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The bike wont start up! I just replaced my carbs and such, made sure their both set right fuel/air wise. I tried to start it up and it would just crank until there's no tomorrow. I pulled the plugs and they were all gassy and suity. I cleaned them out and let the bike sit an hour or so then tried to start it again and it backfired twice on me! Both times it shot flames out of the left side pipe! What could be up?!
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Did you rebuild the carbs with new o-rings and intake boot o-rings while they were off?Ed
To measure is to know.
Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182
Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846
Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf
KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection -
Did you fudge with the coils, coil connection or wires at any time, possibly crossing them?Comment
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i got new O rings and stuff for the bike ahead of time and I didnt mess with wiring at all.Comment
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Is the airbox installed?1983 GS850G, Cosmos Blue.
2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
2015 Yamaha FJ-09, Magma Red Power Corrupts...
Eat more venison.
Please provide details. The GSR Hive Mind is nearly omniscient, but not yet clairvoyant.
Celeriter equita, converteque saepe.
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Co-host of "The Riding Obsession" sport-touring motorcycling podcast at tro.bike!Comment
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airbox is installed as well. I had the seat off on the last attempt to start it and flames shot out of the air box at me. I'm kinda scared to work on this thing now.Comment
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Backfiring out of the tailpipe sounds ignition or cam timing related.1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
1985 GS1150ES stock with 85 Red E bodywork.
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confirm that you have the coil leads in correct positions
prime the carbs before crankingGS850GTComment
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It really sounds like timing to me. I know you haven't touched your valve timing, but have you disturbed the contact breaker plate? It's getting an absolute gutful of fuel to back fire but it's at the wrong time, thus maybe timing. With a twin, you may have put the plug leads onto the wrong cylinder. Swap them over as you won't be any worse of than now and check. Go away and think about if you've missed something. It's not much, good luck eh.Comment
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Did the bike run before the work? To get a reference...Originally posted by Nick View Post
Describe "carbs and such"
Correct - fuel float needle valve(s), floats installed, and float height adjustment? Or were these replacement carbs from flea bay?
Pull (or replace with clear tubing) the fuel petcock vacuum line hooked to left carb and see if fuel is present...it should be dry at all times. If its wet, replace / rebuild petcock.Comment
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replace the plugs and try starting it again without using the choke at first.Comment
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I agree with CHEF. It really sounds like cam timing to me. We need some answers from you. Was the motor running before you put the new carbs on. If not go over everything. Check cam timing, ignition timing. Check wiring to coils and ensure correct HT lead goes to correct cylinder. The mixture is firing with the inlet valve open. Give us some history on the bike.Comment
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check the following...
1) pull the plugs and crank - is there a spark ?
2) is there fuel coming into the carbs.
3) blow in the two breather pipes on the carb (between 1 and 2, 3 and 4) and then crank.
4) Backfire could also mean lean mixtureComment
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The bike was running for me before the carb replacement. It was running off of one carb (the right side) for a while but now after I replaced the floats, needle valves, O rings, and intake boots. I pulled the plugs after a few cranks on the first attempt and they were wet and suity so I let it sit and i sanded / cleaned the electrodes and conductor on there and put them back in. After a few cranks an hour or so later some smoke came out of the left exhaust pipe which i thought was good because I know fuel was getting in there some how. I checked the carb bowls and their getting fuel. I dont think its cam related or timing. If it were the thing would have the same problems before, well atleast i think.Comment
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Most 450's are transistor ignition bikes & automatic cam chain adjusters....not much to go wrong, if they haven't been tinkered with.
However, with CV carbs:
How and to what height were the floats set?
"Needle valves" means the needle & seat, or just the needle?
Does your tank have any rust in it? What was the condition of the float valve screens and float bowls regarding sediment?
Did you check the carb slide diaphrams for condition?
What is the condition of the air cleaner?...I once put a shop rag under my seat to wipe the bike off and keep it clean, ran like a dog till I realized the bike needed air to breathe.
Has the bike ever had a valve check / adjustment?
I vote for RB's idea of new B8ES plugs...they're cheap. Like the owners manual says for troubleshooting, place the plugs on the side of the head & check spark quality. This will also allow you to dry out the engine...
Hope we're helping you
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