Tbr7 carb and sprocket change

Fish_Master · 07-11-2021, 02:37 PM

Alright guys I’m gonna upgrade the carb and front sprocket. I got a 17 tooth fri t But I know almost nothing about carbs. I mean I can turn a wrench and shouldn’t have any trouble replacing it but I do t k ow what carb to get. Do I get just a new carb entirely or should I just get this one up. Also what jets do I get. Ive heard talk about mikuni carbs but I don’t know what fits or not. Also I have a Chile cable on my bike so will this new carb (if I get a new one) have the mounts to keep that?
Please forgive my ignorance.

Plump Kibbles · 07-11-2021, 11:17 PM

Hey man - there's no ignorance here that I can't top!! HA! I kid..

Which carb do you have on it now; I'm assuming the PZ30?? Basically, taken lightly, any 30mm carb will do - can even get fancy with the pumper carbs, but I couldn't get mine to work right lol

I got rid of the stock one I had because I couldn't open the bulb to modify the jets. I could, but then the Dremel would have to be involved, and for 30 bucks - I got all I need plus the jets! Also grab some jets that fit - you'll want to go up in main jet right off. I have a 110 main jet, 38 stock slow jet that came with my Mikuni clone. Mine also came with a pod filter that I recently popped on and had to retune the mix screw for 2.25 turns out (two and one-quarter). There are SO many videos and tips and tricks and a bombardment of things to 'tune' your carb - I would say... get the carb you want that fits, put a 100-115 main jet (depending..), pop on a pod filter - more fuel = more air.. stock air box / paper filter won't be able to keep up with the bigger jets. After you get the carb on and a high(er) flow filter on - start the bike. Raise the idle a good bit so you can hear the RPMs well - now, turn the mix screw (usually on the bottom of the bulb) all the way to the right, but DO NOT tighten. Just to where it bottoms out and stop. The bike should be sputtering at this point, almost stalled. Now, start backing the mix out - take note on the screw head position. Picture a dot or marker where the screw head is either left or right - a complete 360 degree turn will be 1 turn; easy. So, take note on how many turns you go to the left. Usually, you can start around 1.5 turns to 2 turns out. Rule of thumb, anything over 2.5 or 3 turns and you'll need to jet up. Also, while you're backing out the mix screw, you can dial this in by ear. Listen for the fastest RPM idle while backing out the screw. Just remember how many turns! And if you go over 2.5 - 3 turns with no change, you'll need to rejet.

I believe the carb I got was the VM27? Still 30mm, even came with a 100 main jet! But, that wasn't enough for my bike. You can also take a look at the spark plug to see if you're rich / lean. A nice creamy coffee color means a good mix. Darker colors mean rich, lighter color - almost like it's not seen any real combustion - means lean.

Take a look at the Resources thread - there's a good bit of info on it through there. A quick YouTube on carb tuning can get you going in the right direction, too.

Fish_Master · 07-12-2021, 12:24 AM

Thanks man

Plump Kibbles · 07-12-2021, 01:32 AM

No worries!

What were you thinking about in terms of sprockets; acceleration or speed?

I went with the 520 X-ring chain by Niche, 12T front, and 30T rear. Might up the rear five teeth for better acceleration. The 520 chain is going to be really beefy, so 13T might be kind of tight. Even with the 12T, my chain was smacking the front sprocket cover. Changed that out to one of the ABS colored ones to match the bike.. no more smacks!

Your chain should give you a number, probably the 428? That's your pitch. Then the next thing would be is get some JT sprockets for the Hawk:

Front Sprocket: JTF259 | Rear Sprocket: JTR269 <-- Hawk resource guide

those are for the stock chain btw..

Adding teeth to the front and rear sprockets have opposite effects. Installing a larger countershaft sprocket creates higher gearing, while a larger rear sprocket lowers gearing. Similarly, a smaller front sprocket lowers the gearing while a smaller rear sprocket makes gearing higher.

The setup I have is a pretty low RPM drop from where it was stock, but I really wanted it to drop. I am able to jump on the interstate IF need be, but don't really like to; WOT the whole time pretty much.. But, with what I have on it it's pretty much in the middle. I can still accelerate well on and off road, as well as not bog out while riding the more difficult terrains.

