My holiday PTO is rapidly coming to an end. I did not get nearly as much work done on the VT500FT as I had intended. The weather has been rainy and cold, and the decreased sunlight exposure is definitely getting to me. I’ve made some good progress on a few important aspects though, so I will share those.
Whoever did work on this last, whether the guy I bought it from or the guy before him, they either didn’t own a torque wrench or just didn’t care. A large number of the bolts that I’ve encountered have only been loosely in place. The side spark plugs, for instance, spun freely without the need for any socket tool. The seat and tank similarly could be removed without putting any pressure on the wrench at all; I probably could have taken them out with just my fingers had I tried.
Since I paid relatively little for the bike I’m not upset when I find things like that, it just makes me laugh. I keep finding all these signs of neglect, but under it all there’s a solid motorcycle that somehow has managed to keep running just the same. I can see that with some attention and care this could be a really solid machine.
Note on California Emissions
The 1984 VT500FT had two variations: normal, and California. The cali variant had features meant to meet the stricter emissions standards for that state. The carbs on this bike appear to be cali, but none of the supporting hardware is present.
The cali design is such that the gas tank vents into a charcoal cannister rather than to open air through the gas cap. Gasoline vapor collects in that cannister, and a purge-control-valve connects the carburetors to the callector and the tank vent. When the bike is running, part of the air supply would be fed from those lines, causing the vapor to be burnt as part of the combustion process.
The problem here is that there’s no evidence of the charcoal cannister or purge-control-valve left on the bike. There’s also no vent built into the gas tank. Best guess is that these carbs are replacements for the originals, and they’re just the wrong ones.
In the first VT500FT video I recorded, there is a dangling hose that causes the engine to struggle when I put my finger over the end. This line is what would normally connect to the PCV. I need to completely plug that line - right now it’s sucking unfiltered air right into the carbs. I’ve already adjusted the pilot screws to compensate – the cali setting is significantly more “lean” since it intends to be sucking vapor from the tank to augment any other mixture.
I’m hoping the normal pilot setting and plugged vapor inlets will get things running smoothly.
I started disassembly late one day on the week before Christmas. I removed the seat and tank, and took a good look around. I was happy to see that the air plenum was in pristine condition. The various pieces of clamping hardware didn’t look too terrible, but there was definitely corrosion and gunk. I went around the engine and hit every single screw, nut, bolt, and clamp I could see with a liberal shot of WD-40, and left that to soak for the night.
The next day I removed the air plenum, disconnected the throttle and choke lines from the carburetors, loosened all the clamps, and fidgeted with it until it finally came free from the engine.
The caps covering the vaccuum cylinders are terribly pitted for both carbs, far more beaten up than the carbs themselves. I wonder if these are replacements scavenged from another set?
The float bowl for one carburetor was filled with a blubbery mess that looks like threebond’s liquid gasket. My best guess is that the bowl had been leaking and someone “fixed” it. It looked to have definitely been interfering with the operation of the float, and I wouldn’t be surprised if it was also covering some of the jet intakes. The bowl of the other carb was better, but had some varnishing and an unfamiliar dark green substance smeared along the gasket.
I replaced both float bowl gaskets with new ones.
The vaccuum cylinders were fine, with the exception of a major kink and bend in the spring of the left/rear carb. I ordered a pair of new matching springs. The needles themselves were fine, though the right/front one had a bit of varnish and corrosion at the very tip.
I cleaned some suspicious black grit in a few places. Might have been sucked into the system from the dangling vapor line?
A few of the screws were stripped, so I replaced them all with new ones as well. It’s amazing how much a parts supplied will try to charge you for what is simply an M8 screw! I now have 100pc baggies for a fraction of that cost thanks to amazon.
I found that the pilot screws had been un-plugged (they are set in place at the factory and covered with a plug to prevent altering). The rear carb was turned out the suggested 2 ¼ turns. The front carb however was set all of the way in! I’m anxious to get the carb back on after cleaning and adjusting those pilot screws, I bet that will have fixed the 300F temperature difference in the cylinders.
Since there wasn’t any really major evidence of varnishing being a problem, I didn’t do any kind of full-immersion carb cleaning. With the exception of the float-bowls, I just wiped everything down with marvel and called it fine. The bowls needed to be cleaned of their odd gasket sealants and had a bit of stinky varnish pooled in the recesses. Easy enough to clean up by hand.
