Quote:
Originally Posted by garth285
Well I started having this issue when I started to tune the bike and I Thought it was possibly a bad ecu but I verified its not, now a while ago I tried just free revving the bike in neutral to see how high the RPM's are going, it was only going to about 10k rpms but that was with the turbo charge pipe hooked up. Now what I did recently was remove the charge pipe and put a N/A map in the bike and free revved the engine, well it went to 10k in a heart beat but it was slow to rev from 10 to 13k.
Motor is BONE STOCK, stock cams, stock compression.
I am thinking two things, 1 I do not know if this engine has ever been into. I wonder if someone jumpped a tooth on the timing, that will be easy for me to figure out.
But what I am concerned with is the TDC mark on the flywheel, I am wondering if they match up on the 300's to the 250's. Wondering if its throwing things off possible.
I wont be able to dig into my motor until later this week so wondering if anyone can compare the 250 and 300 flywheel if the keyways match to the TDC on both.  |
like I told you, carbed 250's has different "reading" positions, however it can't have different marks since cams (lift and duration) and cam timings are identical for all (250 FI,carbed and 300)... I used my '09 Fi 250's flywheel on my 300 new engine after verifying they are identical...
If I am not mistaken it is the crank position sensor that is placed in a different position on the carbed models so if you have kept the carbed 250's side cases it could potentially be an issue
In any case, if you've left the compression stock (which is fine, however a bit high for a turbo setup even if you keep it low boosted) cam timing can be ok but not 100% certain of optimum result...
what is certain though is that with stock comp and even some low turbo boost it is imperative you retard advance timing because -as you probably know- it creates a sometimes soundless pinging/pinking etc which eventually will blow a hole in the piston top... do you recall the turbo busa project of an American magazine which took as guideline a '00 bike that had been turboed with stock comp too, by some tuners and just because they used a '03 bike, which had different advance timing ecu map, suffered the same problems you are encountering until they managed to blow through one piston, melt the rest of them and then realized what needed to be done ?
please Shawn, take very much care on advance timing, any kind of boost requires at least 2* less advance...if that is stock too, it is most probably the root of the problem...