I need to adjust the carbs on my bike (I'm running too rich) and was reading about doing a plug chop. From what I understand, to adjust the carbs for WOT I need to run the bike with the throttle completely open for about a minute then kill the engine. And I guess that means that I need to run it with some resistance (under load) so that I can hold the throttle completely open without revving the engine too high (past redline). The page I read suggested driving uphill to do that. The problem is, I don't have anywhere nearby where I can drive really fast uphill for a minute (not to mention having a safe place to suddenly pull over and check the plugs). Is there some way to add the load in my garage? I guess using the brake would work, but would wear my brakes out pretty quickly. I'm thinking something like a magnetic brake from a treadmill/elliptical. Do they make things like this (that are affordable)? What does everyone else do?
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79-GS550-L
putting bike under load in garage
Hello,
I need to adjust the carbs on my bike (I'm running too rich) and was reading about doing a plug chop. From what I understand, to adjust the carbs for WOT I need to run the bike with the throttle completely open for about a minute then kill the engine. And I guess that means that I need to run it with some resistance (under load) so that I can hold the throttle completely open without revving the engine too high (past redline). The page I read suggested driving uphill to do that. The problem is, I don't have anywhere nearby where I can drive really fast uphill for a minute (not to mention having a safe place to suddenly pull over and check the plugs). Is there some way to add the load in my garage? I guess using the brake would work, but would wear my brakes out pretty quickly. I'm thinking something like a magnetic brake from a treadmill/elliptical. Do they make things like this (that are affordable)? What does everyone else do?Tags: None
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Easiest way is to run about 35 mph in top gear, hold the throttle wide open to about 60 or so, then chop.
.sigpic
mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
#1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
#2 son: 1980 GS1000G
Family Portrait
Siblings and Spouses
Mom's first ride
Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
(Click on my username in the upper-left corner for e-mail info.)
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Originally posted by 79-GS550-L View PostHello,
I need to adjust the carbs on my bike (I'm running too rich) and was reading about doing a plug chop. From what I understand, to adjust the carbs for WOT I need to run the bike with the throttle completely open for about a minute then kill the engine. And I guess that means that I need to run it with some resistance (under load) so that I can hold the throttle completely open without revving the engine too high (past redline). The page I read suggested driving uphill to do that. The problem is, I don't have anywhere nearby where I can drive really fast uphill for a minute (not to mention having a safe place to suddenly pull over and check the plugs). Is there some way to add the load in my garage? I guess using the brake would work, but would wear my brakes out pretty quickly. I'm thinking something like a magnetic brake from a treadmill/elliptical. Do they make things like this (that are affordable)? What does everyone else do?
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txironhead
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Originally posted by txironhead View PostGet a Morgan Colortune and do it that way.
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Billyboy
Just get one buddy to stand in front and push and another buddy to sit behind you. Do a burnout and there you go!:-D
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txironhead
Wonder if there would be a way to rig a temporary-mount O2 sensor to the exhaust....it would be more expensive than checking the plugs, but it could fit several bikes and there'd be less chance of burning your hands or getting pulled over for "excessive demonstration of speed". Yeah, the cops in my area hate bikes. And they would think plug chop was either a Kung Fu move or some kind of drug.
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madjack57754
I know this may sound stupid but it works. Take the caps off 3 of the four plugs. put extra plugs in the plug sockets and ground them to the cylinder head. to make this a bit clearer you would now have 7 plugs on the bike, one in the head with a wire on it,3 in the head with out wire and 3 with plugs in them that are touching the head to ground them.
If the load from compression of the cylinders is to much, pull a plug from one of the cylinders that are dead . Take a plug out of the dead cylinders one at a time until there is just enough load to run WOT at about 5500-6000 rpm. Just make sure that the plug wires have plugs in them and they are grounded to the motor. You do your plug chop and read the firing plug.
I've done this with my drag bikes when ever I go to a new track to see how far off the jetting is. A quarter mile is not long enough to get a decent color on plugs. I learned this from Dave Schultz. It was how he set up bikes before there were onboard computers. I always figured if it was good enough for him It was good enough for me
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madjack57754
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Originally posted by madjack57754 View PostI know this may sound stupid but it works. Take the caps off 3 of the four plugs. put extra plugs in the plug sockets and ground them to the cylinder head. to make this a bit clearer you would now have 7 plugs on the bike, one in the head with a wire on it,3 in the head with out wire and 3 with plugs in them that are touching the head to ground them.
