kyleag89 Posted October 7, 2010 Share Posted October 7, 2010 Ok guys I got an 86 Bayou 300 to play around with. I cleaned the carb but all it does it backfire through the carb. I mean this thing literally blows a flame from the intake boot. What would cause this? Link to comment Share on other sites More sharing options...
beaterheep Posted October 7, 2010 Share Posted October 7, 2010 timing is off, if i remember right those are a 2cyl?? clean the plug, make sure all your grounds are clean and tight, i believe the cdi box controls the spark on those?? Link to comment Share on other sites More sharing options...
kyleag89 Posted October 8, 2010 Author Share Posted October 8, 2010 It is a single cylinder 4 stroke motor. I was thinking the timing must be off after messing with it for awhile today. Looks like I will need to invest in a repair manual so I can time it properly. :fs1: The spark is great and all the grounds are good, it also has a new batt and starter. Link to comment Share on other sites More sharing options...
JACKED88 Posted October 8, 2010 Share Posted October 8, 2010 Popping back through the carb does sound like a timing problem. Being an 86 model and no telling how many hours are on it or how it was ridden, I'm thinking worn/stretched timing chain. As you may know, when the chain gets worn and stretched it will start causing excessive wear to the timing chain gears. Once that happens it is very possible for the chain to slip a few teeth making the crank and cam to be out of time. Only way to check it will require taking a few things of the motor. First being the valve cover and the second being the left side cover exposing the stator and rotor assembly. 1. Rotate crank to top dead center. The key way on the crank shaft should be pointing up. (you'll have to remove the bolt in the end of the crank shaft to see it) 2. Remove valve cover and check cam position. There should be a mark on the cam gear that also should be pointing up. Both cam lobes should be pointing down. 3. If none of the above line up properly, the timing chain is most likely stretched to a point where it jumped time. (slipped a few teeth either on the crank or the cam gear. If thats the case, replace the chain, cam gear, and both chain slippers. Here, this might help ......... http://www.kawasakipartshouse.net/pages ... KgoddlaTDg There is one other thing that can cause the timing to be off. That being the key in the key way for the crank shaft and rotor assembly has sheered. Again you'll need to remove the bolt out of the end of the crank shaft to see the key way on the crank and rotor. If they are not in line with each other you have found your problem. Remove the rotor assembly and replace the key way key. BTW .... There is no adjustment for the ignition timing. Only the cam to crank shaft timing or a sheered key way key can cause a timing issue. WAIT!!! HAVE YOU DONE A COMPRESSION TEST??? You could have a stuck intake valve. That or one thats staying open a little due to being out of adjustment. (too tight) Remove the two screws holding the intake rocker arm cover and check your valve lash. Link to comment Share on other sites More sharing options...
kyleag89 Posted October 8, 2010 Author Share Posted October 8, 2010 Thanks! That helps a lot. I did do a compression check and it held a steady 122psi. I also adjusted the valve lash to I think 0.05 which was only a hair looser than what they were already set at. The guy I bought it from(original owner off a PA farm) just installed a new starter. So he may have messed up the timing when he installed it. Maybe he took the flywheel off and put it back on wrong. :dunno: Very possible Link to comment Share on other sites More sharing options...
JACKED88 Posted October 9, 2010 Share Posted October 9, 2010 Compression sounds good and your valve lash should be OK. If the pre-owner pulled the rotor assembly its possibly that he didn't get the key way key in properly. As a result allowing the rotor assembly to slip on the crank shaft causing the ignition timing be off. Remove the rotor assembly and be sure the key was first re-installed and second re-installed properly. You should have that thing running in no time. Have fun!!! Link to comment Share on other sites More sharing options...
kyleag89 Posted October 9, 2010 Author Share Posted October 9, 2010 Thanks I will mess with it Monday and let you know. Link to comment Share on other sites More sharing options...
kyleag89 Posted October 12, 2010 Author Share Posted October 12, 2010 Timing was correct but I found out my idle speed screw was damaged!! So I got the new one today and she fired right up and runs great. I now have a new problem, the gas tank is leaking from a couple small pin holes. :fs1: Link to comment Share on other sites More sharing options...
