View Single Post
Old 06-02-2011, 05:33 PM
mapbike's Avatar
mapbike mapbike is offline
Motorized Bicycle Elite Member
Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Default Re: what did you do to your motor bike today?

Well got the expansion pipe put on and went for a 7 mile trip on the same roads I always ride on around here, and I have to say that the bike does pull the hills a tad bit better and it may accelerate just a tad bit better as well, top speed remains the same not a mph more not a mph less, I hit 41.6 mph and it will hold steady at 38-39mph on the flat & will maintain 26-30MPH on the hills around here and is much quiter also.

So my conclusion is that the SBP Expansion Chamber Exhaust does a great all around job of increasing the torque and flowing free enough to allow a good top speed and it does it pretty darn quite too.

Now, this is a bone stock engine internally, nothing polished, nothing deburred, nothing tweaked other than the carb jet has been reduced by soldering up and redrilling with a #72 bit.

Bike has a 36T sprocket which I made from a small kids bike by drilling all the holes in it for the rag joint coupler.

When I get my new upper rod-wristpin bearings and seals in and I get a few more miles on this engine I will do some minor port work make better gasket for jug to engine case and take a few thousands off the head and I may give it a wider squish band that more closely matches the bore to its outer edge, not sure this will help anything but I'm sure it cant hurt, then this engine will get the new RT carb. and nice air filter I just got in from Duane at Thats Dax......

I may need to shorten the lead pipe from engine to expansion chamber, not sure yet, it is running pretty good like it is so I will likely leave it alone until I get all the other stuff done to this engine and then I may tweak it a bit.

it's just kinda rigged up on it right now as you can see in the pic but that was a quick get-ur done deal to see how it would perform.......

I'm Happy with it......

Attached Images
File Type: jpg 06022011.jpg (95.3 KB, 29 views)
File Type: jpg 06022011(001).jpg (104.9 KB, 36 views)
I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!

Last edited by mapbike; 06-02-2011 at 05:37 PM.
Reply With Quote