Topic: Plugs loading up?

[City Boy]

I have a 1 owner '70 750.Very annoying is the plugs loading up in town,then you hit the highway and bap bap bab till the plugs clear.New plugs fix it,for about a day.Sound familiar?I have cured mine and many others by installing projected nose plugs.I use NGK DPR8EA .Depending where you live,also DP8EA,DP8ES is also fine.Fear not problems!My unit is now a RC 1000 and these plugs have caused no trouble after many years.Only exception would be sustained high speed [road racing-Autobahn]Every 750 I have tuned gets them;customers always happy.On a related note,if modifying these old girls does not cause you ulcers;I highly recommend a pointless ign. and better coils.I have a Martek 440,dyna green 3.0 coils,and 8mm silicone jacket solid core wires in the 1000.Dyna makes a good ign. also that I have installed on other units.Every thing your engine should do it will do better.Yes, if you have a failure,you are going home on the trailer,while the points system MIGHT nurse you home.The improved performance more than tips the balance scales ,in my view.

[mrbreeze]

Loading up with fuel or oil?

[City Boy]

Unburned fuel deposits.What I offered up was a fix not a band aid.The alternative of course is to keep the engine at high rpm all the time.

[mlinder]

.... or lean out your idle mixture?

[savannahcafe]

Forgive my ignorance. What is a projected nose plug? How is it different from a regular plug?

[Bob Wessner]

Here's a pretty good pic difference between standard and projected nosed plugs..

http://www.strappe.com/plugs.html

[savannahcafe]

aHHH nice article. Now for my next question which we all knew was inevitable.  What projected nose plug can I use for my 75 CB550? Or, how can I find out?

[Bob Wessner]

aHHH nice article. Now for my next question which we all knew was inevitable.  What projected nose plug can I use for my 75 CB550? Or, how can I find out?

I'm by no means the most experienced wrencher here, but is your bike stock? If so, why do you feel you need them?

[savannahcafe]

No it isnt stock. I have a dyna s ignition, dyna green coils, accell 7mm wires. I have rebuilt the carbs and got it running decent. I have not yet had it synced nor do I ride it yet. I start it up and bip the throttle or ride it in the alley behind my shop getting up to maybe 10mph. I have had 1 & 3 plugs get some carbon fouling enough to make it extremely hard to start. I pull the plugs, clean them off and presto, starts right up. I turned in the small screws on 1 & 3 and it helped #3 a little, but still fouling on 1. Should I just wait till I'm riding it normally to see if anything really needs to be done?

[HondaMan]

aHHH nice article. Now for my next question which we all knew was inevitable.  What projected nose plug can I use for my 75 CB550? Or, how can I find out?

Look on the Internet for the Nippon Denso X22ES-U. It's a projected tip with the D7.2-ish heatrange, perfect for the 500/550. The X24ES-U is my favorite CB750 plug, and the "22" for winter riding.

[GNXFan]

My K1(15,000 miles) had the same problem of loading up on fuel at low speeds but getting better at highway speeds. The best thing I did to remedy the problem was replace the worn needles and needle jets with new Honda parts. Do not use aftermarket parts here such as Keyster or K&L. Those rebuild kits only come with new needles and no jets. They must be replaced as a set. The parts cost about $18.00 per carb. I have not had the problem since I made this change.

[HondaMan]

No it isnt stock. I have a dyna s ignition, dyna green coils, accell 7mm wires. I have rebuilt the carbs and got it running decent. I have not yet had it synced nor do I ride it yet. I start it up and bip the throttle or ride it in the alley behind my shop getting up to maybe 10mph. I have had 1 & 3 plugs get some carbon fouling enough to make it extremely hard to start. I pull the plugs, clean them off and presto, starts right up. I turned in the small screws on 1 & 3 and it helped #3 a little, but still fouling on 1. Should I just wait till I'm riding it normally to see if anything really needs to be done?

The K0 and K1, in particular, were too rich at idle. Just 10 minutes in traffic could load up the plugs. You can try setting the idle screws about 1/8 turn leaner to help. Also, go look at the FAQ in the "Thoughts of Hondaman" section: there's more info in there about some minor jet mods that really help with the earlier 750s, K0-K3.

[754]

I ran the first extended tip plug that came out, think  it may have been NGK Hot U's.

It never started, I had cut down 350 pistons as a bore kit, every one kissed a plug..end of that idea..

[Short Round]

Yeah piston clearance was what I was wondering in the 550's.