I'm new to go kart racing. I built a gx160 with a flat top piston, billet rod,14cc head,methanol carb that is bored,ported head,and a 356 cam. It bogs on the low end takes a half of a lap to get up to speed and starts pulling hard 3/4 way down the straight away. I'm running a 11t clutch and 71 rear gear. I'm going to try a 75 tooth rear but I'm thinking that I might have too big of a cam for the track size. 6250 is the highest rpm I got. A friend drove it and felt the low end bog but it performed better for him. I weigh around 260 and I have 100lbs on him. Looking for some sound advice besides loose weigh lol..
Gx160 low end bog
- Thread starter Bellinger
- Start date
steve baker
Moderator
What carburetor? Sounds like it needs more fuel at lower RPM levels.
Bored 625 carb with .038 pilot and. 059 main. Stock looking carb not a slide carb. I know the gx160 is small but it's what I had laying around. Small oval dirt track. Running slicks I believe the chassis is a margay. I know very little about cart set up. Very new to this only raced the track once and when I asked for an idea for air pressure I was told they had air in their tires. Not a professional track or anything but in a guy's back yard for fun. Working on a good clutch so I can get 4000 engagement. I have a temp sensor on it most I saw was 210 for temperature I think I'm putting too much fuel to it was told I need to be around 300 on methanol
Colt sr
Member
What front drivers and rear gears do you currently have? A 6.45 gear ratio seems pretty high. I don't run your engine package but we tend to try to keep our flatheads and animals around a 4.5 gear ratio. Only reason I referenced to these two engine packages is because we run methanol in those as well.
Colt sr
Member
He said he was on slicks. Which makes me wonder if the engine is bogging because he may be gear bound. I have experienced this with an old straight rail invader kart with an lo206 before.
What's gear bound? I did notice that my rear gear was out of round and the hub has a wobble. I ordered a new hub..going to try that. I've read that the honda and the clones are supposed to have good torque around 3000 rpms but I'm not sure. I don't have any other jets at this point but I'm trying to locate and buy some. The plastic pilot is different than I'm used to dealing with. The .038 pilot seems like a big jump from stock. Have have a few stock carbs. Idk if I can use something from them. Going to be a few days before I get the hub so I have time to try to locate jets if needed
flattop1
Dawg 89
Drill a stock jet .
.038 is a little big but i think its needed for low and mid range...
Could try the stock carb on gas see what happens.
Gear bound to me is you cant gain rpm because the engine can't pull anymore. Going with less teeth on the rear gains speed without sacrificing rpm .
.038 is a little big but i think its needed for low and mid range...
Could try the stock carb on gas see what happens.
Gear bound to me is you cant gain rpm because the engine can't pull anymore. Going with less teeth on the rear gains speed without sacrificing rpm .
I don't think I'm gear bound because when I get it up to speed it literally comes to life like a 2 stroke hitting its power band 3/4 the way down the straight away. Only reason I slow down is going through the corner. Early in the day I could hold it wide open through the whole corner to the next straight away til they watered the track down and then I lost that cause I'm still learning how to adjust for different track conditions. The engine just won't Rev up when I take off. Could be just my weight and gearing and possibly some jetting too. If I spin out I can't spin the cart around like he rest of the guys. Just seems like I have no power/torque on the bottom end. Once I get m new hub for my rear sprocket I'm going to try a 75 rear sprocket and see what happens.
Colt sr
Member
Your gear is too tall for the height of the rear-end. That's why the hub, gear, and guard were all bent. Typically in dirt karts 68 is pushing it.