Leadfoot350 Posted December 2, 2003 Report Share Posted December 2, 2003 I changed my stock quad over the summer so I can beat some of my friends 250r atcs. I went to these mods, t-5s, v force, +4 timming, ted boyko ported cylinders, 2-1 35 carb, 18cc domes and thats about it I think. The first trip out at glamis the quad ran great just some gearing problems. When I got home I wanted to make sure the comp was still 140 and when I took out the plugs the right side plug's tip was burned off and the white porsilin was gone and fell into the motor and messed up the bore and piston and dome. I got the top end redone and tried again not knowing why this happend. Well I went to glamis last weekend and I even went from a 180 to 188 main and put the neddle one down as well. It ran great again if not better but when I was looking at the plugs again tonight the right plug again was fucked up. I run half 110 and 91 with 927 at 37 to one ratio. I need to buy more pistons and get it rebored again. I need help this is costing me 180 bucks each time and I am already at 40 and will have to go to 50 over and I dont want to go to a big bore when I resleve it. Why is it only one side that is doing this???? and why is it doing this? Quote Link to comment Share on other sites More sharing options...
frocashmoney24 Posted December 2, 2003 Report Share Posted December 2, 2003 if its burning and melting it off its preignition. but thats all i know Quote Link to comment Share on other sites More sharing options...
fixitrod Posted December 2, 2003 Report Share Posted December 2, 2003 Have you checked the flywheel side to make sure your stator isn't loose or your key has sheered allowing the timing to shift. What comp and timing are you running? What elevation? What size domes? Sounds like to high of compression, lean jetting, bad fuel, or timing trouble. Quote Link to comment Share on other sites More sharing options...
boonman Posted December 2, 2003 Report Share Posted December 2, 2003 Detonation my friend. What octane were you running? HEat range on the plug? Squish band incorrect? All these things play a factor here.... Quote Link to comment Share on other sites More sharing options...
Leadfoot350 Posted December 2, 2003 Author Report Share Posted December 2, 2003 I am running half 110 and half 91 with comes out to 100.5 octaine at sea level or glamis level what ever that is. The domes are 18 the timming plate is set at +4 the plugs are ngk b8es at 30 gap. The other piston is fine again and I want to know why only one piston side is having the spark plug burn up? Could it have anything to do with the trinity 2-1 carb? WHY ONLY ONE SIDE??????????????? Quote Link to comment Share on other sites More sharing options...
SDD Posted December 2, 2003 Report Share Posted December 2, 2003 Check for air leaks on the side that burned up. Do a leak down test to make sure your not leaking any fluids through the seals. Quote Link to comment Share on other sites More sharing options...
Leadfoot350 Posted December 2, 2003 Author Report Share Posted December 2, 2003 do you guys think that I am not running high enough octaine? does anybody else have a ported motor with 18cc domes and +4 timming that runs at glamis or sea level? Quote Link to comment Share on other sites More sharing options...
fixitrod Posted December 3, 2003 Report Share Posted December 3, 2003 Since it is ported you will have to check with your builder on the dome size. Sounds like an air leak to me too. It could be a crank seal if everything on the outside looks good. Do a vacuum test to make sure like boonman suggested. Quote Link to comment Share on other sites More sharing options...
Leadfoot350 Posted December 3, 2003 Author Report Share Posted December 3, 2003 I dont have a vacum tester and dont even know where to get one or how to use it. It idles good and revs clean and revs back down fine as well. Quote Link to comment Share on other sites More sharing options...
boonman Posted December 3, 2003 Report Share Posted December 3, 2003 What is the squish? There could be a problem with that cylinder. BEing that it is the right cylinder, that pretty much eliminates a crank seal, because it would be sucking oil from the tranny. You would know it, it would be smelling like crap. You could have an air leak at the intake, base gasket, or both. I had a leak in the intake boot on the right side once..... Couldn't even find it on a 7" leakdown. Anyways, go to the local parts store, (automotive) and they will have mityvacs there for brake bleeding purposes. This is what you need to do the leakdown test.. Quote Link to comment Share on other sites More sharing options...
