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Discussion Starter · #1 ·
I recently picked up a worthy candidate to turn into a race bike.

This poor little Honda was abandoned under a balcony for several years, left to rot. The guy I bought it from said it was his old roommates's, and that it had ran before if was parked, but Atlanta is never kind to bikes left outside. I offered him $150 bucks, which he happily took for me to remove what he thought was a pile of junk. Little did he know the glory that awaits this awesome machine.

I want to participate in the AHRMA Novice Historic Production Lightweight class, but I may just have to miss the first few races before I can get the bike safe and reliable, and hopefully fast.

First thing I did was give the bike a wash, and drain the tank.
The tank has some dents and rust on the outside, however the interior looks pretty decent.
Tank removed, I noticed its missing ignition coils. Everything else seems to be there.

Someone threw some paint on the wheels and engine, all of which are peeling badly.
Lots of rust everywhere, but most of it appears to be surface rust. The original exhaust is in surprising good shape, as does the chassis and wiring harness. Engine does seen to turn over, although I want to spray a little wd40 into the cylinders before I kick it over completely. Who knows how long its been since oil has been up in the top end of the engine.

So far what I plan to do:
-Drain oil
-Change plugs
-Install coils
-New battery
-Fresh gas
-Carb rebuild
-Adjust points and timing

That should hopefully get it to run. Updates to come. Carb kits and used coils are on the way!
 

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Discussion Starter · #2 ·
More pics, anyone know how to upload more than 10 at once?
 

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Didn't know this class existed. I was going to reference a couple of the other race bike builds but the rules are different for this class. Here's the basic rules
10.6.4 REQUIREMENTS AND MODIFICATIONS FOR HISTORIC PRODUCTION

a) Carburetors: Must be OEM and same type (e.g., if CV, must use CV), no larger than the original OEMbore size. (Restrictors may be introduced to ensure parity of performance.)
b) EXHAUST SYSTEMS: All four-strokes must use OEM configuration exhaust systems (i.e., two-into-two, four-into-four, etc.). Effective silencers are required; no straight pipes or open megaphones. Pipes may be tucked in and mufflers raised for ground clearance. All two-strokes must use original OEM exhaust pipes as fitted on THAT motorcycle. No tuned pipes or expansion chambers. Pipes may be tucked in and mufflers raised for ground clearance.
c) BRAKES: Front and rear may be upgraded to Sportsman 750 specifications.
d) RIM SIZES: WM3 (2.15 inches) maximum front, WM4 (2.5 inches) maximum rear. Must be steel or aluminum OEM.
e) Side stands and center stands must be removed.
f) FOOTRESTS: Must remain in the original OEM location fore and aft. NO REARSETS. Footrests may be raised or modified for ground clearance.
g) Lighting equipment must be removed or totally taped over to the tech inspector�s requirements.
h) FAIRINGS AND BODYWORK: Fairings of any type are NOT allowed. Gas tank, seat and fenders must be OEMequipment or period replacements. NO modern "GSXR style" bodywork will be allowed.
i) NUMBER PLATES: 10-inch by 12-inch rectangular. White background with red numbers. Also see rule 9.5.
j) Specialty machines such as Rickman, Dunstall are not eligible.
k) Historic Production machines are NOT allowed to bump up into any other AHRMA class.
l) Except as noted above, rules 9.3, 9.4 and 9.7 apply.
 

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Discussion Starter · #5 ·
Didn't know this class existed. I was going to reference a couple of the other race bike builds but the rules are different for this class. Here's the basic rules
10.6.4 REQUIREMENTS AND MODIFICATIONS FOR HISTORIC PRODUCTION

