'Twas the oil ....

[KelKel]

So I recently acquired a 1985 VT500c for use in commuting to work. It took quite a bit of work getting it running but I FINALLY got it to where it was useable and started commuting to work on it. There were problems though. For one, the headlight went out and riding to work at 6:30 in the morning this is a big deal. I replaced the bulb but on the interior of the housing, all the chrome mirror paint had flaked off leaving a VERY dull light. To solve this, I installed two 55w driving lights which lit the way VERY well. While doing all of my initial maintenance, I changed out the plugs and changed the oil as well. I bought the "v-twin" oil, not really paying much attention to the weight (stupid me) it was 20w50. So my problems started in this order ... first I was having a VERY difficult time starting the bike. At first I thought it was my battery so I took a trickle charger everywhere I went and plugged in the battery to make sure I had a full charge. This kind of worked but it was still difficult to start even though the battery was turning the starter pretty good. In fact, I had to push start it most of the time even with the full battery. Next, the battery started dying on me if I made a stop or two on the way home from work. It wouldn't turn the starter at all. I had to get a jump on more than one occasion (with the car off) I put it on the charger over night (where it reads as charged) and still have a difficult time starting the bike. So I replaced the battery with a stronger one (even though the other battery was brand new - less than a month old) It was still having issues though. So I bought a multimeter to see what was going on electrically. The battery had a charge of 12.7v at rest. While engaging the starter, the voltage goes to 10.5v. After starting (by push starting) the voltage went to 14.2v with some gas and 13.7v at idle. I then turned on my driving lights and the voltage dropped to 12.3vwhile running with some gas. So basically, I figured that when I ride with the lights on, the battery is constantly discharging and then doesn't have power enough to start again. So I replaced the headlight with a new sealed bulb Silverstar headlight thus eliminating the driving lights. The bike had MUCH better voltage when running but was still difficult to start. So lastly, I decided to change the oil from the 20w50 to a 15w40 oil. (it has been in the mid to high thirties here in the morning and warming to low to mid 60s in the afternoon) It worked like a charm. The bike cranks right up. It very well could be the increased power due to not discharging the battery (not likely though since I have been leaving it on a charger) or it could be the lower weight oil. Either way, it worked. I just figured some of you may find this useful.

[justinmahn]

Wow that was some thick stuff. My VT750DC takes 10w40 in cold weather and 10w30 in hot weather.

[h13man]

I assume you are using a battery maintainer type charger? (Battery Tender Jr.) If not you might cook your battery with a 2 amp trickle charger if you leave it on all the time. And yes too thick of oil can cause a starting issue.

[KelKel]

It is definitely a maintenance charger
MEGABOOST Parts & Accessories - Pro Series 4000 Charger/Maintainer - Cycle Gear

[jpr1968]

I doubt the oil was the problem. Those 2 55watt lights you put on were overtaxing the electrical system.

[KelKel]

I agree that they caused my electrical issues, but the difficulty in starting was largely unrelated. (well sort of largely unrelated ... After all when the battery was weak from powering the lights it obviously had less power to start the bike) However, even with a fully charged battery and both the headlight and the driving lights turned off, the bike STILL had difficulty starting, hence my deduction that the oil also played a large part.

[gdb069]

20W and even 15W is pretty thick for that temp. I think you may try a 10W30 or 10W40 and have better flow. My bikes are parked for winter but I use a 5W and now my cars want a 0W.

G.

[verdeva]

Do your driving lights shut off when you hit the starter?

Honda didn't want the 55 watt headlight load when the starter was running. The 110 watt driving lights should be powered from a relay that is triggered from headlight power.

[KelKel]

I actually had them on an independent switch wired to the key switch. At first I had them wired straight to the key but realized quite quickly that trying to start it while those lights were on was next to impossible. So I put them on on a switch and always had them off when starting. The headlight does indeed turn off when starting also so I was trying to crank it without any light load and it was still very difficult.

[Scrapdog2grand]

Originally Posted by KelKel

I actually had them on an independent switch wired to the key switch. At first I had them wired straight to the key but realized quite quickly that trying to start it while those lights were on was next to impossible. So I put them on on a switch and always had them off when starting. The headlight does indeed turn off when starting also so I was trying to crank it without any light load and it was still very difficult.

I am using PIAA super white 35Watt H3's in the wifes VLX - get very good lighting with them, and I am using 25 Watt H3 standard bulbs, they're are pretty decent.