Input Needed

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weazel

New Member
#1
#1
Ok here is the deal. Im building a drag bike of sorts and I have a question regarding the clutch set up.

First off the engine is a Tec 8hp. Im running 6in wheels with I believe 8in rear tire. I have 2 different rear sprockets, 40 and 72 tooth. Now Im debating about running a centrifugal 12 tooth or a Tav 30 set up. What would the optimal set up be? I would like it to be fast(er) than my Arctic Cat mini's which are stock. I just dont want it to take forever to get out of the hole. If need be I could buy a different rear sprocket. Those of you that built drag bikes how did you set them up? Thanks
 
LSCustoms

LSCustoms

Moderator
#2
#2
how fast are you trying to go, as far as mph... is your motor a stock 8hp tec? how high does it rev? your tire is only 8" tall on the rear (with a 6" rear rim, seems like it should be taller), or do you mean the rear rim is 8"? what is you total tire/wheel height?

if your motor spins to 8000 rpm (with a 12t/72t), with that rear tire (with your measurement of 8"), you would be traveling about 32 mph
 
W

weazel

New Member
#3
#3
LSCustoms said:
how fast are you trying to go, as far as mph... is your motor a stock 8hp tec? how high does it rev? your tire is only 8" tall on the rear (with a 6" rear rim, seems like it should be taller), or do you mean the rear rim is 8"? what is you total tire/wheel height?

if your motor spins to 8000 rpm (with a 12t/72t), with that rear tire (with your measurement of 8"), you would be traveling about 32 mph
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I dont have a certain speed that I want to hit, but I would like it to be fast enough that it may scare me to slow down. Faster than 32 for sure. The Tec is stock, I dont know of hop up parts for them so if this is available it is something I may do at a later date.

Sorry I didnt realize but yes your correct the rear wheel is taller. Its a 12" on a 6" rim.

I guess Im more curious as to what clutch type set up I should be using first. The Tav or the Centrifugal. Then after we determine which clutch would be best we can work on the sprockets. Thanks
 
LSCustoms

LSCustoms

Moderator
#4
#4
weazel said:
I dont have a certain speed that I want to hit, but I would like it to be fast enough that it may scare me to slow down. Faster than 32 for sure. The Tec is stock, I dont know of hop up parts for them so if this is available it is something I may do at a later date.

Sorry I didnt realize but yes your correct the rear wheel is taller. Its a 12" on a 6" rim.

I guess Im more curious as to what clutch type set up I should be using first. The Tav or the Centrifugal. Then after we determine which clutch would be best we can work on the sprockets. Thanks
Click to expand...
with a 12t/72 (6 : 1 gear ratio) at 7500 rpm would be about 45 mph...

even with the tav, if you set the gear ratio to 6 : 1, would be about 45 mph. 45 mph is a good speed for a mini bike... with that motor you should be ok with that gear ratio as far as torque... and with a reg clutch...

what would scare you is relative... i dont think a mini bike could be fast enough to scare me... but my goal is to be up over 100 mph soon... with the newest motor project....
 
W

weazel

New Member
#5
#5
LSCustoms said:
with a 12t/72 (6 : 1 gear ratio) at 7500 rpm would be about 45 mph...

even with the tav, if you set the gear ratio to 6 : 1, would be about 45 mph. 45 mph is a good speed for a mini bike... with that motor you should be ok with that gear ratio as far as torque... and with a reg clutch...

what would scare you is relative... i dont think a mini bike could be fast enough to scare me... but my goal is to be up over 100 mph soon... with the newest motor project....
Click to expand...
45 is a good speed, I doubt it will scare me. Probably the GF but not me. Well unless I get some sort of tank slap going on, if that is even possible on these things. I would like to be up in the 60mph range but not sure if that is doable with my stuff. I suppose its just trial and error.

I wasnt sure if one of the clutches was better over the other, that is why I asked.
 
LSCustoms

LSCustoms

Moderator
#6
#6
weazel said:
45 is a good speed, I doubt it will scare me. Probably the GF but not me. Well unless I get some sort of tank slap going on, if that is even possible on these things. I would like to be up in the 60mph range but not sure if that is doable with my stuff. I suppose its just trial and error.

I wasnt sure if one of the clutches was better over the other, that is why I asked.
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I havent used the TAV stuff, but it helps out with low end torque, but allows for the bike to reach a higher speed, than if you were to use a jackshaft...

in my opinion, since you want to gear it to go faster than 45 (given the 8hp motor), i would go with a TAV...

but what you can do, since the normal style clutches arent too expensive to try... grab a 12t and use it with the 72 and see how you like it... then go from there... you can get a clone TAV (upgrade the belt on it) for a decent price over all too...

do a search on TAVs and the issues people have had with them, some seem to like them and some dont...

or send a pm to Newoldstock... he has played with them, so he may be able to give you a better opinion on you goal of 60 mph with a 8hp motor and TAV...
 
W

weazel

New Member
#7
#7
LSCustoms said:
I havent used the TAV stuff, but it helps out with low end torque, but allows for the bike to reach a higher speed, than if you were to use a jackshaft...

in my opinion, since you want to gear it to go faster than 45 (given the 8hp motor), i would go with a TAV...

but what you can do, since the normal style clutches arent too expensive to try... grab a 12t and use it with the 72 and see how you like it... then go from there... you can get a clone TAV (upgrade the belt on it) for a decent price over all too...

do a search on TAVs and the issues people have had with them, some seem to like them and some dont...

or send a pm to Newoldstock... he has played with them, so he may be able to give you a better opinion on you goal of 60 mph with a 8hp motor and TAV...
Click to expand...

Thanks for the tips.

One final question for you. Do you know where to buy hop up parts for the Tec or are there none available?
 
LSCustoms

LSCustoms

Moderator
#10
#10
fistfullabar said:
all stock engines are set to 3600 rpm 8hp tec hi-po parts may be pricey but can make for a killer build
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fistfullabar said:
tav works great on a stock engine vke or mike clements but be ready for sticker shock $$$$$$$$$$$$:scooter:
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yes, what fistfullabar said... Im actually making an order or two with Go Kart Racing Home Page for Clements Racing Products

and they do have parts for your motor, but you will have to call them and get a price... going into those motors can be pricey... i found a star motor for a decent deal, but it was still up there with briggs animal prices... and not as aggressive as i wanted... so i have to pass on it...
 
fistfullabar

fistfullabar

Well-Known Member
#11
#11
LSCustoms said:
yes, what fistfullabar said... Im actually making an order or two with Go Kart Racing Home Page for Clements Racing Products

and they do have parts for your motor, but you will have to call them and get a price... going into those motors can be pricey... i found a star motor for a decent deal, but it was still up there with briggs animal prices... and not as aggressive as i wanted... so i have to pass on it...
Click to expand...
what cha building now LS:eek:ut:
 
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