Temperature of one exhaust pipe is much lower.

More
15 Nov 2015 11:51 #698785 by car5car
Temperature of one exhaust pipe is much lower at idle. Measured about 4" from head.
Any ideas? Thanks.
The cylinder works, RPM drops when spark plug wire removed.

96 Yamaha Royal Star
82 Yamaha Virago 920

Please Log in or Create an account to join the conversation.

  • ThatGPzGuy
  • Offline
  • Sustaining Member
  • More Sparky than Speed Racer
More
15 Nov 2015 12:30 #698789 by ThatGPzGuy
Replied by ThatGPzGuy on topic Temperature of one exhaust pipe is much lower.
Too rich on that cylinder or the others are too lean?

Jim
North GA
2016 Yamaha FJR1300ES
1982 GPz750 R1
1974 Kawasaki H1
1976 Kawasaki KZ400
1979 Yamaha XS650 cafe'
2001 KZ1000P
2001 Yamaha YZ426
1981 Honda XR200 stroked in an '89 CR125 chassis
1965 Mustang
1967 Triumph GT6
1976 Bronco
"If you didn't build it, it's not really yours"

Please Log in or Create an account to join the conversation.

More
15 Nov 2015 13:18 #698801 by Nessism

Please Log in or Create an account to join the conversation.

More
15 Nov 2015 13:31 #698807 by jdvorchak
Replied by jdvorchak on topic Temperature of one exhaust pipe is much lower.
There has to be more to the story that this. Why did you measure the exhaust temps? There must have been some running issue that prompted the check.

A little history helps a lot. New to you bike? You've owned the bike for years and this just cropped up? Bike been sitting for a while? Months? Years? Bad or rough idle? Pulling the spark plug on one cylinder is not really a good test like on an old car. These use wasted spark ignition and pulling one plug wire will shut of two cylinders most of time.

Don't fix it until it's broken.
John

83 KZ550M1
83 KZ1100LTD

Also own:
2010 Harley Ultra Classic Limited, 2008 Harley low rider 71 CB350/sidecar

Please Log in or Create an account to join the conversation.

More
15 Nov 2015 13:37 #698809 by redhawk4
Replied by redhawk4 on topic Temperature of one exhaust pipe is much lower.
It could be caused by an irregular misfire, or if the carbs are not synched and set up properly that cylinder may not be contributing fully to running at idle. If your idle is for example 1000 rpm, this cylinder might only be getting the fuel to run at 500 rpm because of the slide position or something to do with the air screw or pilot circuit. As a result it will run cooler than the cylinders doing more work - it's a bit like riding a tandem bicycle and the person on the back isn't really pedaling, you'll get hot and sweaty and he'll be relatively cool.

1978 KZ1000A2 Wiseco 1075 kit
1977 KZ650B1
1973 Triumph Tiger TR7V
1968 BSA Victor Special 441
2015 Triumph Thunderbird LT
1980 Suzuki SP400

Old enough to know better, still too young to care

Please Log in or Create an account to join the conversation.

More
15 Nov 2015 14:02 #698815 by bountyhunter
Replied by bountyhunter on topic Temperature of one exhaust pipe is much lower.

car5car wrote: Temperature of one exhaust pipe is much lower at idle. Measured about 4" from head.
Any ideas? Thanks.
The cylinder works, RPM drops when spark plug wire removed.

Carb balancing issue.

1979 KZ-750 Twin

Please Log in or Create an account to join the conversation.

More
15 Nov 2015 16:24 #698831 by 650ed
Which cylinder is running cooler than the others? #2? Ed

1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

Please Log in or Create an account to join the conversation.

More
16 Nov 2015 04:05 - 16 Nov 2015 04:22 #698903 by car5car
Thanks for all responses!
I cleaned carbs and adjusted valves about 2 years ago and didn't ride it since because I had rattling generator. Finally I fixed generator problem and then had to rebuild petcock and replace carb bowl gaskets.
I have infra red thermometer and was checking head temp to prevent overheating, then checked exhaust pipes
I guess my 4th cylinder is dead because exhaust pipe temp is lower than head temp. Adjusting mix screw didn't change anything.
Right now I have bunch of problems:
bowl gaskets leak (ordered good ones)
timing chain rattles
4th cylinder is dead(?)
no gauges illumination lights
headlight died for a few minutes when I rode the bike at night
if 15V is too high, I have a regulator problem

I need a plan, solving worst problem first (cylinder)
1.Check compression of 4th cyl.
2. Check spark plugs (I installed new ones yesterday)
3.If spark plug is dry, I'll do carbs cleaning/adjusting/synchr.
I rode about 2 miles yesterday, so new spark plugs should show something.
4.Check timing marks.
5.Adjust timing chain

What did I forget?

96 Yamaha Royal Star
82 Yamaha Virago 920
Last edit: 16 Nov 2015 04:22 by car5car.

Please Log in or Create an account to join the conversation.

More
16 Nov 2015 05:03 #698913 by redhawk4
Replied by redhawk4 on topic Temperature of one exhaust pipe is much lower.
If you cleaned you carbs two years ago, but ran them on the bike and let them sit it's quite possible that you could have a blocked or partially blocked idle system in that carb, it doesn't take much particularly if using the 10% ethanol fuel. If the cylinder is running when you open the throttle etc. the fault is almost certainly in the carb unless you have low compression on that cylinder.

1978 KZ1000A2 Wiseco 1075 kit
1977 KZ650B1
1973 Triumph Tiger TR7V
1968 BSA Victor Special 441
2015 Triumph Thunderbird LT
1980 Suzuki SP400

Old enough to know better, still too young to care

Please Log in or Create an account to join the conversation.

More
16 Nov 2015 07:07 #698930 by car5car
That is interesting:
temperature of "dead" 4th cylinder is higher than 1st one! (measured next to spark plug)
OK, I'll check synchronizing before cleaning carbs.
BTW I cleaned petcock 2 years ago and it was clogged!

96 Yamaha Royal Star
82 Yamaha Virago 920

Please Log in or Create an account to join the conversation.

More
16 Nov 2015 16:15 - 16 Nov 2015 16:16 #699012 by bluezbike
Replied by bluezbike on topic Temperature of one exhaust pipe is much lower.
As Nessism suggested, do not forget to also check/adjust valve gaps.......don't ask me how I know......

79 KZ 1000 LTD
77 KZ 1000 B1 LTD (awaiting electrical resurrection)
Last edit: 16 Nov 2015 16:16 by bluezbike.

Please Log in or Create an account to join the conversation.

More
17 Nov 2015 15:08 - 17 Nov 2015 15:10 #699146 by car5car
I adjusted valves 2 years ago. Yesterday I checked synchronizing, and it was perfect. I also adjusted mix bolt turning it by 1/4 turn and watching RPM.
I rode about 10 miles yesterday, bike ran perfect except some farting around 3K RPM(backfiring of frontfiring(?))! Still low temp exhaust pipe!!!!!!!!
I have pod filters and 4 in one exhaust pipes, so cannot check which cylinder is frontfiring (exhaust). I tried to hold hand next to filters, didn't feel anything.
I'll check spark plugs tomorrow. Backfiring happens around 3000 RPM, so it has nothing to do with clogged idle jet.

96 Yamaha Royal Star
82 Yamaha Virago 920
Last edit: 17 Nov 2015 15:10 by car5car.

Please Log in or Create an account to join the conversation.

Powered by Kunena Forum