not sure if I would do that cjtmini suggested using that size drill bit for the idle jet not the main jet...and that was for the 6.5 clone engine, not a 2.8 motor. Read thread here
http://www.oldminibikes.com/forum/honda-clone-engines/42480-diy-re-jetting-6-5-a.html
For the 2.8 jet if it were me I'd start with one size larger drill bit then the stock jet is now and go from there.JMO
http://www.oldminibikes.com/forum/honda-clone-engines/42480-diy-re-jetting-6-5-a.html
For the 2.8 jet if it were me I'd start with one size larger drill bit then the stock jet is now and go from there.JMO
I'm going to drill out my main jet. I removed the carb and was looking at it. There is no way to adjust the idle mixture on it and the main jet hole is smaller then my numbered drill bits so I will have to go buy a set to get the job completed. Any good ideas about the size of the jet and what it will need to be drilled out to? I have read just go up one size. This makes sense to me but I did not want to just attack it blindly!
I would just order one of DudleyDR's 2.8 carb kits...they come with a bigger jet.
I just got one for my daughter's DB today. The kit comes with gaskets, O-rings and the bigger jet, along with some really good instructions. Hoping we can run it with the choke fully open after we install it.
So far to the 2.8 DB we removed the throttle limiter screw, added the pro-mod J/S kit, drilled the muffler and moved the gov spring up to the highest holes and pumped up the tire pressures to 25 psi.
Doing these few simple things has got the little 2.8 running surprising well. In fact, with our weight difference, she keeps up with me pretty good on her 2.8 and me on my 6.5 clone DB30.
I figure these mods to the 2.8 will hold us over till she's a little older and we put larger motor in it. Figure we can recycle the J/S kit into the next build as well, while teach her the basics as we go.
I just got one for my daughter's DB today. The kit comes with gaskets, O-rings and the bigger jet, along with some really good instructions. Hoping we can run it with the choke fully open after we install it.
So far to the 2.8 DB we removed the throttle limiter screw, added the pro-mod J/S kit, drilled the muffler and moved the gov spring up to the highest holes and pumped up the tire pressures to 25 psi.
Doing these few simple things has got the little 2.8 running surprising well. In fact, with our weight difference, she keeps up with me pretty good on her 2.8 and me on my 6.5 clone DB30.
I figure these mods to the 2.8 will hold us over till she's a little older and we put larger motor in it. Figure we can recycle the J/S kit into the next build as well, while teach her the basics as we go.
If your running the jet that came on the bike. Then you need to step up to a 62mm jet anyway. If you purchased the carb kit then you should be fine with the 62 jet that came with the kit.
I ran my bike in cold air with no exhaust or air filter and the bike did not need more fuel. Yeas checking to see if the factory exhaust and air filter was restrictive. They were not and I didn't need larger jet.
Get the carb kit and you can have an extra jet to play with. After putting on the modded pipe and filter see if the choke turned on helps the bike run better. Drill only .02 mm each time. If you use the correct drill for a 64mm jet it will be closer to 65mm because of vibration and a lot of other factors.
I ran my bike in cold air with no exhaust or air filter and the bike did not need more fuel. Yeas checking to see if the factory exhaust and air filter was restrictive. They were not and I didn't need larger jet.
Get the carb kit and you can have an extra jet to play with. After putting on the modded pipe and filter see if the choke turned on helps the bike run better. Drill only .02 mm each time. If you use the correct drill for a 64mm jet it will be closer to 65mm because of vibration and a lot of other factors.
I'm going to drill out my main jet on my stock 2.8 doodlebug. First I check the stock size of the jet. it is a # 77, so I drilled it out by hand with a #76. Now I'm going to reassemble the carb install it and test it. If things improve a little I will drill it out one more size. If I go too far I will solider and re-drill to the correct size. I will keep you all posted as to what goes on!
John
John
Today I bought a new 6.5 hp engine from Harbor freight. It took me about 3 hours to replace the asthmatic 2.8 stock engine. On my first run, it scared the crap out of me!
I had expected a lot more exceleration, I did not expect it to pull a wheely with my fat butt on it! I'm now happy with my toy! That engine was the best $100.00 I have spent in a long time. Now to make it so I can set it up for kids to ride it safely.
John
I had expected a lot more exceleration, I did not expect it to pull a wheely with my fat butt on it! I'm now happy with my toy! That engine was the best $100.00 I have spent in a long time. Now to make it so I can set it up for kids to ride it safely.
John