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  #6341  
Old 11-07-2013, 01:12 AM
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Danschutz Danschutz is offline
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Default Re: what did you do to your motorized bicycle today?

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Originally Posted by mapbike View Post
I've noticed since installing this expansion pipe, the extra low to mid pull is nice but I have lost around 6+mph on the top end and only have a 40MPH top speed on the flat since adding this pipe, low to mid pull is extremely increased with this pipe though

Map
Recently installed the sbp exhaust and replaced the 44t sprocket with a 41t. My low mid power is unbelievable, there is a hill near my house that I test my bike on. The bone stock motor struggled about 15-17 mph with a top speed of 22 (unknown that i had a cylinder issue) then after installing the hi head, ported cylinder and notched piston I was sustaining 22 mph up the hill with a top speed of 31 while four stroking like crazy.

With the addition of the expansion pipe (and 41T sprocket) I can take that hill at 27mph. Here's the twist, I can only get about 28mph top end, tonight I hit 30 mph.

Cruising at 20-22 mph is hardly a chore for the motor right now and it gets there in a hurry. I can't believe I'm about to say this but you can feel it shove you right along. I rode with my buddy Brian and his very nice running Arrow 4.5 hp motor and was eating him up around the hills and leaving him in the dust up to 28-30 mph then eventually he catches and blows by me.

I added one 45 degree elbow to the Sbp kit so I'm guessing I need to shorten the pipe somewhere to get back some top end OR do I get a 36t sprocket?

Also upgraded the stock bolts on the sprocket, so much nicer lol.



Dan.

Last edited by Danschutz; 11-07-2013 at 01:56 AM.
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  #6342  
Old 11-07-2013, 01:18 AM
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Danschutz Danschutz is offline
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Default Re: what did you do to your motorized bicycle today?

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Originally Posted by BonusParts View Post
Well, I took the bike out today with the SBP expansion chamber.

I dont know how I feel about it yet. I wasn't expecting the degree of quiet It has. it also falls on its face in low RPM at 3/4+ throttle input. once its kicks in though it has a great tone and finds its stride. Seems to have lost 6-9mph top speed.

I shortened the header on it and we will see tomorrow if i miss the rain if that helped
I just posted that my sbp exhaust gave me incredible low to mid torque, a real hill puller but I'm sure I lost some high end. I'm not certain high much I lost because I swapped out sprockets also.

The low end is so strong I can pull a pretty big hill by my house from a dead stop no peddling and about a ten yard head start with no issues.

Does your motor have any other mods?

Dan.
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  #6343  
Old 11-07-2013, 02:12 AM
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Default Re: what did you do to your motorized bicycle today?

Quote:
Originally Posted by Danschutz View Post
Recently installed the sbp exhaust and replaced the 44t sprocket with a 41t. My low mid power is unbelievable, there is a hill near my house that I test my bike on. The bone stock motor struggled about 15-17 mph with a top speed of 22 (unknown that i had a cylinder issue) then after installing the hi head, ported cylinder and notched piston I was sustaining 22 mph up the hill with a top speed of 31 while four stroking like crazy.

With the addition of the expansion pipe (and 41T sprocket) I can take that hill at 27mph. Here's the twist, I can only get about 28mph top end, tonight I hit 30 mph.

Cruising at 20-22 mph is hardly a chore for the motor right now and it gets there in a hurry. I can't believe I'm about to say this but you can feel it shove you right along. I rode with my buddy Brian and his very nice running Arrow 4.5 hp motor and was eating him up around the hills and leaving him in the dust up to 28-30 mph then eventually he catches and blows by me.

I added one 45 degree elbow to the Sbp kit so I'm guessing I need to shorten the pipe somewhere to get back some top end OR do I get a 36t sprocket?

Also upgraded the stock bolts on the sprocket, so much nicer lol.



Dan.
A 36T rear sprocket and a well tuned carb will likely get you at leas 5mph more on top end, the RT carb from dax is an excellent upgrade that makes a felt in the seat of your pants difference all the way around and will likely put you at 35+ mph on top end and a good cruise speed of 30-32mph maybe better jst depends how well balanced your engine is.

Map
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  #6344  
Old 11-07-2013, 02:15 AM
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Default Re: what did you do to your motorized bicycle today?

