TM34 and 240BBK jetting?

[Budget_Blaster]

Got the carb on its way to me and si's jug and head on its way to him I:I

He says it has a 45 pilot and 330 main he didnt mention jet needle (any ideas si if you read this?) anywho with my current mods how close would you guys figure ill be?Im trying to figure out what i should order if anything at all?Ive got every main jet from 230-340 to fit it so im hoping and figuring ive got that covered but what about jet needles and pilot jets?

My kdx will go from night and day just off the jet needle alone with that PWK keihin on it and is kinda finicky to tune but once it was tuned its nasty for 200cc!

So to all the tuning gurus and 240BBK guys out there where do you think i need to be on jetting?Right now temps are in the 20's and i plan to run it now that i went out and geared up for winter riding (awk you will be glad to know ill have a full facial AGV helmet on ).Or do you think ill need higher than 340 on the main for temps in the 20's with these mods/combo?

Thanks guys!

 

[Awk08]

ken oconnor uses a 34 mikuni on his bbk, maybe a pm to him will get ya some answers
as for what needle...........the correct needle seems to be the secret to getting these 34/35's to run right on our blasty's

i called the dude at carb parts warehouse, he sold me jets and a needle for my keihin 34 and the mods i had, runs great, dude knows his sh*t fo-sho

heres the link right to the tm34 page on cpw's website, it shows general jetting, but thats prolly too rich for our bikes, dude's # is at the top of the page...........

TM Series Flat Slide Carburetors, Dimensions & Power Jets

 

[Budget_Blaster]

I pm'ed ken what are your opinions bro?

Not many running this carb?Is there a reason why not?

 

[Awk08]

I know ken is supposedly heading for FLA., not sure exactly when, but he'll get ya an answer ASAP, I think the keihins are more popular since they were used on far more 2 stroke bikes than the mik's

 

[dbowhntr]

Go with the 5fp17 needle. Gonna need some bigger pilots too. I am running a oconner modded engine and im at a 55 pilot and a 320 main at 30f. 290 at 70f. This is not big block though

 

[Budget_Blaster]

Go with the 5fp17 needle. Gonna need some bigger pilots too. I am running a oconner modded engine and im at a 55 pilot and a 320 main at 30f. 290 at 70f. This is not big block though

The carbs coming off an lt250r you think the bbk 240 will need more than the 250?

 

[Awk08]

The carbs coming off an lt250r you think the bbk 240 will need more than the 250?

no, the lt will still have superior port design and all, requiring more fuel than our's, bbk and/or ported
you'll be safe to start with the lt's jetting in that carb, but give it a look and compare to what dbowhntr listed above, just to be sure whats in there before running it, never can tell what someone else did in there

 

[Budget_Blaster]

no, the lt will still have superior port design and all, requiring more fuel than our's, bbk and/or ported
you'll be safe to start with the lt's jetting in that carb, but give it a look and compare to what dbowhntr listed above, just to be sure whats in there before running it, never can tell what someone else did in there

Good point.

Yea i planned to open her up and if nothing more just get familiarized with it.I trust sicivic and dont think hes a slacker and he told me 45/330 so im sure thats what itll have.

But yea i do want to know the carb in and out for tuning/maintenance purposes.

Just out of curiousity awk where do you think ill be with those jets 45/330?I want a small area of cushioning so id prefer it a tad rich especially now that its cold out but not to the point performance suffers.If i do end up needing to change one of the jets out which do you think itll be main or pilot?

 

[Awk08]

i wish i had a clue about the bigger mikuni's to give you my opinion, but i just don't, i'm only familiar with the stock mikuni, and my 34mm keihin.
thinkin of upgrading to a 28/30mm on my sons and i'll be on here just like this thread asking for help

 

[Budget_Blaster]

i wish i had a clue about the bigger mikuni's to give you my opinion, but i just don't, i'm only familiar with the stock mikuni, and my 34mm keihin.
thinkin of upgrading to a 28/30mm on my sons and i'll be on here just like this thread asking for help

Well damn that sucks bro!


Appreciate the help though.I:I any ideas on power?

Anyone else maybe braaaptor?I know he runs one of these and is pleased with it.

 

[Awk08]

Appreciate the help though.I:I any ideas on power?

i'd say at least high 30's, possibly low 40's ???? ported BBK !!!!
but, your gonna lose at least 5 HP. when you switch carbs, that yellow bowl on the stocker has to be worth at least that !!!!! LOL

 

[super noober]

i would guess mid 30's on power, u coming to any forum rides? riding and racing around with other blasters is oe of the best parts of the rides. gives you a chance to see what ur machine has I:I I:I

 

[sicivicdude]

The carbs coming off an lt250r you think the bbk 240 will need more than the 250?