Wheatchex Posted December 3, 2003 Report Share Posted December 3, 2003 Since you have a single carb, and you are saying that the left side is ok or at least implying that its ok, your jetting should be fine. If the octane was too low you should be seeing the same problem with the left side as well as the right. So now we've eliminated two potential problems although the jetting may need to be dialed in better once the problem is solved. Anyway, this leads us into finding out why your right side cylinder is running lean which would explain the melted electrode and fractured insulator. Since the left side is "ok" there has to be an air leak some where after the carb and the carb intake junction. Check all the junctions between the intake and the cylinder. Another potential problem area is the cylinder base and case junction. Have you had the cases apart? If so there could be a problem with the seal between the case halves on the right hand side. I don't think the crank seal is the problem as someone else correctly pointed out you would be drawing transmission oil into the right side. Have you checked the head for a good seal? Also what did the engine builder reccomend you jet at for your particular engine set up? Hopefully this helps. Wheatchex Quote Link to comment Share on other sites More sharing options...
fixitrod Posted December 3, 2003 Report Share Posted December 3, 2003 ***EDIT*** What I had here was already mentioned by bonnman.. Quote Link to comment Share on other sites More sharing options...
Nightrider Posted December 3, 2003 Report Share Posted December 3, 2003 So far this is what we've figured out... Obviously if its only from one side,then you can eliminate the carburators. You can also rule out ignition timing and octanne issues.If only one cylinder is being affected. Plug heat range shouldn't be a factor if the other plug is totally normal. If it was a seal leaking,it would be sucking tranny oil. Which leaves two possible things...Air leaks? And possibly a bad port job.What exactly did he do to the cylinders?I'm not 100% sure,but port timing might have some effect.Unless somebody can rule it out. With 18c domes,I would be running the b9's instead of b8's.I always run the colder plugs anytime I add timing or compression.Better safe than sorry.A colder plug will transfer that heat away from the electrode faster. Quote Link to comment Share on other sites More sharing options...
Leadfoot350 Posted December 4, 2003 Author Report Share Posted December 4, 2003 I remember that harry at trinity said not to use the orings on the 2-1 carb manifold becuause they did not work with the v-force reeds. His new cv manifold now is able to use v-force reeds. I did not use them and instead used the gaskets that came from the wiseco kit and in addition used black silicone. Everything on the motor is torqued down very precisly so that is not an issue. I might be leaking air at the bottom on the right side base gasket for the cylinder. Could I be leaking from the case halfs? The head does not leak air because it does not leak anti freeze. I aggree with running colder plugs so next time I will do that. Ted Boyko did the porting and added bost ports and did the transfers and everthing in a dunner style port. I took my cylinders to port magic last time because I called mission yamaha and they wanted 150 bucks to bore them out and Rudy only wanted 60. Rudy said that he has seen the wildest dirtiest ports out there and that he can most likely rule mine out as being the problem. He said mine were mild. He recomended that I get another 35 pwk and get rid of that 2-1 set up. He said the only guys that run those are the trinity guys and you loose a lot of top end. I was going to get 28's but I ride full throttle in glamis only so I dont really need that much bottom end. In the future I would like to go to either a 4 or 7 mil stroker and the 35's should be perfect for that motor. Quote Link to comment Share on other sites More sharing options...
BaddestBanshee Posted December 4, 2003 Report Share Posted December 4, 2003 When you installed those domes, did you make sure they were both 18cc domes? Are you sure that was a 4 degree key? Are you sure that key was installed correctly? Did you check the piston to head dome clearance (squish)? What gaskets did you use on the base of the cylinder on the rebuild? What spark plugs are you using? How are you performing this compression test? Where did you get these base jetting specs? Lay out a list of what is happening with the motor. State the FACTS about what parts you have. We then can list the possible problems causing meltdowns. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.