going to spend some coin, how should i go about it... bb????

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greasemonkey85

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Oct 25, 2010
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ok guys, this is my third thread now, lol i love this sight.

i had a good talk with ken o'connor the other day, very nice guy top notch! we talked about porting and such....my motor needs to be redone for sure, needs crank and other stuff.

so i m looking at getting a stroker crank for sure, most likely the vitos +3mm, i dont really want the +4 and to have the cases trenched, looks like it gets pretty close in a few spots. i m just looking for 30+hp and a good RELIABLE motor.

so here is where it comes.....i bought the f7, ct power, power pro, right bend pipe, it is sitting in my garage as we speak, but i didnt know my crank and stuff was bad so now i kind f'd.

anyways i am looking at getting the la sleeve 240 bb kit, with the 250r reed cage. i have lots of 250r parts and motors as that is what i was going to run in my mini sprint kart this year.

the big question, is how reliable is this thing? and will it do for what i am looking for? i want a strong quad, but i dont race it, just aggresive trail riding, just looking to get the kit and rebuild the motor, then later on decide from there if i want it ported or not.

has anyone ran this kit yet, and if so how is the power band?

what pipe and carb are you running? have a several 36mm and 38 keihin pj carbs that a can use, but i am not sure if the f7 pipe will work with this motor combo?

what are your guys thoughts? i want the quad to have power all over but mostly mids, and into the highs.

please comments and thoughts on a build like this would be greatly appreciated, i want some feed back before i drop a grand in my blaster, to see if it is worth it or just spend the grand on another quad.

thanks dan
 
greasemonkey85 said:
ok guys, this is my third thread now, lol i love this sight.

i had a good talk with ken o'connor the other day, very nice guy top notch! we talked about porting and such....my motor needs to be redone for sure, needs crank and other stuff.

so i m looking at getting a stroker crank for sure, most likely the vitos +3mm, i dont really want the +4 and to have the cases trenched, looks like it gets pretty close in a few spots. i m just looking for 30+hp and a good RELIABLE motor.

so here is where it comes.....i bought the f7, ct power, power pro, right bend pipe, it is sitting in my garage as we speak, but i didnt know my crank and stuff was bad so now i kind f'd.

anyways i am looking at getting the la sleeve 240 bb kit, with the 250r reed cage. i have lots of 250r parts and motors as that is what i was going to run in my mini sprint kart this year.

the big question, is how reliable is this thing? and will it do for what i am looking for? i want a strong quad, but i dont race it, just aggresive trail riding, just looking to get the kit and rebuild the motor, then later on decide from there if i want it ported or not.

has anyone ran this kit yet, and if so how is the power band?

what pipe and carb are you running? have a several 36mm and 38 keihin pj carbs that a can use, but i am not sure if the f7 pipe will work with this motor combo?

what are your guys thoughts? i want the quad to have power all over but mostly mids, and into the highs.

please comments and thoughts on a build like this would be greatly appreciated, i want some feed back before i drop a grand in my blaster, to see if it is worth it or just spend the grand on another quad.

thanks dan
Click to expand...

Dan, I really can't speak from experience on the BB kit, since I have yet to try one, but from what I've heard, they do very well. You will see a huge gain in power over stock for sure; even moreso if you get the BB kit ported later. From what I know, it is not wise to run a stroker crank with an un-ported BB kit (or any cylinder, for that matter), because the increased piston travel provided by the stroker crank will affect the engine's port timing. Yes, it will run, but you will be cheating yourself out of some HP and engine efficiency.

Hopefully somebody more experienced than I on this subject will chime in soon. As far as I know, BB kits are fine in terms of reliability as long as you have the engine jetted properly and run good quality oil mixed to the proper ratio (32:1). That being said, I would not want to take a big-bore air-cooled engine such as this out duning, etc for hours on end until you are sure that the carb is dialed in. Even the best-built engine will overheat if run too hard, close to or at WOT, if the carb is not properly jetted....

I will say that I'd go ahead and spend the $$ on your Blasty once you get the package you want all figured out. Even if you end up buying something other than a BB kit. Sure, you could go out and buy a new quad, but you've got a machine with a known set of problems that you like, and one which is easy and (fairly) inexpensive to modify. Anything else you buy will present you with a whole 'nother set of headaches. Plus, Blasters can be made to run and you'll be surprised at just how much reliable power you can get with the right tricks and expert help.

Oh, and don't forget that most other quads out there today are 4-strokes. Blow one of these up, and its all-too-easy to spend $ 800 - $ 900.00 just to get a basic engine rebuild done. Cams, valves, timing chains...headaches 2-stroke guys like me tend to want to avoid.
 
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My choice would be 3mm stroke and LA sleeve. I am a big fan of porting so either way i would have it sent to ken or any reputable shop. Its all about how much coin you want to drop. Anytime i build a motor i allways want more and if your like me go all the way with it. You will get tons of opinions here but i say Port that LA!!!
 
Like I have said several times, I am not a motor guy... BUT WTF????

