1981 KZ1000 J-to-K build

I'm not sure that fork bag I ordered is going to be large enough, but I found a little larger one in real leather from a US seller that I got ordered. I also found a complete set of the four rubber grommets for hanging the mufflers, Both are due to be delivered on Tuesday.

In the meantime I got the tank wet-sanded and about one and a half cans of clearcoat sprayed on before some white stuff got blown into the fresh paint. At least the clearcoat doesn't take so long to dry, so I should be able to wet-sand the stuff that got in the paint and then try to get another couple cans worth of clear on the tank Monday or Tuesday. Otherwise it's looking pretty good, will be nice to finally get this tank on the bike.

I also started building the sissy bar today. The bar itself was easy, just bent some 1/2" steel rod around a 4" pipe and hammered it a bit to smooth out the curve. The portion to bolt to the frame is made from some 1/4" x 1" flat steel. I had to break out the forge to get the pockets made which slip in behind the shocks, and the right side has a pretty serious S-curve to clear the helmet lock. I think I'm done with all the hot work, I just need to clean up the shapes and get both flats to come out at the same point behind the seat, then weld the 1/2" bar to the flats. I will also need to add some tabs to the flats for the bolt hole beside the turn signals. The back rod was sized to fit the bag I had made for my old bike, but only about half as high. This should be about right so that the bag sits just above the rear fender, trying to keep everything fairly low. I should probably go ahead and weld a flat across the back bar so I have something to mount a seat pad to later on when I get around to making one. Once it's all done I'll hit it with the sandblaster and give it a coat of gloss black to match the frame.

My god, so much body pain from today. It's been a long time since I did so much physical labor and I'm really feeling it. And it's been years since I fired up the forge -- it's nice to see some things just work every time you pull them out. Unfortunately I'm going to be putting so much time into projects this weekend that I won't have any time to ride. Don't think I'll even get around to balancing the carbs, but if I can get this sissy bar frame finished up and the new fork bag arrives on time then I should be able to start riding in to work towards the end of next week. Crossing my fingers as the temps will be back up near the 90s again by Thursday.

Sissy bar is complete, and I got it painted and cleared just before the rain hit. I normally hang stuff from the garage door hinges when I'm painting but the rain came in so sudden and hard that I had to move it back into the garage to keep the wet clearcoat from getting splattered.



You can see the S-curve bends I had to put in the right side to clear the helmet lock. For now this will only be used for holding one of my storage bags but if I plan to use it for a passenger later on I definitely need to add angle brackets between the rod and flats for more support. And somehow, despite what I thought were careful measurements and marks, the triangular additions for the bolt holes ended up not being square to the holes. Ah well.



One quick trial-fit, and a small adjustment to the flat on one side to square up the bar with the seat, and then I started painting it. I have a light sanding disc on my angle grinder that works fantastic for cleaning up hot-rolled steel before painting, plus it takes out the hammer marks . Because of the approaching rain I was in a bit of a hurry and the black paint sagged a bit on one of the side brackets, not a big deal but if I rework this as a seat rest later on I'll sand it down and re-finish that area (it's near where the angle supports would go anyway).

My small fork bag from China finally had an update on sipping. Turns out ALL the things I ordered are scheduled for delivery tomorrow. Got another chance of rain by the time I get home from work tomorrow so we'll see how that turns out, but I hope to have everything attached to the bike by Wednesday evening and ride in to work on Thursday. Because of the funky S-curve I'll have to take off the right shock to get the sissy bar mounted to the bike, otherwise the rest should go on easy.

I didn't get a chance to wet-sand the fuzzies out of the gas tank today, but it's been sitting on the back porch in the sunlight and damn the color looks good with that first coat of clear on it. At some point this week I'll get it cleaned up and shoot the last coat of clear, then give it at least a week to really cure. A wax coat should really finish it off and maybe help protect from any gas spills, but time will tell. And someone pointed out to me this weekend that I still having hit the side covers with clearcoat, so I need to finish them up at some point.

I was burnt out from working on other things yesterday so I decided to go for a ride. Was out for two hours and it ran ok the whole time although I think I still have an exhaust leak somewhere. I never got a chance to balance the carbs this weekend but now that the sissy-bar is done I can get back to tuning as time allows. It is still idling well and cold-starts with no problems so I don't think it is too far off, but it does still have sort of a rough feel to it. I'll get to that soon...

Hmm I think I should have cut another inch off the length of the brackets. Got it mounted to the bike today and it feels like it is too far back. On the other hand, I left space between the sissy bar and the back of the seat to leave clearance for a padded back-rest. I dunno, maybe it will look right if I add the padding.

