SBP expansion chamber

[HumanPerson]

So how is the top end? It's been long_ enough for break-in?

The 29'er with the yellow forks still hasn't been more than 40 seconds of WOT
It's been cruising at 36 MPH on long flat rides at a little more than half throttle and the 40tooth sprocket helps.


The Columbia Klunker has not even been started yet

 

[Marc W]

Haven't kept it at WOT yet, just been cruising at 18 to 26 MPH for 30 minutes one way then another 30 the other way back lol
This particular engine is from zedamotorsports with a 6.cc actual fred head, along with some transfer port modifications and other small mods wich hopefully should add up, after broke in, to a fairly reliable ride as long as i keep it under 50
What kind of bike are you building @Mark W
Moderators Note:
Please be aware that Zeda Motor Sports and Robert Bianchi have nothing to do with Zeda itself which is a manufacturer of Zeda Motors in China.
A reputable vendor of the Zeda line of motors can be found at bicycle-engines.com

So I put my sbp expansion chamber on today,road 1/4 mile, front tire failed bummer

 

[HumanPerson]

So I put my sbp expansion chamber on today,road 1/4 mile, front tire failed bummer

That sucks.
Did you get it fixed and what happened?

Crusied the yellow forked 29'er at 36 today for a 15 mile ride one way then on the way back WOT and it topped out at 39.
With the 44 tooth it would have a better top end i guess, with this 40 tooth it does have quite good low rpm torque though.

Going to get an 11 tooth engine drive gear/sprocket and see what that does soon.
So what did you think about the SBP pipe on your short trip?

 

[Marc W]

That sucks.
Did you get it fixed and what happened?

Crusied the yellow forked 29'er at 36 today for a 15 mile ride one way then on the way back WOT and it topped out at 39.
With the 44 tooth it would have a better top end i guess, with this 40 tooth it does have quite good low rpm torque though.

Going to get an 11 tooth engine drive gear/sprocket and see what that does soon.
So what did you think about the SBP pipe on your short trip?

Well got it put back_together after work,so I will be riding it to work tomorrow, from my short ride yesterday it seemed to have better power but I will know more tomorrow,and it's way quite than I thought but that's a bonus

 

[Marc W]

That sucks.
Did you get it fixed and what happened?

Crusied the yellow forked 29'er at 36 today for a 15 mile ride one way then on the way back WOT and it topped out at 39.
With the 44 tooth it would have a better top end i guess, with this 40 tooth it does have quite good low rpm torque though.

Going to get an 11 tooth engine drive gear/sprocket and see what that does soon.
So what did you think about the SBP pipe on your short trip?

So I got her up and roadworthy again,my commute to work includes a 20 degree hill 300' Long and the sbp expansion chamber gave me an increase of 7 mph,that's up the hill not bad! I had to do a little modification to make it work but well worth it

 

[HumanPerson]

Nice isn't it? Walking up those hills at 3 miles per hour is a b**ch Always check your engine and everything else before every ride.
What modifications did you do to the SBP expansion chamber exhaust system?
I opened up the flange a bit and took all of the burrs off of everywhere that needed it and just cleaned things up.
It seems to do pretty well for me in my area.
Keep us posted and post some pics here if you want.
I'm now looking at that pipe from zedamotorsports and the 11 tooth engine gear

Moderators Note:
Please be aware that Zeda Motor Sports and Robert Bianchi have nothing to do with Zeda itself which is a manufacturer of Zeda Motors in China.
A reputable vendor of the Zeda line of motors can be found at bicycle-engines.com

 

[Marc W]

Nice isn't it? Walking up those hills at 3 miles per hour is a b**ch Always check your engine and everything else before every ride.
What modifications did you do to the SBP expansion chamber exhaust system?
I opened up the flange a bit and took all of the burrs off of everywhere that needed it and just cleaned things up.
It seems to do pretty well for me in my area.
Keep us posted and post some pics here if you want.
I'm now looking at that pipe from zedamotorsports and the 11 tooth engine gear
Moderators Note:
Please be aware that Zeda Motor Sports and Robert Bianchi have nothing to do with Zeda itself which is a manufacturer of Zeda Motors in China.
A reputable vendor of the Zeda line of motors can be found at bicycle-engines.com

I also opened up the manafold and shorten the middle by 5 inches to make the pipe fit my bike

 

[HumanPerson]

I also opened up the manafold and shorten the middle by 5 inches to make the pipe fit my bike

what did you shorten up by 5 inches?
How's it running now?
I hit 38 today for a while then backed down to 30 and just cruised along without a care in the world

 

[Marc W]

what did you shorten up by 5 inches?
How's it running now?
I hit 38 today for a while then backed down to 30 and just cruised along without a care in the world

The part that fits into the expansion chamber,bike runs good but is four stroking a little more than I like might have to go down a jet size but power is good top speed is 34 mph on a 44 tooth sprocket

 

[HumanPerson]

hmm, i wonder how removing that 5 inches affected the pipes performance.
I trimmed 1/8th inch off of the header pipe and it actually seems to perform great, in my opinion.
What size jet are you using currently? I'm using a #64 jet in the delorto clone carb.
Switch to a 40 tooth sprocket and see how you like that. I did and i really like the 40 tooth better than the 44 tooth.
34 is good man Get it all dialed in and you'll see that cruising at 35 and having a good throttle response is even better
Post those pics of your bike and let's compare
Ride Safe Marc W