Hey guys i just bought a 98 blaster, motor is fresh with a hot rod crank n wiseco pro lite piston stock bore stock stroke with an fmf fatty and vforce reeds. The thing runs great, but when i get up around 7000 rpms (rough guess) the motor flattens out it does not want to rev any higher under a load. If i stay in the gas it will stay at that rpm and jump up some rpms then fall back down to 7000 in whatever gear im in. At first i thought it was a little lean and it was starving for fuel at high rpm but the jetting was good. Plug was dark grey/light brown not dry but not wet. Strap was dark grey all the way across .030 gap. 32:1 mix. To me im thinking ignition box, thoughts?
7000 rpm gets flat??
- Thread starter Jheff29
- Start date
No I am not. I am say you are probably over revving it. The power is fading off and you don't know what rpm you are at.
I'm with Jimmer.
Even the FMF Fatty doesn't take a Blaster very high in the rpm realm.
That pipe is all that is building power in that poor little 17hp engine and the airbox is strangling it.
Get a good rechambered head on it and open up the airbox a bit to get it screaming.
That might get you another 10hp and 1000rpm.
Even the FMF Fatty doesn't take a Blaster very high in the rpm realm.
That pipe is all that is building power in that poor little 17hp engine and the airbox is strangling it.
Get a good rechambered head on it and open up the airbox a bit to get it screaming.
That might get you another 10hp and 1000rpm.
Its the fmf pipe that is making the motor act like that.they make their power in low to mid range of the powerband and at about 7500 rpms it falls on its face like you said. If you look at any exhaust dyno chart comparison for the blaster with fmf, it shows it dipping in the upper rpm sooner then any other pipe even the stock exhaust .a better pipe and porting can get these engines rev up past that
this Toomey pipe never stops pulling
best left bend mid/top end pipe made
http://www.blasterforum.com/threads/toomey-full-exhaust.65629/#post-799593
My son and I actually have had fair luck with FMF pipes.
Pipes tune for an rpm band, how high do you want to run it?
Tuned for higher rpm means less power at lower rpm and often means peaky and short life.
The thin windowed piston skirts don't like running much over 8500 rpm.
I'll take a fat mid-range over a narrow peak hp any day, unless you are actually racing.
We can't keep these machines at the peak rpm all the time, and don't run it there on the trail.
Don't go too crazy on the porting, let the carb breath, and get a good head on it.
Compression helps low end torque (but don't go crazy here either), head squish and shape help to run it.
Pipes tune for an rpm band, how high do you want to run it?
Tuned for higher rpm means less power at lower rpm and often means peaky and short life.
The thin windowed piston skirts don't like running much over 8500 rpm.
I'll take a fat mid-range over a narrow peak hp any day, unless you are actually racing.
We can't keep these machines at the peak rpm all the time, and don't run it there on the trail.
Don't go too crazy on the porting, let the carb breath, and get a good head on it.
Compression helps low end torque (but don't go crazy here either), head squish and shape help to run it.
Well i guess i wasnt expecting the power to drop off that early. I race micro sprints and we utilize a 93-01 cr250 stroked out billet cranks are standard, no clutch, light weight clutch hub high compression interchangeable domes on alcohol. And this is the only power ive ever been used to for 9 years so in hindsight i guess it makes sense why i feel such a difference lmfao a built blaster has always been my dream quad for some reason. I expected it to rev to the moon like my race motors lol i guess it is something i just have to get used to. Im used to power bands being at 9200 to 9700 depending on what pipe i have on. I will still mod this blaster up for sure and just get used to the lower power band i suppose. I just thought something was wrong when i hit that rpm and it was such a severe halt. Ive never felt anything like that before i thought something was wrong haha
It is quite easy and cheap to get over 30hp from a Blaster engine.
With their small size and light weight this brings an exciting ride.
My son has built a couple Blasters that run up to the 9000 rpm mark, hard on pistons and cranks.
I have a stroked and bored Blaster with no other mods besides an FMF pipe.
Power is only around the 25hp mark and rpm still drops off quick.
Feels dead compared to my KTM 250 powered Blaster. Work needed!
Just bought another stock Blaster, wow, I know what you mean. Pretty dead.
Hope is here good buddy! Very easy to perk these up.
Steve
If your are used to the higher rpm than get a higher rpm pipe. Make sure who is porting it ports it accordingly to what pipe you end up wanting to go with. High rpm/ top end porting isnt going to help with a mid range fmf pipe. Open airbox up, lil head work, decent porting, and a good pipe and you should be happy. It doesnt take much but a few mods "working together" to wake thse lil things up.
Thank you guys for all the responses, im hoping to have this thing somewhat mx ready come february. There is an indoor mx event at summit in tallmadge ohio and id like to give it a wing. Im pretty much still at square one. But ill be posting before and after stuff in the coming months. As long as they can find a class for me to run in. As far as pipes i was going to check out that dyno comparison, figure on which pipe i want send the jug to dby of course with the reedcage/pipe/carb info. I just removed the tors system last night, going to ride her once more sunday then do all the suspension/engine mods. I love this thing
Here is a pipe shoot out link with dyno just incase you cant find one.
http://www.blasterforum.com/threads/pipeshootout-from-1996-with-dyno.39519/
http://www.blasterforum.com/threads/pipeshootout-from-1996-with-dyno.39519/
