Author Topic: 76 F model project- mono shock suspension(aka-Kingsnake)  (Read 139712 times)

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Offline gschuld

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Re: 76 F model project- mono shock suspension
« Reply #800 on: March 04, 2020, 07:14:47 AM »
Looking fwd to hearing results.😉

George


Offline POPS 911

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Re: 76 F model project- mono shock suspension
« Reply #801 on: March 05, 2020, 06:45:05 AM »
FRANKIE: A blue NOS bottle with 900 on the gauge in the upper gears will get you a 9 something in 1320'.

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Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #802 on: March 05, 2020, 01:35:23 PM »
FRANKIE: A blue NOS bottle with 900 on the gauge in the upper gears will get you a 9 something in 1320'.

POPS BK911
Hello Richard. Glad to see you surfaced for a moment. 

Yes, a 9 second pass is easily attainable with this bike on nitrous.  Its already set up with a complete progressive system. I need to make a lot more motor passes to see how quick I can go on horsepower before I spray this thing. Stand by and I'll eventually give you a 9 second time slip. Lol.

Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #803 on: March 24, 2020, 09:03:36 PM »
Did a little work to the bike since racing season has been postponed. Got the carbs synched but only after having to use a different set of gauges.  I've got to put a WEGO on the bike soon to verify my AFR numbers. I rejetted the carbs right out of the box using the same jet sizes as my F3 with 36mm carbs.  I really need actual AFR readings for this particular bike in order to properly jet these 34mm flatslides.

I could be overly optimistic, but once fully tuned, and the suspension tweaked properly this platform may be a good candidate for a high 9 second N/A pass under the right conditions. Only time will tell.

Excuse the junky condition of the shop, its mainly what i consider "winter time clutter". Well, maybe its actually year round disorganization- lol.



« Last Edit: March 24, 2020, 09:17:11 PM by dragracer »

Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #804 on: March 24, 2020, 09:51:51 PM »
I thought I had posted these videos from my last time testing. This is only the 2nd pass on the bike. It didn't immediately shift into second gear so I had to hit the button twice. Not the quickest pass of the day but it had a 1.40 sixty foot time. The video quality seems to be a degraded on this post. My wife emailed it to me and it lost some clarity  upon upload for some reason.

What i learned from the audio side of this video is when i launched the bike, the rpm's dropped a little more than i would have liked. With that bit of knowledge, i now know i need to increase the rpm's a bit more which should give me a better 60 foot time. The suspension seems to have worked well so i feel leaving harder won't be a problem. This is a good example of the advantages of the mono shock suspension set up versus the limited adjustments from the stock dual shocks on our SOHC bikes. Te bike left so darn smooth, i ad no clue te 60 foot time was tat low until i looked at te time slip. I'm extremely pleased with the outcome of my effort on building this chassis set up.  The results speak for themselves.
« Last Edit: March 24, 2020, 10:14:35 PM by dragracer »

Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #805 on: March 24, 2020, 09:59:12 PM »
This is the third pass since the bike was built. It shifted perfectly every time, had a 1.41 sixty foot time and a  ran 6.39 at 103.89mph. I'm satisfied  to say this was only the 3rd pass on a totally new bike.  I haven't become 100% comfortable with the bike yet. As I get more seat time,  I'm hopeful the sixty foot times and ET's will drop even more. I'm still uncertain if i was actually WOT as this is not a 1/4 turn throttle and i may not have reached around enough to lock it.
« Last Edit: March 24, 2020, 10:18:23 PM by dragracer »

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 76 F model project- mono shock suspension
« Reply #806 on: March 25, 2020, 09:06:23 AM »
Damn good start Frank  ;)
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: 76 F model project- mono shock suspension
« Reply #807 on: March 25, 2020, 01:01:00 PM »
Damn good start Frank  ;)

Depending upon which ET conversion calculator you use, that 6.39 1/8th mile ET would equate to between a 9.98 to a 10.06 quarter mile pass.  Of course those conversions don't take everything I to account so until I make an actual 1/4 mile pass, I can't say with certainly if this is just a ten, or possibly  a nine second SOHC.  Definitely low 10 second regardless.

Offline Medyo Bastos

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Re: 76 F model project- mono shock suspension
« Reply #808 on: March 25, 2020, 01:39:21 PM »
Hot dawg!


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Offline gschuld

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Re: 76 F model project- mono shock suspension
« Reply #809 on: March 25, 2020, 03:01:26 PM »
Love it!

What mph would the 9.9 1/4 theoretically end up in?

A bit shy of 130?

George

Offline 754

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Re: 76 F model project- mono shock suspension
« Reply #810 on: March 25, 2020, 03:30:40 PM »
I think over 130...
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Offline Medyo Bastos

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Re: 76 F model project- mono shock suspension
« Reply #811 on: March 25, 2020, 04:32:02 PM »
Love it!

What mph would the 9.9 1/4 theoretically end up in?

A bit shy of 130?

George

Why stop now???  Zoooma zooom zooommm


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Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #812 on: March 25, 2020, 05:45:55 PM »
Hard to predict the mph in some cases. A lot of it will come down to
60 foot times,  gearing and the flow of the head along with the total weight of the package. I have the bike as light as I feel comfortable with  for now but I did add a few pounds myself over the winter months. I'll shed that quickly I hope.

