phil63146 Posted August 25, 2011 Posted August 25, 2011 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
Moderator drewpy Posted August 25, 2011 Moderator Posted August 25, 2011 I'd check your carb diaphrams, sounds like the main system is not kicking in as it should. the timing is done by electronic ignition. did you clean the main nozzle out with all those little holes?
phil63146 Posted August 27, 2011 Author Posted August 27, 2011 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
Moderator drewpy Posted August 27, 2011 Moderator Posted August 27, 2011 did you strip the carbs though ie into little bits of mains etc?
phil63146 Posted August 27, 2011 Author Posted August 27, 2011 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).
Moderator drewpy Posted August 27, 2011 Moderator Posted August 27, 2011 did you clean the little orifice in the float bowl? took me a while to do that one!
phil63146 Posted August 28, 2011 Author Posted August 28, 2011 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
phil63146 Posted August 31, 2011 Author Posted August 31, 2011 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.
Moderator drewpy Posted September 13, 2011 Moderator Posted September 13, 2011 well done, 14 lbs ft torque on those sparks
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