KZP engine rebuild

daveo wrote: What do you have the RPM's set to when synchronizing the carbs?

idle so ~1,200 or so... Is that too low?

Hey Jim, been awhile since I synchronized my BS34's. I used a Motion Pro tool I had at the time for them, and switched to the Morgan unit after shelving those carbs, which BTW is awesome IMO.
It may help to bring up the low readings by adjusting the rpms to 1500 or so...maybe. :huh:

Please keep us posted, and good luck!

old_kaw wrote:

daveo wrote: May be a good time to replace the old stretched out cylinder head studs with a APE hardened set. Cured my problem of corner O-ring leaks with 42lbs. torque.
Not a drop or seep since.

As usual, you are probably right Dave. Those 37 year old studs are actually supposed to act like a "spring" with proper torque, but after that many heat cycles, I assume the spring action has sprung.
Just some NOS stockers would also probably cure the seeps too. The automotive "torque to yield" head-bolts get replaced almost every time the heads are off. Not so much on these motors... It is ~$150 for studs, from what I see advertised.

but GREAT! NOW I have something else to buy! lol

The left side 6mm bolt threads are hurt too (installed longer bolt), which is also not helping the seepage. I am going to helicoil both, along with a bunch of cam bearing cap threads too, the next time the head is off. I had to repair a cap thread the last time, and yet another torque session on them is not going to go well... I just have that feeling.

I don't know about the "right" thing, though I am conservative minded...sometimes. I only own one motorcycle, and that is plenty enough for me.
Not sure how APE heat-treated studs work, but they are well-worth the expense just for the resulting peace of mind. I'm on my second head with the set. Used sets come up occasionally on ebay.
IMO, the outer two 6mm bolts don't offer much that I can tell.
One thing worth mentioning about the corner O-rings. Before my most recent head installation in early 2015, I sought one expert opinion about applying sealer to help hold those O-rings in-place and potentially enhance the seal. It was recommended to "install them dry" by Jeff/Z1E, and I am happy to pass-forward that awesome piece of advice to you.

daveo wrote: Hey Jim, been awhile since I synchronized my BS34's. I used a Motion Pro tool I had at the time for them, and switched to the Morgan unit after shelving those carbs, which BTW is awesome IMO.
It may help to bring up the low readings by adjusting the rpms to 1500 or so...maybe. :huh:

Please keep us posted, and good luck!

I put a few miles on it yesterday making a beer run. It's a little weak on the bottom and has what feels like a lean surge at cruise. I haven't gone much over 4K yet but the upper parts of the rev range seems strong. I haven't adjusted the fuel screws yet beyond installing them 2 1/2 turns out. It also seems to be running a bit hot although it was in the 90's when I took it out.
It's drippping a little oil from where the case was repaired but not nearly like before. It has also developed a leak from the pulsing coil cover. I installed that gasket dry but now I am wondering if I should have coated it.

After all that work, and it's still leaking oil? I feel your pain brother.

My bike also seemed a bit "off" when I first got it running with new rings, but I also had never replaced those 36 year old carb holders (36 at the time), so I did that next, and ordered in some different shims from Z1, and set the valves all to spec after it all had a chance to run in and seat.



I also went through my carbs last January, and replaced the starter enrichment booties on all four carbs, My bike is like a caged animal, it wants to GO. Although it has always been so, it is even more now.



Those bootie things are pricey at ~15 bucks each, but the cheap replacements aren't like this and are just dust seals, not boots. I polished this stuff up in my cordless drill.



Notice I soda blasted the carb bodies, polished any brass I could get to, and bought a bunch of metric stainless hardware from fastenall. (it was 19 degrees here) I think it's cheaper to buy the Z1 screw sets (did that too), than to piecemeal the screws / washers, but it's soo gratifying. lol Fastenal also has some meaty small flat washers that look great ( gold looking plated).



I just got some new spring clamps too.



I did see that you did a lot of carb swapping, so something is probably out of whack in the fuel / air department too. 2 1/2 turns is too much on the idle mixture screws, I think my manual lists 1 1/4 turns as initial on the CV carbs. Normally on the idle mix adjustment, you want to main idle down as far as possible without dying, then adjust the screws in until the rpm's go down, then back out until they go back up, and I usually go ~1/8 turn out past that. If this makes any sense to you? I think mine are around 1 3/4 now. Not really critical as long as the bike idles ok and is not acting stupid at stop lights etc.

old_kaw wrote: I did see that you did a lot of carb swapping, so something is probably out of whack in the fuel / air department too. 2 1/2 turns is too much on the idle mixture screws, I think my manual lists 1 1/4 turns as initial on the CV carbs. Normally on the idle mix adjustment, you want to main idle down as far as possible without dying, then adjust the screws in until the rpm's go down, then back out until they go back up, and I usually go ~1/8 turn out past that. If this makes any sense to you? I think mine are around 1 3/4 now. Not really critical as long as the bike idles ok and is not acting stupid at stop lights etc.

