Ha! I was too fast! I should’ve shopped around! Thanks Jim
Yeah... one thing I like about Niche Cycles is that they offer both Mikuni and brand X. They literally make you click on one or the other. If you choose brand X, you made a conscious decision to do it.One special feature that 5twins has warned to watch for, involving clones and counterfeits, is the unique Mikuni "square within a square" identifier. He knows that jets-r-us deals with only Mikuni parts, and warns to watch out for the other offerings...
In this picture you can see a silhouette of the original gasket, showing where it was cut out in an arc linking two of the holes. Your new gasket isn’t. Is this relevant.Well, I went out to my shop this morning filled with fresh enthusiasm, determined to iron out my cranky carbs.
To begin, I reset my throttle stop screws and air mixture screws to baseline settings, then started my bike.
I got the idle set down low, around 1000 rpm, then tried to get the air mixture screws dialed in. All it wants to do is sputter, miss and pop and die. I tried and tried different settings but no joy. I have no interest in riding it in this condition, I want to figure out what is causing this. I am convinced it has an ongoing problem with the enrichening circuit or the idle circuit. Which leads me to this.
“Hello darkness my old friend, I’ve come to talk to you again.”
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I am going to really get aggressive with cleaning out the air and fuel passageways this time. After removing all the jets and breaking down the carbs again. I shot an entire can of carb cleaner through all of the tiny passageways, paying particular attention to the air passages and the mixing screw passages. I would hold a blast of cleaner until I was seeing a liquid jet coming out the other end, then hold it some more.
I also wanted to take the opportunity to double check that all the jets were the correct size....they are.
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I also sat down and really looked at my choke plunger, to assess the fit. I believe it fits like it should. It is a pretty close machine fit, you can just barely wiggle it, but if it were any tighter it wouldn’t move up and down easily.
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I also wanted to give a close examination to the gasket I made for my choke assembly. Just to make sure I didn’t accidentally cover something I shouldn’t have.
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Finally , I also wanted to be as accurate as possible with my bench set up, and make notes on how many turns I made on the throttle stop screws. Using 2Ms reference photo as a guide.
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He said that he turned his throttle stop screw 1/2 turn past first contact to begin to expose the first transfer port.
For me to achieve that same exposure it took me 1 1/4 turns.
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So the carbs are back together ( AGAIN ) on my bench, waiting to go back on.
I also got the petcocks installed in my XS2 tank today.
And one more thing. Remember when I painted my Motion Pro clutch cable silver, and said how nice it came out.
Well......something weird started happing, after days. The paint started becoming soft and sticky and rubbing off on anything it touched. The paint was clearly reacting to something in the cable sheath, so I removed the cable from the bike, took a rag and some lacquer thinner and cleaned it all off. It’s waiting to be re installed now.
So, I DO NOT RECOMMEND SPRAY PAINTING CABLES.
Until next time, hope springs eternal.
Bob
Wow lots of eyes on your restoration Mailman and it is nice to see the investigative work being helped out by all.
Absolutely! By reading and following this thread I've learned so much about my own bike. The factory manual and this thread is about all a guy needs.You have no idea how many times I’ve hit a wall and was completely stumped until someone or a whole group of people helped me through it. I never would’ve attempted a restoration of this magnitude if I didn’t have confidence that the members of this forum could help me through it. It really is a great place.
So it seems you've discovered an error in the Carb Guide, or at least an area that could have been explained and clarified better. As mentioned above, the VM22/210 pilots used in the '76-'79 BS38s do not require the air holes, and as also mentioned, the BS30/96 pilots used in the '75 and older BS38s most likely do need them. I didn't have an early float bowl available back then to examine so I just assumed ..... and you see what often happens when you do that, lol.
I think the no-hole style BS30/96 jets you got are actually another pilot jet type, the N151.067. They look just like a BS30/96 with the metering orifice on the bottom but they have no bleed holes in the sides .....
So, the lack of bleed holes would explain your rich running and black plugs. Those pilots were most likely flowing all fuel and not a fuel/air mix like they are supposed to.
Oh my gosh you really stood your ground and got something sorted out !I’ve gotta say , this was a real head scratcher. I was driving myself crazy trying to figure out what I did wrong.
So it seems you've discovered an error in the Carb Guide, or at least an area that could have been explained and clarified better. As mentioned above, the VM22/210 pilots used in the '76-'79 BS38s do not require the air holes, and as also mentioned, the BS30/96 pilots used in the '75 and older BS38s most likely do need them. I didn't have an early float bowl available back then to examine so I just assumed ..... and you see what often happens when you do that, lol.
I think the no-hole style BS30/96 jets you got are actually another pilot jet type, the N151.067. They look just like a BS30/96 with the metering orifice on the bottom but they have no bleed holes in the sides .....
So, the lack of bleed holes would explain your rich running and black plugs. Those pilots were most likely flowing all fuel and not a fuel/air mix like they are supposed to.
Well, Bob. There it is!
It's your pilot jets.
You have the wrong type, missing the side aerator holes, like this.
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Haha, absolutely well done, Bob. Sounds great!
You just made my day.
Glad that the helicoil kit worked in there. I bought the same kit a couple months ago, have yet to use it. Thanx for trailblazing.
Soon you'll be feeling thesandwind in yer face...