If the load from compression of the cylinders is to much, pull a plug from one of the cylinders that are dead . Take a plug out of the dead cylinders one at a time until there is just enough load to run WOT at about 5500-6000 rpm. Just make sure that the plug wires have plugs in them and they are grounded to the motor. You do your plug chop and read the firing plug.
I've done this with my drag bikes when ever I go to a new track to see how far off the jetting is. A quarter mile is not long enough to get a decent color on plugs. I learned this from Dave Schultz. It was how he set up bikes before there were onboard computers. I always figured if it was good enough for him It was good enough for meOriginally posted by madjack57754 View PostI forgot to mention you do this in neutral, in the confines of your garage
No muss, no fuss
Nice tip. I will try it. :-D
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79-GS550-L
Yeah! This is exactly the kind of thing I was hoping for. We do have some places here where a good rider could get up to speed... but I am still learning how to ride, so I wouldn't want to take my chances trying to get up to 60 mph in residential streets... and I wouldn't feel safe pulling plugs out on the side of the interstate. Oh, and technically I can't even go on the interstate with a learner's permit
The colortune seems like a great idea, and I was very close to buying one, but then I realized you couldn't use it under load, so since I have to do plug chops anyways for mid & wot, it seems silly to spend the money on a colortune for just the idle circuit.
One question though... I heard that it is bad to run the engine with a plug missing for longer than a few seconds. Is that true? Is it just because dust/grit could get in? If so I'll just cover the open ones with some foam or cloth or something. I have a feeling I won't be able to start my engine with 1 cyl firing and 3 blocked off.
Thanks for the help,
Alex
Originally posted by madjack57754 View PostI know this may sound stupid but it works. Take the caps off 3 of the four plugs. put extra plugs in the plug sockets and ground them to the cylinder head. to make this a bit clearer you would now have 7 plugs on the bike, one in the head with a wire on it,3 in the head with out wire and 3 with plugs in them that are touching the head to ground them.
If the load from compression of the cylinders is to much, pull a plug from one of the cylinders that are dead . Take a plug out of the dead cylinders one at a time until there is just enough load to run WOT at about 5500-6000 rpm. Just make sure that the plug wires have plugs in them and they are grounded to the motor. You do your plug chop and read the firing plug.
I've done this with my drag bikes when ever I go to a new track to see how far off the jetting is. A quarter mile is not long enough to get a decent color on plugs. I learned this from Dave Schultz. It was how he set up bikes before there were onboard computers. I always figured if it was good enough for him It was good enough for me
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txironhead
You'd be amazed....my brother-in-law's Nighthawk 650 will run on only one plug.....matter of fact, that's about the only way it does run.....piece of crap......
Actually, what I'd like is for someone to post definitive, high-res pics of just what exactly the stages are from lean to rich. I can tell when it's one extreme or the other, but the middle stages get iffy.
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Originally posted by 79-GS550-L View PostI heard that it is bad to run the engine with a plug missing for longer than a few seconds. Is that true? Is it just because dust/grit could get in? If so I'll just cover the open ones with some foam or cloth or something. I have a feeling I won't be able to start my engine with 1 cyl firing and 3 blocked off.
.sigpic
mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
#1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
#2 son: 1980 GS1000G
Family Portrait
Siblings and Spouses
Mom's first ride
Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
(Click on my username in the upper-left corner for e-mail info.)
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Forum LongTimerGSResource Superstar
Past Site Supporter- Oct 2006
- 13969
- London, UK to Redondo Beach, California
That's how I read it too Steve.....
If there is too much compression to turn it over using only one plug then take another plug out of the head but leave the other 3 grounded to the engine so the electrics work.
Interesting way to do it.
1980 GS1000G - Sold
1978 GS1000E - Finished!
1980 GS550E - Fixed & given to a friend
1983 GS750ES Special - Sold
2009 KLR 650 - Sold - gone to TX!
1982 GS1100G - Rebuilt and finished. - Sold
2009 TE610 - Dual Sporting around dreaming of Dakar..... - FOR SALE!
www.parasiticsanalytics.com
TWINPOT BRAKE UPGRADE LINKY: http://www.thegsresources.com/_forum...e-on-78-Skunk/
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I love it! You never know when advice like this can come in handy!1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
1985 GS1150ES stock with 85 Red E bodywork.
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