New Member....carb issues

85 MaximX, sat in storage for 6 years, finally pulled it out, and ran it through the gauntlet, tires, fork seals, brakes, all fluids yada yada yada. The 'gauntlet I mentioned alsoo included carb rebuilds (Mikuni). That's where my nightmare began.

After finishing the carbs, I decided ( in my infinite wisdon) to change form the stock air filter to K&N's, knowing I would have to rejet the carbs, rejetted the carbs, and it started up, came down from idle quite slowly, and idled a little rough. It got progressively worse, to the point where I left the house one morning, and couldn't go over 45mph, surging and backfire.

I assumed (dangerous as that may be) that it could have been an intake leak, 6 years in a storage shed is a long time, so 48.00 later, she instantly fired up, ran great for all of about 20 minutes, then.......surging backfiring etc.

My problem remains, despite the new intake O rings, idles rough, top speed 45 MPH. It's obviously running lean. So here is where I need some thoughts advice et al.

I am looking at a Dynojet kit for the Mikuni carbs, Stage 3. They come with the main jets obviously, but will I need to replace the slow jets as well? When I rejetted after the air filter change, I didn't use a kit, it was trial and error on the jet size. A Harley machanic friend of mine and I tackled this project in his garage.

Am I treading into a dark area of the forest where I am going to come out rocking back and forth drooling on myself? Should I just go back to factory settings and jets, and put the Yamaha air box etc back on? Should I shoot it? Burn it? Marry it?

Any one have experience with the DynoJet kits?

If I posted this to the wrong section, or if I am rehashing an old subject, just point me in the right direction and I will sift through the archives.

Many thanks.

Mike

 

Hi Mike welcome, is the petcock functioning properly, have you got an in-line fuel filter? it just sounds like you have draged up some crud, I know you cleaned the carbs, but did you clean out the tank, after standing so long, you could have some crud in the screen filters.

 

Wizard<

Petcock kit is on it's way. I thought about replacing it with a gravity feed, but for about 25.00 including shipping, I got all the necessary parts to rebuild the one that is on there. I did replace the inline filter, and trying to be somewhat preemptive, I also changed it every 100 miles, it ran ok for about 400 miles, and that's when it went downhill.

I did find some trash in the filter the first time I changed it, but the other times, and now, it appears to be clean. I rinsed the tank, but didn't use a proper tank cleaner on it. Speaking with a variety of machanics (Harley, Yamaha and Shadetree), they all were pretty much in agreement that they hated the commercial products, though none gave me an option of anything else. Any ideas there?

I guess I could pull the carbs again (got that down to a science) and clean them again and see what happens.

I have actually contemplated getting another set of carbs, jetting one factory and doing the DynoJet kit on the other. Running the factory carbs until I get the kinks worked out of the other.

Pain the rear is finding a complete set of Mikunis for the XJ700N, I have had no luck there, the haystack is big and the needle......not so much...

 

When you spend all that time / effort cleaning the carbs, it's as well to make sure you have a pristine fuel supply.

 

Pulled the tank today, planning on stopping at the dealership tomorrow and picking up some tank cleaner.....hopefully by then the petciock kit will be in and I will have had time to pull and clean the carbs.....