AHRMA Vintage Superbike Middleweight Racer

T_Dub wrote: Wow, I thought I'd seen it all here in rustland, but thats some bad rust. Good thing its a stripped down thing you're looking for.

Yeah, I think I would feel bad tackling this project if it were in good shape. But given how things are, I feel like it's the perfect candidate.

I'm a little concerned about getting the rest of that one plug out, but I'm hoping once I get the head off I can back it out the other way, or at least free it up and clean up the threads enough to get it out.

If not, I have a 750 head that I could probably use, although I need to double check the regulations to make sure a head swap from a different model isn't against the rules.

hey serious though...dont try and make a barley saver into a racer....what are you mad...these things pop up with the goodies already "tricked out :woohoo: ) what i think you have is the start of a nice set of 650 finds...two three bikes and you can mix and swap the needed and be way ahead to some head turners....m 2 pennies


who tf even rides a 650

What does barley have to do with this? :huh:

But I hear where you're coming from. My challenge is more that I am limited in the "tricked out" stuff I can do. If you see any pop up for cheap with larger front shocks (can't be cartridge shocks), YKB/YSS/Ohlins with piggyback reservoirs and rebound adjustment (can't be remote reservoir), wider rims in 17" variety, newer calipers with 2 pots max, point em out for me.

But I can't take a 750 swap, 810 kit, or hell, even the 710cc wiseco kit.

So I figure what I have is great for what I'm planning on using it for. The whole thing is gonna get torn down anyways, I'll know exactly what's inside her, and it was $$FREE$$. Did I mention free?

Most of the money I'm going to have to spend will be on suspension work. I'm going to try to stiffen the frame up some, hoping to cast my own fork brace and have someone help me machine it, put on some better shocks/stiffer springs, Avon AM22/23 race tires for the stocker spoke rims, and have a blast.

If I love it, I'll sink more money into it. If I don't, I'm out a couple grand and had a good time.

Peace. Later.

Have an update from tonight - will post soon. More wtf's and a couple broken fins.

I continued taking parts off of the bike last night. I found a random toggle switch connected to the left switch block and mounted in the left ear. I don't care what it was for, just more interesting stuff.





I also found that the pull side of the throttle cable appears to have been home made as you can see from the crimped end on it. I had to cut the cable to remove it from the carb.



The carbs appear to be Mikuni VM24's (measured just over 24mm on the inside diameter of the engine side of the carb throats) with an accelerator pump. I'm hoping to replace these with Mikuni VM26's from a Kz900 or VM28's from the Z1's. 29mm carbs are the maximum size that can be used for AHRMA Vintage Superbike.



I also measured the cams out of curiosity. The cams from my Kz750 motor measure almost 1mm taller than the Kz650, but I don't know quit enough to know what to measure. From what I know this means the Kz750 had a slightly higher maximum lift than the Kz650.





This is the distance I measured on both sets of cams:



The good news from the evening is that all pistons came free as I attempted to remove the head. The bad news is that the head seems to be very attached to the cylinders still. I may have to take the engine out of the frame to separate the head from the cylinders.

I managed to break a few chips off of some fins. Saved them and will JB Weld or repair properly before putting back together. Makes you feel like a noob.

DoubleDub wrote: ...found a random toggle switch connected to the left switch block and mounted in the left ear...

....

One SWAG could be an on-off switch for an always-on headlight, with the headlight's ground wire going through the toggle switch.

Or maybe a substitute for the ignition switch, by supplying battery voltage to the ignition coils through the toggle switch.

Good Fortune!

That was my thought as well. I just don't care enough to care.

DoubleDub wrote: This is the distance I measured on both sets of cams:

now measure the width of that lobe. subtract the width from the height and u have the lift .
this is the # used by manufactures to advertize the lift of a particular cam.

Thanks, Mark. When you say the width, you mean perpendicular to the current measurement, right?

I suppose duration would require a degree wheel and the cam installed (or some similar arrangement) to determine?

DoubleDub wrote: Dissection Begins

First gift – a spark plug which would not come out. Never had one break at the threads before…

try mixing trany fluid and acetone 50/50. use it as penetrating oil. best u can buy.
then drive in an easy-out and give it a good rap(to try to break the seal).

if legal, the 750 should have bigger valves.
good luck

mark1122 wrote: ...try mixing trany fluid and acetone 50/50. use it as penetrating oil. bust u can buy. then drive in an easy-out and give it a good rap(to try to break the seal)....

Could also use a propane torch to heat the engine head area surrounding the plug hole, immediately before attempting extraction.

This is supposed to help loosen female threads grip on male plug threads, as heat application should expand the aluminum head more than the steel plug threads.

And using left-hand (reverse) drill bit might also be considered.

Good Fortune!

DoubleDub wrote: Thanks, Mark. When you say the width, you mean perpendicular to the current measurement, right?

I suppose duration would require a degree wheel and the cam installed (or some similar arrangement) to determine?

Yes, thats right on both counts. OMR has a writeup in the archives i believe. it describes how to degree your cams. use that sett-up and u can see what degrees, the valves open, and close. then determine the overlap. but since these are stock cams the info should be in the manual.