My son races a Blaster we finished 3rd in points for the season. I dont know what else i can do to get more out of it. Worked raptors smoke us. A raptor can be worked to a 300cc and a Blaster cant be over 200cc. As for the motor we are running a factory seven Fire Breather cylinder 34mm keihin pj carb with f7 airbox vforce reeds and lrd pipe. The four pokes have so much bottom end in the turns and thats where we get killed. Any input would be great
Raptor or stay with Blaster?
- Thread starter lilgrizz
- Start date
what kind of raceing do you do and i race flat track and iv got to buy a 4poke to race next year because i can beat the other 2 strokes nut i cant beat the 4 pokes
This is the exact reason Triplecrown and I are looking for mid-range power instead of top end drag porting. A screaming top end power band just results in tire spin and slide, no go. Give it some grunt so you can get around the corners without shifts and have linear power like a 4stroke instead of a rock spitting peaky powerband.
Smaller carb, fill in the intake, shallow hemi or toroidal head, widened exhaust port raised no more than 0.020", stock timing, 0.040" quench. If the cylinder is already ported for peak, try running it without a basegasket, just use Yamabond or Tri-bond sealer ont the joint, and you may have to shim your head (thin aluminum sheet) to get the quench right. Motor will be a torquer instead of a screamer. You will run a gear higher and faster.
There is no magic bullet, you have to find the balance to win. If you can buy your way to the winner's podium, you will always find someone else always has deeper pockets than yours. Tinker and learn. Why are the Raptors winning? More hp? More traction? Figure it out and start putting more eggs in that basket!
Smaller carb, fill in the intake, shallow hemi or toroidal head, widened exhaust port raised no more than 0.020", stock timing, 0.040" quench. If the cylinder is already ported for peak, try running it without a basegasket, just use Yamabond or Tri-bond sealer ont the joint, and you may have to shim your head (thin aluminum sheet) to get the quench right. Motor will be a torquer instead of a screamer. You will run a gear higher and faster.
There is no magic bullet, you have to find the balance to win. If you can buy your way to the winner's podium, you will always find someone else always has deeper pockets than yours. Tinker and learn. Why are the Raptors winning? More hp? More traction? Figure it out and start putting more eggs in that basket!
that lrd pipe is killing your low end, i had one, on a basically stock motor internally, the power band didn't "hit" until late then pulled forever.
bring that power back down into the lower RPM's with a reed spacer in front of the reed cage and an FMF, DMC or Toomey pipe
kgibson has tried every pipe imaginable on his son jordans mx blaster, he claims the FMF performed the best for low end grunt on the mx track.
get that head squish and compression tested, there may be some gains to be had with it too, as steve mentioned above
bring that power back down into the lower RPM's with a reed spacer in front of the reed cage and an FMF, DMC or Toomey pipe
kgibson has tried every pipe imaginable on his son jordans mx blaster, he claims the FMF performed the best for low end grunt on the mx track.
get that head squish and compression tested, there may be some gains to be had with it too, as steve mentioned above
You can spend tons of money to keep up down low but its still going to be hard to match 300cc of raptor down low.
^^^^^ what he said. The 4 strokes can make power while maintaning traction while u just smoke the tires. Make sure u have the best rear tires for the soil. Also the rear shock is important for best traction. Make sure the set up will transfer weight back. Make sure ur not geared to low which will be wasted when u just spin the tires. If u can run hybrids in the class put a crf250r in the blaster and you'll smoke the raptors. You'll be turnin 12,500 with torque I:I
blasters can be bored to a 260 i belive. if not that, a 240. i was rtacing in schoolboy and when i wasent having problems, i mostly kept up with the raptors and EX's. mainly because i wasent scared to do the doubles they were 
lol
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I thank you all for the info. I really need to do my homework in the off season. As awk said the pipe is an issue we have ran a couple different pipe combos just cant get it right. Also what kgibson said if i gear it down it just screams and spins the tires. There is alot more to mx than I knew it has been a great learning experience for me. I just want my son to get better and not give up. and the guys on this forum have helped alot.
Best of luck to you! If the budget allows, Id look into installing a 4mil stroker crank this winter. A stroker crank gives the engine more 'leverage' and will boost low-end output.
Also, are you running the 200cc version or the 240cc version of the Firebreather cylinder? Im not 100% sure, but I think both versions of this cylinder kit were ported more for top-end power. You may want to consider ditching the Firebreather cylinder and running a ported stock cylinder with head work, or, if rules allow, a ported Vito's or CT 240 BBK. Even a ported stock cylinder will rip if done right, and a good trail/MX port job will give your son's Blaster the low-end and midrange punch he's been needing.
