ok i have a 2.5 and i have aded a boost tube it is 38cc. also i have cut out the stock air box where the tiney stock holes were and put in a 68 jet in.
the problem im having is at low rpm when i riv it gas it wants to stall unless i ease in to it. I cant tell if it is going lean or rich. the temps out right now are 65-75 so do you think that i need to go larger ir smaller. im not having any power problems up top so i dont know what to do if this helps im runing K2 race oil and 110 octange leaded at 45:1 any ideas
also is there any where that will tell me how to read a plug on a 2stroke im filimar with reading them on a 4stroke thats how i tune the nitrous on my car . i just can see the diffrence in colors on the oil/carbon crusted plug
68 sounds a bit big for that bike. You are looking for a medium tan color on the plug. If it is white you are lean if it is black and sooty than you are rich. I would also not waste the money on the race fuel with that bike. It should run just fine off 92 or 93 pump gas. You will also get a better read on the plug with the less refined gas. Maybe someone else (if they have a real blata) can chime in and tell what size main jet they are using in their 2.5. I also know of a reed that can really wake that bike up. When you start testing for jetting make sure you either clean the plug or put a new one in so you can get an accurate reading. Good luck Where in indiana are you? FRank
Actually, with the Polini filter conversion, the bike jets perfectly at 68, but we actually use a 72 main, which is probably because we have the updated '04 pipe.
Frank, what reed are you talking about that really wakes the bike up?
ok i have a 2.5 and i have aded a boost tube it is 38cc. also i have cut out the stock air box where the tiney stock holes were and put in a 68 jet in.
the problem im having is at low rpm when i riv it gas it wants to stall unless i ease in to it. I cant tell if it is going lean or rich.
You did not mention what carb you're using. If you are using the stock Dell Orto 1412 that came with the bike with a 68 jet, then you are running "rich" which is giving you that low rpm/stalling problem. A 68 jet is used with the 1414 carb. If you are still using the stock 1412, go back to the stock 52 jet, or just get a 1414. And IMO, I would stay away from boost tubes. It also could cause an air leak which can also be your low rpm/stalling problem.
The reeds are custom cut for the blata 2.5's and the cags and come in a kit with two thicknesses. We had them made from mossbarger. We had the stock reeds in one 2.5 and the new reeds in another and the difference was night and day, especially through mid and top end. Let me know if you need some we had some extras made and we dont mind sharing. Frank
You did not mention what carb you're using. If you are using the stock Dell Orto 1412 that came with the bike with a 68 jet, then you are running "rich" which is giving you that low rpm/stalling problem. A 68 jet is used with the 1414 carb. If you are still using the stock 1412, go back to the stock 52 jet, or just get a 1414. And IMO, I would stay away from boost tubes. It also could cause an air leak which can also be your low rpm/stalling problem.
Assuming that he has the 14/12, that definitely isn't the problem. We've used a 68 main in that carburetor without a problem and had a perfectly tanish brown plug. Besides, most don't know that when using the 14/14, you need to bore out the stock manifold because you're still only getting about 12.5mm of flow.
He also said that he modified the air box, so reverting back to the 52 main with any modification / increase in air flow will cause a very lean condition. On the flip side, he's probably running far too rich with the 68 main because he didn't modify the stock air box correctly and/or enough to generate enough air flow to warrant using a 68 main.
Also, like Frank said, I would discontinue use of the racing gas. It smells awesome, but is definitely not needed on this machine.
[quote=MinimotoPilot]Assuming that he has the 14/12, that definitely isn't the problem. We've used a 68 main in that carburetor without a problem and had a perfectly tanish brown plug. QUOTE]
Hmmm...thats weird, cause I ran my stock 1412 with a 68 jet and I had some sluggish, stalling problems. So I checked my plug and I found that it was running rich. I solved that problem by just switching over to a 1414 with the 68.
Using the 68 main entirely depends on what filter you use with this machine in particular. With the polini filter conversion, using a 68 main in the 14/12 isn't a problem at all. It's definitely worth the extra $32.
Using the 68 main entirely depends on what filter you use with this machine in particular. With the polini filter conversion, using a 68 main in the 14/12 isn't a problem at all. It's definitely worth the extra $32.
