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Discussion starter · #21 ·
a quick update,
I was planning on building a mild yet reliable motor for this bike. Not any more... i have been talked into going as far as the budget will allow, so here are the parts I have ordered
THR- PVL ignition
THR- lowered 5th gear
Boretech- megacycle X5 cam
Boretech - timeable cam gear
I will be doing a full race valve train but have yet to decide which and where to buy..
I spent a few hours in the garage last night and the day before getting the cases ready for assembly. This set of cases was from a 69 CL350 , and I previously had them hot tank cleaned and then blasted. I removed the head studs and have tapped all of the threaded holes. You wouldnt believe how much gunk can come out of the threaded holes!!! the cases are sparkly clean (you think) and then pure black coming out of the holes!! haha
I am happy to know these cases are now truly clean and nothing will contaminate the motor.
pictures to follow tonight!
 
darksidephoto,

Good timing (for me at least)! I'm working on a track bike for the upcoming season as well, though you’re doing a lot more performance upgrades. My goal now is to turn a barn find into track bike in the next few months so my goal is to get the bike running with a reliability being paramount and I’ll go from there there. I'll be watching you progress,

Cheers!
 
porting is good with straighten out the intake as your main objective.

polishing is NOT recommended on the intake side of carbureted engines (it reduces swirl which leads to poor fuel atomization which lowers power and makes it difficult to properly tune...polishing is fine on the exhaust side; do the valves and the port. it reduces the amount of carbon build up)

why only 65mm pistons?

with the X-5 cam (I personally prefer the midrange advantage of the 123-40 cam) you should be running larger high compression pistons. you will also need the heavy duty valve springs to prevent float contact over 10K RPM. The 5mm valve stem kit reduces float as well.
be sure to check your valve to piston clearance with any of the race cams as well .060" is minimum clearance.

going up 1mm on the valves adds good power and helps cool the valves, but check current class rules on that one.

the slotted cam sprocket is good, you must degree your cam. expect the cam to be as much as 6 Degrees off in either direction
 
Discussion starter · #25 ·
Outobie
thank you for the reply, I believe we are on the same page.
I will be running 67.5 pistons, either the THR or Team Hansen
the valve train will be the 5mm Kibblewhites, still shopping them.
I had previously dropped off a head with new valves, and a cylinder with new 65mm pistons - my machinist is finishing up this work, and now it will go on my bone stock 68 when it needs a rebuild.
I have already dropped another cylinder and will drop another head to be used for the race build (+1 on intake valve/ kibblewhite 5mm full valve train/ KA cut/67.5 bore/ port head)
 
Discussion starter · #26 ·
Ok, just got the off phone with Kelly at Boretech, my Megacycle X5cam and timeable cam gear are shippping tomorrow. She also told me that Kibblewhite is direct shipping me 5mm stainless valvetrain tomorrow!! It is going to be like christmas all over again!!!
 
we are building almost the same engine except for the cam and I went with the standard size kibblewhite valves since I'm running my motor on the street

what exhaust are you running?
Jemco?
 
Is there a reason you guys would not want to run the small stem valves on the street? Is it just a cost outweighing benefits thing?
 
it's not the stem diameter, it's the valve diameter...

the 1mm larger valves flow better on top but leave a hole in the lower middle.

fine for a race bike that stays above 8000 RPMs but not for a street bike that lives below that most of the time
 
Discussion starter · #30 ·
so supposedly my frame is going to be done today and delivered, if so I will take some pics of the additional welding. This is just first round of fabrication, next will be hoop at rear, a couple new tabs including one up front for the Ohlins steering damper; and a tab for the tach/ number plate frame.
 
any bracing under the motor to replace the footpeg stay (look at a stock SL350K0 frame for inspiration)
or from the backbone to the shock stays?
These are highly recommended and make a tremendous difference in handling
 
Discussion starter · #32 ·
outobie,
yes I will be putting in (2) braces from the back bone to the rear triangle (each side)
I thought about putting in a tube under the motor side to side, but the racers I asked didnt seem to think it would add much. Thoughts?
 
darksidephoto said:
outobie,
yes I will be putting in (2) braces from the back bone to the rear triangle (each side)
I thought about putting in a tube under the motor side to side, but the racers I asked didnt seem to think it would add much. Thoughts?

my race bikes are noticeably stiffer and smoother than stock and bracing under the motor is key...it keeps the swing arm pivots in the backbone straight under cornering load so it can move without excess stiction.

even Honda added a brace there when they wanted to stiffen up the frame for the SL350 K0
keep in mind, that when you remove the footpeg bracket that ties the two siderails together you have just made your frame weaker than stock (not a good idea on a race bike :) ) on the SL350K0 Honda thought bracing there was so important that they used a brace AND the footpeg bracket.

tell your "racer" friends they were right as you smoothly pass them in the turns while their bikes are chattering into the ditch

If I get a chance I'll go take a pic of one of my race frames and show you were to put it. One other point...Honda cast the bottom engine cases of all the 350 motors with a notch in the finning where the brace goes. it was their intention all along to have that brace even from the first K0 bikes
 
Discussion starter · #40 ·
here is a pic of my new THR - PVL ignition that showed up yesterday! its a crank fired magneto, so no battery , regulator, rectifier, or additional wiring other than an "on/off" switch.
 

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