Re: Found a fix my Keihin 754 carbs, 76 CB360, before & after
Tuning these damned Keihin 754 carbs they used on the 1976 Honda cb360t. I have been fighting them for a while. The reasons for the carb changes is tuning for use w pods and pipes. Tuning has not been a walk in the park. But now Ive got it. No sputters, pops, cutting out, hiccups any where on the tach scale from 1200-9000 in any gear. Oh and the best part. I am still a touch rich down low...so pipes still cackle when slowing to a stop. The fastest I have ridden is 85, I can easily accelerate up hill in 6th gear. I believe she would do 100 +, but Im not gonna find out.
So, if you are tuning your 754s due to filter and pipe changes. Good F-ing luck. Here are a few obstacles I overcame.
I bought 2 kits from Keyster, Almost useless. The main secondaries were wrong...they include 100s, stock is 110. The bowl gaskets are a nothing more than a bad joke, o-rings = crap. I found the gaskets I currently have in the bottom of a 5 gallon bucket of old gaskets and o-rings, stuffed under a work bench, down at my local service station Dons Marathon Parts plus, Don was nice enough to let me dump the bucket on a workbench and sift through to see if he had anything I could use...I ended up w 5 gaskets that work perfectly, FREE. Also the kits include new springs for the air/fuel needles. If you use them be sure to file the sharp ends down smooth. They can cut into brass needle seat, causing your carbs to clog w brass particles. So, it would just be best to re-use your original springs from kehein if possible. I also had mods done by a Mechanic/friend I met online, in Florida. PJ (crazypj), I dont know exactly what kind of voodoo he did. But, he did something good. When I sent them they were way to rich w stock 110s. So, I tried leaner jets, ran better...but no power at all. when I got them back from PJ they were rich mid range rpms and lean in High rpms w 112s. So, I was able to work w that, on the fine tuning.
Also I found apparently money cant buy Primary mains. I found a pair from another carb could be modified to work in these kehein 754s. I took them to a new friend/machinist/Instrument maker...Stuart DeHaro, and had him "fix" them. Also, dude will make you custom French Horns in his spare time. http://deharohorns.com/ check it out.
So here is my current carb configuration: (yours may be different, due to the 36 year old personality of the beast) I just ordered a couple new Secondary mains (122s, 125s)and needle shims. I believe plugs could use just a touch more color. I have been talking w PJ about this jet modification and he may start making these Primary mains in the future...you will have to speak w him about that.
New 3/16" fuel lines
K&N stainless steel mesh fuel filters
Original stock needles (no shims)
Original stock #35 Pilot jets
New #62 Primary Main Jets
New #120 Secondary Main Jets
21mm Float height.
4-4 1/2 turns on air/fuel
and whatever PJ did.