Play with it; try a few combinations out and see what suits you best!

Fish_Master · 07-15-2021, 03:08 PM

Basically I’m just trying to get this thing to cruise a little bit more comfortably at 60mph. I do t do a lot of dirt riding so I do t need a ton of low end.

Plump Kibbles · 07-17-2021, 06:58 PM

Quote:

Originally Posted by Fish_Master

Basically I’m just trying to get this thing to cruise a little bit more comfortably at 60mph. I do t do a lot of dirt riding so I do t need a ton of low end.

Gotcha - That's what I've got for mine, basically. I'm going to up the rear to 35T next change though. But, I'm cruising pretty comfortable around 65. For your stock chain, I don't have a suggestion about ratio. Check out the resources guide in here and see which is recommended for middle ground. But, with my stock chain, 428, 13T front 45T rear and honestly could have kept the smaller chain but na, I do a lot of dirt too - 40T rear probably would have been middle
though.

Plump Kibbles · 07-20-2021, 10:44 PM

Quote:

Originally Posted by Fish_Master

Basically I’m just trying to get this thing to cruise a little bit more comfortably at 60mph. I do t do a lot of dirt riding so I do t need a ton of low end.

Hey man, got some info for you that you may want / need..

Just got my new carb (link below) and jets - previous carb started to fall apart! But anywho - I got a 30mm carb this time, I think the other was like a 28mm? Weird, but got the right size this time. Also jetting - so it came with the 100 main jet, I had this in the old carb - does well, but not enough flow. I got a 110 jet for the carb that was on it, ran it for a while, did well. Now I'm almost at 1000mi on that carb, some things fell off. But, I went up to a 120 main in the new carb, kept the stock slow jet at 42, and moved the needle position up one slot. Which means (if you're looking at the needle taper down), take the C clip off and move that sucker one slot down - you should then have one space left on the C clip grooves. That's for your 3/4 to full throttle input adjustment. This really, really made the difference! I'm cruising at 55-65MPH not even half throttle now. Very pleased with my tune now. Only thing I need to do is set the mix screw to 1.5 turns out - stupidly started with 2 turns out, tis a bit too rich now. I'm going to take it back out tomorrow and see how it does at 1.5 turns out.

Just a heads up, brother! I've been fighting with getting this bike to be comfy on the road - it's right at home however I set it up OFF road; just wants to really show it doesn't like pavement lol So, grab some jets, the 30mm carb - https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 - note: you won't be using the spark plug or the intake manifold; you will need the pod filter though. It even has 'Made In Japan' on the side!! That part made me smile

But yeah man, not sure how far you've gotten with this so far - but our bikes should be similar if not almost the same. I did remove the SAI stuff and capped off the vacuum port on the intake. Have heard this helps if you're wanting a nice smooth setup? Not sure if it really does help, I did it before starting the engine for the first time - only 8 bucks for a blocker plate and the hardware. These bikes are a bit tricky to get them to play well with 65MPH+ in my eyes - plus that missing sixth gear holds things back a little - wouldn't have to WOT the thing to get it to hold a steady high(er) speed. A 'racing' CDI would help out as well, especially with the bigger jets and the need for speed - those usually remove the rev limiter and advance the engine timing just a tad. I got the blue one off Amazon for around 12 bucks? Works pretty well! Unless you have a really high flow filter, not sure if the air box is restrictive, the pod filter will be the one to go with though. Lots of air flow, easy to get on / off.. Lemme know how it goes, dude!

07-11-2021, 02:37 PM	#1
Fish_Master Join Date: Feb 2021 Posts: 31	Tbr7 carb and sprocket change Alright guys I’m gonna upgrade the carb and front sprocket. I got a 17 tooth fri t But I know almost nothing about carbs. I mean I can turn a wrench and shouldn’t have any trouble replacing it but I do t k ow what carb to get. Do I get just a new carb entirely or should I just get this one up. Also what jets do I get. Ive heard talk about mikuni carbs but I don’t know what fits or not. Also I have a Chile cable on my bike so will this new carb (if I get a new one) have the mounts to keep that? Please forgive my ignorance.
	0

