|
SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Another noob needs help /cgi-bin/YaBB.pl?num=1228523698 Message started by Justinmkantor on 12/05/08 at 16:34:58 |
|
Title: Another noob needs help Post by Justinmkantor on 12/05/08 at 16:34:58 OK Stats first. Bought used 1987 savage with 12,000 miles from dealer who let it sit for 3 years. Took it on as a project and bought new battery, changed oil, oil filter. Ran poorly but ran. Backfire cough sputter. Cleaned carb but found no luck. Tried to get the air fuel mix right after buying a lancer carb, iridium plug, and cone filter. Installed tach to make sure rpm's were set correct. set to 1100 rpm's. trying to set air/fuel mix and sounds good even throttle running better but still backfiring louder when hotter. When setting air fuel mix it backfires when hot all the time. >:( Have not touched timing, TDC, will check plug soon. hints on where to start since I know some mechanics knowledge (armchair style). What things do you set first? TDC, then RPM, then Air fuel mix. Header bolts were tight, so was muffler clamp. Why would it always backfire more when hotter. hints or help. Fuel flow is good through petcock. did not use old fuel, got new when bought. Nice bike, gets some attention, mostly when I turn it off due to the shotgun I ride. ;) |
|
Title: Re: Another noob needs help Post by verslagen1 on 12/05/08 at 17:20:45 Nothing to do with timing, sensor's under the left cover. And you can't adjust TDC. What are you doing to make it back fire? Does it idle ok? How does it accel? How's the top end? |
|
Title: Re: Another noob needs help Post by Justinmkantor on 12/05/08 at 17:34:02 Idles OK but rpms come down in like 3-4 sec sometimes. It backfires when it turns off about 1-2 secs after shutting off. Do't know about the top end, not much highway time. |
|
Title: Re: Another noob needs help Post by verslagen1 on 12/05/08 at 17:42:44 Adjust the idle mixture screw out about an 1/8 to 1/4 turn. that should kill the shut down kerpow. here's a test for the main jet sizing. find a nice hill, one that you can go up for a while at full throttle once speed has maxed out at WOT, back off about an 1/8 to a 1/4 turn. Does it seem to pick up? If so than you can go up a size in jet. once you have idle and max set, play with the white spacer thickness till it accels smoothly. |
|
Title: Re: Another noob needs help Post by Justinmkantor on 12/05/08 at 18:08:37 Well I had it down around 800 when I put the tach on and put it up to 1100. should I put it back down? with my VM lancer carb he said he put a 190 jet in when he shipped it. it has stack muffler I think. I know the stock carb uses around a 152 but thats a different carb. It does slow RPM's when I get over 1.5 turns out though. Does that mean the jet is too large? Do you need to mod the white spacer in the lancer VM carb? |
|
Title: Any other help? Post by Justinmkantor on 12/05/08 at 19:24:59 anybody else got any tips? |
|
Title: Re: Another noob needs help Post by verslagen1 on 12/05/08 at 20:38:35 You didn't say you got a VM carb All dem tips is for a stock carb, fraid I can't help you. |
|
Title: Re: Another noob needs help Post by justin_o_guy2 on 12/05/08 at 20:44:59 Dont run it low RPMs. The top end will starve for oil.Keep it up at the 1,000 rpm idle. |
|
Title: Re: Another noob needs help Post by Justinmkantor on 12/05/08 at 20:53:04 If I keep it at 1G then what dod I do about the shotgun? Is there anything else that could set it off like that? Timing, valves, unseen hole in exaust system? A gremlin that belches who live inside? |
|
Title: Re: Another noob needs help Post by LANCER on 12/06/08 at 07:27:43 1C2325223F383B3D3738223924560 wrote:
Agree with keeping the idle at 1000 rpm at a minimum. On the VM carb, the pilot adjusting screw works opposite of the stock carb. Stock carb screw turns out (counterclockwise) to richen mix...on the VM carb the pilot screw turns IN (clockwise) to richen the mix. This is probably one of the primary sources of frustration for you. The carb manual covers the tuning steps for all 3 throttle ranges. Also, you should recheck your exhaust system. Don't just check to see if the bolts are tight, but take the muffler and header off, install a new head/header gasket and reseal the header/muffler connection and then make sure of proper alignment when the bolts are tightened. The bolts may be tight now but with the age of the bike, if the seals/bolts have been untouched for a long period, it is possible that the seal is broken (allowing air into the system and creating backfiring) even though the bolts still seem to be tight. Better to take a little time and redo the sytem and make sure there is no air leaking into it and causing backfiring. There are only 2 primary causes of backfiring, the pilot circuit of the carb running lean & air getting into the exhaust system, so your solution is likely to be found in those systems. |
|
Title: Re: Another noob needs help Post by Justinmkantor on 12/07/08 at 10:14:38 Thanks Lancer! I must have missed the backwards air/fuel screw thing, and I will replace the header seal and see what happens. Awesome! |
|
Title: Re: Another noob needs help Post by T Mack 1 on 12/08/08 at 11:34:41 To check for exhaust leaks, use a candle or cig lighter. Hold the flame to the joints. It the flamse gets moved (pushed away or sucked in) then you have a leak. T Mack |
|
Title: Re: Another noob needs help Post by PipJones on 12/08/08 at 14:42:40 what would an exhaust leak cause? cuz i know i've got about 3 on mine, right after the header. |
|
Title: Re: Another noob needs help Post by T Mack 1 on 12/08/08 at 19:06:54 5168714B6E6F6472010 wrote:
Extra air coming into a controlled space (the muffler) can cause just the right conditons to create a backfire. |
|
Title: Back again with same problem. Post by Justinmkantor on 12/14/08 at 09:45:39 Well, another fix did'nt fix it. I replaced the header gasket. When I took the old one off it did look like it was getting leakage, had black soot on the port (left side) of the cylinder gasket seating area. Also felt some coming out of the exhaust header meets muffler may or may not have fixed that with aluminum foil. I think I might have to bring in some outside help, i.e. a real mechanic god forbid. |
|
Title: Re: Another noob needs help Post by Charon on 12/14/08 at 10:08:12 This might be a "devil's advocate" question, but I'll raise it. Most discussion of exhaust systems seems to center on reducing back pressure, or the requirement for a certain amount of back pressure. Almost by definition "back pressure" implies a pressure above atmospheric (ambient) pressure. How then can a leak in the exhaust system allow extra air INTO the exhaust system instead of allowing the pressurized (back pressure) OUT? |
|
Title: Re: Another noob needs help Post by verslagen1 on 12/14/08 at 10:18:20 Exhaust transits the pipe as a pressure wave. Resistance to that wave is back pressure. suddenly closing the throttle and dropping the velocity of that wave will cause it to go negative in between pulses. |
|
Title: Re: Another noob needs help Post by Digger on 12/14/08 at 18:21:11 Justin, Sounds like you are at a stage where you need to eliminate some potential culprits. Try crimping the petcock vacuum hose tightly enough so that NOTHING can get through it. Turn the petcock to PRI and try running the bike. Does it run better? Worse? The same? Report back up. Remember to turn the petcock to ON or RES before walking away from the bike. Oh, and you may want to pop in a fresh plug before trying this test. Good luck! |
|
Title: Re: Another noob needs help Post by Justinmkantor on 12/15/08 at 13:44:53 Just replaced plug with iridium plug. Did Petcock mod now only has on/off/reserve switches but will try more clamps. |
|
Title: Re: Another noob needs help Post by Justinmkantor on 12/31/08 at 15:20:55 Replaced the stock muffler with a dyna and backfire is more like a "poof" than a bang now. I used aluminum foil as a spacer for the metric-SAE gap. Anybody see anything wrong with that? |
|
Title: Re: Another noob needs help Post by T Mack 1 on 12/31/08 at 15:38:50 6A555354494E4D4B414E544F52200 wrote:
The aluminum foil will eventually flake apart, bt it will take awhile. But.... should be good for now. When it comes time to replace it, use a slightly thicker gauge aluminum . |
|
Title: Re: Another noob needs help Post by justin_o_guy2 on 12/31/08 at 20:33:11 Coke/beer can might handle the job. |
|
SuzukiSavage.com » Powered by YaBB 2.2! YaBB © 2000-2007. All Rights Reserved. |