Dark Posted September 18, 2008 Share Posted September 18, 2008 Hello, I'm new here and picking up a '74 TX500A this afternoon. The bike has under 1000 original miles but from what the PO told me, it doesn't start. He has replaced the battery, plugs, and resealed the inside of the tank (I think he said it has some rust in it). I am almost certain that the carbs are probably sticking or that the fuel lines are clogged BUT I wanted some third party advice. The last time it was ridden was in 1981, stored till just recently. Should the motor (internally) be okay after sitting for so long? Aside from cleaning/rebuilding the carbs and replacing the fuel lines, what else should I do engine wise to prep it for running? (I will be doing a lot of other maintenance outside of the motor but I familiar with those parts) I appreciate any and all the help I can get! Ryan Link to comment Share on other sites More sharing options...
Twin Shock Posted September 18, 2008 Share Posted September 18, 2008 Hello, I'm new here and picking up a '74 TX500A this afternoon. The bike has under 1000 original miles but from what the PO told me, it doesn't start. He has replaced the battery, plugs, and resealed the inside of the tank (I think he said it has some rust in it). I am almost certain that the carbs are probably sticking or that the fuel lines are clogged BUT I wanted some third party advice. The last time it was ridden was in 1981, stored till just recently. Should the motor (internally) be okay after sitting for so long? Aside from cleaning/rebuilding the carbs and replacing the fuel lines, what else should I do engine wise to prep it for running? (I will be doing a lot of other maintenance outside of the motor but I familiar with those parts) I appreciate any and all the help I can get! Ryan Replace the air filter to the carburators, If the tank has been sealed install inline fuel filters, change the engine oil. If the oil seals have not dryed out you should be ok. After you get the engine running have the valves checked, or before. Link to comment Share on other sites More sharing options...
Dark Posted September 19, 2008 Author Share Posted September 19, 2008 Great! Thanks for the help. I am no in possession of the bike and I was glad to notice that when turning it over there is compression (feel it coming out the exhaust). I'm going to yank the carbs, clean them up, and hope that gets it running. Plans right now: Pirelli demon tires, new front brake pads, rebuild front master cylinder, and clubman handlebars. Link to comment Share on other sites More sharing options...
Dark Posted September 19, 2008 Author Share Posted September 19, 2008 Does anyone know where I can find the carb rebuild kits for the TX500? Link to comment Share on other sites More sharing options...
Twin Shock Posted September 20, 2008 Share Posted September 20, 2008 Does anyone know where I can find the carb rebuild kits for the TX500? Motorcyclecarbs.com has the kit. Link to comment Share on other sites More sharing options...
Dark Posted September 20, 2008 Author Share Posted September 20, 2008 Motorcyclecarbs.com has the kit. Awesome, thanks! Link to comment Share on other sites More sharing options...
Dark Posted September 28, 2008 Author Share Posted September 28, 2008 UPDATE I rebuilt the carbs and brakes. Today the motor fired up after a few turns, a bit rough at first but eventually smoothed out and the little bit of smoke went away. Rode it up and down the street and determined that it really needs to be tuned/sync'd/jetted (no filters on the carbs). I went to fire it up again about 30 minutes later and it started but after about 15 seconds it just died and refused to start again. There is fuel (at least I can see it in the filters). My guess at first was the heat got to the coils; some folks mentioned they can start it cold but not hot. Once it cools off I will go give it another shot but is there anything I should be looking for? I will verify spark when I am out there next. I just need it to run decent so I can take it up the street to the shop on Tuesday for them to do some work on it. Link to comment Share on other sites More sharing options...
