Topic: couple questions about plug chops/tuning

[drumstyx]

First and foremost, I'm assuming a plug chop is the best/fastest way to tune? This seems like a very tedious and expensive process, so I thought I'd ask first...I'd be willing to buy some fancy analyzers if I could avoid this...Heck, I'd pay someone that knows what they're doing, but shops around here would probably ding me for 5 hours at a shop rate over $100/hr.

Questions about the actual process: Do you have to actually CHOP (cut the threads of) the plug to get a half decent tune? I know you can read all the way down for a perfect tune, but I'm not racing here, I just want approximately factory quality tune.

If the answer above is "no", do you need brand new plugs for every single test? They're not super expensive, but they're not free, and come to around $12/set plus tax and shipping (Canada). Obviously if I need to, I need to, and I bought 4 sets in anticipation of this, but being that this is the first time I've had to actually tune carbs (other carb'd bikes I've had were basically 100% after a clean, but they were CV carbs) and I'd hate to burn through $50 of plugs only to have to WAIT for more in the mail (hardware store sells them for something like $5-7 a piece!!!)

And as an extension to the previous question, for a newbie, how many sets will I run through? Should I just go ahead and order 40 more plugs?

[Deltarider]

The plugchops have reached a level of hysteria in this forum. Here's my advice. Set your carbs to standard settings and start from there. If you have the standard air intake I dare say you're practically there, even with an aftermarket exhaust system. Lots of folks here that proudly present the theory from the books as if they discovered it themselves and send you into the woods with I don't know how many plugchops. If you're not satisfied with how it runs at a specified throttle position, you could have a look at the plugs after you've shut off the engine and simultaneously have pulled the clutch. And NO, you don't need new plugs. Used ones will indicate just as fine and I know mecs that say they even show better. It's about the colour (tan) and that will show also on residues. No wonder if you realise how hellish it's in there. If you're the happy owner of a model with a 4-4 exhaust, you could just check the tan by peeping in the pipes at the rear.

[drumstyx]

Well, I definitely need to at least *check* the tuning, now that it's nicely timed. The new plugs I used in there were quite black while I was working on getting it running at least half decent, probably because I just kept starting it with the choke, running it for 3-5 minutes and checking the throttle response by goosing the throttle.

Now that it's running OK, she's got a full tank of fuel, and with the exception of tightening the head bearings, the chassis is ready to rock. I just want to make sure I'm not running too out-there. I've got a stock airbox (though an aftermarket filter, but not a high performance one, EMGO maybe?) and Delkevic 4-1 exhaust.

My biggest concern is off-idle performance, which is absolutely atrocious for the first maybe 10 minutes even. This is in my garage too, so not much cooling (fan in front of the engine). I can only imagine if it were a cooler day, and the oil didn't get nice and hot, off-idle could suffer continuously. Because of that, I'm thinking it might be lean at idle, as it might not have enough 'oomph' to survive the rush of air the instant before the (confirmed working) accelerator pump squirt reaches the cylinders.

[TwoTired]

"Plug chops"  is a shorthand abbreviation for the process.

Have a test track in front of you after the engine is at operating temperature.
Stop engine, install new/or known clean plugs with no deposits on the tips or center electrode insulator.
Start bike, accelerate at one and only one throttle position, or 15-30 seconds.  (I start with W.O.T.) Simultaneously Chop throttle, Hit the kill switch, and pull in clutch.
Come to a stop and remove spark plugs, noting the deposits made on the spark plug tips and center electrode insulator.

Compare deposits to this chart:
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html#1

Make changes as appropriate to attain the plug deposit pattern for the throttle setting used in the test.

If there were no deposits, you can reuse without cleaning for the next throttle position test.  Otherwise new plugs or a cleaning of the used one can be done.
You don't want a previous test run's deposits to contaminate the next test results.

This process is repeated until WOT, 1/2, 1/3, 1/4 and idle RPM "plug chops" all show the desired deposit patterns on the plugs.

Go ride.

If you can get to a DYNO facility, they can load the engine and give a fuel map by sniffing the exhaust during the run.  You can then make adjustments to all the ranges outside of desired requirements.  Then repeat the DYNO run for a corrected fuel map.  A good tech will only make 2 or 3 runs to get the carbs dialed in, assuming the carbs are working properly.

The dyno should also make a HP and torque map for your engine.