After I’d taken the carb off, I ran a compression test. I was very happy to see the pressure gauge get to 170 psi for both cylinders after a few cranks of the starter. I won’t be doing anything with the rings or valves (except checking/adjusting the tappet clearance later).
Since I knew I wouldn’t be running the engine again for a while, I put a bit of marvel into either cylinder through the plug holes and the intake and then stuffed the holes with oily rags. It’s been wet, cold, and generally horrible and I didn’t want anything collecting condensation while it sat.
The echo chamber had been removed from the exhaust collector, and a plate had been sloppily welded over that side. In a similar vein, the muffler’s packing screws are gone, and big sloppy welds have the can permanently closed (and there’s SOMETHING rattling around inside of it, where the packing used to be).
I found a used exhaust on ebay that promised no holes in either the muffler or the echo chamber, so I’ve got replacements en route.
Additionally, I’d already noticed that there was a hole burned into the tool box which sits just behind and below the rear cylinder’s exhaust port. Upon removing the exhaust entirely, I noted that it was only loosely bolted into place (with the wrong bolts). I’ve got new front and rear exhaust gaskets, and I’ll try to dig up the proper flanged bolts so that I can re-attach those pipes with the appropriate torque to prevent any future blow-by.
I managed to find a center stand with spring and spacers on ebay, and installed it.
However, it turns out that the center-stand uses the echo chamber as a stop when in the up position. Without the echo chamber, it lifts to the point of interfering with the rear brake rod. Luckily I’ve got that covered with the replacement exhaust coming soon.
I removed the front wheel and brake calipers, line, and master cylinder.
The pads are completely black, greasy, and do not appear usable. I have new pads anyway. I’m baffled as to how they ended up in this condition, though.
The caliper appears to have been given a coat of black spray paint at some point, right over any road gunk that was present at the time. This became evident as I was cleaning it, and the paint started to peel off, revealing grime beneath.
The brake pistons have black flecks and pits on them. I removed and tried to clean them, but haven’t had any luck. The dust seal on one cylinder was not intact. There was also a buildup of dark grey mud inside the cylinder itself.
There was evidence of more threebond liquid gasket on the threads of the bleeder valve.
The rubber boots on some of the mounting hardware were very frail and one was torn. Removed all of those.
New boots, seals, and pistons are on the way (relatively inexpensive). I also have a new master cylinder and a nice braided line ready to go.
I’m waiting on some CRC Brakleen to really get into the insides of the caliper before rebuilding. There’s a lot of solid contaminent in there that needs to come out.
After inspecting the disk itself, I don’t believe it is too worn to use, and the fault of the bad braking action can easily be attributed to the disastrous condition of the pads and caliper.
I picked up a pair of inexpensive Emgo bars with a slightly lower rise than the originals. The originals are damaged, with the right side having a crimp at the bend, indicating they were the ones on it when it received the dent in the tank and the scuffs to the right side of the engine.
The bike currently has some drag-style bars in place. These come terribly close to hitting the tank. In fact, the only reason they don’t actually hit the tank is that one of the previous owners had limited the turning range by attaching a few bolts through a bent clip at the stops. I’ll restore the full range by removing those and putting on more comfortable bars.
The original clutch adjustment was very tight – only slightly pulling in the clutch lever would completely disengage the clutch. It was so tightly adjusted that even all the way out, the clutch would slip a bit. I ended up changing this on the fly during the ride home, moving the friction zone towards the center of the lever’s movement. I noticed that even after that was done, giving the bike a bit of throttle seemed to still slip! I am intending to replace the clutch springs and friction plates. I have the parts, I just haven’t gotten around to removing the sub-frame and side cover yet. I should have done that today (New Years day) but I find myself completely out of motivation.
Oil and filter
I’ve got oil and a new filter on-hand, but I’ll be doing that the same time as the clutch adjustment above. I wish I’d have thought to have broken the seal on the filter when the bike was still warm from the last time I ran it. I’m guessing it’s going to be a real bear to get the strap wrench to move that filter.
I wonder when the oil was last actually changed?
I need to get the rear wheel off and take a good look at the drive shaft and the final gearing itself. I’m expecting to see a mess, but maybe I’ll be pleasantly surprised and see clean grease and fresh, adequate oil in there!
So Much To Do
Well, that’s about where I am now. I’ve taken a few pictures that I’ll try to link into here later. For now it’s time to get some sleep!