Author Topic: Time to freshen up the F Model bracket bike  (Read 118090 times)

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Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #375 on: November 19, 2014, 09:48:30 am »
FRANK:   You should have told me you needed jets = I had my jet kits [ with sets of 4-8 ] and my jet drills  [ 42 size 81-40 ]  in my truck...... never go to a race with out these little brass things that tune the carbs, since 1991.

Pops,

I appreciated you being in the lanes to drop some words of advice along the way. The suggestion on changing to a higher octane fuel was right on target to compensate for the lean conditions- it was one of those head slapping moments for me. I would have put your advice into play if I was racing the bike on sunday. I had to take the battery out of the Honda to put it in one of the top gas bikes so I was out anyway. Thanks for the fuel tip. I'll keep that one under my hat.

This was not my best weekend for racing but I'm not complaining. I'll be sure to bring my jets the next time in case they are needed. Having Lectrons on all the others bikes has caused me to go brain dead with the need for fuel adjustment with the flatslides on the Honda. Lets just say; "that won't happen again".   

Practice tree time, practice tree time, practice tree time. Oh, and a Gen2 clutch for my no bar Kaw.

Looking forward to next year fellas. Its definitely going to be an SOHC kind of year.   

Offline Bill/BentON Racing

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Re: Time to freshen up the F Model bracket bike
« Reply #376 on: November 20, 2014, 04:31:18 am »
You still need a petcock ?
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
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1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
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Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #377 on: November 20, 2014, 06:08:18 am »
You still need a petcock ?
Ummm, I needed one last Friday :-[. The big race is over now Bill.  :-\
« Last Edit: November 20, 2014, 11:24:27 am by dragracer »

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Time to freshen up the F Model bracket bike
« Reply #378 on: November 20, 2014, 05:30:29 pm »
I didn't see a leak??
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #379 on: November 20, 2014, 07:12:26 pm »
I didn't see a leak??


Had to keep turning it off when the engine wasn't running- thats why you may not have noticed it dripping fuel. Unfortunately, i neglected to turn it back on when i made my 3rd round elimination pass saturday night. I had a better reaction time and 60' time than my opponent, got out about 330' and it started to sputter. By the time i reached down to turn it on i had lost momentum, by the 660' mark he caught me right when the bowl started to recover. Bike didn't run right until the 1000' mark. By that time, he had crossed the line with me in pursuit only to see his win light come on.OH well, my fault and only my fault. Too much going on with getting the transmission issue worked out and the engine back on the bike, then wiring up the ignition kill for the air shifter and working on the other 2 bikes. Nevertheless, i'm grateful to have the bike shift through all the gears now- one less thing to  worry about for next season. 

If we weren't at the BIG SHOW, i would probably not have raced the bike with the petcock leaking. Its my own fault for not realizing i had the leak until a few days before the event. I did order one to be drop shipped to the track. Had i known those jokers wouldn't be picking up the mail, i'd have sent it to the hotel instead. Live, and learn. Still had loads of fun and got to hang out with my SOHC brotheren.

Offline Bill/BentON Racing

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Re: Time to freshen up the F Model bracket bike
« Reply #380 on: November 21, 2014, 03:24:28 am »
Wow, yes you did and so did we! Sh*t happens, not sure we had one, but I had Jerry gather up the
extra ones I had. We just forgot to let you know! Damn.....communication breakdown! It's not like either of us was doing anything else ! Saw your buddy's run on the tape! K. Next year will be more fun....and we'll be going more rounds than before! We are scheming in the background!  8) Bill
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
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Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #381 on: November 21, 2014, 11:09:37 am »
Wow, yes you did and so did we! Sh*t happens, not sure we had one, but I had Jerry gather up the
extra ones I had. We just forgot to let you know! Damn.....communication breakdown! It's not like either of us was doing anything else ! Saw your buddy's run on the tape! K. Next year will be more fun....and we'll be going more rounds than before! We are scheming in the background!  8) Bill

Bill, it would have been wrong of me to stop your progress to help me. My fuel problem was irrelevant compared to your engine issue. I figured since neither you or Jerry said anything, that you never found a petcock. I really want to thank you for the effort of gathering them up and bringing them down.

Communication, communication enhances team work!

