1985 vt1100

[simonjmartinez]

I recently bought a 85 vt1100. It is cold starting but it does start. And runs good. But after it warms up it dies. Then doesn't want to start until it cools down.

Sent from my Zio using Motorcycle.com Free App

[GrumpyOldMan]

Mebbe the carbs need cleaning? Did it sit for a while before you got it? The 85/86 VT1100s were setup very lean and stock jets mean you almost always need to use the choke to start and until it is warmed up. Sounds like yours might be a little plugged. Can you keep it running after it is warmed up by using the choke? That would mean it has partially plugged jets = carb teardown/cleaning/rebuild. When I first got Lazarus, he had sat for a while, so I did this:

1. Drain the carb float chambers.
2. Pour in some fresh gas, blip tghe kill swithc to pump fresh fuel up into the carbs and let it sit overnight.
3. Drain the carbs.

Repeat until the gas coming out of the drains is clear and clean. Any greenish/yellowish color indicates jet corrosion 'cuz they are made from brass.

Another trick is to get a can of carb cleaner spray and after draining the carbs, spray up through the drain - that can cleanup stuff in the float chambers a bit. Again, repeat until the liquid coming out of the drains is clear. If there are still problems, the full teardown/clean/rebuild is probably necessary. Once you do go the rebuild route, replace the float needle valve and seat, gaskets, O-rings and adjust the float level. It would be a good idea to upgrade the jets a bit while you have everything opened up.

Rebuild kits - scroll down to the 1985-1986 kit:
Carb Kit Capital - Motorcycle Carb Parts

Jet calculator and kits:
Honda Jet Kits :: Honda 1100 cc Jet Kits :: Honda VT1100C Shadow 1985-1986 - Jet kits for Carburetors

Obviously, you will need a manual with diagrams and procedures. One tip - if at all possible, do not disconnect the cabs from each other, doing so almost always means a resync. If you are lucky, they are not too badly out of sync as is. You will prolly want to do a resync after getting it running better anyway, but why make more work for yourself at the start

[simonjmartinez]

Yeah after it warms up it idles good, not great. The cam pulse generator goes high. It reads 649 when its cold and like 1200 when the bike heats up. After that I can't even get a reading until it cools down

Sent from my Zio using Motorcycle.com Free App

[GrumpyOldMan]

By "goes high" what are you saying - RPMs or voltage output? Higher voltage should not be a prob. If it stops putting out anything, that would be a real problem. Replacements are only available from Salvage Yards and/or eBay unless you can find one from a different bike that will fit and puts out the same or similar voltage...
I would find an "experienced" Honda mechanic and ask if he knows of any other bikes that have a compatible pulse gen...

[simonjmartinez]

By high I mean resistance. I also have an 86 vt1100 that runs great but is STUCK in neutral. I tried rocking the bike and trying to shift, nothing. The clutch does not feel right but shouldn't it still shift even if the clutch is bad?

Sent from my Zio using Motorcycle.com Free App

[GadgetDad]

i had an 83 750 that had a bad pulse generator. when it heated up it would lose all power. I think i remember somebody explaining it as one of the wires in the coils broke, but still worked because they were lined up, until it heated up and expanded then they no longer lined up. Or something like that.

[93gc40]

Originally Posted by simonjmartinez

Yeah after it warms up it idles good, not great. The cam pulse generator goes high. It reads 649 when its cold and like 1200 when the bike heats up. After that I can't even get a reading until it cools down

Sent from my Zio using Motorcycle.com Free App

Cam PG is bad, res should be about 400-450. Maybe more to the issue, but that generator is bad.

[GrumpyOldMan]

Since you have an '85 VT1100 and an '86 VT1100, you should be able to get one of them working and use the other for parts. My guess is that swapping out the bad cam pulse gen for a good one might be easier than rebuilding a broken/frozen tranny.
Yes, you should be able to get it into neutral even if the clutch is locked up by rolling the rear wheel a bit to take pressure off the shifting dogs.

[boxybike]

hey! Did you get your poor idling issue resolved ?.....hard to follow these threads sometimes. i have a 85 vt1100c and it runs great when its cold and then after about 10 minutes, like a light switch being flipped the rpm"s tumble and poor performance. I've shot a short blast of w d40 in the carb's (one at a time ) when this happens and noticed that the left carb doesn't respond at all but with the right carb the rpm's drop....as it should be! i can't find any vacume leaks, I've rebuilt the carbs in hopes of fixing this but i still have the same thing going on.

[simonjmartinez]

I found a bad cam pulse generator. I had to remove the engine to replace it. The bike slipped out of 2nd, and 3rd doesn't grab at all. So it is totally apart right now. Have to wait till after holidays to buy shift forks, shift drum, pulse generator and then see if that does the trick.