Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
We noticed you are blocking ads. DO THE TON only works with community supporters. Most are active members of the site with small businesses. Please consider disabling your ad blocking tool and checking out the businesses that help keep our site up and free.
With my current bike breathing better, I am searching around for a new pilot jet with limited luck. It seems as if my pilot is a 2 piece jet, and I was wondering if anyone with experience can better speak to this or point me in the proper direction or etailer.
Stock is a 38 pilot jet, and like I said it appears the pilot is a 2 piece jet if that makes sense. The first part comes out and has a similar shape to the main jet, albeit much smaller, and if you take a very small flathead you can get the remainder of the pilot jet out from the carb.
I am hoping for some insight into the proper 1 up pilot jet and maybe an online etailer to purchase from.
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
I had trouble finding them as well - z1enterprises had them, but call and talk to someone. They used to be labeled wrong on their website and it took some back and forth.
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
Well I have an answer for you. Sirius Consolidated Inc currently sells a carb kit for the early Black Bomber (1965-68 Part# KH-1201) that contains the next size up pilot jet in the kit. I contacted them and asked if they could get the larger pilot jet #40 separately they said yes and shortly afterwards they changed their web-catalog to include listings for the stock and larger pilot jet (Part# KHS-070040) and (Part# KHS-070038). Although they still say they are not in stock as of yet.
Either way you can wait for their arrival or spend the cash and by two carb kits for the early model and get the jets earlier. I hope this helps 8)
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
To a certain extent it does, and thanks for the help guys.
3 more questions...
1)the stock 38 pilot jet, should it have a hole in the top of it as the main jet does, or just a pin hole on the threaded side with 2 holes at the end of the thread?
2) Is the 'emulsion tube' above that in the carb just that? Not part of the pilot jet?
3) What should my float height be? My manual is incredibly vague on this.
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
The emulsion tube you speak of is the pilot jet the brass threaded cap is a plug and should not have a hole through it. The air is drawn from the air jet in the front horn of the carb through a runner in the carb to the column where the emulsion tube is and it meters the fuel and air as it travels through another runner in the carb body to the pilot/mixture screw.
Your float height should be set to 20mm from the base of the carb body on which the float bowl gasket sits to the bottom of the float. Take the carb off the bike hold it upright in its normal position with your right hand so the float falls away from your hand. Rotate the carb clockwise so the float starts to pivot towards the carb body. When the float stops falling it has made contact with the valve mechanism. stop rotating the carb, hold it in that position and do your measuring while holding the carb at that angle. If you rotate the carb too much further the weight of the float will cause the small internal spring in the float value to compress and your measurement will be off.
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
cqyqte said:
The emulsion tube you speak of is the pilot jet the brass threaded cap is a plug and should not have a hole through it. The air is drawn from the air jet in the front horn of the carb through a runner in the carb to the column where the emulsion tube is and it meters the fuel and air as it travels through another runner in the carb body to the pilot/mixture screw.
Your float height should be set to 20mm from the base of the carb body on which the float bowl gasket sits to the bottom of the float. Take the carb off the bike hold it upright in its normal position with your right hand so the float falls away from your hand. Rotate the carb clockwise so the float starts to pivot towards the carb body. When the float stops falling it has made contact with the valve mechanism. stop rotating the carb, hold it in that position and do your measuring while holding the carb at that angle. If you rotate the carb too much further the weight of the float will cause the small internal spring in the float value to compress and your measurement will be off.
HuGE HELP. It threw me off because it was the 'plug' that had the '38' marking on it. The pilot jet itself SHOULD be the right size based on my research but that is incrdibly helpful in pinpointing the proper pilot if need be.
I've been doing a lot more digging today. My spark isn't that bright white it should be, it's more of a yellow/orange. I just picked up a multimeter so I will be checking to see if I have 12v off the coil. If I don't I know that's where my issue lies.
Could the fact that I do not have the headlight wired back up (or any of the front end electrical: horn, signals, kill switch, etc) be robbing the front half of the harness of voltage?
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
If you don't have the white and yellow wires in the bucket hooked up then you are discharging your battery; those connect the charging system back together.
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
Rich Ard said:
If you don't have the white and yellow wires in the bucket hooked up then you are discharging your battery; those connect the charging system back together.
I'm at work so I don't have the bike or wiring diagram near me. What would those connect usually? It's highly possible that I have them disconnected right now but I can't be sure. If they are in fact disconnected, should I just connect them back up?
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
Check your wiring diagram, follow it (or look for 'CB450 charging mod' at hondatwins.net) and when you have it idling check voltage across the battery terminals to make sure you're pushing >13V.
Re: 1974 CB450K7, stock Keihen carbs. NEED PILOT JET HELP.
So, here's where I am at with the bike.
-Good compression (+/- 180 to temp)
-Straight dump exhaust right before passenger pegs (where I have rearsets mounted). No 'lolipops'... yet.
-uni foam style pod filters, properly lubed (stock ones where MIA)
-rebuilt carbs, stock pilot and slow/+1 (150) main
She will start second kick and idle fine. Right side exhaust pipe has a more noticeable 'pop' on idle. Under load (read: in gear) the bike struggles bad to get out of the 1/4 throttle DEAD area and will sputter, backfire, etc, sometimes dying out. Once I can get the bike past 1/4 it will wind out nicely and feels strong. In neutral it will still struggle a bit to wind out but obviously does just fine since there is no load on the bike.
I was not able to do a WOT pull before shutting down, but the left side plug is black and sooty, the right side is a bit too, but the right side looks cleaner, and when pulled almost looks wet.
All signs point to carb adjustment/bowl float levels. Thoughts?
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
