gsl65 Posted December 31, 2008 Report Posted December 31, 2008 I recently did a top end on my fairly stock Banshee (FMF Gold series w/Q-sparks, bored to 66mm & cut air box). It started second kick and ran great. I took it to the dunes, after a few day trips to my local riding area, and it ran very strong for the first hour or so. It stalled out. Every time I kicked it over it would fire but not run. I checked the plugs and they looked a bit fouled and kind of wet. I dried them off and it fired right up. I rode it back to camp and changed the plugs (BY THE WAY THE PLUGS LOOKED PRETTY GOOD AFTER THE RIDE BACK). After a short test ride everything seemed fine. It sat for about an hour and then when it started it was very boggy. I feathered the throttle and it seemed to clear up for a while. It did that off and on and then during one of the "boggy" times I heard a pop and then it cleared up and it seemed to run great until I noticed that there was coolant coming out of the overflow. I let it cool down completely and started it again. At first it seemed ok no fluid no bog but at high RPM's and a load (going up hill) coolant started spewing from the over flow. My first thought is a head gasket but it sure seems to run strong for a head gasket leak. It starts with one kick! I guess I have at least two problems, the bog and then the coolant out of the overflow. It's hard to believe that the head gasket would blow that soon after the top end rebuild. I don't know maybe the head is warped. What caused the head gasket to blow? Why the intermittent bog? Maybe the timing is off (I'm ignorant to the twin-cylinder 2 stroke. Is there even a way to set the timing)? I'm new to the Banshee world and so far am very frustrated with it! I did do a "down to the frame" refurbish so I guess I should expect a few problems. Ok, enough words! Please help!!!!!! Quote
Handyman Posted January 1, 2009 Report Posted January 1, 2009 There's no timing with the 2 strokes...just put together and kick and it should run....When you bored the motor did you rejet for the bigger bore and more air coming into the motor after you cut the airbox...running hot sounds like the jetting is off...The pop you heard could have been a back fire from a dirty carb..mine did that and it scared the shit out of me since I had my hand back by the pipe feeling the presure coming out of the exhaust...I'd check the jetting and go from there....I think the head gasket should be ok.. Quote
gsl65 Posted January 1, 2009 Author Report Posted January 1, 2009 Thanks the quick response! It doesn't seem like it was overheating because it would gush coolant at high RPMS while still cool. Do you have any suggestions on jetting (main. pilot and needle possition)? Quote
sleeper06 Posted January 1, 2009 Report Posted January 1, 2009 Thanks the quick response! It doesn't seem like it was overheating because it would gush coolant at high RPMS while still cool. Do you have any suggestions on jetting (main. pilot and needle possition)? Did the pop u heard sound like a lean pop, if so could be lean,but thats not why its spewing fluid cold,whats your set up Quote
gsl65 Posted January 1, 2009 Author Report Posted January 1, 2009 Did the pop u heard sound like a lean pop, if so could be lean,but thats not why its spewing fluid cold,whats your set up The sound was more of a gush. It didn't sound like a backfire (not very loud). I find it hard to describe. I don't know what a lean pop sounds like. FMF Gold series pipes w/Q-sparks bored to 66mm cut air box (about 1.5"x3"-I got it that way) I think the main jets are 280 I don't kmow what the pilot jet is or how the needle jet iis set. Thanks for your help! Quote
AKheathen Posted January 2, 2009 Report Posted January 2, 2009 welcome to the hq :thumbsup: did you re-torque your head after a couple of cycles?. your radiator cap could be bad, and the float needle(s) could be leaking or need adjusted. you probbably loaded up with fuel a few times, and that pop was fuel igniting in a pipe. also, did you set the pickup gap @ 16-20? Quote
gsl65 Posted January 2, 2009 Author Report Posted January 2, 2009 welcome to the hq :thumbsup: did you re-torque your head after a couple of cycles?. your radiator cap could be bad, and the float needle(s) could be leaking or need adjusted. you probbably loaded up with fuel a few times, and that pop was fuel igniting in a pipe. also, did you set the pickup gap @ 16-20? I did not re-torgue. Oops! I'm going to pull the head off this weekend to see what's up. I tried the radiator cap from my bike and had the same problem. I picked one up today just in case. I didn't think about the float needle(s). I probably take the carbs apart for a good cleaning. I'll also check the pick-up gap. I haven't had the side cover off yet. Thanks a lot for your input! Quote