It's not so much about displacement as it is about efficiency. Getting an engine ported and head redesigned CAN decrease the jetting needed to satisfy that particular engine....

no, the lt will still have superior port design and all, requiring more fuel than our's, bbk and/or ported
you'll be safe to start with the lt's jetting in that carb, but give it a look and compare to what dbowhntr listed above, just to be sure whats in there before running it, never can tell what someone else did in there

The LT has a superior port layout but a head chamber design second only to the stock blaster setup. It's not particularly efficient.....




I put a 330 main jet in there because the one that was in it was beat up and I couldn't read it. The 45 pilot is what was in the carburetor when it came off the LT so I'm figuring that's quite right.

Believe it or not, just because you're going up in carburetor size, doesn't necessarily mean you're going to go up in jetting size..... you may end up using the exact same jet you're currently using in the VM26 carb.... I *think* 330 should be a safe cushion (which is why I installed that versus any of the other jets I have) but you're really gonna have to use your judgement when it arrives.... Listen to it, feel it, make sure it's 100% before tearing off on it and then go do a plug chop first thing. I have a feeling you'll be just a tad rich on the 330 main but that's ok, you can just turn it down a little bit and rock on....

Most folks don't use the Mikuni's because they're not as popular as the Keihin's. Self serving prophecy I know, but just the way it is. Keihin's come stock on pretty much every Jap dirtbike except honda's so they're more readily available used.

 

[dbowhntr]

You should be ok to start with the 330. The issue I ran into was coming off the needle into the pilot. It would lean out and hang with a high idle. If this happens go up on the pilot and you may want to go to a q4 on the needle jet. This is the tube that the needle goes into. Carb warehouse has them. Stick with the 5 fp17 needle second or third clip.

 

[Braaaptor]

I also run a 5fp17 needle and it does well on the Blaster engine. This needle is too rich right off idle for my ported stock jug Blaster, but it should do well for you on your BBK. Needle will be best in the center clip or one clip position down from center.

I run a 35 pilot and a 290 main jet on my Blaster. I do NOT have a BBK, so my main jet is gonna be a little smaller than what you need. The 35 pilot is perfect for my setup. You may need one size larger than that for the BBK.

Like Sicivic already said, most people run Keihins just because they're so popular and tuning knowledge is already widespread. With a Mikuni, you're more on your own when it comes to tuning, but if threads like this continue, it won't be that way for long!

You can run a Blaster engine on just about any brand of carb as long as you take the time to tune it properly. Mikuni, Keihin, Lectron...even a Tillotson. lol.

 

[Budget_Blaster]

Nice!!!!


Hey si what needle is in the carb?

Im going to order the choke assembly this week some time and get it on there and start tuning.

So even in 30 degree temps you think the 330 is a safe starting point?

 

[sicivicdude]

Nice!!!!


Hey si what needle is in the carb?

Im going to order the choke assembly this week some time and get it on there and start tuning.

So even in 30 degree temps you think the 330 is a safe starting point?

I didn't take the needle out so I can't tell you. It has two little screws holding down the retainer plate so I didn't monkey with it....

Need to order the choke assemble like right now so you can run it when it gets there. I did include the old one with the busted knob so you COULD figure out a way to rig a knob of some sort (cast one out of JB weld maybe?!) to use it but for $9? Be better to just buy a new replacement and be done with it...

I think the 330 will be a safe starting point even at 30deg F. You'll know if it's safe enough for a plug chop anyway..... if it's not enough jet it'll just "BOOOOOOGGGGGGGGGGGG" as you come up onto the main jet.

 

[Budget_Blaster]

i would guess mid 30's on power, u coming to any forum rides? riding and racing around with other blasters is oe of the best parts of the rides. gives you a chance to see what ur machine has I:I I:I

Highly doubtful bro unless you guys are holding a meeting closer to illinois.

When we aint riding the woods and okaw river here we go to southfork or badlands.

 

[Budget_Blaster]

I didn't take the needle out so I can't tell you. It has two little screws holding down the retainer plate so I didn't monkey with it....

Need to order the choke assemble like right now so you can run it when it gets there. I did include the old one with the busted knob so you COULD figure out a way to rig a knob of some sort (cast one out of JB weld maybe?!) to use it but for $9? Be better to just buy a new replacement and be done with it...

I think the 330 will be a safe starting point even at 30deg F. You'll know if it's safe enough for a plug chop anyway..... if it's not enough jet it'll just "BOOOOOOGGGGGGGGGGGG" as you come up onto the main jet.

How would i find out on the needle without having it here so i can go ahead and order what i need to now?

 

[sicivicdude]

Highly doubtful bro unless you guys are holding a meeting closer to illinois.

When we aint riding the woods and okaw river here we go to southfork or badlands.

Dude, Brandon from Wildcard Racing drove from UTAH to Busco Beach last September. I know you could make it down from Illinois.