a) Carburetors: Must be OEM and same type (e.g., if CV, must use CV), no larger than the original OEMbore size. (Restrictors may be introduced to ensure parity of performance.)
b) EXHAUST SYSTEMS: All four-strokes must use OEM configuration exhaust systems (i.e., two-into-two, four-into-four, etc.). Effective silencers are required; no straight pipes or open megaphones. Pipes may be tucked in and mufflers raised for ground clearance. All two-strokes must use original OEM exhaust pipes as fitted on THAT motorcycle. No tuned pipes or expansion chambers. Pipes may be tucked in and mufflers raised for ground clearance.
c) BRAKES: Front and rear may be upgraded to Sportsman 750 specifications.
d) RIM SIZES: WM3 (2.15 inches) maximum front, WM4 (2.5 inches) maximum rear. Must be steel or aluminum OEM.
e) Side stands and center stands must be removed.
f) FOOTRESTS: Must remain in the original OEM location fore and aft. NO REARSETS. Footrests may be raised or modified for ground clearance.
g) Lighting equipment must be removed or totally taped over to the tech inspector�s requirements.
h) FAIRINGS AND BODYWORK: Fairings of any type are NOT allowed. Gas tank, seat and fenders must be OEMequipment or period replacements. NO modern "GSXR style" bodywork will be allowed.
i) NUMBER PLATES: 10-inch by 12-inch rectangular. White background with red numbers. Also see rule 9.5.
j) Specialty machines such as Rickman, Dunstall are not eligible.
k) Historic Production machines are NOT allowed to bump up into any other AHRMA class.
l) Except as noted above, rules 9.3, 9.4 and 9.7 apply.
Thanks for posting that up, helpful for me instead of having to scroll through the ahrma rule book haha.

I've started stripping everything off the frame, engine out for new seals and gaskets and a proper assessment, tear down has begun. Nothing alarming yet, worst thing I've seen was the crossed up spark plug in the right cylinder, which I had to pull the engine out to repair anyway. Aside from a lot of crud buildup and some minor parts rusted it's in very good shape! Only 2800 miles on the clock, I believe that may actually be accurate.
Cylinders have some vertical scoring all the way around most evident on the bottom half of the bore, also evident on the piston skirts. None of it deep, a good hone should do the trick. On the fence about getting new pistons, may just run the stockers until I have to bore a size up.

Here's a quick list of what I'm planning for this build so far:
1. Refresh engine, lap valves, hone cylinders and new rings, maybe new pistons. Crank is in great shape, as is the clutch, have yet to split the cases
2. Swap in the later models front end for the upgraded forks (have to be stock forks to the model so long as it's oem equipment)
3. Upgrade rear shocks
4. Install free flowing race oriented cans, foam filters, and re-jet
5. Electronic ignition conversion
6. Starter delete (is it possible to remove the starter clutch as well, or does that act as a spacer on the crank behind the magneto?)
7. Source and install stock front fender
8. Build custom wiring harness, source some coils and bracket
9. Source wider rims for better tire selection, can go up to 2.15" front and 2.5" rear, thinking some aluminum 36 hole xs rims which I've read are an easy drop in
10. New cables, brake shoes, tires, and any other regular maintenance item

More pictures to come, it's all at my workplace now.
 

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As for #6, you can remove the entire starter clutch from the back of the alternator rotor (not a magneto as it's battery/coil), the rotor stops where it's supposed to based on the crankshaft taper. Speaking of coils, 4into1.com sells good repros for a decent price, I'm running them on my CL450 build
 

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Get your rear drum resurfaced and the shoe’s arched to match the diameter of the drum......(a must for front drum brakes) but it won’t hurt.

I use a place that re-pads shoes for trucks.


Sent from my iPhone using Tapatalk
 

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Discussion Starter · #8 · (Edited)
Got the engine out and disassembled, everything is looking pretty good. Working on removing the old paint and cleaning everything proper, got the engine rebuild kit in the mail. In the process of removing the thin sheet metal plate bolted into the lower case half under the crank I managed to break and tear the plate into a few pieces, I'm wondering if it's necessary to have it in place. I'm guessing it's just so the gunk that accumulates at the bottom of the cases doesn't contaminate the crank bearings causing them to wear faster. Any thoughts?

