You be carefull! You are getting close to the rarified atmosphere of 88ft/sec.! Stuff happens fast.
Pocket Bike Engine Project
- Thread starter lowracer
- Start date
I had to fix my new Dax 'fuel tank cap spitting problems' & came up with an easy & effective solution.
I have another smaller fuel tank that also has a crummy fuel cap that allows fuel to spit out at high revs or over bumpy terrain, but also allows the engine to bog & konk out by not allowing the fuel tank to breathe. I remember as a kid riding dirtbikes with fuel caps vented by a long length of tubing to keep fuel from escaping & allowing the tank to breathe.
I pulled the plastic insert out of each cap with a needle nose plier & drilled a small hole thru the top of the cap just a bit smaller than the fuel hose I planned on running thru the hole. I cut each end into a diagonal angle like this pic '/' making it easier to feed thru the tight hole. Then I grab the end with a needle nose plier & pull it thru a few inches. They work real well & now I can fill the tank close to the top & not have to worry about wearing fuel that spits out of the tank & onto me (front wheel drive) or konk outs. Here are 2 pics of both tanks.
-Lowracer-
I have another smaller fuel tank that also has a crummy fuel cap that allows fuel to spit out at high revs or over bumpy terrain, but also allows the engine to bog & konk out by not allowing the fuel tank to breathe. I remember as a kid riding dirtbikes with fuel caps vented by a long length of tubing to keep fuel from escaping & allowing the tank to breathe.
I pulled the plastic insert out of each cap with a needle nose plier & drilled a small hole thru the top of the cap just a bit smaller than the fuel hose I planned on running thru the hole. I cut each end into a diagonal angle like this pic '/' making it easier to feed thru the tight hole. Then I grab the end with a needle nose plier & pull it thru a few inches. They work real well & now I can fill the tank close to the top & not have to worry about wearing fuel that spits out of the tank & onto me (front wheel drive) or konk outs. Here are 2 pics of both tanks.
-Lowracer-
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Still another good fix Lowracer! I found this tuned system, looks like it might work on my application since the engine is backwards. I might be able to rotate the header and get the system over to the side and back. Naturally its out of stock. I have changed so much to the bike I am installing this on that it will probably be almost a new build. If I can make it all come together, should be pretty cool.
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LOWRIDER
I never thought I would do a front wheel drive, but you have changed me!! lol Also at my age it is getting harder to lift my leg over a rear rack mount, also like rear panniers.
I have 2 Blackcomb dual suspension bikes with dual disk brakes that would be fine for frt mount. Was wondering what your belt length in inches or mm so I can be sure they sell a cogged flat belt in that length. Am not using a v belt like you in my current idea.
Ron
I never thought I would do a front wheel drive, but you have changed me!! lol Also at my age it is getting harder to lift my leg over a rear rack mount, also like rear panniers.
I have 2 Blackcomb dual suspension bikes with dual disk brakes that would be fine for frt mount. Was wondering what your belt length in inches or mm so I can be sure they sell a cogged flat belt in that length. Am not using a v belt like you in my current idea.
Ron
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Got my engine today. First thing I did was reach in the box and pull out a bubble wrapped carb, man I thought, I got lucky like Lowracer getting 2 carbs, nope only one dang! Anyway pulled the head for inspection, absolutely no oil in this engine! The bore is 44mm and it looks like a chrome cylinder, or some Chinese facsimilie. Bless the Chineses hearts, they just assemble whats given to them I guess, one of the head bolts was hard to remove. Of course, it had a flattened starter thread. Had to chase it with my 6mm die. Finally got everything straightened out and reassembled the head, coating the head bolts with red Loctite. I torqued them to 80in/lbs, that was about as hard as I wanted to pull them, they came apart around 65. The cylinder has a slot half way up the bore, a compression release I guess. This one has the 4 piece head. Waiting on the muffler which might be here tomorrow, then we will see.
Neat Times,
Gotta go front drive! It handles really well too with these lightweight little pocket bike engines. The v-belt I use is the AX version (cogged). It just helps go around the 1.5" pulley better being notched. Once you install your rack & engine onto it, you'll need to measure around both pulleys with a piece of cable housing or rope. Then buy the v-belt on eBay (the belt sizing is 2" different since they are measured around the outside of the belt).
-Lowracer-
Gotta go front drive! It handles really well too with these lightweight little pocket bike engines. The v-belt I use is the AX version (cogged). It just helps go around the 1.5" pulley better being notched. Once you install your rack & engine onto it, you'll need to measure around both pulleys with a piece of cable housing or rope. Then buy the v-belt on eBay (the belt sizing is 2" different since they are measured around the outside of the belt).
