Schwinn High Timber hi speed build
- Thread starter graydog8josh
- Start date
biknut... 32 has been the fastest ive been able to go. I dont know why, i guess i misread someone's post and had jetted my carb to 72. Today i got a new NT carb and moved the needle to the center position. I put my 66 jet on the new nt carb. Hopefully if its not raining tommorrow i can tell you how it went.
So to recap:
bicycle
Schwinn High Timber 26" bike 21 speed
26 1.95 kenda tires
cloud nine big cushion seat
origin 8 low rise bars
engine
Dax F80 engine
Arrow ported reed cylinder body
fuel/air
Nt carb jetted 66 with c clip in middle position
SBP heavy duty air filter
electrical
ngk b6hs plug
SBP spark plug boot
drivetrain
36T sprocket
spring chain tensioner
exhaust
stock pipe with 1" cut off of stinger
exhaust wrapped header
estimated top speed:36.7
achieved top speed:32.8
goal: 36mph flat out
So to recap:
bicycle
Schwinn High Timber 26" bike 21 speed
26 1.95 kenda tires
cloud nine big cushion seat
origin 8 low rise bars
engine
Dax F80 engine
Arrow ported reed cylinder body
fuel/air
Nt carb jetted 66 with c clip in middle position
SBP heavy duty air filter
electrical
ngk b6hs plug
SBP spark plug boot
drivetrain
36T sprocket
spring chain tensioner
exhaust
stock pipe with 1" cut off of stinger
exhaust wrapped header
estimated top speed:36.7
achieved top speed:32.8
goal: 36mph flat out
it went... bad. New carb didn't seat right so i had an air leak right off the bat. Chain stretched some more and spring stretched some more. so chain kept jumping up and jamming into engine housing. when i did get it to start air leak symptoms prevented me from checking engine power. I know this thing can pull so i really hope to get some good things out of this engine this month.
ordered a gasket set and 68 jet and a head bolt kit, when i get everything dialed in right, i want to try the 50cc hi hi head again. with a much cooler b8 plug
ordered a gasket set and 68 jet and a head bolt kit, when i get everything dialed in right, i want to try the 50cc hi hi head again. with a much cooler b8 plug
today's run i moved my needle back to the middle position, and changed the jet to #70 jet. i ran my bgf expansion chamber, and i still top out at 30 on flats.
On all my bikes a 70 would be way too rich. Usually I end up with a 66, and the needle clip in the next to the top for NT carbs. If it's a speed carb the needle clip likes the top position more.
me either. I had the clip at the 2nd position and it had no power. so i moved it back to the middle. i had the 66 jet and it ran really hot and it wasn't going any faster. with this it seemed to run better but when i get to 28-30 WOT it starts oscillating like, it will pull and then release and pull and release. also, ive found that it runs smoother with the choke partially on until it warms up.
That sounds like 4 stroking, which usually indecates too rich.
You've made sure you're not starving for fuel I assume? Gas cap vent is good? Float level is not set too low? Petcock flows well? How many miles are on the engine?
i dont know how to set my float level. I recently cleaned the petcock that was my problem last week it was filled with paint. theres about 400 miles on this engine. I am pretty sure the gas cap vent is okay and when i push the prime i can see flow.
I don't have any experience with a reed valve, so I can't help much with that. It could change the jet requirments though. What did the manufacturer recommend?
that i shouldnt need to jet. Im guessing that means whatever worked before should work. Before i got the reeds i was running 66 jet 2nd clip position.
let me make sure i understand this:
the second position is like this on the picture, right?
let me make sure i understand this:
the second position is like this on the picture, right?
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so if its not bogging but fluttering/oscillating at wot is that a lean condition or a rich condition