Rock Racing mdb detail photos

R

rockracing59

New Member
#21
#21
Twid said:
Lookin good! Do you think the diamond plate will have enough grip for yer bum when you rip off that line it would suck to lose a race cus yer sliding of the back of the bike. Imo I'd keep it all in one thread as well.
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Yup, your right.....made a few 300ft runs today and it kinda scared me just a bit....this thing goes like stink. The claimed 25hp is right on and I will definitely have to do something with the seat pan.
 
Twid

Twid

Active Member
#22
#22
may be glue a piece of foam on the diamond plate or some of that grip stuff for a bathtub. Iv also seen skateboards cut in half for seats. What I would do is contact Manchester1 aka Karen and have a custom seat made.
 
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Twid

Twid

Active Member
#29
#29
trinik7597 said:
You should be hitting 40/45 within 100 ft.
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I was thinking the same thing, I remember massacre telling me that is what a lot of you 100 footers mph are.
I bet gearing has a lot to play with rr59 25hp 40-45 300 foot run. I have stock 5hp Briggs in a invader that does about 35-40 in 300'.
 
trinik7597

trinik7597

Active Member
#30
#30
For sure twid that gearing has a ton to do with it !!! We are gearing to be hitting top speed at the line !! But in 300' with 25 HP you should be hitting 60 .. There is no way to Gage HP by just guessing and a dyno can say what u want it to !!! Look at the motor builders challenge that Brad hill put on . mdb got first at 28.9 HP and Barry young got second at 28.8 another member here put down a real respectable run with a bored stroker build ... There is just no way with a stock bore and stroke on a comparable dyno even on meth you can lay down close to those #'s the difference in 1 HP at the top of the mark is at least $1000 per with these small motors .. Just saying
 
Twid

Twid

Active Member
#31
#31
trinik7597 said:
For sure twid that gearing has a ton to do with it !!! We are gearing to be hitting top speed at the line !! But in 300' with 25 HP you should be hitting 60 .. There is no way to Gage HP by just guessing and a dyno can say what u want it to !!! Look at the motor builders challenge that Brad hill put on . mdb got first at 28.9 HP and Barry young got second at 28.8 another member here put down a real respectable run with a bored stroker build ... There is just no way with a stock bore and stroke on a comparable dyno even on meth you can lay down close to those #'s the difference in 1 HP at the top of the mark is at least $1000 per with these small motors .. Just saying
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Do you have a link for the Brad hill challenge?
 
massacre

massacre

#34
#34
trinik7597 said:
You should be hitting 40/45 within 100 ft.
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Tim I don't think anyone has gone 40 mph yet, have they?

I know we talk about going 40 but last I heard wasn't 36 the record or something? I could be wrong about this though. If I remember right you built your drag bike specifically to go 40 mph?

Gearing is crucial in a 100ft race, I'm sweating that part right now actually. Right now my gearing is 3.33 which in my mind is not enough.
But the size difference between the Polar clutches is a "gear reduction" as well, so that 3.33 is really higher than that. How much higher is an unknown, i should really turn everything over and start counting revolutions lol.
 
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trinik7597

trinik7597

Active Member
#37
#37
No I think 38 was the fastest !! But you are right we have talked about this a couple times ... All I am saying is my stock animal that is a pig out of the hole due to gearing will top 45 in 300 feet . I am not trying to highjack the thread though !!!! Its a very nice bike !!!!
 
R

rockracing59

New Member
#38
#38
i was just making an educated guess...not sure if I was even in the ball park. My baseline final drive is 5.3.....where the clutch hits is important also..May 1st is a points race at my local drag strip, I will hopefully be ready for that and my gf will take some video. Having some jetting issues also
 
R

rockracing59

New Member
#40
#40
trinik7597 said:
For sure twid that gearing has a ton to do with it !!! We are gearing to be hitting top speed at the line !! But in 300' with 25 HP you should be hitting 60 .. There is no way to Gage HP by just guessing and a dyno can say what u want it to !!! Look at the motor builders challenge that Brad hill put on . mdb got first at 28.9 HP and Barry young got second at 28.8 another member here put down a real respectable run with a bored stroker build ... There is just no way with a stock bore and stroke on a comparable dyno even on meth you can lay down close to those #'s the difference in 1 HP at the top of the mark is at least $1000 per with these small motors .. Just saying
Click to expand...
also, i did not pace out the parking lot....it could be maybe only 200ft....idk for sure
 
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