-Lowracer-
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Cannonball2,
Glad you got your new engine.
I'm really looking forward to your reviews of it once you get it on the road.
I still cant get over how much power this little screaming monster puts out. I took 'The Beast' & my nephew took 'Wimpy' out for a ride just now & he was running WOT on Wimpy (EH035 Subaru Robin) going around 30 mph. I was @ half throttle & not even into the powerband of the engine yet. I did a few passes & my nephew couldnt believe how much additional acceleration & difference there was between the 2 engines.
-Lowracer-
Glad you got your new engine.
I'm really looking forward to your reviews of it once you get it on the road.
I still cant get over how much power this little screaming monster puts out. I took 'The Beast' & my nephew took 'Wimpy' out for a ride just now & he was running WOT on Wimpy (EH035 Subaru Robin) going around 30 mph. I was @ half throttle & not even into the powerband of the engine yet. I did a few passes & my nephew couldnt believe how much additional acceleration & difference there was between the 2 engines.
-Lowracer-
Cannonball2,
I sold the Lifan 2.5 98cc engine & shipping it out today. Thanks for the referral.
I also sold the pocketbike clutch w/6T pinion that came on the Pocketbike engine (wont be needing that w/ V-Belt drive). Anyone you know interested in the modified 5/8" Max-Torque V-Belt pulley clutch I got w/ cartridge bearings (no oillite bushings) & upgraded shoes & springs? I may post it on the for-sale section & use the money to buy another pocketbike engine. Possibly the Stage 3, if you like yours.
-Lowracer-
I sold the Lifan 2.5 98cc engine & shipping it out today. Thanks for the referral.
I also sold the pocketbike clutch w/6T pinion that came on the Pocketbike engine (wont be needing that w/ V-Belt drive). Anyone you know interested in the modified 5/8" Max-Torque V-Belt pulley clutch I got w/ cartridge bearings (no oillite bushings) & upgraded shoes & springs? I may post it on the for-sale section & use the money to buy another pocketbike engine. Possibly the Stage 3, if you like yours.
-Lowracer-
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You shouldnt have any trouble selling in the Maxtorque, but I dont have any suspects. How did you install the pulley on the pocket bike clutch? Unless you need two engines, the stage 3 kit is only $59 form Zero Pulse, or are you going to give the Robin/Suby a rest.
Cannonball2,
I have 3 bikes now to motorize, so I would add a new engine to the stable.
The pulley driver I use is the 1/2" shaft unit I've had from Staton (w/double bearings & super smooth) see pics. I installed a 1.5" v-pulley w/set screw that I got from Drillspot.com for a few dollars.
I have 3 bikes now to motorize, so I would add a new engine to the stable.
The pulley driver I use is the 1/2" shaft unit I've had from Staton (w/double bearings & super smooth) see pics. I installed a 1.5" v-pulley w/set screw that I got from Drillspot.com for a few dollars.
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I am thinking of re-building my front rack using the same specifications, but instead of the heavy steel stock I have now, I would use 1/4" 6061 Aluminum 1" 'L' angle stock & 1/4" aluminum flat stock. I think it would be just as stiff but pounds lighter. The switch from the heavy Lifan engine w/centrifugal clutch to the lightweight pocketbike engine made a big difference in the way the bike handles & a few extra pounds of fat shed from the front engine rack couldn't hurt.
-Lowracer-
-Lowracer-
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6061 is more than strong enough, especially for an engine you can throw across the room single handedly. Still waiting on parts.
Cannonball2,
I just ordered the Aluminum. I should end up with enough to build 2 engine racks.
I gotta know what you think of your engine before I order my next engine. I'm either going to go for the Stage 3 or another Stage 2...
-Lowracer-
I just ordered the Aluminum. I should end up with enough to build 2 engine racks.
I gotta know what you think of your engine before I order my next engine. I'm either going to go for the Stage 3 or another Stage 2...
-Lowracer-
Well it all came together fast. The tires got here around 4 the stuff from Dax around 5:30. I have been a busy boy. Took it on a test run and WOW, just kept winding and winding and..... Really pretty smooth. Had to cobble together a throttle cable and the thumb throttle isnt ideal with this one but man was it FUN. It is a bit noisy but its a cool kinda noise. Running the cannister muffler. Need to spend some time tomorrow finishing details but it gonna be AWSOME! BTW the 300x24 tires are great too. Plenty of area for FD and the ride is incredible.