I was running it with one size larger pilot and main. The exhaust is stock and I have a K&N in the stock air box. It is running hot (compared to previously). I rechecked the compression and I am still at 130 across all four with the engine warm. I pulled the plugs and the electrode tips are whitish. I have already replaced all the boots and I don't see where I might have a vacuum leak.. Still shows low vacuum at idle.
As far as adjusting the fuel screws I have been using a colortune which I will try again as well as looking at the plug color with new plugs,

ThatGPzGuy wrote: I was running it with one size larger pilot and main. The exhaust is stock and I have a K&N in the stock air box. It is running hot (compared to previously). I rechecked the compression and I am still at 130 across all four with the engine warm. I pulled the plugs and the electrode tips are whitish. I have already replaced all the boots and I don't see where I might have a vacuum leak.. Still shows low vacuum at idle.
As far as adjusting the fuel screws I have been using a colortune which I will try again as well as looking at the plug color with new plugs,

The colortune is supposed to be the "holy grail" of carb tuning. There may still be a vac leak if the plugs look white instead of tan, (lean condition), or something might be plugged. Try a stock air filter to see if it makes any difference. The CV carbs are finicky and need that air box restriction to run properly. I ass-u-me the rings still haven't completely seated yet.

Keeping the rpm's under 4K? LOL I broke my bike / rings in like I ride it.. hard. I did at least go a few miles going easy.. Being careful is smart, too careful is boring.

Out of curiosity, what caused the cracked case? Left side under the stator?

SWest wrote: Those chains are tough. I'd put it together and ride the piss out of it.
Steve

Now THIS is my kinda man! lol

old_kaw wrote: The colortune is supposed to be the "holy grail" of carb tuning. There may still be a vac leak if the plugs look white instead of tan, (lean condition), or something might be plugged. Try a stock air filter to see if it makes any difference. The CV carbs are finicky and need that air box restriction to run properly. I ass-u-me the rings still haven't completely seated yet.

Keeping the rpm's under 4K? LOL I broke my bike / rings in like I ride it.. hard. I did at least go a few miles going easy.. Being careful is smart, too careful is boring.

Out of curiosity, what caused the cracked case? Left side under the stator?

LOL. I have been careful with it because I could tell something was off about it. No reason to stress it unnecessarily but I'll be pushing a little harder now it's firing on all four. I am going to go up another size on the pilots because to get close to the right color on the Colortune I am backed out 3+ on the fuel screw.
Not sure how the case got broken since it happened before I got it. I have another set of cases to swap over but I wanted to sort out these issues first.

Just a wild guess here, but a stock air filter would probably fatten up the fueling a little. It really doesn't need any help breathing,, I bet at this point just running right would probably be a blessing. It 's not like it's some super duper racer, it's a old cop bike.

The reason I was asking about the cracked case, it because that area does look a little weak, and I noticed the other day, I have evidence of somthing hit that area on my bike, weather it might have been from a floor jack at some point, or hit it loading on a trailer, or curb, OR? I don't think mine is cracked, but I would like to clean up the area, to prevent any cracks from forming. It may be time for the bur on my die grinder. I really do hate to touch it, because everyone knows if a little is good, a LOT is better. lol

I took this pic today.


Not all that bad, but the jagged edge may give it a place for a crack to start.

ThatGPzGuy wrote:
I was running it with one size larger pilot and main. The exhaust is stock and I have a K&N in the stock air box. It is running hot (compared to previously). I rechecked the compression and I am still at 130 across all four with the engine warm. I pulled the plugs and the electrode tips are whitish. I have already replaced all the boots and I don't see where I might have a vacuum leak.. Still shows low vacuum at idle.
As far as adjusting the fuel screws I have been using a colortune which I will try again as well as looking at the plug color with new plugs,

It shouldn't be necessary to bump the pilots. Even Dynojet recommends running stock pilots with most of their Stage 3 jet kits. I'd tune the pilot screws until you achieve the highest idle setting. Sometimes it's hard to tell where that is in which case make all the screws the same amount open, typically somewhere north of 2 turns open.

Oh, and how many miles on the engine? You mention not taking it over 4k which is a red flag to me. Your piston rings need cylinder pressure to seal. Don't race the engine or anything but ride it in a good assertive manor, driving around city streets. Accelerate away from stops and let the engine spin some.

Nessism wrote: It shouldn't be necessary to bump the pilots. Even Dynojet recommends running stock pilots with most of their Stage 3 jet kits. I'd tune the pilot screws until you achieve the highest idle setting. Sometimes it's hard to tell where that is in which case make all the screws the same amount open, typically somewhere north of 2 turns open.

Oh, and how many miles on the engine? You mention not taking it over 4k which is a red flag to me. Your piston rings need cylinder pressure to seal. Don't race the engine or anything but ride it in a good assertive manor, driving around city streets. Accelerate away from stops and let the engine spin some.

Hello Nessism,
I will run it a while with the 40 pilots but it does seem lean and is def running hot. I run the same pilots in my 750 and my plugs are a perfect light chocolate color although I have a 4 into 1 on that.
The engine has new pistons/rings and valves and has only traveled a sum total of 34 miles. It has an overall 46K on the bottom end. I'll start getting more aggressive on it when I get the oil leak fixed. Thanks for your help

Jim