carb rebuild...one replacement part wasn't quite right (atc70)

[lilatv]

I have something of a problem, I purchased a rebuild kit for my carb, everything interchanged pretty good. Then something doesn't quite interchange correctly. In the schematic from www.bikebandit.com
it is part number 31 (picture attached). I believe this is the secondary jet, when I removed mine it was a press in type, but the new one has threads. Should I have known to tap the carb, to accept the jet or have I received the wrong one? Over all the jet looks the same as the old one, except it has threads..???? I cleaned and reinstalled the old one for now but I would like to replace it if possible, any thoughts appreciated.

I also removed the casting ridge left in the intake during production (very noticable), so I should expect what 20 more hp, just kidding, once I removed it with a carbide bit, I used 60 grit to swirl around the port so the smooth transition hopefully, will help gain at least another hp or two.

Thanks

[lilatv]

Well fellas I thought it over and couldn't resist taking the secondary jet out to see why they were different. I am not a patient person.

I noticed that even though the new one had threads, the outside diameters were very close. So I figured the threads on the jet were more of a resistance fit than a standard tapped thread and bolt/screw scenario. So I payed attention to how far the old one stuck out and made sure that I screwed the new one in at least that far, I knew it was supposed to bottom out, seems to have worked out. Guess I will know later when I start it up.

I also took the old head to intake gasket and trashed it. I noticed that the gasket actually disrupts with part of the flow. So I ran a very very small bead of gasket maker, about the width of a sewing needle, to make sure there were no interferences and a tight seal. Something to think about I guess, just something I noticed.

Lemme know if what I have done is correct or not, as far as the jet goes. Thanks

[lilatv]

Man I like to ramble on and on.

Here is where I am at now, I did many searches in hopes of comparing different, what I believe to be called an idle jet or at least that is what one site called it, another site called it the secondary jet and both were the same picture(?). The site shown a picture of an idle jet just like my new one, and stated screw in, not a replacement for 80-81 press in...uh-oh...haha... My kit specifically states for 78-82 carbs. First thought would be, were there two different idle jets in the package and the answer is no. Why would they include two years that require a press in vs. screw? Seems my 79 model was made late in the game just far enough to get the newer at the time press in idle jet/secondary jet. Oh well, lemme know how bad I screwed up. I am thinking it should still work okay but then again that remains to be seen, will know in a few hours. Any input appreciated, thanks

[lilatv]

Well once I had the gas flowing, she idled good and no longer has the 3/4-full throttle bog it used to have. As a matter of fact, it seemed to fire a lot quicker than it did before. I will give it a few days before I make a judgement on that though.

I would still like thoughts on why using the threaded jet as a replacement for the pressed in jet is either okay or not a good idea. Thanks

[lilatv]

Well just in case someone else is qurious, I will post were I am at this far. Seems I have a cold start problem and there is what I perceive to be a lean spot when you get on the throttle and for some reason it wanted to die sometimes idleing. I blame it all on the slight differences in the idle jet (besides one is threaded and one is not). I went back in and took the new piece out and put the cleaned old one back in. IMO, it made it run 100% better, the lean condition is gone and the bog it had before at 3/4-full throttle is still gone, so it was worth it to rebuild the carb, however I wish I would have just cleaned the old pieces as opposed to spending the $13 for the kit, guess it was worth getting new seals though. I won't know if the cold start problem is gone until tomorrow though, it used to fire the first pull without the choke but after the rebuild it required some playing around with the choke, hopefully that problem will be gone as well. For what its worth, the kit I purchased was made by moose utility division, it states for 78-82 atc70's but thats not correct, the kit contains a screw in idle jet vs the press in that 80-81 and some late 79 models require.