Please Help

Ok here is the deal. I have a 1985 Honda Shadow VT1100. When I got the bike I notice one side of the choke cable was unhooked and a pin was missing off the choke cable but the bike ran great. So I found a carb on ebay and bought it and swapped them out. When I put the bike back together it ran bad if you tried to give it gas to fast it would die. So I put my other carb back on and it was a little better but still does the same thing. I can rev it very slow to 2000rpm and then rev it fast but if I try to rev it fast from idle it dies and will start right back up. I changed the plugs and checked to see if I am getting fire and I am. Also I did notice the front cylinder gets hotter quicker than the back. So I pulled the plug to see if it had compression and they all do. I am at a loss please help.

Attached Images

image_ 166.jpg (100.0 KB, 1 views)

Hi John
First and foremost, get a compression test done. If you get more than 15 psi difference from cylinders or below 100psi on test, you need valve or engine overhaul, not a new carb. I'm optimistic since you say it is easy to start.

An engine with the choke left on will stall when hot. Carb mixture too rich or clogged air filter will produce the same effect. Contaminated fuel, clogged gas filter (there is one on the VT1100 1985) or old gas may produce such choking effect. I it is very bad, you may get smoky (dark smoke) exhaust too. Your carb jets might be clogged or damaged by improper cleaning. Your carb float level might be incorrect.

Poor carb synchronisation, faulty ignition timing (defective CDI/ pulse generator) obstructed mufflers, may also cause poor performance and overheating.

How do I know that ? Simply by reading trough troubleshooting section of my Clymer's shop manual, checking part schematics and some basic deductions. If compression test is good, it is worth the trouble to buy a shop manual and proceed by elimination. A professional mechanic would probably find out faster, but with vintage bikes, it is a good idea to do as much as you can by yourself AND the shop manual.

Buying parts on Ebay is a very expensive troubleshooting technique, especially if you are talking of carbs ! Let's proceed one system at the time, from the fuel tank to the carb, from the air filter to the carb, mufflers, then check on the electronic ignition, with a new set of spark plugs, compared to shop manual specs of each part you can test. With a shop manual and patience, I'm confident you can troubleshoot most problems on your own.

You are not lost, you just found out you need more accurate and reliable information to continue.

Good luck on your diagnostic adventure.

Martin

__________________
There is nothing like riding a Honda MC !