Airbox/Carbs issue

[hmsa42]

I've just recently restored a majority of my bike, '82 GS 750TZ, but I seem to be having a problem with either the airbox or the carbs. I cleaned the carbs, dipped and double checked all the holes were clear either visually or with air. It appears the PO may have taken off the rear part of the airbox and just replaced it with a KN filter, and the rest of the bike appears to be stock aside from that. The issue I'm having is that the bike will be difficult to get running without choking it, and if you give it throttle it will bog the bike down and kill it. At first I thought maybe it was the carbs, so I recleaned them and double checked everythingn before I put them back together, but when I was putting the airbox back on, I noticed that the box is bowed. This causes the middle two air boots to not mount on flush like the outside two, the tops are somewhat more flush but the bottoms look like they'd be right on the edge of the carbs(and where I suspect the leak). Then if I'm having troubles trying to get the bike started, if I take the filter off and slightly cover up the hole, it finally gets the right mixture and fires off and runs like she did last summer. I have the screws on the carbs turned out at 2 1/2 turns right now and doesn't appear to be helping much the further I go out.

I guess my question is, could the airbox be my issue with the boots not sealing and possibly pulling in more air? Or could I have maybe missed something with the carb rebuild that could be throwing it all off? Then my other question would be about what I can even do about the airbox being bowed? The one time I was able to force all the boots flush, the airbox just pulled them back off the middle two again after a few minutes. I know people do pods, but from what I've read on the forums so far is that they can be a pain as well, and I can't seem to find any airbox's online that I trust are in better condition vs the price of going with pods.

Thanks for any help, so far these forums have been helpful to me while I've been restoring this bike(powder coated the frame, new paint job, and replaced gaskets in the engine that were starting to leak)

[BassCliff]

Greetings and Salutations!!

Hi Mr. hmsa42,

I sounds like you do have air leaks. If you're patient, I'm sure an airbox will show up on ebay eventually. Or you can try to fix the one you have. Check in the Parts Wanted and Parts For Sale sections of the forum. Somebody here may have an extra one. You never can tell.

Now let me give you the unofficial "mega-welcome". Pay particular attention to the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator papers.

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[hmsa42]

Thanks for the reply. What I might try to do since the box is of little use to me right now, it to slowly heat up the troubled area and see if I can't get it back to somewhat normal. If I destroy it in the process then it'll decide my mind on going with pods I guess.

[hmsa42]

Well, after I spent most of the afternoon the other day fixing the airbox via heatgun and clamps, the bike was still running the same way. I then decided to check the boots for leaks by spraying some starting fluid, and nothing changed with the RPM's, so I assumed that the issue with air leaks was fixed with those. After thining about it for a while and cursing at it, I remembered that the PO had given me the old stock airbox, so I decided to ditch the K&N filter and place the stock setup back on, and low and behold she runs like a dream after that. Now all I have to do is get a new filter(old one looks bad) and I think this project is finally to a close.

BTW, on a separate note, is there a certain spot that the brake pedal will only fit into? I cannot get it mounted right now and I'm afraid to force it much more than I already have.

[hmsa42]

Figured out the brake pedal issue, nothing a dremel couldn't fix.

[hmsa42]

Took the bike out for a test spin today after I had adjusted the brakes and the clutch, and she was running great up until about 6K RPMS, then she'd start to sputter until I released the gas. Went back in the garage, parked it, came back onto the forums, and decided that it looked like a symptom of not enough gas. Looked things over and saw that the vacuum hose was slightly kinked, so replaced it with a longer hose to fix the kink, and took her out for another spin. She is reaching all RPM ranges now without hesitation, have to love this site for the troubleshooting it provides.

[BassCliff]

<sniff!> I love happy endings!

Thanks for sharing your success.


Thank you for your indulgence,

BassCliff