Head after some cleaning with the dremel, need to go back at it again:
303947

303948


Pistons and cylinders exhibiting some scoring, probably due to turning the engine with some debris in it:
303949

303950
303951



My carburetors are in poor shape, I managed to get them stripped down but finding some issues with them.
  • The plastic bushing on the butterfly shaft that holds the felt seal in place is breaking apart on one of the carbs, I think it will cause a big air leak, I'll have to rig some sort of repair for it.
  • The flap on one of the choke butterflies has a broken spring and moves around freely. Not a huge issue but I'd like to get it secured.
    303953
  • Ripped diaphragm on one of the slides, have a replacement on the way
  • Not sure if the mixture screws are supposed to be different between the two carbs, on one side the threads are at the head of the screw, with an o-ring under the spring. On the other carb the screw is threaded down the length of the shaft, and no o-ring was present. Curious...
  • The jets located behind the needle jet emulsifiers are very much stuck in place, tried several cycles of heat and penetrant and some tapping with a chopstick to try to dislodge them but no luck yet. I may leave them in place if they prove to be too stubborn
I'll post up some more pictures tomorrow, it's been a long productive day!
 

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Discussion Starter · #11 ·
Photo dump! Polished up the valves and parts splayed out. Got some pretty bad galling and pitting on one of the cam lobes, need to get them resurfaced
 

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You apparently have two different model/type/setting mark carbs.......On the carb body, look for the setting mark (350-A, 3C, or 3D).....It would be easier/better if the carbs matched because different setting mark carbs use different size jetting, different mixture screws, and different adjustments
 

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Delta Cam in Tacoma WA for the cam and rocker repair
I'd replace all of the valves. Get a 3-5 angle valve seat grind at the local machine shop. The valve/head work is one of the more important pieces for making power
 

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Discussion Starter · #15 ·
Delta Cam in Tacoma WA for the cam and rocker repair
I'd replace all of the valves. Get a 3-5 angle valve seat grind at the local machine shop. The valve/head work is one of the more important pieces for making power
Duly noted, thanks for the tip! I'll get the cam sent out this week and hoping to get all parts engine cleaned up and ready for reassembly by the first week of March. For this build I'm trying to keep it low budget, so more than likely going to reuse the old valves, especially since they are well within spec. I'll do a leak test without springs installed after I love on the head a bit, if they weep I'll get a new set.

You apparently have two different model/type/setting mark carbs.......On the carb body, look for the setting mark (350-A, 3C, or 3D).....It would be easier/better if the carbs matched because different setting mark carbs use different size jetting, different mixture screws, and different adjustments
Interesting... and annoying, I'll have to do some more recon.
 

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why is it in the usa people pick up bikes like thais for $150. and in the uk theprice is more like£700 even in this condishion.
any how do you know if they are the same size jets in both your carbs? and also what are they.
should look nice when you have it all fixed up
 

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Discussion Starter · #17 ·
why is it in the usa people pick up bikes like thais for $150. and in the uk theprice is more like£700 even in this condishion.
any how do you know if they are the same size jets in both your carbs? and also what are they.
should look nice when you have it all fixed up
I really did get lucky with this find, I've seen bikes in way worse shape than this going for several hundred more.
Haven't taken a close at the jets, I'm pretty sure they are aftermarket and not the stock jets. I'm thinking I'll try running these carbs, if it runs like totally crap I'll consider getting a matching pair, but I'm fairly confident I can make it work.
 

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why is it in the usa people pick up bikes like thais for $150. and in the uk theprice is more like£700 even in this condishion.
Believe me, they're not all as cheap as what he found - I bought a CB350 late last year for a project and the engine is supposedly rebuilt but won't turn over, the kickstarter is frozen and it has a fair amount of rust and I paid $400 for it
 

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Good deals are still out there. Some take a lot of searching, and some just find you. My 2 CB350's and an XL100 with a new Lifan 150 cost me $550 and 2 steaks a week ago.
I was just watching a cool CB engine build by the famous Stan Lipert on YT. He suqeezed out 48 HP of a 350 mill and does a very well documented video of the assembly.
 

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Discussion Starter · #20 ·
Good deals are still out there. Some take a lot of searching, and some just find you. My 2 CB350's and an XL100 with a new Lifan 150 cost me $550 and 2 steaks a week ago.
I was just watching a cool CB engine build by the famous Stan Lipert on YT. He suqeezed out 48 HP of a 350 mill and does a very well documented video of the assembly.
Great video, you know you're a gearhead when you watch this kinda stuff for fun. I wish I could get all my engine parts that clean! Got quoted $850 to have all the whole engine steam blasted. That's with it completely disassembled, all paint and grease removed prior ?
 
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