Also, are you running the 200cc version or the 240cc version of the Firebreather cylinder? Im not 100% sure, but I think both versions of this cylinder kit were ported more for top-end power. You may want to consider ditching the Firebreather cylinder and running a ported stock cylinder with head work, or, if rules allow, a ported Vito's or CT 240 BBK. Even a ported stock cylinder will rip if done right, and a good trail/MX port job will give your son's Blaster the low-end and midrange punch he's been needing.
Even with a high rpm ported cylinder, you can lower the rpm band a bit and increase tractability to the engine by
lowering the cylinder using a thinner basegasket or no basegasket.
The same ThreeBond 1194 or Yamabond 4 sealer you use on the cases will work on the cylinder base.
The head may have to be shimmed a corresponding amount to maintain quench distance, if it was set right to begin with.
Sometimes I see engines modified to the hilt, to the point they only have peak rpm power or even less than stock.
Backing off on some of the mods (smaller carb, less timing, etc) actually brings the motor back into reality from LaLa land.
I used to shoot competitively, and occasionally a top shot would get all messed up.
Coach would tell him to forget all the fancy stuff and get back to basics. Start from the beginning to get back on track.
So it is with building a motor.
If all the mods don't seem to be working, try putting much of it to stock and working out from there, one step at a time.
lowering the cylinder using a thinner basegasket or no basegasket.
The same ThreeBond 1194 or Yamabond 4 sealer you use on the cases will work on the cylinder base.
The head may have to be shimmed a corresponding amount to maintain quench distance, if it was set right to begin with.
Sometimes I see engines modified to the hilt, to the point they only have peak rpm power or even less than stock.
Backing off on some of the mods (smaller carb, less timing, etc) actually brings the motor back into reality from LaLa land.
I used to shoot competitively, and occasionally a top shot would get all messed up.
Coach would tell him to forget all the fancy stuff and get back to basics. Start from the beginning to get back on track.
So it is with building a motor.
If all the mods don't seem to be working, try putting much of it to stock and working out from there, one step at a time.
Best you have it summed up for me pretty well. It is all top end power and not what I need. I am going to try and lower the cylinder with no gasket just yamabond. The quench distance i will have to check the head has 0.075 cut off compared to a stock head.
Do you know what the quench is now? Solder taped across the piston will tell you.
You are looking for a quench of about 0.030" to 0.080" with 0.040" as ideal when done.
Typically stock quench runs 0.130"-0.150", so a 0.075 shave will have you pretty close to ideal.
You may need to shim the cylinder head 0.030" or so with thin aluminum or gasket paper cut out in the shape of a head gasket.
Try it, if I am wrong tell me.
You are looking for a quench of about 0.030" to 0.080" with 0.040" as ideal when done.
Typically stock quench runs 0.130"-0.150", so a 0.075 shave will have you pretty close to ideal.
You may need to shim the cylinder head 0.030" or so with thin aluminum or gasket paper cut out in the shape of a head gasket.
Try it, if I am wrong tell me.
you are going to have a hard time matching those big bore raptors. We have the airsal and it is ported to the hill. My son has finally found his rhythym on the quad to keep up and compete with well built raptors but the 80% rider 20% quad rule applies. If you want to beat those raptors you need more HP. The only cylinder capable of competing with those big bores is the Pro Cross by LA Sleeve or CT. However they are less dependable than your airsal. However as Ken said if they allow dirt bike motors get a 250F dirtbike motor and you will kill them!
Im sorry but i think racing a raptor is plain silly. Haha. If i had a choice between a raptor 250 raptor 350 or a Z 400 or 400ex. Id choose the 400's. I mean sure go ahead mod your blaster but if your lookin to compete with the 450's and get 1st place finishes your gonna have to upgrade or follow what these guys are sayin. I might be racing my blaster at the local MX races next year but im not to confident those 450s are insane. got more luck on a 400. I got 3rd place on my z400 going up againes 7 other 450's. Just sayin
I think allot of you guys are on the east coast, is their people racing 700 raptors out their for moto x?
Was this his first season?
As mentioned in first post he is limited to 200cc. If he was to "cheat" w/stroker, won, then disqualified upon inspection, it would probably crush the kid.
Solid advise otherwise from above. They may be right about firebreather cyl/pipe combo. How is the suspension set-up? Arms/shocks?
As mentioned in first post he is limited to 200cc. If he was to "cheat" w/stroker, won, then disqualified upon inspection, it would probably crush the kid.
Solid advise otherwise from above. They may be right about firebreather cyl/pipe combo. How is the suspension set-up? Arms/shocks?
He is racing a class not going for everyday riding so he has the options of Honda 250r 300ex raptor 250 blaster and lt250r
