Thanks, that's really cool being able to see the relationships like that. If it will ever stop raining here I plan to get out there and do this. I spent today reloading the garage laptop so I can have my internet radio and shop manual PDF out there again. I got most of the bearing grease off of the spacebar too. ;)
-Kyle -Sent from Houston, TX, United States On Fri, Sep 11, 2009 at 11:14 PM, Dennis Hammerl <[email protected]> wrote: > These came from a time of mechanically operated slide carbs. The reference > to cutaway is because the slides on most of those carbs could be changed. > The cutaway is the arch that opens as the slide is pulled up. They were > numbered 1.0 through 3.0 in half steps. They had a profound effect when > changed. Needles and needle jets (one fits into the other) could be changed > as well. Needles came in different tapers in addition to a possibility of > five different clip locations to change depth into the needle jet. Almost > none of this applies to vacuum operated slides. The effect this assembly has > at different throttle openings remains. Many "jet kits" will include a shim > to raise the needle and entrichen the range it affects. This replicates the > changing of clip settings on the manual slide carbs. The one graph shows the > "pilot air screw and jet" as having an effect across the whole range. The > key word here is "air". Carbs back in the day took two different paths to > the same goal. Today we meter the fuel as it enters the passages to idle and > early transition ports. That's the idle mix screw in front of the bowl, on > the bottom of your carbs. The "pilot air screw" was on the side of the carb > near the air inlet opening. It was used to meter air into the passageway > that bled fuel into the idle and slow speed circuits. All of this does still > apply to motocross bikes and racing bikes in general. The single cam CB650 > used mechanical slide carbs untill the last ones in '82. The whole idea of > vacuum slide carbs is to make them load sensitive and respond well at all > speeds. They don't work on motocross or most racing applications because > they tend to bounce under those conditions. Now that we have determined that > your bike has been modded a bit... extra insulators, 650 forks... Look at > the graphs and you'll see that the problem area you are experiancing may be > caused by some tinkering. Try this: ride it at the problem speed for as long > as you can (half mile will do) and shut the motor off with the switch and > coast to a stop. Remove and check a spark plug. Sooty ? too rich. Where ? > too large a main or maybe a shim under the needle. > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en -~----------~----~----~----~------~----~------~--~---