Cheers,

[Jimray23]

A idle plug chop is the way to go. Get the bike warm so it will idle without the choke and no blimping of the throttle. Then put new plugs in and start it up, let it idle under a fan for 3 to 5 mins and shut it off. See what color the plugs are. Thats all there is to it

--------------------------------------------------
Jim
I really don't see why people ask for advice if their not going to take the advice given.

[flybox1]

First and foremost, I'm assuming a plug chop is the best/fastest way to tune? Unless you have cash and access to an A/F analyzer. This seems like a very tedious and expensive process, so I thought I'd ask first...I'd be willing to buy some fancy analyzers if I could avoid this...Heck, I'd pay someone that knows what they're doing, but shops around here would probably ding me for 5 hours at a shop rate over $100/hr. Probably.

Questions about the actual process: Do you have to actually CHOP (cut the threads of) the plug to get a half decent tune? NO I know you can read all the way down for a perfect tune, but I'm not racing here, I just want approximately factory quality tune.

If the answer above is "no", do you need brand new plugs for every single test? They're not super expensive, but they're not free, and come to around $12/set plus tax and shipping (Canada). Obviously if I need to, I need to, and I bought 4 sets in anticipation of this, but being that this is the first time I've had to actually tune carbs (other carb'd bikes I've had were basically 100% after a clean, but they were CV carbs) and I'd hate to burn through $50 of plugs only to have to WAIT for more in the mail (hardware store sells them for something like $5-7 a piece!!!)

And as an extension to the previous question, for a newbie, how many sets will I run through? Should I just go ahead and order 40 more plugs? NO

Just one set will do for now.  Get your bike to operating temps..and then park it.  Take out the old plugs, put in new ones, and start the bike.  Let it idle, under a fan for 4-5 minutes.  do not blip the throttle.  shut off the engine. pull the plugs out and have a look at their tips.
post a picture of them here.

Please tell us what model carbs you have.

[drumstyx]

I always forget the designation, but it's a '78K, so it's got the non-round-top carbs

[flybox1]

PD's
42b's is my guess...so turning OUT your IMS will make your idle mixture RICHER.  IN = leaner.

[drumstyx]

PD's
42b's is my guess...so turning OUT your IMS will make your idle mixture RICHER.  IN = leaner.

Yep, but not only that, they are a PAIN to get at while mounted. I even have a 100 degree screwdriver, still can't really get it in there right. I'll probably just get good at removing them.

[flybox1]

Ive got big hands and its no problem 
Take a 1" driver bit, file it down so the tip is 3mm wide and fits the slot in the IMS, glue it into a drilled out wine cork.
Makes it easy to handle/turn and easy to find.

[drumstyx]

How do you all handle getting the plugs out when the engine is hot? It's such a pain in the arse getting them out cold, how the heck do you get them out hot?

[riverfever]

I use the factory plug wrench to loosen the plugs and then use a 4" or so section of fuel line that fits on the plug and use that to unscrew it and reinstall them. Living up here at altitude I feel like all I do is plug chops trying to get this bike close(r).

[TwoTired]

The honda tool kit spark plug tool has a foam holder within it, making removal and installation pain free,as it holds the plug in the socket.

Cheers,

[riverfever]

Correction. Mine looks like the stock tool but it does not have anything inside to hold the plug.

[flybox1]

grab them with a shop towel or needlenose pliers

[drumstyx]

I've been using the tool from my concours, which gets the job done, but it's still a pain -- for some reason my #2 plug is a bit sticky going in/out for most of the range (or maybe it the angle) so it's a pain in the butt using a wrench on it. I'm getting a ratcheting wrench that will make the job easier though, as the ratchet doesn't really fit in there well.

[PeWe]

Plugs will tell if floats are floading. Isolator pitch black after idling shortly and plug need to be replaced. When fixed you'll feel how bike is running and response when twisting throttle and release a little at full speed.
No rich smell at idle. I have not replaced plugs for minor rich. Plugs got better colour after tuning carbs. Important to check all plugs now and then to discover too lean in time.
Important to verify ignition before changing any jets.
I'll change my carbs when back home from vacation. My last dyno run showed too rich needles. Needles to be lowered one step, it's washer one step up.

If engine is unmodified, why a problem? Std setting should work with clean air filter, no leaks. 4-1 usually 1-2 steps richer mains, pods one more plus ev needles 1 step up.