Oops just noticed you have the RT carb...... so tune is well and get a 36t on the rear and enjoy the extra power and top speed........!
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  #6345  
Old 11-07-2013, 02:28 AM
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Danschutz Danschutz is offline
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Default Re: what did you do to your motorized bicycle today?

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Originally Posted by mapbike View Post
Oops just noticed you have the RT carb...... so tune is well and get a 36t on the rear and enjoy the extra power and top speed........!
Shan,
The cylinder and piston mixed with a stock pipe and 44T on another bike was making 32 mph with me on it, nearly 33 actually. I figured with a 36 I would get more top end speed?

Im not super worried about this build because Im going to put forth more effort on the Dax motor but at the same time I want to learn as much as I can off this motor. My bud is running a 42T and getting 35+ mph and he is about 65 lbs heavier, Im light at 165.

I trust what your saying, Im just confused I guess. I was hoping the 36 would get me at a 35mph cruise speed. Im I asking to much?

As always thanks Map,
Dan.
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  #6346  
Old 11-07-2013, 06:01 AM
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Default Re: what did you do to your motorized bicycle today?

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Originally Posted by Danschutz View Post
Shan,
The cylinder and piston mixed with a stock pipe and 44T on another bike was making 32 mph with me on it, nearly 33 actually. I figured with a 36 I would get more top end speed?

Im not super worried about this build because Im going to put forth more effort on the Dax motor but at the same time I want to learn as much as I can off this motor. My bud is running a 42T and getting 35+ mph and he is about 65 lbs heavier, Im light at 165.

I trust what your saying, Im just confused I guess. I was hoping the 36 would get me at a 35mph cruise speed. Im I asking to much?

As always thanks Map,
Dan.
Dan
I was being conservative with what I said, I have gotten 38mph with a 36t and a mostly stock engine with well tuned carb and free flowing exhaust and you could very well see the same results.

Map
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  #6347  
Old 11-07-2013, 09:09 AM
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NineFive_163 NineFive_163 is offline
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Default Re: what did you do to your motorized bicycle today?

Broke my clutch cable last night, plan on replacing it today
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  #6348  
Old 11-07-2013, 11:14 PM
BonusParts BonusParts is offline
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Default Re: what did you do to your motorized bicycle today?

Quote:
Originally Posted by Danschutz View Post
I just posted that my sbp exhaust gave me incredible low to mid torque, a real hill puller but I'm sure I lost some high end. I'm not certain high much I lost because I swapped out sprockets also.

The low end is so strong I can pull a pretty big hill by my house from a dead stop no peddling and about a ten yard head start with no issues.

Does your motor have any other mods?

Dan.
My motor has cleaned intake an exhaust ports, they have been smoothed slightly enlarged, the combustion chamber is polished, head is milled down. .016 copper gaskets, NT speed carb,with air filter & .66 jet from SBP. ngk iridium plug, jag cdi and coil, accel 8mm plug wire.

Its on a 36t sprocket.

Oddly enough i've noticed that at low rpm it runs great on low throttle input, but at wot it just bogs. not four stroke, bog. Not sure what to make of it. I shortened the header, but it was rainy all day so no test yet.

I've maxed at 43.62mph on the 36t via GPS (MyTracks)

Recently (right before i hit the deer) it was about 39mph
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  #6349  
Old 11-08-2013, 12:10 AM
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Huffydavidson Huffydavidson is offline
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Default Re: what did you do to your motorized bicycle today?

today I met the anesthesiologist and the whole medical staff that will be transplanting the Fred motor into the body of blue , she will be in room 66 C , the smokers unit.
LMAO
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  #6350  
Old 11-08-2013, 10:54 AM
BonusParts BonusParts is offline
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Default Re: what did you do to your motorized bicycle today?

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Originally Posted by Huffydavidson View Post
today I met the anesthesiologist and the whole medical staff that will be transplanting the Fred motor into the body of blue , she will be in room 66 C , the smokers unit.
LMAO
Which fred motor did you get? I've got one of his engines BNIB in my basement that i keep pushing to the back of my parts stash. Idk why, but I just really dont want to run that engine. Something about my BS cobbled together grubee variant makes me happy. and FWIW my buddy has a fred motor on his bike, 36t and i still romp a few mph faster.
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