phil63146

I think I may have found it. It struck me that when I removed the plugs to check the compression they were finger tight. After putting them back in and making sure they were tight I took the bike around the block a few times. There seems to be a definite difference! Normally, I would have pulled the carbs and done probably 10 more hours worth of other work, put it all back together, have it run great, and not have the slightest idea what I did that might have been the fix. Looks like I may have lucked out. Thanks.

Still haven't gotten to it yet.

If it's there I would bet a week's pay that I did. Idea! I will take the air box off the bike, start it, speed it up, and see if the piston valves lift. If so that would indicate to me that the bike should be getting (hopefully enough) fuel through the Main jet. I will try to see if both lift at the same rate. May be a day or two on results. thanks

Yes I removed all that could be removed from the body (main jet, pilot air jet, main nozzle, etc) , but I did not disassemble the jet needle from the piston assembly, separate the carbs, or remove the starter plunger (choke).

I have inspected the diaphragms under a magnifying lens and held them up to light and see nothing out of the ordinary. They are very supple. I'll pull them again and reinspect. Yes, I have cleaned all the passages in the cards and run fine piano wire thru the openings. I compared passages/openings between the both carbs and everything between then is the same, blew all the passages out with compressed air. Phil

1982 XS400RJ, 30,000 miles with absolutely no horsepower. In the 1,000 miles I have owned it top speed was 45 MPH which was OK cause I didn't need to go any faster. Now I do. I had the engine out earlier this summer and here is what all I have done to/around it, with added info. After all that work the bike seems to have no more power than before. Compression is 135 and 140 PSI, new plugs, adjusted valves (way off), new fuel filter and lines (see thru), premium gas, cleaned carb and passages, spotless internals, diaphragms look great, changed both needle and seat assemblies (both old and new same float height setting), adjusted air screws and synched carbs, no popping or backfiring, smooth idle, bike starts instantly, clean air filter, gas tank is clean with no trace of dirt in fuel lines, clutch adjusted properly, different ignition box. Throttle response is great, it's just that I'm in 5th gear by 20MPH. I have not checked the timing yet, what is the best way?. Exhaust seems to have sufficient output but maybe I need to disconnect them. Anyone have a way to check mufflers without disconnecting them? Is there a sane way of checking float level? Unable to talk to prior owner. I can hold the brake and when I engage clutch the engine dies. It will also hold me on downhill slope with engine off and clutch engaged. Any ideas greatly appreciated! Thanks in advance. Phil

Found them from another owner. Thanks

I have a question you might be able to answer. On the pilot screw is there just one O-ring and washer per screw or two washers with a O-ring in between? If just one, I assume the washer goes against the spring (dumb ? I know). Thanks for the lead but I'm hoping to find someone on the west side of the pond.

Where can I find the flat washers and O-rings that fit on the pilot screw (air mixture screw) on the Mikuni carburetor. All of the items are about 5mm on diameter. Thanks in advance. Phil

Thanks for the info! I'll be ordering those along with carb kits. I'll be sure and post the results. Phil

No, it is definitely gas and not oil. Looking at my factory book I can't identify what cap need to be pulled to be able to adjust the air/fuel mixture. What is the air/fuel adjuster called in the parts manual? Thanks, Drewpy. Phil

1982 XS400 bike. This bike will make your eyes water after 15 seconds, it runs so rich. The air filter is clean and both plugs are firing. The factory book shows no air/fuel mixture screws on the carbs. Earlier years show having the air/fuel mixture screws. Does anyone have experience in correcting this problem on this vintage bike? Thanks in advance. Phil

Here's what you do. Get a 6 or 12 point 12MM deep socket. Put it over the lock nut, hold the socket with a vise-grip. Insert a Phillips head screwdriver (through the 3/8 or 1/2" opening where the ratchet attaches) and holding the screw stationary, turn the socket counter clockwise to loosen the lock nut. Make necessary adjustments. To tighten the screw after adjustment, hold the screwdriver steady and turn the socket clockwise to tighten the nut. HINT: replace the clutch cable (I wasted a lot of time on a seemingly good but stretched cable). I will forward from the factory book the clutch adjustment procedures (in correct sequence) if desired. Let me know. Good luck. Phil

Good thing I bought the extra ignitor because the rebuild project has so far been a failure. I don't know if I will ever attempt to find out where things went wrong.

This bike runs so rich it makes your eyes water within 15 seconds. The air filter is new. Both plugs are firing. The factory book shows no adjustment for air/fuel mixture. Surely syncing the carbs wouldn't fix the problem, would it? Any ideas before I tear into the carb to check float, etc.? Thanks in advance. Phil