to allow my RPM to remain a little more steady throughout all throttle.

SUPER happy to report ZERO bogging or hesitation at WOT or anywhere else. Overall I am VERY pleased and happy with how much smoother and small performance I was able to gain by simply changing out the stock internals of the stock carb.

I know a lot of people go with a cheap $30 one off amazon, but from the build quality I have seen with the stock vs those it would be silly to not modify your stock for cheaper. Since our stock carbs are built very well.

Before this mod I also added a 45T rear sprocket from CSC. The sprocket alone greatly improved my cruising performance by allowing me to go a little faster but overall stopped the bike from sounding like a jet engine at maxed RPM while trying to do 50. I also have changed out my plug to a NGK which did not give me any noticeable performance (not surprising ) but did allow for much faster start ups. I am around 190LBS my bike will run 55-60 MPH GPS confirmed in the 5.5-6K range without any hesitation and still have power to go faster without any "bogging" on the flats. My top confirmed was around 65MPH which read 71 on the speedo. I do not plan or recommend going any faster than that on these little guys. I only have about 650 miles on my 2018 purchased late last year. I plan to do valves around 1k.

TLDR ; Changing my rear sprocket with a 45T and swapping out the jets of my stock carb with $12 kit turned my bike into a perfect 80/20 commuter that will do 55-60MPH for miles without sounding like a jet engine. IMO no other "performance" mods needed and these are both VERY easy to do with supplied online guides from CSC.

Photos are the following :

• Stock air mixture screw slotted and halfway removed.
• kit from CSC ( some stock jets already changed just visual of what you will get from CSC)
• Left is how the stock came removed from the bike. Right is new mixture screw. It seems they simply snip the adjustment head and cap it off at CSC.
• New air mixture. This is almost impossible to adjust on the bike or when running.. surprisingly and thankfully I did not have to touch mine.
• Main needle

Links to 2 tutorials from CSC to do the two 'mod' I would recommend.

Carb : https://www.cscmotorcycles.com/check...or-maintenance

Rear Sprocket : https://www.cscmotorcycles.com/check...t-installation

[Megadan]

A tuned carb and 17/45 sprockets makes it a good bike? Who would have guessed...

I kid, I kid.

Funny thing is, the Hawks come with a 40 pilot jet stock, but a smaller main jet. Most unmodded Hawks end up with a stock pilot, mixture around 1.5 turns out, and a 105-110 main jet and run pretty good.

If you plan on upgrading the exhaust in the future, be prepared to jump the pilot jet up to around a 45.

As far as the carb tuning. If you were getting a rich bog with the needle in the 4th clip position, you might be able to set it in the 2nd slot to lean out the mid throttle range a bit if you want to try and chase economy. Otherwise, the middle sounds like your winner.

In all, your top speed and cruising RPMs line up smack bang exactly where most Hawks do with that gearing combo. Admittedly, our stock exhusts are terrible compared to the TT250, so they have to be decatted or upgraded to see it. That gearing is essentially the same one I run on my bike once you adjust for tire diameter.

[GatorBootz]

Originally Posted by Megadan

A tuned carb and 17/45 sprockets makes it a good bike? Who would have guessed...

I kid, I kid.

Haha I know I know but the facebook group and I have seen a few on here where people have issues with the WOT or similar and always jump to buying a amazon carb and throwing it on!

I almost got the hawk but pulled the trigger on the TT250. No regrets as of yet!

[NzBrakelathes]

I sell a bigger kit with more stuff for first tune etc