should always pressure test before a teardown to find out if seals are bad. how much alcohol did you put in. that will lean it out. nasty stuff! should use a sock to absorb water. its hard to find a good gas station that takes care of their tanks. selfserves are the worst!
Sorry took so long to get back to you, I kinda get into too many troubleshooting post at 1 time and I forget to look for updates. Kinda hard to remember everyones post.
You are correct and have stock uncut heads, so they are ok, oilpump gap is ok, so bleeding the pump will need done as you mentioned, the pulse line to the fuel pump should be replaced with yamaha stock hose.
So the cylinder that went was the ported one but yet you had a stock main jet and needle setting on that cylinder, am I understanding this correctly?
BTW_ most burndowns occur on the needles and not the main jet, most think that with big mains it wont burn down but the mid range is where 80 percent of all piston squeeks happen.
You are correct and have stock uncut heads, so they are ok, oilpump gap is ok, so bleeding the pump will need done as you mentioned, the pulse line to the fuel pump should be replaced with yamaha stock hose.
So the cylinder that went was the ported one but yet you had a stock main jet and needle setting on that cylinder, am I understanding this correctly?
BTW_ most burndowns occur on the needles and not the main jet, most think that with big mains it wont burn down but the mid range is where 80 percent of all piston squeeks happen.
Thanks for the info on the heads.Yes the stock mains and neddle settings were/are back in the carbs and I understand about the neddle jet governing the fuel flow at mid throttle so I think to be safe I'm going to set my e clip down one notch and see what kind of readings I get on the plugs.
I saw a pic on ebay for an SRX engine that had a burndown pretty well identical to mine with detonation around the ring landing but the center of the piston looked untouched and the cause listed for that one was running out of oil.I'm thinking that my oil pump being air locked caused mine because my crank seals looked good and the reed gages seemed sealed tight.I dont know how to tell if the base gasket was leaking but I didn't notice anything out of the ordinary,no antifreeze present or oil from pressure blowing out.
I saw a pic on ebay for an SRX engine that had a burndown pretty well identical to mine with detonation around the ring landing but the center of the piston looked untouched and the cause listed for that one was running out of oil.I'm thinking that my oil pump being air locked caused mine because my crank seals looked good and the reed gages seemed sealed tight.I dont know how to tell if the base gasket was leaking but I didn't notice anything out of the ordinary,no antifreeze present or oil from pressure blowing out.
YAMAHIZAL700
New member
I may be in the same boat as you so Im learning as well but you still may have a bad crank seal. It wont blow out oil but instead suck it in thats why a can of eather or carb cleaner will make the engine idle higher sort of like giving it more gas. I still have my motor together so Im going to put the pipes back on and try a leakdown test.fourbarrel said:
98 only
98s hand the cranks pressed together but not tack welded,they would turn on the pins and put the cylinders out of time with eachother. this would usually make handlebars viberate, foul plugs and pop back through carbs on start up. check that reeds are not burnt from popping back. also check thermostat, cooling system totally bled and water pump impeller is still on shaft,they were pressed on and would fall off. plugged exhaust pipe or can,mice are great!! overheating will do strange things. most places will tell you you didnt store it properly and there was rust on crank,if so all those crank parts come up the transfer ports and mess up the pistons.what ever you do have crank timed and spot welded so it does not move if its rebuildable, a new one should come welded. these are all problems i have come across some may sound stupid but those are the hardest ones to find .
may help , may not.
98s hand the cranks pressed together but not tack welded,they would turn on the pins and put the cylinders out of time with eachother. this would usually make handlebars viberate, foul plugs and pop back through carbs on start up. check that reeds are not burnt from popping back. also check thermostat, cooling system totally bled and water pump impeller is still on shaft,they were pressed on and would fall off. plugged exhaust pipe or can,mice are great!! overheating will do strange things. most places will tell you you didnt store it properly and there was rust on crank,if so all those crank parts come up the transfer ports and mess up the pistons.what ever you do have crank timed and spot welded so it does not move if its rebuildable, a new one should come welded. these are all problems i have come across some may sound stupid but those are the hardest ones to find .
may help , may not.
nystateboySRX
New member
I didnt read the whole thread but is there any slop on the rod?