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Cannonball2,
Looks great!
Gonna have my expansion chamber on Tuesday & will bust out a new hacksaw blade for it. I think you have a bit of room going straight down for a shorty expansion chamber. As long as it doesnt it the ground when you lean it way over...lol
Lookin forward to your reviews once you get her broken in...
-Lowracer-
Looks great!
Gonna have my expansion chamber on Tuesday & will bust out a new hacksaw blade for it. I think you have a bit of room going straight down for a shorty expansion chamber. As long as it doesnt it the ground when you lean it way over...lol
Lookin forward to your reviews once you get her broken in...
-Lowracer-
Education time. Got up at the crack to get a little time on the new engine while its cool out. Where I live this little buzz bomb wont bother any one. Was running along great, then began to miss. Slowed down and stopped, it tried to idle then quit, wouldnt restart. I thought great, crappy Chinese, spark plug, ignition, seals...on down the line. I finally tried it with choke and it fired right off and ran great. I headed home, quit just as I got there, but I had if figured brfore I got home. Got the tank from Dax, very nice quality part. I was impressed, that it had a cap with a duck bill one way valve, that meant I wouldnt be having the fuel splash issues Lowracer was having. In fact you can even invert the tank and it wont leak. I know very well these caps are made for pumper carbs that can pull a small vacuum then the valve opens to equalize, not so with a gravity feed. Funny what you can over look when in a hurry to get something up and running. So if any one is having a similar problem look for the duck bill. Remove it and do Lowracers mod. This little engine is amazing on power and RPM, it winds so high you can no longer distingush the power strokes, sounds like some sort of buzzer maybe. If the battery in my old Tiny Tach hasnt given up will tach it later. The duck bill is the little protrusion in the very middle of the cap in the pic. If you squeeze it it will open.
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Cannonball2,
Small world huh?
I sent DAX my fix report for any customers he gets that may be having the same problems. I had this same problem on all 3 of my engines that come with the 'small black plastic fuel cap' (not the Lifan).
I actually removed that duck bill protrusion with a needle nose plier and threw it in the trash when I drilled the cap hole to run the short piece of fuel line thru it to make my breather. Only problem I had was that the fuel line breather wants to stay in its original shape & curl over like a pigtail, so I thought of an easy fix for that by using a Bic pen shaft...see pic (aka Spitball shooter). Now when I slide the Bic shaft off the hose it stands up tall.
-Lowracer-
Small world huh?
I sent DAX my fix report for any customers he gets that may be having the same problems. I had this same problem on all 3 of my engines that come with the 'small black plastic fuel cap' (not the Lifan).
I actually removed that duck bill protrusion with a needle nose plier and threw it in the trash when I drilled the cap hole to run the short piece of fuel line thru it to make my breather. Only problem I had was that the fuel line breather wants to stay in its original shape & curl over like a pigtail, so I thought of an easy fix for that by using a Bic pen shaft...see pic (aka Spitball shooter). Now when I slide the Bic shaft off the hose it stands up tall.
-Lowracer-
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Cannonball2,
I found this expansion chamber & like it for your application if you cutoff just the top expansion chamber section & use some 'ceiling fan drop pipe' or looks like there is enough metal tubing here to cut & pipefit the rest without needing the drop pipe & then clamp-in the bottom near the road with a $3.00 1/2" sausage muffler from Tractor Supply. Let me know what you think?
-Lowracer-
I found this expansion chamber & like it for your application if you cutoff just the top expansion chamber section & use some 'ceiling fan drop pipe' or looks like there is enough metal tubing here to cut & pipefit the rest without needing the drop pipe & then clamp-in the bottom near the road with a $3.00 1/2" sausage muffler from Tractor Supply. Let me know what you think?
-Lowracer-
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I had seen that pipe on ebay. From what I have read it is better to have a given length of pipe before the chamber, rather than the chamber at the flange. I think that pipe only comes on at a very high end with little mid range, which is probably where a pocket bike lives its life. This thing is faster than me or the bike its on need to go now. With a pedigree bike like you have I wouldnt worry so much. Mine seems to have good low and mid range with the cannister, and the top end (rpm) is just scary for a 4stroke guy. Once the clutch grabbs solidly, a jam to full throttle and the little thing accelerates like a bat! Try to keep the fore pipe on your chamber as close to its original length as possible, even if you have to use the flex pipe to snake it around.