Topic: Update on jet needle height modification (Measure twice, cut once cont'd)

[Raul CB750K1]

Ok, so I mount my carbs back and had a terrific riding afternoon -it was a while since I don't get my bike and weather was just fine-. I recently raised the circlip one notch, from the 3rd to the 2nd from top of needle, and this is what I got:

Before: 6.10 l/100 km, or 38.72 mpg
After:   5.56 l/100 km, or 42.27 mpg

Haven't checked spark plugs yet, but if they were sooty black before I believe they will be fine now.

I didn't change anything more. The air screw setting was the same than before, everything the same. The bike now keeps the idle at 1000-1100 rpm without hesitation, just like before. I didn't notice any flat spot on the rpm range.

Main jet 120. Slow jet 40. Needles have an inscription: 2720. HM300 stock pipes.



Just for your information


Raul



P.S. Actually the fuel efficiency should be a little better. When I had ridden about 20 km I remembered I didn't insert one of the fuel lines up to the end while assembling. I stopped the bike and found some gas was pouring from there....


Seems like all my bikes leaks gas lately. Luckily they don't leak oil.... ;-)   (For your information too, "leaking oil" is the spanish euphemism to say somebody is gay)

Stream of consciousness at its best. Regarding genres, I've read that many of you refer to the bike as "she". What's the correct genre for a bike? And for a car? Shouldn't they be simply "it"?

[Raul CB750K1]

BTW, when I was riding, everytime I moved the throttle, I couldn't help but imagining those four slides and needles rising at the same time. It was addictive. If you  have rebuilt your carbs you know what I'm talking about.


Raul

[oldbiker]

Thanks for the update Raul. Feedback is ALWAYS useful.

[MetalHead550]

How ya been Raul?  Glad she's runnin better.  I dont know if its just a blue collar American thing but we usually call our vehicles "she" to indicate a higher level of intimacy with the machine, e.g. youve had it a long time, its an antique, you freakin love it, you grew up in a farming community in central Illinois where groups of guys would stand around a machine (or the engine/other large identifiable parts) drinking beer, staring at it and refering to it as "she".  "She's a mean one"  or  "shes a beast".  Yeah were poetic like that.  Ive always refered to my car as a "He"...it has balls. 

Leaking Oil huh?  I dont get it...but Ill use it!  Later!

[Kevin D]

Raul, my 48-50 mpg is on mostly flat, straight roads, 800 ft elevation, 45-60mph farm country cruise with occasional redline blasts. No canyon carving or mountain passes to climb here in Michigan. Whats the terrain like in Spain?

You would have to leak an awful lot of gas to lose 10 mpg >> burn 1 gallon, leak 0.2 gal.

My sooty plugs are also better with 115 mains in place. I recently acquired a Motion Pro Deluxe - the price was right - so if I replace my rock hard rubber inlets I may tear down the carbs this winter for needle adjustment and synch. No gas leaks here, or oil leaks for that matter, and I pity the next poor guy who posts an oil leak.

[Raul CB750K1]

Yeah were poetic like that. Ive always refered to my car as a "He"...it has balls.

You don't mean that plastic nuts that you hang from your car, do you?

In spanish language, "car" is masculine and "bike" or "motorcycle" is femenin.

Whats the terrain like in Spain?

I live near a small mountain range on the outskirts of Madrid, with plenty of curvy roads, pine trees and this time of the year, beautiful autumn scenery. Not too elevated, but I will check mpg again when riding through flatter roads.

Regarding the "oil leaking", I can't explain really why did it become popular. Actually it doesn't mean "gay" but "effeminate", you know the kind of man with femenine gestures and voice tone. I guess it's just like saying "there is something wrong with that guy" and maybe making some associations between oil and private sexual practices.

On a flight back to Madrid, you know when people gets into the plane, looks for their seat and accomodate, the stewardesses greet them "Hello, welcome" and so on. It was an Iberia flight and there used to be stewards, I guess to promote the "equal oportunity employer" policy. So, there was that effeminate steward that tell us: "Welcome, good afternoon" and looking with those lovely eyes. When we were all seated, on guy told his friend in the seat behind me: "if the plane leaks as much oil as this guy we are #$%*ed". There was a blast of laughter around.

[MetalHead550]

Good stuff.  No I dont have plastic balls hanging off my rear bumper,  I havnt seen those in a long time.  My car is an ex-police car and has respectable power for a daily driver so it "has balls" and therefore a male in my eyes.

[Raul CB750K1]

Hey Metalhead, that's a Manowar quote, isn't it?


I removed plugs #1 and #4 today to check the condition. They were sooty black before the needle position change. Surprisingly, number #4 looks fine after those 130 km, while #1 still looks like if the mixture is too rich. Anyway, 130 km are not enough, and I guess I should also check plugs #2 and #3. But I feel I'm in the right track.


Raul

[Gordon]

You had me worried there for a second.  I thought you were using two different size plugs, but then I realized that's two different pictures stuck together. 

I'm wondering what would cause the #1 cylinder to run rich while #4 is fine?  Have you checked the float levels recently?

[Raul CB750K1]

You are right, after posting it seemed the same to me. They come from different pictures. I use irfanview to crop the part of the picture that doesn't give information, without caring about the size. Then, I use the Create Panorama option in Irfanview, and it puts the two pictures together, resizing the bigger one so they have the same height or width, depending the Panorama is created stacking the pics vertically or horizontally.

Yes, I just cleaned the carbs at the same time that I raised the circlip. As I was at it, I checked the float height too. It was perfect, at whatever the height should be (I can't remember, wasn't it 26 mm). No wonder, I just rebuilt them less than two years ago.


By the way, do you remember that I asked about the Mystery Spark Plug Size? I managed to buy a 18 wrench, a little longer than the one on my Suzuki tool kit, that is perfect because it fits on plugs 2 and 3, while being longer it is easier to use the bar to turn it. Furthermore, it is slightly oversize, so it lets you incline it a little to give you even more clearance. It costed just 3 euro.


Raul

[Gordon]

By the way, do you remember that I asked about the Mystery Spark Plug Size? I managed to buy a 18 wrench, a little longer than the one on my Suzuki tool kit, that is perfect because it fits on plugs 2 and 3, while being longer it is easier to use the bar to turn it. Furthermore, it is slightly oversize, so it lets you incline it a little to give you even more clearance. It costed just 3 euro.


Raul

This is what I've been using for a few years now. 

It's a typical tool kit style plug wrench with a standard size spark plug socket.  The wrench end of the standard socket fits perfectly in the large end of the tool kit wrench, then I use the channel lock pliers to turn it.  Works great!

[MetalHead550]

Wow Gordon, so thats how they fit together! .....Just being a smart ass.  Good idea though.

Hell yeah thats a Manowar quote Raul!  Opening track on Louder Than Hell.  "Burn up the Night"  All about riding around on motorcycles, blasting Metal, and drinkin brews till you the day you die!  Speaking of which, I recently saw Judas Priest w/ Anthrax,  kicked major ass!  Halford's getting old but he can still wail and strut around in leathers like a badass!

Yeah that pic messed with me too.  Anyway #4 is dead on for mixture but yeah #1 is pretty damn rich.  Those plugs were pulled after idleing right?  I was gonna say mabey a spark problem but 1 and 4 run off the same coil so that wouldnt make sense.  I dunno man...