750cc pushrod bike build

[Rchop]

I like running in the 750cc pudshrod class. I just sold my last 750cc bike and have started on a new 750cc pushrod build. I am just about finished with the frame and still working on the motor. The motor is a lower end of a Buell XB9 with sportster cyclinders and heads. The XB9 has a 3.125 inch stroke and the 883 cylinders have been bored to 3.050 inches. This gives me a 748cc displacement. I will be running it with the stock XB9 EFI system and I have the software for remapping. I will start with high compression pistons and run it NA. After I get the EFI system figured out, I will change to lower compression pistons and a turbo.

Here is a pic of the frame as it sits now. I still have to build quite a few brackets and add some gussets when I do the final welding. The front end is from an R6 and the rear end is from a GSXR 750.


http://www.frsengineering.com/pp54.jpg

Here is a pic of the fairings I will be using...


http://www.frsengineering.com/pp41.jpg

More pics can be seen on my website in the "Rubblemaker" photo gallery

[Rchop]

I split the case yesterday to send the crank in for true, tig and balance. I'm glad I did since I found a problem with the inner pinion bearing race...





Just another thing to add to the list

[fredvance]

Looks a little slicker than the BMW

[Rchop]

Looks a little slicker than the BMW

I hear ya  even if it isn't more powerful NA, is should be faster without those jugs hanging out

[interested bystander]

Jugs hanging out?

Read the rule book. Riders have to be completely covered and that includes FEMALES.

At least my daughter does on her roadgoing BMW that she proudly informed me yesterday she just passed 3000 road miles.

However, it's now in the shop -oil leak! She parks too close to her husbands Harley, apparently!

[55chevr]

Randy,

This build is looking good. It looks fast on the bench.

Joe

[Rchop]

Thanks Joe, and I look better dancing in a chair, but that's where it ends  I do hope it runs good. Make sure you check your pinion bearing

[55chevr]

New crankshaft ... Joe

[1212FBGS]

check the crankcase... not sure on the casting quality of the XB motor but the races can get beat up in a sportster case...
kent

[oz]

Cool Just love the Bikes looks likeyou are going to need some fair sized gussets around the headstock area though.
like the streamlining is that off the shelf or have you had it made one off.

Oz

[Rchop]

check the crankcase... not sure on the casting quality of the XB motor but the races can get beat up in a sportster case...
kent

The casting looks pretty good Kent. I found a dull shaded spot on the outer race too, so I will be replacing that also.

[Rchop]

Cool Just love the Bikes looks likeyou are going to need some fair sized gussets around the headstock area though.
like the streamlining is that off the shelf or have you had it made one off.

Oz

Gussets are planned for the headstock connections, the fairings are standard issue "Charlie Toy LSR" made by Kent's company, AirTech.

[Rchop]

Jugs hanging out?

Read the rule book. Riders have to be completely covered and that includes FEMALES.

At least my daughter does on her roadgoing BMW that she proudly informed me yesterday she just passed 3000 road miles.

However, it's now in the shop -oil leak! She parks too close to her husbands Harley, apparently!

LOL, keep those BMW's away from the Harleys, they pick up bad habits

[oz]

Very Nice I didnt realise Air Tech was kents company.

[JimL]

Hi Rchop....looking at your pics of the crank brought back an old memory (all of 'em being old at this point).  First, a question.... are those marks just on one side of the crank journal?  If so, this may be brinneling like we suffered with Honda CL450 back in 1971-72.

Seems the "batwing" tank paint was kinda' unpopular (on those Scramblers) and sales tailed off....just when the dockworkers went on strike on the West coast.  Honda wound up unloading bikes in Ensenada, where they sat on the docks (crated) for MONTHS!  Electrolysis set in and Brinneled the crankshafts where they were resting on the bearing rollers.  I had to change a few cranks, when the bikes we sold started knocking within the first couple hundred miles!

If your engine was sitting in a wrecking yard, for a long time, that could be what happened.  If that is it, be aware that Brinneling due to electrolysis goes deep into the dendrice (of the crystalized iron).  The crank can be hard faced and refinished, but polishing (only) will not last.

Hope this helps....or I could be completely off base!!  That's how it works on this site. :-P

Regards, anyway, JimL