Got the bags in the mail today. God I wish people knew how to use a tape measure. "This bag is 12 inches wide!" Oh no, that's only 10.5 inches, and that's just enough difference to mean that neither my jacket nor my thermos will fit in it. I went ahead and strapped it to the forks anyway. It's a decent fit and maybe I can use it for something else.

Also received the set of rubber grommets for hanging the mufflers. I hung the pipes back up with wire again, but now at least they're hanging from the right spot. I'll have to make up a short metal strap to complete the hangers, shouldn't be too difficult.

The weather forecast is looking great for riding in to work on Thursday. Clear skies and 90 degrees. God it's been more than a decade since I last rode to work. Where did the time go?

I had a somewhat successful, albeit educational first ride to work today. First off, man this thing is not happy about running in cold weather. Temps were still in the 50's when I left this morning and I was out of town before it finally ran smooth without the choke. And by 'smooth' I mean it felt ok but sounded really rough and seemed rather loud from the pipes, and I had to keep my hand on the throttle because the idle speed was too low to keep running at the lights.

So I made it in one piece. Coming home was a different story. Two blocks from my parking lot they just finished re-paving a stretch of road yesterday, so we have fresh oily blacktop and the temps were near 90. Someone hit a crosswalk signal and the guy in front of me seemed to stop on a dime. Oh shit! I hit the brakes, locked up the wheels, and slid like I was on ice. Not good! Let off the brakes, zipped into the other lane (glad there WAS another lane), locked up the brakes again and slid half way across the intersection before stopping. Well that was exciting. However what really impressed me was the stability of this bike. I mean I locked up the wheels twice and it slid straight as an arrow. On my old Yamaha when that sort of thing happened the whole bike would get squirrelly and you had no sense of control. On this bike I felt totally in control the whole time, it wasn't even enough to get my heart pounding. SWEET!!! I am really loving everything about how this bike handles!

OK the rest of the trip home was uneventful, although even with the heat it still sounded like it was just running like shit and I chewed through about 1/4 tank of gas for a 40 -mile round trip. Something needs tweaked. I let it cool down for a bit after I got home then pulled all four plugs. Three of them were a bright sandy color, one even having spots of red on it, and the fourth was oily. OK the oily plug is on the left where I'm sure I was hearing some popping inside the muffler, and the other three are running way lean. I left the rich cylinder alone and pulled the mixture screws out another half turn on the other three. Took a couple runs up and down the block, and yeah that definitely feels smoother. I'm ready to try again in the morning, and we should be into the 60's by the time I leave for work. Crossing my fingers, but I'll check the plugs again after I get home.

Good weather forecast for this weekend, I plan to get the clearcoat finished on the tank and then try again at balancing the carbs. Assuming I have time. Everybody always wants me to work on *their* projects on the weekends, I can't remember the last time I had a weekend for myself. Ah well, it's no wonder it took me over four years to get this bike running again.

Damnit I'm getting frustrated with painting this gas tank! Got the tank wet-sanded, and it looks like I've embedded several bits of lint after the previous prep and wipe-down before I clear coated. Also seems like there's a lot of primer grey showing, especially along the black trim lines. Well screw it, this whole paint job is an experiment anyway and I really want to get this tank on the bike. So I wipe it down and start doing the next coat of clear. Well hmm, I don't understand why but it seems like the clear is hiding all those spots, including what I thought was visible primer. It doesn't make sense, but I'll go with it. Time to get on the next coat of clear. I start working around the tank and finish off the can of clear. Grab another can and get to shaking it.... and oh no... there's a major sag happening where I left off. And there's another sag across the top. And more on the other side of the tank. Shit the whole thing is completely screwed.

So once again I'm waiting a few days for the paint to cure enough that I can sand out yet another problem. I just don't get it. I've done so many projects with spray paint and almost never have problems with sag, yet it happened on the sissy bar, and now it's happened spectacularly on the tank. I was thinking maybe we had high humidity today that caused it, so I checked... 89 degrees and 18% humidity. Hot and dry, the only time I've had paint issues in this kind of weather is from the paint drying in the air and leaving a powdery finish. Yeah, I just don't get it. I'm so frustrated.

I did have better luck yesterday. The changes to the mixture screws made a big difference on the ride to work. After I got home I checked the plugs again. Two look almost perfect, and the other two are still slightly on the sandy side. OK another 1/2 turn on those two, and we'll see how it goes. Maybe tomorrow I'll get a chance to try and balance out the carbs (which of course screws up all my mixture settings). I plowed through a surprising number of items on my list today, so as long as there's no rain I actually should have some time to work on it and then do some short rides to try and bring the mixture screws back where they need to be. Sure hope it goes better than the gas tank.

