Ironhead Hesitation at 3000

[cajun1957a]

Recently, I posted on here that i had thought one cylinder was cutting out when the rpm's hit 3000 in fourth gear. It felt as if perhaps it was running on one lung and with a squirt of fuel and the revs coming up even 100 more rpm, the problem stopped. I have since determined that it is not a cylinder dropping off but perhaps a jetting issue.

I can replicate the hesitation every time. Holding at 3k, it will drop down a little and or buck just enough for me to notice it. It is not there at any other rpm. Now, going back to the last time i did anything to the bike, was that i had put a Yost 1 inch spacer and emulcifier in the carb but really never paid much attention nor did i do a whole lot of rideing after that and when i did, it was more short blast around town, where i would rarely stay constant at 3k. The bikes runs at 50 mph/80 kph at 3000, but usually im above that or below. Pondering this whole issue, i realized I had not re jetted the carb since adding the Yost parts and am wondering if that is the issue.

I am currently running a .068 main and .028 intermediate jet and perhaps I am thinking this combo is not right in fact I suspect they are on the large size for this motor. I cant remember what the jets that were in it new, but it did come with others and I have changed them around. The motor is a 65-900 bored .040 over. large valves and pb+ cams. It is not easy for me to just change the jets since i must remove the carb because there is not enough room to just drop the bowl given the Mallory "distributor" is there. Im not running drag pipes but baffled, stagard one peice fishtails

What do you guys think, too big on the main and or intermediate for the issue im haveing?

randy

[Boom-Boom]

I remember your previous thread and you got some good advice there. You probably already know that the intermediate jet controls fuel flow below 3000 rpm. A lot of people, myself included, have noticed improvements with a .0295 intermediate jet. A .068 main seems a bit high, but each bike is a little bit different and it doesn't seem that what you are describing has anything to do with higher rpm. I'd still try a .066 with a .0295 intermediate and see how the transfer feels. I'm willing to bet it will smooth right out. You had stated that your plugs were white, they should be light brown. So, sounds a tad lean. Jets are cheap, so get a few for each end and play a little. Also, do yourself a favor and switch those plugs to Autolite 85. They are fantastic.

[Hopper]

Drag pipes? Reversion issues?

[cajun1957a]

boom boom, thanks, i will do just that.

randy

[cajun1957a]

Hopper, no i dont have drags, fishtails, fully baffled. They are a balanced set. No reversion in these.

randy

[brucstoudt]

i,agree with boom boom,it sounds lean.i,would up the intermediate first,before i,went down with the main.[did you ever change your fuel line routing,away from the front cylinder head?]

[cajun1957a]

I just looked at the jets i have and i was mistaken. I do have the .0295 intermediate jet in because the .028 is in the drawer with the other two mains i have. So what i have in there is the .0295 and the .068 main. Will have to rethink this now unless i drop the main down. It appears that i have the larger of both in there so for a 900 maybe they are both too big. Im told these Super Es will run with factory jets on much larger displacement bikes. As far as the routing of the fuel line, no it is still forward and about two to three inches away from the front cylinder head forward of it slightly so it actually gets the wind before the head does.

The bike most definately appears and feels to be stumbling and or starving for fuel exactly at 3k. I will richen up the carb a bit too to see if that helps.

randy

[ultra...good]

Originally Posted by cajun1957a

Im told these Super Es will run with factory jets on much larger displacement bikes.

randy

A Super E on a 900? That is way too big of a carb for a 900. A G is pushing it. Are you sure it is an E?

EDIT; DISREGARD THE ABOVE INFORMATION.

[cajun1957a]

Ive been running a super E for four years without any issues untill now and it think its something minor.

[tracbike]

The intermidiate is the issue and the 68 is ok with yost power tube, you can usually bump up with that tube, Play with one thing at a time not both because you won't know what worked. Use the one Boom Boom suggested and leave the 68 alone. Then put some miles on. going down on jet with power tube is backwards.