looking for box muffler for 48cc Grubee, lawnmower style
- Thread starter happycheapskate
- Start date
happycheapskate
Active Member
re: drill frame
I wouldn't blame you. Drilling a hole through an aluminum lightweight frame and mounting a vibrating engine that runs 1000's of RPMs probably will shorten its fatigue limits.
On that thought, I highly recommend using a STEEL handlebar, esp if you need to drill the pilot hole for the throttle grip. I also would use Gorilla Glue on one half of the clamp if you do not use the locating pin. If your grip comes it would be bad.
I don't know if I mentioned earlier, but you can cut down the throttle twist grip to 1 or 2 fingers size, and then mount it without the pin, and use a conventional bike grip and superglue or sticky tape. This should be as strong a method as conventional bike grips, and you could turn it just like a gripshift. Safety Wire also works on really cheap or old grips, but don't cut through them by twisting too much, and leave enough twisted end that you can poke it down away from your hands or you could jab your hands.
Steel riser bars can be had for standard threadless 1 1/8 stems at nashbar.com for $15.
I wouldn't blame you. Drilling a hole through an aluminum lightweight frame and mounting a vibrating engine that runs 1000's of RPMs probably will shorten its fatigue limits.
On that thought, I highly recommend using a STEEL handlebar, esp if you need to drill the pilot hole for the throttle grip. I also would use Gorilla Glue on one half of the clamp if you do not use the locating pin. If your grip comes it would be bad.
I don't know if I mentioned earlier, but you can cut down the throttle twist grip to 1 or 2 fingers size, and then mount it without the pin, and use a conventional bike grip and superglue or sticky tape. This should be as strong a method as conventional bike grips, and you could turn it just like a gripshift. Safety Wire also works on really cheap or old grips, but don't cut through them by twisting too much, and leave enough twisted end that you can poke it down away from your hands or you could jab your hands.
Steel riser bars can be had for standard threadless 1 1/8 stems at nashbar.com for $15.
happycheapskate
Active Member
Update. The $5 maxpower briggs muffler is still doing great. Its reasonably quiet like a common echo trimmer at about 1/2 throttle with light pedalling (around 15-20mph with stock 44). Its loud as a Mcculloch chainsaw at open throttle, and seems to work like an expansion pipe. (see photos for shape)
Update, I have found a source of gas scooter box mufflers if you want one with side exhaust instead of straight out like mine.
$10 or so
http://www.monsterscooterparts.com/rescex.html
Update, I have found a source of gas scooter box mufflers if you want one with side exhaust instead of straight out like mine.
$10 or so
http://www.monsterscooterparts.com/rescex.html
happycheapskate
Active Member
I am on my second engine. My friend said lack of back pressure killed the last one. Maybe that or running alcohol mix in it.
Either way, the new one has the same max-power muffler, but with the center exhaust-directing plate mounted in the center hole, and the stock holes are left alone, with a new gasket. Its much quieter now, and I'm also using 18:1 mix with Penzoil 30weight real oil, and only 90% gas/10% ethanol bc. the local gasoline stores only sell it and not regular.
Either way, the new one has the same max-power muffler, but with the center exhaust-directing plate mounted in the center hole, and the stock holes are left alone, with a new gasket. Its much quieter now, and I'm also using 18:1 mix with Penzoil 30weight real oil, and only 90% gas/10% ethanol bc. the local gasoline stores only sell it and not regular.
happycheapskate
Active Member
Sorry that Tinypic bombed this thread. I don't use Tinypic anymore.
Here is a 5minute video of this bike with the lawnmower muffler, and a boost bottle. It runs well on 40:1 with 2cycle outboard oil. The Pennzoil was thick and seemed to clog up fuel filters. No problems since switching. I'm just cruising along here, not really gunning it (got pulled over by police a week ago.
http://www.youtube.com/watch?v=ZjWYUhmy5aw&feature=related
The bike 4 strokes a little when just maintaining a speed and moving the throttle to keep a speed on flat ground, but it pulls hard on hills, even from 5mph. It likes when I open up the throttle and sings. There is a nice spot in the RPM band where it just grumbles along. With the c-clip at a higher notch, it does not pull well and the plugs seem more ashy. At lower levels, it just seems to use more gas and not really do much more, but 4x's a lot more.
I still plan to get a scooter muffler for it and see if that does nicely.
Here is a 5minute video of this bike with the lawnmower muffler, and a boost bottle. It runs well on 40:1 with 2cycle outboard oil. The Pennzoil was thick and seemed to clog up fuel filters. No problems since switching. I'm just cruising along here, not really gunning it (got pulled over by police a week ago.
http://www.youtube.com/watch?v=ZjWYUhmy5aw&feature=relatedThe bike 4 strokes a little when just maintaining a speed and moving the throttle to keep a speed on flat ground, but it pulls hard on hills, even from 5mph. It likes when I open up the throttle and sings. There is a nice spot in the RPM band where it just grumbles along. With the c-clip at a higher notch, it does not pull well and the plugs seem more ashy. At lower levels, it just seems to use more gas and not really do much more, but 4x's a lot more.
I still plan to get a scooter muffler for it and see if that does nicely.