Sounds lie you got in too much of a hurry. Remember, one thing at a time. Pics?
Steve

Sorry no pics, but yeah it seems like that must have been the case. I try to keep my coats just heavy enough to get good overlap so it blends together, and with the heat it should have been drying pretty quickly. The only thing I can think of is that while seeing how the cleatcoat seemed to hide all of the flaws I probably got that first coat a lot heavier than I realized and should have given it about 15 minutes to really set up.

Oh happy day -- something went *right* today! Finally was able to take the time to balance the carbs (using the single-guage method). 3-4 were pretty close, within 1 (what's the measurement, Hg?) of each other, but 1-2 were around 3 or 4 points from each other, with #2 being almost the same as 3-4, but #1 was pulling a whole lot more vacuum than all the other cylinders. Got #1 and #2 balanced to each other, then adjusted so the pairs were balanced. Took it out for another loop around the block and yeah I'm feeling the difference! Taking off from a stop no longer creates the hesitation in the throttle and is quite a bit smoother at getting started from the line. It's smooth enough that I can take off from second gear now.

I let it cool down after the test run and then checked the plugs. Yeah #1 is running real rich now and the other three are all lean. Since I've already done a lot of adjusting on #4 I decided to check how far out the screw was. Yikes, four whole turns! I turned in all of them by 1.5 turns and then checked #1... ok it's only a little over half a turn out from seated, but the other three still have room to play. Took another loop and yeah it's running pretty smooth now. Not only are the take-offs better, but there's a lot more power for acceleration now.

Out of time for today but I'll be riding in to work again tomorrow, will see how it performs on the highway and in rush-hour traffic. Should be fun.

Well that was... unfortunate. It occurs to me that after I adjusted all of the mixtures screws inward, I forgot to make any adjustments based on the color of the spark plugs, except I think on #1. Ah well it was still running better than last week, guess I'll re-check the plugs again tomorrow after I get home.

All right, made some more small adjustments to the mixture screws last night. It's running pretty smoothly although there's still some issues. From idle if I suddenly crank the throttle there is a short hesitation and it still seems to be a little slow coming back down again (although nowhere near as slow as when I was running really lean). All four plugs are very close to identical now -- brownish with a slight coloration of the insulator, maybe a little bit of black soot around the outer edge but they're not wet and there's no granular build up on them. I believe all four mixture screws are within about 1.5 turns of each other and probably average about three turns open. Since I continually hear about the BS34's being notorious for running lean I've been trying to err on the rich side with my adjustments.

The other symptoms I'm seeing are in the exhaust. Feeling the output at idle, the right side feels smooth, almost a continuous output, but the left side has a definite chuff-chuff feel to it and is running noticeably cooler. I'm not quite sure what that is about since the plugs indicate all four cylinders are firing fairly equally, unless it's just the engine timing I'm feeling? There's also more of that "Harley" sound coming from the left side during acceleration. I am no longer getting any backfiring in the pipes, except very slightly when I accelerate really hard and then let it coast back down (low popping but no actual explosive backfiring).

I think the vacuum balancing went well. After multiple adjustments across the board while idling at about 1200rpm I think I have all four cylinders within 1/2 point of each other. I didn't mention it before but after the vacuum adjustment I decided to take all the mixture screws back to stock (2.5 turns) and start from scratch on adjusting them. I think they are pretty close now so I'm not sure what else to look at.

Any suggestions?

One other issue I'm starting to have trouble with... this bike feels kind of low to me. I'm just under 6' tall but I'm all legs. So when I'm sitting on the bike the top of my legs are even with the ground and my knees are forward of my feet. It makes me feel a bit cramped and I have trouble moving my feet around on the pedals, but I don't really see any way to change that. Maybe this is why so many people go for bobbers -- to gain extra leg room?

Slight bog when suddenly opening the throttle, slow to retun to idle, and popping in the exhaust on deceleration all indicate a lean mixture.

The seating position is typical of Japanese cruisers, and is actually more comfortable on long hauls than the feet-forward position of typical U.S. cruisers. At least for most folks. Personally, I prefer to have my feet farther back, and my torso leaned slightly forward, as that puts much less pressure on my lower back than the feet-forward , ape-hanger position does.

P. S. If your fuel has ethanol in it, plug readings can be inconclusive .