KZ440 LTD Build

Hello all,

I got my KZ440 LTD back from my mechanic today and it’s running now without dumping gas everywhere (which is an improvement). I thought I’d start this thread to document my work on the bike as time go on. My goal is mostly to get the bike running well and meeting legal requirements so I can take my motorcycle endorsement skills test on it.

 

My first order of business is to fix the idle as it’s borderline unridable right now. I thought rebuilding the carbs would address this, but the bike appears to have a higher and higher idle as it heats up (to ~4000 rpm). Now, I’ve read some topics on this, so tomorrow I’ll pick up some carb cleaner to check for vacuum leaks and play with the throttle cable adjustment if that does nothing.  I suppose checking the timing advance and valve clearance will come after that (although I need to do both of the latter even if I didn’t have this issue).

I’m operating under the assumption this is a vacuum leak as that would explain the rough cold starts as well (it sounds like one cylinder wants to die).

Despite this, I rode the bike around for an hour or so and had a blast. I definitely need to work on my overall stability riding, but this was my first time riding anywhere on public roads so I thought I didn’t do half bad. A friend said I looked like I was wobbling going straight on the road, and I definitely chose some questionable times to be doing things (like shifting in the middle of a turn or using a front brake to slow down when I realized I needed to sharpen up my course mid-turn). I’m sure this’ll come with time and getting more comfortable on a motorcycle.

As a second issue, I installed the horn today and it doesn’t work. I didn’t spend much time diagnosing it because I just wanted to ride around. I’m assuming the lack of a ground for the horn is the issue. I’ll order one and see if that fixes it.

Cheers. 
 

didn't you start by saying you "got the bike back from my mechanic" so what did you pay him for if it isn't running right ??

Good luck with your project.

This may help...   www.kzrider.com/forum/faq-wiki/618026-new-owner-things-to-know

Nessism wrote:

Good luck with your project.

This may help...   www.kzrider.com/forum/faq-wiki/618026-new-owner-things-to-know

 

 That would be it. I didn't realize the aerosol test wasn't conclusive, but that makes enough sense. The boots appear to be in pretty good shape externally but maybe they just got wiped down. I'll still poke around and look for anything obvious besides the boots. 

As for the mechanic, I can't blame him for not noticing this considering he only really took the bike around the block. It took around 10-15 min for the bike to get hot enough for this to be a problem. 

Using carb cleaner for diagnostics didn’t have a noticeable effect, so I pulled the carbs out last night and looked around.
 

(Edit: The crack is just behind the screw on the close carb holder. The far mating surface doesn’t look good either; does it?) 

One of the carb boots has a tear in it. I’m not sure if the tear was caused by me removing the carbs, but either way I’m replacing both carb boots. I already put penetrating oil on the screws and am going to keep doing so for a couple days to get them out.

The second thing I noticed is that the petcock vacuum line was sealed with what appears to be a little clump of foil shoved into it. This bike has a Yamaha Raptor petcock clone on it already so I don’t need the line. I’ll order the matching plug (11012-1129 or 11065-0282) from the other carb and install that instead of the poorly plugged line. 

As for reinstallation of the carbs, I’m probably going to pull the battery case from the bike to get a little more room to push the airbox away from the carbs and reinstall it that way with some engine oil on the carb boots. I’ll be keeping the same airbox boots, but only because the part is on backorder.

Thanks for the help all.

Looks like you are on the right track, the discolouration around the joint between the boots and head suggests leaking

It's been a minute since I've posted an update here for reasons below.

It took a propane torch and chisel to get the carb boot screws off, but I did get them off and replaced the carb boots with a little Permatex anaerobic added to make sure the new ones would seal. After reassembling the bike and a little bit of cranking from the starter, the bike lost all electrics. I started by testing all fuses and the battery with the multimeter. The battery and all fuses tested fine with my multimeter, but the main fuse appeared green for whatever reason. I ended up replacing the main fuse and the battery, and the electrical systems came back to life. 

My issue now was getting fuel to actually flow from the gas tank to the carbs. I don't know why this was so difficult, but it took a lot of screwing around and tilting the bike to get it flowing. After some idle screw fiddling, the bike now runs good enough!. 

The idle is probably set too high as it gets as high as 2100 rpm after 1.5h of driving, but this isn't really a problem for me driving around town and seems to help a little with coldstarts. Also, the throttle hangs on shifts and revs in neutral, but it's not unbearable.

With the bike as it is now, I've been riding around at least an hour every day and even started riding to work as of today for my commute though I'm deliberately offsetting my work hours to avoid rush hours because I'm not there as a rider yet. 

The only real issue I have with the bike currently is that the finding first from neutral is weirdly difficult as of yesterday. It's not a problem from second through, so it's not really a major issue for riding either. I may look into that, but I'm happy where the bike is and am enjoying learning how to ride. 

Thanks for the help all. 

If you are having a problem with 1st when stationary I would suggest checking clutch adjustment against the FSM (selecting the rest when moving are less clutch dependent)

My week of enjoying the running bike was nice, but I would have liked it to be longer than a week.  I took a look at the clutch cable and realized it been rubbing on the headers. It's all worn through/melted, so that's going to have to get replaced. Whatever; that's not an immediate issue as the clutch does mostly work.  

As of Tuesday, the bike now stalls after getting hot and is almost impossible to restart until it cools back down. It will sometimes fire back up for a bit with the choke fully on but dies coming to a stop with the clutch engaged. After it dies again, it may fire once or twice when cranking but won't ever restart until its cool.

I understand this can be a number of things, but I'm hoping it's just a combination of the increased ambient temps, a high spot in my fuel line, and the relatively restrictive fuel filter. I still need to do diagnostics and verify it is not a spark issue. If it is a spark issue, it'd be a bit weird as this should have points instead of a pick-up coil which I know sometimes die like this.

Here's to hoping the bike stays running longer after this set of repairs. 

Keep in mind that ignition coils can die that way as well.

Recommend you carry a spare spark plug or two with you. When the bike dies, pull the plug cap(s), insert one or both plugs from your pocket, and test for spark without burning your fingers.