Cheers
ok it dosent have the polini conversion but it does have a small cart filter on it that fit over the carb so it is equivelent to the polini conversion. also i use the race gas because it is leaded and i also run it in my 12sec honda so i have it around. ok i have a silver pipe so i assume that it is a 04 not the older style.
ok i have also bored the adapter plate to 13.5mm and polished the 14/12 carb was sure not to change the carb bore on the carb.
also why are boost tubes so bad it is made properly to size and it does not leak im sure of it.
sorry I don't know what boost tube 38cc is, but if it wants to stall when you quickly open the throtle, that's an indicator of lean condition, the weird thing is that with a 68 jet on stock engine and carb with the metal filter disc it can't be lean, unless you have a dirty jet or suction tube, clean everything and make sure there's no obstructions, I also recommend you that look closely at the holes on the jets and make sure the 68 looks bigger than the 52, I've seen jets with wrong # marked on them, but most of all I will recomend you keep your 52 for stock engine and carb we have confirmed that it reeves up faster taking off the turns and the top end is the same.
sorry I don't know what boost tube 38cc is, but if it wants to stall when you quickly open the throtle, that's an indicator of lean condition, the weird thing is that with a 68 jet on stock engine and carb with the metal filter disc it can't be lean, unless you have a dirty jet or suction tube, clean everything and make sure there's no obstructions, I also recommend you that look closely at the holes on the jets and make sure the 68 looks bigger than the 52, I've seen jets with wrong # marked on them, but most of all I will recomend you keep your 52 for stock engine and carb we have confirmed that it reeves up faster taking off the turns and the top end is the same.
read my last post it dosent have a screen and it is a home made boost tube it was made to 38cc including the hose fitings and tube.
tube consist of 3/4in coper pipe with cap on one end and a thread adapter on hte other end. it is all soldred together. and presure tested. the fittings are brass hose barbs. it is a rubber 3/8 fuel line conecting the tube to manifold. i drilled and taped the manifold and put in a 1/8npt(pipe) to 3/8 barbe fiting in. milled out the part that protruded into the manifold and smoth bored it all to 13.5mm and like i said b4 the carb is polished but didnt effect bore of carb but maby 0.001 ore 1 thousandth
the 110 octane is not needed.would be easy just too use regular pump gas and see what happens.your ratio is ok and sounds like you know how to read your plugs.get some carb spray and use it around places you might suspect an air leak.your boost tube should be fine unless it has a leak.how did the bike run before,did this just happen when you did your mod's.
it happend after the mods and i have checked for leaks and its no air leaks so i assume it is lean down low going to get some new plugs thus weekend and start looking at those. if this helps if i put in a 71 jet it is fine down low but i have to set the idle pretty high and it has flat spots in it up high
I'm an ASE master technician the only devices I know can produce boost are turbochargers and superchargers, I work with them and I can explain how they work, i guess my knowledge is not enogh to understand this sofisticated device called boost tube. can you explain to me how this litlle thing produces "boost"?
Boost Bottle theory is that the boost/equalizer /tube/bottle is a passageway between intake manifolds with a fixed volume, usually the CC of one cylinder or larger, a (momentary) storage container for pre-atomized fuel/air mixture.
Since the fuel/air mixture is at a high velocity while traveling through the intake manifold, guess what happens when the reeds suddenly close? The mixture has inertia and physics would suggest the fuel/air mixture has to dissipate this inertia, through a tube maybe?
This inertia (pulse) forces the pre-atomized mixture that's already in the tube from the previous cycle into the next intake manifold that's reeds are just opening and ready to receive the fuel/air mixture, this is like a little supercharger to each cycle. This all happens so fast at higher rpm's that it is most effective at lower and mid-range where you are on/off throttle.
It takes venturi velocity to atomize the raw fuel from the main jets. The tube/bottle has a charge of pre-atomized fuel that is instantly ready when you go from off to on throttle. It assists in filling the cylinder for a fraction of a second until the carburetor venturi gets enough velocity to fully atomize the available fuel. The advantage is that it brings up the torque and horsepower sooner in the bottom of the rpm range. Credit to Hartman Inc
thats the philosophy behind it, depends who you speak to some say they are crap, others will swear by them.
no ofense to you obpr and thanx for the time you spent to explain all that theory.
some time ago when I was going to a pb race my girlfriend, gave me a little necklace that she said it will make me go faster (you know how girls are) then we both LOL, ok I think that little necklace will be more effective than the boost tube, so all you guys who want to win a race ask your girl for something like this, it still cheaper than the boost tube.
you know what? now that I see everybody talking about and spending $60 on "boost tubes" I feel frustrated because I realize that I missed the oportunity to become millionary making and sellig that little stupid bottle, it doesn't takes a super engineer to develop such thing, it just takes a great ********er who must be getting rich right now. well, I gess there's a lot of people out there looking for magical ways to gain power like those who buy that fancy "ground distribution system" for the negative conection of the battery on cars.
Man!!! I really have to come up with some product like these to get rich the easy way.
The problem is that when ideas like these come to my mind I jus lugh and tell myself "com'on man nobody can be stupid enough to believe this ********"
I GESS I'M WRONG.
