shellbyzfan33 Posted March 16, 2004 Report Share Posted March 16, 2004 i just installed a cool head with 17cc domes on my 01 shee. i did a compression test and after about 8 tries on each cylinder it stoped at 206 5 out of the 8 times on each. so i mixed 2 gallons of 116 octane with 2 gallons of 93 octane and mixed it maybe a little lean? now all it does is backfire when i twist the throttle??? does anyone have any suggestions??? thanks Quote Link to comment Share on other sites More sharing options...
sredish Posted March 16, 2004 Report Share Posted March 16, 2004 i just installed a cool head with 17cc domes on my 01 shee. i did a compression test and after about 8 tries on each cylinder it stoped at 206 5 out of the 8 times on each. so i mixed 2 gallons of 116 octane with 2 gallons of 93 octane and mixed it maybe a little lean? now all it does is backfire when i twist the throttle??? does anyone have any suggestions??? thanks If I were you, I'd run straight race fuel, skip the half and half shit with 200+ psi. What are your other mods, elevation, airbox setup and what are the jets your running now? It probably is lean. Quote Link to comment Share on other sites More sharing options...
Toomey Banshee Posted March 16, 2004 Report Share Posted March 16, 2004 Agreed, straight race fuel. 200+ is a huge compession #. I hope your crank is welded. As far as the backfiring goes, I assume you have your parking brake disconnected, if not that may be the problem. Back to the compression, try bringing that down a bit, try some 19's. It will be more reasonable to tune and your motor wont wanna jump outta the frame. Quote Link to comment Share on other sites More sharing options...
shellbyzfan33 Posted March 16, 2004 Author Report Share Posted March 16, 2004 yeah i think i need to rejet it or jet it period??? as for mods it's bored .075 over, fmf pipes and silencers ,and the cool head. it's got the pro flow air intake , no airbox lid. why would the parking brake have an effect on it backfiring? straight race fuel wouldn't hurt it??? how much oil per gallon should i mix with it??? Quote Link to comment Share on other sites More sharing options...
MotulMonsta Posted March 17, 2004 Report Share Posted March 17, 2004 Straight race fule won't hurt. Mix it at 32:1 and see how it runs..Does it run better with the choke on?? If it does your running lean Quote Link to comment Share on other sites More sharing options...
Toomey Banshee Posted March 17, 2004 Report Share Posted March 17, 2004 The parking brake is an electrical nightmare. Follow the wires from the parking brake under the tank and disconnect it, dont think twice about it. My 99 was running like shit over the summer, backfiring, bogging, I took my carbs apart several times, cleaned them, rejetted and it would stop and then all of a sudden it would just freaking backfire. Drove me nuts. In the pit one day I just disconnected the sucker and it ran like it always did, strong. Again, back to your compression, bring her down hombre, too high is not alway that good. I run 17's in my 94 but its ported and polished, which lowers the compression a bit. As far as mix, I run, as well as a good portion of us in here a mix ratio of 32:1. Some more, some less. That has worked for me. Jetting is a totally differnet issue, MANY variables, elevation, temp., mods, pipes etc. Trial and error. Read your plugs, let us know how they look and we can help. Good luck. Quote Link to comment Share on other sites More sharing options...
Blacksmith Posted March 17, 2004 Report Share Posted March 17, 2004 I have had a bike run pretty good with 215 psi on avgas, but it takes a lot of fuel to make it work. I feel pretty sure that you are lean. Pump up that main jet. Quote Link to comment Share on other sites More sharing options...
ledofthezep Posted March 17, 2004 Report Share Posted March 17, 2004 yeah i think i need to rejet it or jet it period??? Whichever you prefer. What's your current jetting look like? If you rev it up & hit the kill switch, what's your plugs looking like? Quote Link to comment Share on other sites More sharing options...
shellbyzfan33 Posted March 17, 2004 Author Report Share Posted March 17, 2004 yeah i think i need to rejet it or jet it period??? Whichever you prefer. What's your current jetting look like? If you rev it up & hit the kill switch, what's your plugs looking like? i got a 280 main jet. have not looked yet too see where the e-clip is on the needle. rev- kill plug is a little wet and little black? was i supposed to keep the throttle twistwed even after i hit the kill switch??? Quote Link to comment Share on other sites More sharing options...
boonman Posted March 17, 2004 Report Share Posted March 17, 2004 Don't worry about your parking brake. I see from your pic that you have a TORS removal kit. I just hope that you unplugged the TORS module under the tank adjacent from the coil. Your jetting sounds lean, but this depends on your elevation and temp. I'm thinking wround 310 or 320 at least to start with. Especially with no lid. And you need straight race fuel, no doubt about it with that kind of compression. Trust me, it ain't worth the risk of blowing a hole in the piston. That's alot of compression to be running as well. I would seriously consider bumping that down.. Now, You also say .075" bored over. That is a number I have never heard of before. Who did the boring, and what kind of pistons are in it? Also, check the connections at the coil. (the orange wire, and the black wire). Quote Link to comment Share on other sites More sharing options...
brugal Posted March 17, 2004 Report Share Posted March 17, 2004 What kind of oil do you use? Quote Link to comment Share on other sites More sharing options...
sredish Posted March 17, 2004 Report Share Posted March 17, 2004 and we need to know more about the girls in your avatar... Quote Link to comment Share on other sites More sharing options...
shellbyzfan33 Posted March 17, 2004 Author Report Share Posted March 17, 2004 it's bored closest to what i said it is. it might be like .070 over. i live right on lake erie as for elevation. i just redid all the wiring cause it stalled out when i hit some water so i went over the whole wiring harness and taped it up and checked all my connections. now i'm all worried about blowing the motor cause of what everyone is saying about too much compression? i run motull and caster which ever i can get my hands on. as for the hottie's in my avater , their my bitches . no just kidding the one doing the sucking is my wife and the other is well we just call her a close friend she is also the girl on the far right in this pic---http://sites.webcreators.net/lbz2001/images/indy13.jpg Quote Link to comment Share on other sites More sharing options...
sredish Posted March 17, 2004 Report Share Posted March 17, 2004 Lucky man there. Quote Link to comment Share on other sites More sharing options...
boonman Posted March 18, 2004 Report Share Posted March 18, 2004 Lake Erie. I live near the lake as well. Just south of Buffalo. I'm at about 800'. So, I assume you are about the same.... I am still thinking around 320 to start on the main. And a 27.5 pilot... Quote Link to comment Share on other sites More sharing options...
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