Sucking on the filter?

My SR has this really lousy performance. When I ride it, it struggles to get up to 6000 rpm, 7 is even worst. I have the stock airbox, all new airbox hoses, cleaned carbs twice since last summer and then late december. I put in new o-rings in the carb, needle is set at the third setting, main jet is 56(thats what I saw on the main jet, took a pic of it but it didn't come out right. Rebuilt the accelerator pump, the right way, did the clearances on the bike December, cylinders, rings and piston clearance form cylinder are just right. Got new dyna ignition coils, new wires and spark plugs, read the plugs today too and they all read really good, seems to be getting the right mixture and they are gapped to .36. Air filter I had from I bought it and its still clean,.... I guess. Exhaust is stock and no plans on changing it, its a factory work of art! O and gas flows perfectly out of it's stock petcock with the vacuum setting. I don't know what pilot jet number, I dont think I ever cleaned that.
Did I miss anything that I need to check? did synch and air fuel mixture adjustments also.

Would first assure ignition timing correct and advancer unit operating. If have points, set proper gap before timing with strobe light.

Next, assure correct valve clearances.

Fuel supply -- would assure ample good clean gas; clear flowing petcock, fuel lines, and in-line filter.

Wouldn't hurt to check service fuel levels in float bowls.

Assure fuel tank air vent not clogged. Test by opening fuel tank cap and running at speed to see if there's any difference in performance.

Sometimes crud inside the fuel tank can partially clog petcock pick-up tubes allowing enough fuel at lower speeds, but insufficient fuel at higher speeds.

Good luck!

Actually, the jet size is most likely a "95". You mentioned the accelerator pump. My '79 SR has a set of those and stock main jets are 97.5, but then you're in Denver so that would explain being down one size.

Otherwise, I think Patton gave you enough advice to keep you busy for a while.

Thanks for the reply guys. I never fooled with the float heights, don't know if I want to be taking the carbs off and on like that. I haven't lubed my advancer in awhile to think of it, but I am sure the points are on there and the timing is correct, since it had to be fixed with the previous owner, he got that fixed. I will try that high speed tank open thing and see also.

How are your points (if you still have them and not an elec. Ign) and is your timing advancer lubed and moving freely?

I guess I should have scrolled down a bit. I didn't see the other replies.

I would still check the points and advancer, as you must have put on a fair numbers of klicks since you bought the bike.

Post edited by: rstnick, at: 2007/05/27 18:57

Ok Rstnick! I checked the points and advancer today and those work fine, but I put a little oil on the advancer for good measures. This is what I noticed today and yesterday. Yesterday I rode the bike on the freeway all the way to the end of the throttle rotation and these are my specs: 95 mph@ 7000rpm flat @ WOT, but I think it would of gone further if I closed the throttle and opened it back up again. Sitting still in neutral, it will go all the way up to 10,000 rpm and more but when riding it it wouldn't go all the way up easily. I am gonna get a new air filter and see what happens. Also my red warning light comes on at 102 miles, so I stopped for gas and only had to put in 2 point something gallons. Does that sound normal to you 650 owners? Fuel milage? Thats all for now!

sounds like decent mileage to me.. 47mpg or so?

Hows your battery through all this - still holding a charge and at peak performance?

Yeah the battery is really good to me, charging system is good, new ignition coils and sparkers and wires. I guess I got that fuel milage number cause I was pushing the engine all the way, testing it to see how fast it would go. My 1000 goes close to empty on 144 miles so I thought the 650 would do better. I use Gumout carb and injector cleaner which cleans the valves also, mainly the intake valves.

Well I went on the ride yesterday and they vacuum actuated petcock dipped out and left me hanging. I had to switch to prime for the bike to continue running. So now I figure it is that that causes such bad performance, plus I rode the bike with like an eighth or a sixth of the choke and there was more power while running on prime all the way, but when I would stop the bike would shut off and I would have to start it without the choke.