Cam chain slack, timing off

Thread Tools
 
Search this Thread
 
  #21  
Old 06-25-2018, 01:51 AM
ldkr's Avatar
Member
1st Gear Member
Thread Starter
Join Date: Apr 2018
Posts: 52
Default

Welp, got all the valves dialed back in, I think i got the tensioner dialed in, kicked back the intake cam one tooth

Started her up and I think she's worse off than before, or definitely not any better.... Wants to idle really high, if I blip the throttle will slow down a bit. Never less than 1500 even with the throttle idle cable backed alll the way out. Beyond 1.5-2 turns out, the idle fuel screw on the carb has basically no effect.

Because the carb was recently rebuilt by Bill, and because the jetting is stock from when the previous owner originally installed the kit, I'm guessing that at least one valve or valve seat is ****ed. Now to decide if I want to dig into that.......
 
  #22  
Old 06-25-2018, 04:47 AM
durielk's Avatar
Senior Member
1st Gear Member
Join Date: Jul 2011
Location: Cottonwood, AZ USA
Posts: 1,728
Default

Now that you have your valves adj, next step is to run a compression test... easier than pulling the head.
With the fuel screw not effecting the idle, I think you still have carb issues. Go to a smaller pilot jet.
I have never had an engine with a bad valve, maybe someone else here can offer advice on that, but it would seem to me if you have problems with a valve, the engine would backfire and be very difficult to start.
 
  #23  
Old 06-25-2018, 11:39 AM
klx678's Avatar
Senior Member
1st Gear Member
Join Date: Aug 2009
Location: Delaware, Ohio
Posts: 4,509
Default

I had burnt exhaust valves. Hard starting, loud backfire while trying to start, high erratic idle, .
 
  #24  
Old 06-25-2018, 04:40 PM
ldkr's Avatar
Member
1st Gear Member
Thread Starter
Join Date: Apr 2018
Posts: 52
Default

Hmm I'll try a compression test first. Will disable the ACR and see if i can find a leakdown tester.

As far as the fuel screw -- I'm not convinced the pilot jet is the problem. I'm using the jetting recommended by Bill for my altitude/setup, and the same jetting the previous owner used. I think it seems like the fuel screw has no effect because my idle is so ****ed anyway

The engine doesn't backfire, it isnt SUPER hard to start, but it doesn't start very easy. I have a kickstarter and I've never been able to kickstart the engine. I'm able to pop start it with a couple tries. I notice that recently almost every time i kill the engine after its been running i get a little 'burp', which i think is the ACR?
 
  #25  
Old 06-25-2018, 07:30 PM
ldkr's Avatar
Member
1st Gear Member
Thread Starter
Join Date: Apr 2018
Posts: 52
Default

Dumb question: is it possible i installed the cams 180 or 360deg off?

The crankshaft has a T to indicate TDC, but I believe it has 2 T's per revolution right? does it matter which T i am at when i install the cams?
 
  #26  
Old 06-25-2018, 08:22 PM
Brewster's Avatar
Senior Member
1st Gear Member
Join Date: Feb 2009
Location: Hayward, CA
Posts: 667
Default

Originally Posted by ldkr
Dumb question: is it possible i installed the cams 180 or 360deg off?

The crankshaft has a T to indicate TDC, but I believe it has 2 T's per revolution right? does it matter which T i am at when i install the cams?
There's only one sideways "T" on the flywheel. There's another mark but not a "T". If the cams were installed 180 degrees off, a full turn of the flywheel would put everything in time. Cams turn once for two rotations of the crank. The piston doesn't know if it's at the top of the compression stroke or top of the exhaust stroke. 360 degrees............think about that one.

Ride on
Brewster
 
  #27  
Old 06-25-2018, 08:46 PM
ldkr's Avatar
Member
1st Gear Member
Thread Starter
Join Date: Apr 2018
Posts: 52
Default

Hahaha, i guess i was thinking: if the lobes are pointed out, and i rotate the crankshaft 360d, should they still be pointed out. Sounds like the answer is NO. So i could have the camshafts installed backwards (180d) relative to a 360d rotation of the crankshaft
 
  #28  
Old 06-25-2018, 09:34 PM
klx678's Avatar
Senior Member
1st Gear Member
Join Date: Aug 2009
Location: Delaware, Ohio
Posts: 4,509
Default

If they were off 360 degrees, no difference. It is still right. The ignition fires every revolution, the extra spark is a "wasted spark", firing during the exhaust stroke.. That is the beauty of the single, it works regardless, so in other words you cannot be off 360 degrees. It works.

It's either jetting or bad valve in my mind, not being there to see what is going on. Turning the idle mix screw should affect the idle. That is the screw accessed just in front of the float bowl, from below.
 
  #29  
Old 06-25-2018, 09:50 PM
ldkr's Avatar
Member
1st Gear Member
Thread Starter
Join Date: Apr 2018
Posts: 52
Default

Gotcha, thanks again

I'll check compression and then decide if its easier to rejet or check valves first....
 
  #30  
Old 06-25-2018, 11:57 PM
Brewster's Avatar
Senior Member
1st Gear Member
Join Date: Feb 2009
Location: Hayward, CA
Posts: 667
Default

ldkr, what is your location? Maybe you're near one of us that are more familiar with the workings of the bike.
 


Quick Reply: Cam chain slack, timing off



All times are GMT. The time now is 01:08 PM.