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Past the power curve ?
Discussion at Motorized Bicycle Engine Kit Forum in the Motorized Bicycle General Discussion forum. I've got a stinger sd"80cc" motor on my board tracker. Have run about a gallon of gas through it @16 ...  | | 
11-19-2009, 06:03 PM
| | Motorized Bicycle Newbie | | Join Date: Oct 2009 Location: wilmington nc
Posts: 8
| |  Past the power curve ?
I've got a stinger sd"80cc" motor on my board tracker. Have run about a gallon of gas through it @16 to 1.I just swithched to synthetic motorcycle racing oil @ 50 to 1. Engine makes real good power under load but when bike is atwide open throttle and cruising ti kind of fallsoff and surges . throttleback and put load on it pulls hard again. I have 44 tooth sprocket. Should I goto a smaller rearsprocket to keep it in the power band better. My friends bike with 80cc slanthead motor and I think36 tooth rear sprocket seems to pull all the time even at cruise wide/open. Plug is fresh ngk and nicegrey/tan color after hard run. Anythoughts |
11-19-2009, 06:48 PM
|  | Custom Builder / Dealer | | Join Date: Mar 2008 Location: Los Angeles, CA.
Posts: 2,165
| | Re: Past the power curve ?
Re-jetting the carb a hair smaller has always fixed this problem for my bikes!  |
11-19-2009, 06:53 PM
| | Motorized Bicycle Elite Member | | Join Date: May 2008
Posts: 155
| | Re: Past the power curve ?
Ditto! Same for me. |
11-19-2009, 08:23 PM
|  | Motorized Bicycle Elite Member | | Join Date: Apr 2009 Location: granbury
Posts: 428
| | Re: Past the power curve ?
Quote:
Originally Posted by Venice Motor Bikes  Re-jetting the carb a hair smaller has always fixed this problem for my bikes! | What size drill bit would I use to do this????Resoder it and then redrill the hole????I think I will just wait until SBP gets there carbs back in stock....
John-John
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IF I CANT FIX IT,IT ISN'T BROKEN!....ummmmmmm so I thought....
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11-19-2009, 10:40 PM
| | Custom Builder / Dealer | | Join Date: Mar 2008 Location: Los Angeles, CA.
Posts: 2,165
| | Re: Past the power curve ?
Just go to a hardware store that sells tiny 'jewlers' bits; find the one that fits in your jet perfectly, & then buy the next two smaller sizes!! I think #70 is what the stock jet is?? |
11-20-2009, 03:21 AM
|  | Moderator | | Join Date: Jul 2009 Location: Maine
Posts: 2,181
| | Re: Past the power curve ?
Another thing to check/try is bending the float tabs up a hair - could be just a starvation issue... It was with mine anyway |
11-20-2009, 07:48 AM
|  | Godfather of Motorized Bicycles | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 7,894
| | Re: Past the power curve ?
....or a loose jet.
#70 is .028"
#71 is .026"
#72 is .025"
I got a whole set off of ebay for 6.99 shipped.
__________________
If it ain't broke, and you mess with it long enough, it will be. |
11-20-2009, 09:30 PM
|  | Motorized Bicycle Elite Member | | Join Date: Aug 2009 Location: Howell, New Jersey
Posts: 207
| | Re: Past the power curve ?
Quote:
Originally Posted by fall_down_stand_up What size drill bit would I use to do this????Resoder it and then redrill the hole????I think I will just wait until SBP gets there carbs back in stock....
John-John | Spooky will have the CNC Carbs on day after thanksgiving. |
11-23-2009, 06:48 PM
| | Motorized Bicycle Newbie | | Join Date: Oct 2009 Location: wilmington nc
Posts: 8
| | Re: Past the power curve ?
Ive tried your suggestions about going to smaller jet size . my original was in between #70 and # 71. TI have a metal lathe and can make my own jets ,wanted to save the original intacked. went down .004" problem seems a slight bit better but much. I'm not sure this thing is fukky broken in yet, I'm going to run it more and see what happens. even after going down in jet size plug still looks just a touch rich. How long does it take to fully break in one of theses motors? thanks for all the help. I'm stuborn and wont quit until it runs right! |
11-23-2009, 08:37 PM
| | Custom Builder / Dealer | | Join Date: Mar 2008 Location: Los Angeles, CA.
Posts: 2,165
| | Re: Past the power curve ?
Quote:
Originally Posted by rob king Ive tried your suggestions about going to smaller jet size . my original was in between #70 and # 71. TI have a metal lathe and can make my own jets ,wanted to save the original intacked. went down .004" problem seems a slight bit better but much. I'm not sure this thing is fukky broken in yet, I'm going to run it more and see what happens. even after going down in jet size plug still looks just a touch rich. How long does it take to fully break in one of theses motors? thanks for all the help. I'm stuborn and wont quit until it runs right! |
Don't try to re-jet your carb until you've fully broken in the engine!!! (about 4 gallons!)
It will start running different as it breaks in! (& you'll have to re-jet again) | | Thread Tools | | | | Display Modes |  Linear Mode | 
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