freakjeep93 Posted October 12, 2010 Share Posted October 12, 2010 is it a metal or plastic tank. on my 93 bayou its plastic. so you could likely plastic weld it. Link to comment Share on other sites More sharing options...
kyleag89 Posted October 12, 2010 Author Share Posted October 12, 2010 It is metal, so I will prolly just use some gas tank repair putty from Autozone for now. The holes are literally the size of a pen tip but leak enough to make a mess. I was thinking about maybe brazing them for a more permanent fix, but I'm afraid of the thing blowing up from fumes. Anyone have any input on that? Link to comment Share on other sites More sharing options...
JACKED88 Posted October 13, 2010 Share Posted October 13, 2010 I was thinking about maybe brazing them for a more permanent fix, but I'm afraid of the thing blowing up from fumes. Anyone have any input on that? Drain the tank, fill and rinse with water a couple of times. It'll still smell a little gassy but it aughta be good to go. (test leaks with water in case you have to do um again) You mean to tell us all that flame throwing was just the idle screw??? :shake: I've never seen an idle screw make an engine backfire and throw flames out the carb. Oh well ..... glad to hear its running. Link to comment Share on other sites More sharing options...
kyleag89 Posted October 13, 2010 Author Share Posted October 13, 2010 Yeah me either that's why I expected to find a damaged valve or bad timing. My best guess is that maybe the floats were set to high and let a little too much gas in the head allowing it to pop and flame. So do you think I should use a brazing rod I have for HVAC pipe? I know this rod melts at around 1200 degrees. Link to comment Share on other sites More sharing options...
JACKED88 Posted October 13, 2010 Share Posted October 13, 2010 1200 is pretty hot. Keep in mind your gonna have to get the thin walls of the tank close to the same temp for the rod to stick. If your tank has pin holes that means its probably rusting from the inside out. If thats the case your likely to burn an even bigger hole in it. IF .... you could find some, this is what I used to repair pin holes in a 40 gallon built in tank in one of my boats. http://www.amazon.com/Bondo-Marine-Epox ... B0009LPISE That stuff is great!!! Its impervious to gas and still holding after years of pounding waves in the Gulf of Mexico. Problem is I can't find it anymore. :headpop: I used a disc grinder and cleaned the entire bottom and about 3 inches up the sides of the tank. The grinding disc did a great job of not only cleaning it but also made the surface rough enough for the epoxy to adhere to it better. I then mixed the epoxy and painted it on. Then I covered the bottom and up the sides with fiberglass mat. Once matted I painted on enough epoxy to soak the mat completely. Once it hardened it was done. Trust me when I tell you out in the gulf is no place for fuel to be leaking into the bilge of your boat. That sh-t works. Short of finding some Bondo 2 part Marine Epoxy epoxy ..... try one of those 2 part epoxies you find in self measuring tubes at the hardware store. Just be sure to find one thats impervious or at least says its resistant to chemicals/gas. If you prep the area properly one of those aughta work fine. You could also try Permatex fuel tank repair. http://www.permatex.com/products/automo ... Repair.htm Other than JB Weld (in which I've used with some success) I don't really care for putty type repair products. Putty can't get into the pores of the metal like a liquid can. Link to comment Share on other sites More sharing options...
kyleag89 Posted October 14, 2010 Author Share Posted October 14, 2010 Have you tried West Marine for the epoxy you can't find anymore? I bought some patch kit there before for a Jet Ski and it was the best product I ever used. Link to comment Share on other sites More sharing options...
kyleag89 Posted October 14, 2010 Author Share Posted October 14, 2010 Check this out, I used this before it works awesome. I didn't even think of it until you mentioned the epoxy. :doh: http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=11249&catalogId=10001&langId=-1&storeId=11151&storeNum=10104&subdeptNum=10296&classNum=10300 Link to comment Share on other sites More sharing options...
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