07-11-2021, 11:17 PM	#2
Plump Kibbles Join Date: Sep 2020 Location: Virginia Posts: 233	Hey man - there's no ignorance here that I can't top!! HA! I kid.. Which carb do you have on it now; I'm assuming the PZ30?? Basically, taken lightly, any 30mm carb will do - can even get fancy with the pumper carbs, but I couldn't get mine to work right lol I got rid of the stock one I had because I couldn't open the bulb to modify the jets. I could, but then the Dremel would have to be involved, and for 30 bucks - I got all I need plus the jets! Also grab some jets that fit - you'll want to go up in main jet right off. I have a 110 main jet, 38 stock slow jet that came with my Mikuni clone. Mine also came with a pod filter that I recently popped on and had to retune the mix screw for 2.25 turns out (two and one-quarter). There are SO many videos and tips and tricks and a bombardment of things to 'tune' your carb - I would say... get the carb you want that fits, put a 100-115 main jet (depending..), pop on a pod filter - more fuel = more air.. stock air box / paper filter won't be able to keep up with the bigger jets. After you get the carb on and a high(er) flow filter on - start the bike. Raise the idle a good bit so you can hear the RPMs well - now, turn the mix screw (usually on the bottom of the bulb) all the way to the right, but DO NOT tighten. Just to where it bottoms out and stop. The bike should be sputtering at this point, almost stalled. Now, start backing the mix out - take note on the screw head position. Picture a dot or marker where the screw head is either left or right - a complete 360 degree turn will be 1 turn; easy. So, take note on how many turns you go to the left. Usually, you can start around 1.5 turns to 2 turns out. Rule of thumb, anything over 2.5 or 3 turns and you'll need to jet up. Also, while you're backing out the mix screw, you can dial this in by ear. Listen for the fastest RPM idle while backing out the screw. Just remember how many turns! And if you go over 2.5 - 3 turns with no change, you'll need to rejet. I believe the carb I got was the VM27? Still 30mm, even came with a 100 main jet! But, that wasn't enough for my bike. You can also take a look at the spark plug to see if you're rich / lean. A nice creamy coffee color means a good mix. Darker colors mean rich, lighter color - almost like it's not seen any real combustion - means lean. Take a look at the Resources thread - there's a good bit of info on it through there. A quick YouTube on carb tuning can get you going in the right direction, too. __________________ \|2020 X-Pro Titan DLX\| <-- FOR SALE!!
	0

07-12-2021, 01:32 AM	#4
Plump Kibbles Join Date: Sep 2020 Location: Virginia Posts: 233	No worries! What were you thinking about in terms of sprockets; acceleration or speed? I went with the 520 X-ring chain by Niche, 12T front, and 30T rear. Might up the rear five teeth for better acceleration. The 520 chain is going to be really beefy, so 13T might be kind of tight. Even with the 12T, my chain was smacking the front sprocket cover. Changed that out to one of the ABS colored ones to match the bike.. no more smacks! Your chain should give you a number, probably the 428? That's your pitch. Then the next thing would be is get some JT sprockets for the Hawk: Front Sprocket: JTF259 \| Rear Sprocket: JTR269 <-- Hawk resource guide those are for the stock chain btw.. Adding teeth to the front and rear sprockets have opposite effects. Installing a larger countershaft sprocket creates higher gearing, while a larger rear sprocket lowers gearing. Similarly, a smaller front sprocket lowers the gearing while a smaller rear sprocket makes gearing higher. The setup I have is a pretty low RPM drop from where it was stock, but I really wanted it to drop. I am able to jump on the interstate IF need be, but don't really like to; WOT the whole time pretty much.. But, with what I have on it it's pretty much in the middle. I can still accelerate well on and off road, as well as not bog out while riding the more difficult terrains. Play with it; try a few combinations out and see what suits you best! __________________ \|2020 X-Pro Titan DLX\| <-- FOR SALE!!
	0

07-12-2021, 12:24 AM	#3
Fish_Master Join Date: Feb 2021 Posts: 31	Thanks man
	1

07-15-2021, 03:08 PM	#5
Fish_Master Join Date: Feb 2021 Posts: 31	Basically I’m just trying to get this thing to cruise a little bit more comfortably at 60mph. I do t do a lot of dirt riding so I do t need a ton of low end.
	1