Dark Posted September 29, 2008 Author Share Posted September 29, 2008 Got it to fire again, usually takes a kick to get it running over the starter. It's got a poor idle (I've attempted to adjust it via the idle screw and it helps temporarily), the left cylinder seems to be running rich with the occasional miss (the exhaust pulse is weaker then the other). It will also randomly just to about 5k rpms without change. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted September 29, 2008 Moderator Share Posted September 29, 2008 Got it to fire again, usually takes a kick to get it running over the starter. It's got a poor idle (I've attempted to adjust it via the idle screw and it helps temporarily), the left cylinder seems to be running rich with the occasional miss (the exhaust pulse is weaker then the other). It will also randomly just to about 5k rpms without change. sounds like an air leak, check the rubber inlets for cracking and clean out the pilot jets as these supply the fuel for idle. Link to comment Share on other sites More sharing options...
Dark Posted September 29, 2008 Author Share Posted September 29, 2008 sounds like an air leak, check the rubber inlets for cracking and clean out the pilot jets as these supply the fuel for idle. Manifolds seem good but I'll spray some brake clean or similar on them when I get it running to see it they are leaking. I guess I'll rip the carbs off again and verify that the pilots are clean. Link to comment Share on other sites More sharing options...
Dark Posted September 29, 2008 Author Share Posted September 29, 2008 No leaks around the manifolds. I removed the lower cover, sprayed the jets down again with carb cleaner just to verify they weren't blocked, put some seafoam in the tank, let it idle (would only idle at 1500rpm with a hair of choke). After about 10 minutes I could give it a little gas without it spiking the revs uncontrollably. After this I was able to get it on the road and ride it around a little. It died twice at a stop and wouldn't rev past 6k (the powerband seemed to die off right around 5.5k). I'm guessing I need to have the carbs sync'd/tuned. Link to comment Share on other sites More sharing options...
Dark Posted October 2, 2008 Author Share Posted October 2, 2008 Any idea's as to why it loses power after 6k rpm? I am guessing it's timing but how off can it be untouched with 650 miles? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 2, 2008 Moderator Share Posted October 2, 2008 Any idea's as to why it loses power after 6k rpm? I am guessing it's timing but how off can it be untouched with 650 miles? carb diaphramps are either cracked or the slide is sticking, this prevents it rising under vaccum and from dropping for idle!! Link to comment Share on other sites More sharing options...
Dark Posted October 2, 2008 Author Share Posted October 2, 2008 There are no filters on the carbs at the moment (so I can watch the slides; no diaphragms on the early 500's) and they seem to be functioning normally. I will verify that again. Link to comment Share on other sites More sharing options...
Dark Posted October 6, 2008 Author Share Posted October 6, 2008 ****UPDATE**** Installed a different set of carbs (clean with smooth/free moving slides). Checked the plugs (they look good). Ran some Sea foam through the system while it idled. Checked the points and advance wheel, all look good and the weights move freely. --Problems I can't diagnose: The engine loses nearly all of its power right around 6k rpm (under load). (edit - from what I've been reading this seems to be a problem with running out of fuel i.e. no air filter box. I am going to install it and try again) The engine will almost die if I blip the throttle too quickly, especially at idle. Note that I am not running the stock air box or filters, if this is thought to be a cause or the throttle blip issue then I can put them on and try it again. I appreciate all and any help!!! Link to comment Share on other sites More sharing options...
Dark Posted October 6, 2008 Author Share Posted October 6, 2008 Here are some pictures I took tonight Link to comment Share on other sites More sharing options...
jrhendryx Posted October 6, 2008 Share Posted October 6, 2008 absolutely gorgeous.... Link to comment Share on other sites More sharing options...
Dark Posted October 7, 2008 Author Share Posted October 7, 2008 Thank you! A good side note....I GOT IT RUNNING!!! Installed the stock air box and not only did it start and run fairly smooth but I was able to take it all the way to redline! Tomorrow it gets new tires and a front brake inspection. Link to comment Share on other sites More sharing options...
Moderator mervin Posted October 7, 2008 Moderator Share Posted October 7, 2008 beautiful merv Link to comment Share on other sites More sharing options...
Dark Posted October 8, 2008 Author Share Posted October 8, 2008 Clearer pictures with the turns removed and grips installed. Link to comment Share on other sites More sharing options...
Recommended Posts