fine tuning my combat

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caddy chris

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Jan 23, 2011
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Ol gurtrude is running great, but today im out riding and heard that the exhaust tone is a bit raspier out the left pipe than the right when pulling a long hill at about 60. Now im not sure if its a carb balance issue or maybe an exhaust issue. Only noticable at steady rpms under load. Looking to get her as tuned as possible. So I thought id see what ppl might suggest it is. The valves are rocker worn so I can't use a feeler guage. These are adjusted by the old, feels right method. That said, maybe the exhaust valve is a bit tight?? What do you'all think?
 
Hahaha! That's funny cuz one came loose sunday! So I just tightened them. Could it be that that the gasket ring dealie is off set in there? The sound is not audible up front. Coming out the back. Theright side is nice and poppy the left is more raspy like. Almost rippy like. Does that makes sense? Only under constant rpm up hill. Otherwise sounds good. I don't know if I want to mess with anything, cuz its running great, but I don't wanna burn a valve either. No backfires, idles and runs smooth. Maybe im just nitpicking??
 
Do a plug chop test. Put a plug wrench in your pocket, run it on an upgrade under full throttle, (that is to say under the condition that produces your concern) cut the engine by either buy kill switch or key as you pull in the clutch. Coast to stop and take a reading of the plugs. Let us know what you see. Butter yet, take a picture and post it.
 
+1 on the plug test. It seems like a bit of a hassle but it is better than messing with your carbs without knowing for sure how the mix is.

As for the valves, you can count the number of turns on the adjusters which is better than guessing. The problem is I can't remember how much it is per turn (or quarter turn) and despite searching for it have failed to find it. Somebody here will know.

So guys, where is this bit of trivia hidden and what is the measurement by thread count?

Russ
 
Turn count adjustment would be super helpfull. Right now its kinda by noise and feel. Adjusted hot so they are slightly loose, but not so loose that they are real noisy. My feeling is that its a carb issue though. Slightly out of balance? Gonna be tough to do the plug check right now as the weather has turned and ito snow on the valley floor this weekend, which is very rare. Not uncommon for the temps to gat into the 20's, but snow is a once in 10 year deal here. 75 ft above sea level at my place. I know, spoiled right? When the "storm" passes i'll get out there and do the plug check. Until then, if someone has the turns out info for intake and exhaust, id appreciate it. Curious to see how close I am.
 
caddy chris said:
Turn count adjustment would be super helpfull. Right now its kinda by noise and feel. Adjusted hot so they are slightly loose, but not so loose that they are real noisy. My feeling is that its a carb issue though. Slightly out of balance? Gonna be tough to do the plug check right now as the weather has turned and ito snow on the valley floor this weekend, which is very rare. Not uncommon for the temps to gat into the 20's, but snow is a once in 10 year deal here. 75 ft above sea level at my place. I know, spoiled right? When the "storm" passes i'll get out there and do the plug check. Until then, if someone has the turns out info for intake and exhaust, id appreciate it. Curious to see how close I am.
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Yea, I'm taking the 4WD to work in Fremont tomorrow. Radio said 4 inches snow accumulation at 1,000ft elevation for Friday. From Brentwood there are two hills to go over that are at that elevation.

Are you riding lone wolf or are there other Nortons in the Lodi area? I'm getting tired of riding 70 miles to the start of an NCNOC ride. Jerry Kaplan has a group in the Davis/Sacramento area.
 
Hope I am not stating the obvious here but are both silencers the same type? There are many different manufacturers and they all have subtle differences and sound different. Some have welded seams at the front of the silencer some dont, some have a weld exactly on the rear cone some are slightly forward some have no weld on the rear and some even have baffles. When I first bought my Commando I noticed one side sounded different to the other and when I looked closer one silencer was straight through type and the other had baffles.
Best
 
Illf8d- Brentwood! Haha! Howdy neighbor! Highway 4 east from you sucks! I ride solo, but only cuz my triumph buddy can't seem to get his running! :D Im down to ride whenever... lotsa good stuff east of me (comanche, mokolemne hill, electra rd., salt springs, highway 12, 26, 4, 49, etc.) but delta riding is cool too. PM me!

Snake- silencers appear to be the same. I've never had them off the bike since I bought it. I'll shine a light down em and see if they are baffled. Was kinda thinking along those lines. Maybe one is leaky at the clamp?
 
Had exactly the same problem years ago. Worn Exhaust cam lobe on the left side.
But, hopefully, it is something else.
 
Flo said:
Had exactly the same problem years ago. Worn Exhaust cam lobe on the left side.
But, hopefully, it is something else.
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UGH! ME TOO! That would suck. So it just wasn't lifting enough and hissing out the worn side? Would have to check lift at rockers.to make sure they are the same?
0.441in Inlet
0.391in Exhaust.
gotta find my measuring stick :wink:
 
I recently used my 10 dollar dial indicator from Harbor Freight to check my valve lift. It came out real close but getting the damn thing to sit on top of the valve spring in a steady enough fashion to actually measure it was another task worthy of a pint or two.

Now, getting back to those valves and tappets...see what kind of trouble you have caused? Just look at that other thread. I will hold you responsible for the rep I have gained from it.

Russ
 
Hey! Im the one shade treein', you got no worries. I take full credit for this. Thanks again. Gonna check the valves and tighten up the tubes and silencers n see what happens. While im in there ill check lift and see if they are alike. My tank'll be off anyway so... (new bodywork coming). Gonna check iso's, change oil ( wanna know what brand im runnin?), etc. I've put alot of miles on the bike since september. I'm out on it tonight.
IN the rain.
Gotta get that water in there to burn off the carbon, right?
Thanks for the help! :D
 
rvich said:
I recently used my 10 dollar dial indicator from Harbor Freight to check my valve lift. It came out real close but getting the damn thing to sit on top of the valve spring in a steady enough fashion to actually measure it was another task worthy of a pint or two.

Now, getting back to those valves and tappets...see what kind of trouble you have caused? Just look at that other thread. I will hold you responsible for the rep I have gained from it.

Russ
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do you have something like this?
fine tuning my combat
 
Just a long shot, check the exhaust pipe seam for cracking, it often just looks like the chrome is bubbling in a straight line. I know I've blown my hearing to bits, and to me when the pipe cracks the sound appears to come from behind. :?

Cash
 
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