Offline Old Scrambler

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Re: 76 F model project- mono shock suspension
« Reply #813 on: April 03, 2020, 01:42:02 PM »
Its that 'home-cooking' influence...............Great start on this build ;)..........Did you bore the intake rubbers and manifolds?
Dennis in Wisconsin
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Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #814 on: April 04, 2020, 01:52:41 AM »
Its that 'home-cooking' influence...............Great start on this build ;)..........Did you bore the intake rubbers and manifolds?

Hello Dennis,

I trust all is well with you.  So far, my back yard build has not failed to perform up to my expectations. With only 3 passesr, the numbers show a lot of promise. Its not like i have the very best parts and pieces on this build but i tried not to cut any corners. I focused on the chassis mainly and its paid off from what i can tell by the 60' times.

As to the intake boots and the intake ports on the head, i used late k model boots but haven't bored them except at the immediate carb inlet side. Of course the head has been nicely ported. In reality the boot are probably as slight restriction for the flow and need to be evaluated at some point.  In the end, its just a bracket bike so extracting every little bit isn't really necessary. Hopefully at the  end of the next few months we'lll be able to go back into race mode and i can get some 1/4 mile passes in. I'm curious as to how quick it will run in the 1320.
« Last Edit: April 04, 2020, 01:54:43 AM by dragracer »

Offline Old Scrambler

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Re: 76 F model project- mono shock suspension
« Reply #815 on: April 04, 2020, 07:43:20 AM »
Your adding testimony to how well the RS34s perform and......DID EVERYBODY LISTEN........"He concentrated on the chassis" ;) ;) ;)
Dennis in Wisconsin
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 76 F model project- mono shock suspension
« Reply #816 on: April 04, 2020, 07:51:46 AM »
34's or 36's?
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: 76 F model project- mono shock suspension
« Reply #817 on: April 04, 2020, 08:31:34 PM »
34's or 36's?

34's Jerry. But I rejetted them and raised the needles.

Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #818 on: April 04, 2020, 09:29:11 PM »
Your adding testimony to how well the RS34s perform and......DID EVERYBODY LISTEN........"He concentrated on the chassis" ;) ;) ;)

No issues with the 34mm flatslides Dennis. I've still got some fine tuning to do once I get the AFR data logger on the bike.

Yes, chassis work to me is much more important   than having a big cc engine.  At some point, I'd like to install a totally stock engine on this chassis to see what ET it will show. I believe it would surprise most on this forum that understand drag racing.

Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #819 on: June 29, 2020, 12:38:05 PM »
Well gentlemen,  much to my complete dismay, I'm going be forced to pull the engine off of the bike.  Darn thing is running very well,  has no leaks and has put up some quick sixty footvtimes, ETs and mph.  Unfortunately,  those numbers have not been consistent.  For every perfect pass the bike makes, at least two will end in a missed shift to 2nd gear. I've attempted to make external changes in hopes of remedying my problem. I initially thought maybe i was fanning the shift button because the grip may have caused an obstruction.  I trimmed the grip but the problem was still there- no human error. It shifts into every other gear flawlessly. I changed the kill time. Same flawed results.  I just replaced the shift button and tested this weekend.  It wouldn't shift to 2nd.

The problem likely rests with 2 possible components.  The shift drum or i have a bad shift fork. I will replace both in hopes of permanently solving this frustrating issue. I hate to split the cases at this point. I have zero oil leaks which is rare for a larger engine. If all goes well,  it should go back together the same way with new gaskets in place. 

I'll start the process sometime next week.  I've got an a VW race coming up soon and need to concentrate on getting my little dragster ready. The bike isn't a priority at the moment.

Offline Tintop

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Re: 76 F model project- mono shock suspension
« Reply #820 on: June 29, 2020, 12:54:44 PM »
Not the best of news, but given how well the bike has worked so far a teething issue was to be expected.  Just to bad the remedy is to split the cases. :'(
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Offline dragracer

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Re: 76 F model project- mono shock suspension
« Reply #821 on: June 29, 2020, 04:12:38 PM »
Not the best of news, but given how well the bike has worked so far a teething issue was to be expected.  Just to bad the remedy is to split the cases. :'(

The early performance numbers definitely are softening the blow. I can't move to the next level with this build until it shifts properly.  I cannot complain much because it has met my expectations and in some cases exceeded the cost versus benefits curve. Since I've done all the work myself from ground up,  I've got no one else to blame or rely on to remedy this situation. Sometimes in life we have to go backwards in order to move forward in a position direction.

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Re: 76 F model project- mono shock suspension
« Reply #822 on: June 29, 2020, 04:22:10 PM »
Well that bites! You had the skill to make it leak free the first time so I trust and hope it is a repeatable experience. Good luck sorting it out!
David- back in the desert SW!

Offline Medyo Bastos

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Re: 76 F model project- mono shock suspension
« Reply #823 on: June 29, 2020, 05:08:00 PM »
Well that bites! You had the skill to make it leak free the first time so I trust and hope it is a repeatable experience. Good luck sorting it out!
Ditto!


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Offline scottly

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Re: 76 F model project- mono shock suspension
« Reply #824 on: June 29, 2020, 06:53:06 PM »

The problem likely rests with 2 possible components.  The shift drum or i have a bad shift fork.
I don't think it's likely the drum or fork are at fault, Frank. I've never seen or heard of a bad drum, and you would have noticed a bent fork. The most common problem with 2nd gear is popping out of gear at WFO, due to worn dogs.
For the 1-2 shift, the air shifter needs to travel twice as far, which takes twice as long, as the other up-shifts. I would take a closer look there before splitting the cases. ;)
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