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Time to freshen up the F Model bracket bike
« Reply #382 on: November 21, 2014, 01:56:22 pm »
None of them were a direct match. Like I said, I didn't see a leak  ;D ;) so I figured you had it repaired. I came by multiple times and you were off racing etc. At least your lovely wife was there to greet us.  ::) Just glad you had the Kaws to play with.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline POPS 911

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Re: Time to freshen up the F Model bracket bike
« Reply #383 on: November 25, 2014, 05:06:48 am »
FRANK: Tell the folks what carbs you run on your fine looking 750 SOHC and the main jet size .............. I can always make them jet bigger, 2 minutes after you hand them to me...... many stock 750 DOHC have came to life after the jet drill job , 1980's carb rules for motorcycles were lean on low and main jets.

Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #384 on: November 25, 2014, 07:47:16 am »
Pops,

I bought my carbs new over 18 years ago. I took them straight out of the box. Slipped them on the boots and cranked the bike up. The bike idled and ran fine.  I didn't see a need to rejet them at the time although the carbs came with a variety of new jets. I never took them apart until last year. I needed to replace the float needles and do a thorough cleaning. Up until the last race at Valdosta, I never had performance issues from a lean condition. I also never had an air fuel ratio check done either.  I never discolored a pipe either( indicator of serious lean). For some reason the bike went lean as hell and couldn't get out of its own way. I didn't realize it was a lean condition until the next morning when I took it out of the trailer. The wife asked me why my nice, new  shiny chrome pipe had turned to gold. SNAP!!!! LEAN. Dang it, the light came on. Lol. Funny thing is I've been out testing and racing in MUCH colder conditions with no change in performance. Before I get to messing with the jets, I'm going to dump all the fuel out of the tank and carbs, put in fresh fuel from a new pail, put in new spark plugs and read them at idle.

Find below the specs on the carbs on my bike. Keep in mind that almost 20 years ago, Kenny was not getting specially racked Mikuni's for the SOHC bikes. I happened to luck up on spacing that was close to the Honda when a buddy gave me a set of carbs off an 85 Ninja 900. I put them against the boots on the Honda and they were close to the same spacing. After some offset grinding to get the spacing right and opening up the ID of the boots, I got them to slip in place. I found a used set of 34mm round slides from Star Racing to fit a Ninja but something was wrong with the carbs. I sent them back and got credit towards a new set of flatslides but all they had in stock for that spacing was 36mm carbs. I was in a hurry to get the bike going so that's what I bought knowing they were WAy to big. In the end, I got them to work okay.
+++++++++++++++++++++++++++++++++++++++++++++
RS36-D8-K
Kaw Ninja 900 All, Kaw Ninja 1000 86-87,Yam FJ1100 Al,Yam FJ1200 All

Spacing 77-85-77
(700-17011)
42

Mains, 130

9DZH1*
(-3)

P-4

Pilots, 17.5

1/4-1/2

 

Offline POPS 911

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Re: Time to freshen up the F Model bracket bike
« Reply #385 on: November 26, 2014, 04:18:17 am »
FRANK:  18 years of tuning and you gave the folks the facts, that 130 main jet seems right up or down one size for what a weather station tells you = Friday morning when I got to the track my station was reading -125' [ running in a CAVE like Englishtown ] while the true elevation at SGMP IS 212'.  that's THE TIME YOU WANT TO SELL A DRAG BIKE W/ BEST TIME TICKET.  I had my jet box in my truck with 4 -8 jets in sizes  from 112 - 150  on up = yours for the asking.  Any of them KZ racers need a clean untouched 1000 motor got two and many head parts for the J.MODEL.

Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #386 on: March 14, 2015, 10:06:02 pm »
Decided to do some work today. Adjusted the valves and started it back up. Ran okay. Going racing in the morning. Hopefully all will go well.

Offline POPS 911

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Re: Time to freshen up the F Model bracket bike
« Reply #387 on: March 16, 2015, 07:40:55 am »
One of the first things I learned about drag bike motors living in OHIO WINTER DOWNTIME = back the cams off the valve to give the springs a rest over those long dark cold dayz.  On ST.PATRICKS DAY screw everything back down, adjust valves , fire up motor and put on the dyno to knock the rust off the seats and valve faces. Ran same KZ MOTOR FOR YEARS with only a broke 1st. and 2nd. gear over 18 years.  SOHC 750 motors are tuff and the KZ1000 motors are bullit proof = just ask BRUCE SAUERS............... be getting a lane soon.

