Runs, but it's hard to turn by hand

[AdamJH]

First off, the search function is malfunctioning so I couldn't see if anyone had the same problem. Sorry if this is a re-post.

I have a 1981 gs250t 11660 miles on it, I've driven it 400 miles since I bought it a year ago. The oil is running clean and the carbs need to be cleaned, assuming they're what's causing my engine to not start without the choke on.

As I was adjusting the valve clearances I noticed that the engine gets very noticeably harder to turn as the cam shaft hits the right hand exhaust valves.
This leads me to my previous problem of the starter dying, which now I notice that it would turn the engine to a point and slow down before speeding up again and starting the engine.
I now believe my starter if fine and that there's something wrong with my right cylinder.
If anyone has any input it would be appreciated.

 

[Steve]

Check your cam timing.

I assume the spark plugs are out. :-\\\

Requiring "choke" on a cold engine is normal.

.

 

[Guest]

While looking at the exhaust camshaft,

The left cam lobe is depressing the rocker and is on its way off when the right side is just starting to come on, so in effect your doing twice the work only at that one spot because both are being depressed.

I had a similar hard spot. Turns out it was just where it was timed that made it hard.

How does it run and how does it sound when its cranking?

Could you post a video?

 

[AdamJH]

Steve
Off hand the cams look to be evenly spaced.
Yes the spark plugs were removed
It's over 100f in my garage, it used to start without the choke

Mekanix
Your explanation quells my fears about taking the engine apart.
It was running "okay" before and starting was a good loud crank up to the hard point then almost dropping off before giving another good push until it started. Although recently I've had to push start it.

I'll post a video tomorrow when I get it all put back together and hopefully running. I forgot gasket sealer and it was too late by the time I noticed to go get some :-\\\.

 

[Steve]

Off hand the cams look to be evenly spaced.

Might have to go to the manual to see what it says. I have no idea if "evenly spaced" is the proper setting.

There is a procedure in the manual that usually starts with a mark on the crankshaft aligned with a mark on the case. Then you verify that a mark on one of the cams (usually the exhaust) lines up to a certain point. Finally, there will be a certain number of pins in the cam chain between two marks, one on each cam.

This timing usually does not change on its own unless the tensioner is not doing its job, but since you already have the valve cover off, it is very simple to check.

.

 

[AdamJH]

Cams are good.
I got it all put together and started it, it sounded a lot smoother if you can imagine that. No valve tapping, but then it got warmed up and died before I could check the ignition timing.
I checked the air filter... well what was left of it. It's now got a giant hole in it and it's filled with random crap. So looks like I'll have to order a new filter before I can continue my troubleshooting.
I'm going to start checking the electrical system too. I have a stray ground wire that the PO kindly disconnected from who knows where and tied it to another wire....

 

[Gonzo]

It's over 100f in my garage, it used to start without the choke

Remember that "cold start" is a relative term. When you are talking about what is cold for an engine, 100 degrees is pretty cold when you consider that they basically have thousands of small explosions going on inside every minute. They get very hot at normal temp. Especially when you talk about an air cooled engine.