1. "I have the ct/power pros pipe, dodnt know if it will work:" CT sells that very pipe with their complete kit

2. "youll have a hard time fitting a 36, my 35 is really tight" its a 250r or cr 250 manifold. mine fits a 38 no problem, and I used to run a 39 on my 250r not to mention a 36 or 38 is an option with the complete kit

3. "That being said, I would not want to take a big-bore air-cooled engine such as this out duning for hours on end, because even the best-built engine will overheat if run too hard, close to WOT for 15-30 mins on end.... " WTF are you talking about??? yes you may loose a little bit of power (Im taking tiny) as the motor gets to operating temp, but if its built and jetted right you can hold it wide open all friggin week if you want as long as your moving and have some airflow. Hell I have held on pretty much WFO for 24 hours in 100 degree heat stopping only for 30 seconds an hour for gas and the bike ran just as good at the end as it did in the beginning


The worse thing about your plan is that the 240 cylinder has only 3 overbores, the stock cylinder has 8. the pistons kits for the 240 are also more expensive. So if you cant jet a bike, do leak down tests, service your aircleaner etc... the 240 is going to be more expensive when you keep blowing it up. So if you in the "still learning not to kill my motor phase" stick with a stock cylinder. IF you are good with maint. and tuning etc, go with your plan,,, a the stock blaster motor makes abut 15 hp, a well built stroked aftermarket 240 cylinder will make 45~50.. a 300 percent plus uncrease in power should be rather noticable.
 
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well maintenance is no problem lol, actually ken really was trying to talk me into porting my own motor.....

i build 4 stroke kart motors. i do all the machine work. and if any of you race kart motors then you know what goes into it. i had $3000 into a 390 13hp honda generator engine that made 40 to 50 hp when i was done with it, and it ran on alky. with no oil filter, every time you come off the track you are changing oil, check valve lash, and going over the major parts between races.

the 2 stroke stuff has me alittle over my head for right now. but ken is willing to help. i am just figuring why spend the money, on getting a stock motor rebuilt when i can spend a little extra and have a good monster, you know what i mean?

i dont see why you cant run a stroker crank with the 240 bb kit..... you run a spacer to correct the port timing. yes the motor will have to be assembled and checked to find the correct thickness of the spacer, but everything will fit together once done so.

the only thing i will need to learn is jetting, because or racecars run carbs that i can reach over and turn needles in and out to make it richer or leaner, there is no taking the carb apart and changing needles. you can adjust the carb as you run the motor.
 
so basically this would be a good start by going with the la sleeve bb kit and the vito stroker crank?

you can see the huge difference and design in the port and reed cage size over a stock blaster.

i would like to do this to start then later on have ken do a port job on it, probably the first rebuild.

i havent seen this said here yet, but this is our moto in open engine racing......

"HOW FAST YOU WANT TO GO DEPENDS ON HOW MUCH MONEY YOU WANT TO SPEND"

the thing is with this is, the blaster isnt a racecar, it is a blaster, and is it going to be a good choice to do this or go with a different quad.
 
You can run a spacer with no problem but i prefer porting and head mods instead. You mentioned a monster motor so if i was you i would do a ported BB and be done with it. You can get jetting help here anytime. Don't get me wrong a 3mm with stock jug ported will rip ass but now i want a 240 3mm agressive port and no spacer. Now i wish i would of done the 240. Monster motor in my opinion is a 240 kit.
A diferant quad is way more money!
 
A spacer plate does NOT correct the porting. you have a cylinder with ports in the side of it. you add say a + 3 mm crank, the piston now travels 1.5mm higher AND 1.5 mm LOWER than the bottom of the port.throw in a spacer plate to lift the jug and viola.. your piston now travels 3 mm below the bottom of the port. the port tiimg and duration will not be close to desired. your a 4 stroke guy, say you take a 350 sbc, stroke it to a 383, put some really good heads on it, good intake, big carb, nice headers, but then use the cam from an 82 pickup.. would it run anywhere near as good as a nice custom ground roller matched to the heads??

And if you race karts, you probably already have an egt and are good with it, so jetting should not be an issue.
 
so basically the spacer is just to correct the space from bdc to tdc so the piston doenst cause havok..... ah i got ya, so what needs to be done then?

i'm guessing it will have to be ported to correct the port timing right?
 
ok so if i keep it stock stroke, what am i giving up..... some torque? but will that out weigh the better stroke to bore ratio?

even if i went stock stroke and la sleeve big bore i m still looking at 35 to 40 hp correct? on pump gas.....gotta be pump gas i m tired of messing with alky, nitro, and racing fuels
 
IF jetted properly, setup right, good oil, forged piston etc, I see no reason you shouldnt see considerable lifespan out of it. most people rebuild stuff because they blew it up or didnt take care of it. throw a new set of rings on it and a light hone at 75~100 hours, look the piston over good, I would replace a wiseco at 150 hours, and check the bore... thats play riding with everything correct. I have gone 2 seasons of desert racing on a single bore before, though I did the rings and piston a couple times. saying a year every 6 months etc, is pretty much useless...everybody rides different and different amounts. A good compression test when the motor is new, then look for when the compression starts dropping, then is time for rings. while doing the rings, check the piston etc.
 
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