POPS BK911 NHRA

Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #388 on: March 16, 2015, 04:14:04 pm »
Some time slips from yesterday. 6.69 @101.04 mph with a 1.53, 60 foot on the first pass- a far cry from the crappy passes i made down at the Cup race in November. Best 60' of the day was a 1.49 and the best ET was a 6.62. I'm sure that 1.49, 60' would have netted a 6.5??? pass but the bike didn't shift to 3rd for some reason- i think the chain got slack on that pass.

I went out first round to a red light on a 6.63 dial in but i'm satisfied that the bike is running okay.

Yeap Bill, we're ready for the first Cup race.

Offline Bill/BentON Racing

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Re: Time to freshen up the F Model bracket bike
« Reply #389 on: March 16, 2015, 05:35:31 pm »
K......thought I was....I will be. Nice time's!  K.
BentON Racing Website
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Time to freshen up the F Model bracket bike
« Reply #390 on: March 16, 2015, 08:00:31 pm »
Good news Frank. Thats one that is ready.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #391 on: March 16, 2015, 09:31:37 pm »
A few pictures from yesterday. I brought my go pro and forgot to use it- newbie. Lol.

Someone videod one of my runs and posted it on FB. Not sure i can pull it off there and post here but i'll try tomorrow.

Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #392 on: March 16, 2015, 09:37:53 pm »
Bill, i need one of those Mike heads you got laying around. I bet it would wake my bike up a lot. Unfortunately all i have is a stock valve, ported head. I might go stainless next time i tear it down. Its getting costly maintaining all this racing junk but i enjoy the heck out of having one go down the track.

Offline BPellerine

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Re: Time to freshen up the F Model bracket bike
« Reply #393 on: March 18, 2015, 04:52:15 pm »
ahh that's what sunshine and bare pavement looks like!!
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Re: Time to freshen up the F Model bracket bike
« Reply #394 on: March 18, 2015, 08:28:45 pm »
ahh that's what sunshine and bare pavement looks like!!

Yes sir, great weather- a perfect day for racing. While we're not quite out of the woods yet for cool nights, the worst is behind us here in South Carolina.

I've got another race to go to this weekend. So far it looks good as long as the rain chances don't increase beyond 40%. I won't be on the Honda this time but intend to race my wife's Kawasaki as its a 5.60 index race.

Offline BPellerine

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Re: Time to freshen up the F Model bracket bike
« Reply #395 on: March 19, 2015, 06:21:16 pm »
I have some relatives living in sc and they make me jealous when they talk about the weather we just got 30mm of snow !!!!
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Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #396 on: March 26, 2015, 05:51:23 pm »

Hey fellas, whats the deal on the cams chain again?? Is there an availability issue??  I need to start on another motor project and hate to get caught up without a new one.

Offline bwaller

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Re: Time to freshen up the F Model bracket bike
« Reply #397 on: March 26, 2015, 06:28:00 pm »
My understanding is the Tsubaki HD chains will no longer be produced. There is still inventory. Some longer chains that don't sell as well will be in stock longer and can be shortened.

Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #398 on: March 26, 2015, 06:34:11 pm »
My understanding is the Tsubaki HD chains will no longer be produced. There is still inventory. Some longer chains that don't sell as well will be in stock longer and can be shortened.

I'd better get searching for a few of the HD chains soon. I'd hate to ruin an engine due to a broken cam chain.

Offline dragracer

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Re: Time to freshen up the F Model bracket bike
« Reply #399 on: April 01, 2015, 11:17:27 pm »
Well, i've been working on putting another top end on my wife's dragbike. Got it fired up and the carbs tuned this afternoon so i could test it at Darlington tonight. Went to roll it out of the shop and heard a weird noise from the tranny so i pushed it back in the shop. Since i was all geared up to go test her bike, i decided to ride to the track anyway since i already had my no bar Kaw and the F model loaded in the trailer. I figured I'd take my frustrations with the dragbike out by being at the track.

Made one pass on the Honda just to get my fix of race fuel and burning rubber. I was able to lay down a 1.55- 60 foot, 6.70 in the 1/8th mile,  and a 10.71 @118mph in the 1/4 mile. I think the bike is definitely leaning out when the temps get cooler. The 60' is off by 4-5 hundreths and the 1/8th mile time is off about a tenth since the last time i took it out- the only differrence is it was cooler tonight. Time to do a  jet change before the Cup race.

Bill, there's your 1/4 mile ET to better. Lets see whatcha got my friend!!!!!!!!!! I'll try to post the time slip at some point tomorrow. I did connect up the Go PRo to the bike but have not played it back yet.