gsl65 Posted January 3, 2009 Author Report Posted January 3, 2009 (edited) I did not re-torgue. Oops! I'm going to pull the head off this weekend to see what's up. I tried the radiator cap from my bike and had the same problem. I picked one up today just in case. I didn't think about the float needle(s). I probably take the carbs apart for a good cleaning. I'll also check the pick-up gap. I haven't had the side cover off yet. Thanks a lot for your input! I pulled the head off and saw that the head gaskets is blown. Does anyone have suggestion about the type of head gasket to buy or are there any installation tricks? Edited January 3, 2009 by gsl65 Quote
pitkendall Posted January 3, 2009 Report Posted January 3, 2009 i went through the same thing a while back after askin on here and a few other people this is the suggestions that worked for me thanks HQ 1. torque the head in 3 or 4 steps and after u reach final tourqe go back around and test to see if any backed off a lil 2. fill radiator with coolant and only put the cap on to the first click so the pressure can get out if need be just to let it burb the air bubble out shouldnt take but a minute or so 3. start and let it run till it warms up shut it off let it cool and retourque the head 4. take it for a ride 20 30 minutes or so turn it off and cool and retourque the head again 5. go out and BEAT THE CRAP OUTTA IT LIKE BANSHEE"S LOVE LOL thats what worked for me i also got some bad tips ranging from coat the head gasket with indian head gasket sealer or spray on copper seal doesnt work and makes a big mess for u when u gotta replace the dang thing again LOL also u gotta make sure u have it the right way up most gaskets have it marked and use good quality gaskets GOOD LUCK Quote
gsl65 Posted January 3, 2009 Author Report Posted January 3, 2009 (edited) i went through the same thing a while back after askin on here and a few other people this is the suggestions that worked for me thanks HQ 1. torque the head in 3 or 4 steps and after u reach final tourqe go back around and test to see if any backed off a lil 2. fill radiator with coolant and only put the cap on to the first click so the pressure can get out if need be just to let it burb the air bubble out shouldnt take but a minute or so 3. start and let it run till it warms up shut it off let it cool and retourque the head 4. take it for a ride 20 30 minutes or so turn it off and cool and retourque the head again 5. go out and BEAT THE CRAP OUTTA IT LIKE BANSHEE"S LOVE LOL thats what worked for me i also got some bad tips ranging from coat the head gasket with indian head gasket sealer or spray on copper seal doesnt work and makes a big mess for u when u gotta replace the dang thing again LOL also u gotta make sure u have it the right way up most gaskets have it marked and use good quality gaskets GOOD LUCK Thanks for the info. That's where I screwed up. I didn't retorque after the initial rides. I used a Wiesco gasket since it came as a set with the pistons. Do you have any other gasket brand or type suggestions? Edited January 3, 2009 by gsl65 Quote
pitkendall Posted January 4, 2009 Report Posted January 4, 2009 well of course a yamaha gasket is good but pricey also i had good luck with cometic on an old 250r i had and suprisegly the last one i put on my banshee was the only one in town and its a namura it seems to be doig good but on gaskets id ask an engine builder like FAST or any outher site sponsor they have built thousands of motors im sure they have more experince in the long term results Quote
AKheathen Posted January 4, 2009 Report Posted January 4, 2009 first off, never put anything on a head gasket, install dry only. adhesives may sound good, but actually work as a lubricant under high pressure where you want a friction seal. personally, i am partial to MLM type gaskets, which provide perminant rebound and compression. i have heard some on here using copper gaskets, but they occasionally remove head, and it can be reused. yamaha has a reliable one, but make sure the surfaces are square Quote
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