Stock 50 /175 jets. K&N free flow in stock air filter housing. Standard stock pipes on an 1986 Tour Glide Classic.

I added an EV 27 cam last year and wanted some suggestions to re-jet the carb to improve wide open throttle takeoff. I have a small stumble / hesitation in 1st and occasionally in second.

If you want to read up more about my efforts of late with this carb here's the conversation from the last several days of attempting to fix issues with this.

'85 Keihin Butterfly Carb (Title should have been '86.)

It started with adjusting the carb as the intake began leaking. Replaced the compliance fittings and have timed the bike, rebuilt the carb but it still has a WOT hesitation.

No carb backfire, cough or any other issues. Great idle, great pickup, and works perfect if all I do is steadily roll on the throttle. But taking off, like pulling out of store and getting quickly up to speed it has 3 or 4 quick hesitations and then picks up and rolls on strong with no issues.

Thanks for your thoughts and suggestions.

 

I can`t offer you any jetting advice on the butterfly carb, but...

Until you toss that butterfly carb into the scrap bin, and replace with a Mikuni or CV, you will realize very little gain from the EV27 cam. I have an EV27 cam in my engine, and had to revert back to the butterfly carb once, while I waited for some throttle cables. The drop in performance was very noticeable.

 

I think the information I'm looking for is not available.

On my other conversation about this issue the most recent comment suggested upgrading the accelerator pump. After replacing the pump with a stock replacement and the dramatic improvement it made, this may well be the only thing remaining to give me full performance without a fault.

I have to say that all the work I put in on this overhaul has paid off. Yesterdays extensive ride was the best performance wise in a long time. The bike no longer feels starved and lame, it was full power and quick response anytime I needed it. With only a small hesitation when I took off full throttle.

It may just be the nature of the beast too. No doubt Harley stopped using them for a reason. Guess I'm just too "Old School" wanting to make due with this relic of a carb.

 

To everyone who feels I should replace the carb I'm taking donations.

Sunday I precisely replaced the compliance fittings for a second time.

Saturday I spoke with a 35 year Harley mechanic who now has his own independent shop in Flint called Bootleg Cycle.

Bob told me to fully disassemble the tank, and the engine brace, along with the mounting bracket for the horn / VOES and to precisely clean the mounting point on the heads. He also said to install them without wrenching in between the fittings, between the cylinders like I had done before. In doing so, this time I found remnants of the old gasket baked on and interfering with the compliance fitting gaskets sealing correctly and possibly causing the hesitation. Also I was instructed to not over torque those bolts, which also causes leaks by distorting the compliance fitting. I used WD40 to slip in the manifold and mounted up the air filter to support the carb in the proper position before clamping it in place. Little details that are important to get right.

I did add the Anderson high volume accelerator pump and can feel a real blast of power but unfortunately the stumble remains. I am ordering a jet kit and now realize that with the EV27 cam the carb's main jet needs re-jetting to match the improved performance the cam is giving.

I wish there were other suggestions of which size jet to use. Guess I will be taking it up a size, a step at a time.

I'm determined to fix this and make it continue to work.

 

I ordered a 175, 180 and 185 for my carb from Jets R Us. I'll post back when I get the time to test them out.