Author Topic: 76 F model project- mono shock suspension  (Read 39781 times)

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Offline dragracer

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76 F model project- mono shock suspension
« on: November 30, 2014, 10:28:31 pm »
Well, i decided to uncover the old K model and pull it out of the shed to see what condition it was in after sitting  untouched for around 7 years. As you can see in the attached picture, its covered with dirt and grime but its still complete minus the carbs. I pulled them off a while ago to temporarily put on a friends bike so he could get his bike running. They're now sitting in a bag in the shop waiting to go back on my K.

My intent for this bike is to set it up as a back up dragbike to my F model. I'll probably do another engine build all together and put the stock motor on a shelf til i can rebuild it for later use. Odds are i'll build an 836 with a mildly ported head and a small cam. As far as the chasis goes, my thoughts are to convert it to a mono shock set up with an extended GSXR swingarm with a 17" GSXR wheel in the rear and a Katana wheel in the front.

I kinda hate to cut this bike up as it might not take much to restore it back to its orginal condition. I've still got a bare F model frame in a shed that i can use to build another bike. I'll make a decision soon as to what route to take. Either way, at least the K model is no longer out of site and out of mind.
« Last Edit: October 16, 2015, 09:42:03 pm by dragracer »

Offline TurboD

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Re: 78 K model project
« Reply #1 on: December 01, 2014, 06:01:19 am »
That looks like a cool winter project, I have a couple just like it. I am thinking the same thing about building a second SOHC bike.

Looking forward to following this project. Good luck. ;D
« Last Edit: December 01, 2014, 06:57:45 am by TurboD »

Offline dragracer

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Re: 78 K model project
« Reply #2 on: December 01, 2014, 06:22:28 pm »
Well, it seems i may not be modifying this bike after all. My brother gave me this bike over 20 years ago. He bought it from an older couple in 79' and rode it on and off until he moved to Atlanta. It had been left outside  when the shed he had it stored in was torn down. Thats when i came from Texas and picked it up. Took me a while but i got it running again and rode it a lot until i bought my Harley and moved back to SC. I then lowered the Honda, put the drag bars on it with the sidewinder and bracket raced it for a few years until i built my F model, specifically set up for dragracing. The K pretty much got parked then but ridden from time to time.   

Now that i pulled it, my brother has expressed a desire to restore the bike back to its original condition so he can have something to cruise around on when he visits me in SC. So... this means i'll be digging that spare F model frame out to build a back up bike with instead of the K model. I'll try to  post progress pics of the chassis and engine in the next month or so as i move along.

Offline dragracer

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Re: 78 K model project
« Reply #3 on: December 07, 2014, 08:30:50 pm »
Pulled the old 76' F model frame from under the shed yesterday. Test fitted a few mono shock swingarms to see which would clear the frame. Looks like the Katana arm will work but its not my prefered choice due to it being made of steel and i really want an aluminum arm. It'll have to be extended about 7-8 inches to get the wheelbase i'm looking for on this build. I'm trying to make this bike as low and as long as my 78' F model but use a mono shock versus the stock type, dual shocks. A mono shock will allow me to better tune  the suspension in for drag racing because i can tweak both dampening and rebound to get the best launch and 60' times out of the bike. This will be a slow process since i've got to get 3 other bikes ready for next season and this one is last in line.   Stay tuned.

Oh yeah, i changed the title of the thread too!!
« Last Edit: December 07, 2014, 08:32:40 pm by dragracer »

Offline Retro Rocket

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Re: 76 F model project
« Reply #4 on: December 07, 2014, 09:10:19 pm »
Frank, an easy swingarm swap is the early GSXR1100 arm {use the H or J model, they are slightly longer than the earlier G model}, they are monoshock, about 6 inches longer {used to know exactly, can't remember ::)} and bolt STRAIGHT IN....... ;D  Cheap too... ;)
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 76 F model project
« Reply #5 on: December 07, 2014, 10:07:09 pm »
I'm watching!! Just so happens that extra frame I have for the 1000 is a STOCK frame and I know how much you love drag racing stock frames  ;) ;D ;D Idea - just get 2 of everything  ;D
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline 750cafe

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Re: 76 F model project
« Reply #6 on: December 15, 2014, 09:57:40 am »
Doesn't a '76 750F have a rear disc brake?

Eric
Is there anything more fun than riding? They are between your legs and are quiet when you turn them off.

Offline dragracer

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Re: 76 F model project
« Reply #7 on: December 15, 2014, 11:48:17 am »
Doesn't a '76 750F have a rear disc brake?

Eric

Yes, F models have rear discs. The picture posted was of the K model build  this thread was originally going to document. I changed directions and renamed the thread 76 F model instead of 78 K model. I guess I need to put up a new pic of the bare F model frame since that's all I'm starting with at this point.

Offline Bill/BentON Racing

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Re: 76 F model project
« Reply #8 on: December 15, 2014, 11:55:46 am »
What you need?  ;D  Gold wheels and RC rods in For Sale section!  8) G'luck, Bill
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Offline dragracer

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Re: 76 F model project
« Reply #9 on: December 15, 2014, 02:24:44 pm »
What you need?  ;D  Gold wheels and RC rods in For Sale section!  8) G'luck, Bill

Rods might be needed. I'm good on wheels. Going 17".

What kind of F model body work do you have Bill?? Tank??? Side covers?? Cracked is okay as long as its repairable and has all tabs. Early F model.

Offline Bill/BentON Racing

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Re: 76 F model project
« Reply #10 on: December 15, 2014, 03:21:01 pm »
I'll check.
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Offline dragracer

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Re: 76 F model project
« Reply #11 on: December 24, 2014, 07:49:08 am »
Well, I got a box today. Time to start figuring out this DOHC to SOHC conversion with some help from my friends on this forum. I see more parts boxes coming my way in the near future.

Offline Bill/BentON Racing

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Re: 76 F model project
« Reply #12 on: December 31, 2014, 01:39:22 pm »
Your box about like mine!  ;D Bill
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Offline kmb69

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Re: 76 F model project
« Reply #13 on: December 31, 2014, 03:39:40 pm »
Bill,
You sure that's the correct GL primary to match a 900 crank? Looks like a 1100-1200 to me. I think you need a GL1000 primary for the 900 crank.
Keith
« Last Edit: December 31, 2014, 03:44:32 pm by kmb69 »

Offline dragracer

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Re: 76 F model project
« Reply #14 on: December 31, 2014, 11:17:34 pm »
Bill,
You sure that's the correct GL primary to match a 900 crank? Looks like a 1100-1200 to me. I think you need a GL1000 primary for the 900 crank.
Keith


Yeah, i think the 1000 is the correct GL parts source. I'm about to pull the trigger on a setup from Ebay. Gathering parts now. Unsure of when i'll actually be able to start picking at test fitting anything. At the moment, i'm getting close to making the wifes car tire dragbike into a rolling chassis. Once we get the wheels and tires on, i can get her to "test fit" the bike to see where the foot pegs need to go. From there its just a matter of welding on the various brackets for the electronics, the nitrous bottle, battery box and then reenforcing/bracing the wheelie bars. In addition to getting the chassis ready, i've got to build a brand new motor. Big block is getting resleeved as we speak and then bored out to 85mm and o-ringed. Ordering new pistons, cam chain, case and head studs friday. Cases are being bored and the main cap modification also.  Mark 2 crank is at the machinist being welded. Going to get the bottom end together and then pull the head off her old bike. I'll freshened it up with a valve job, new valve springs and a new set of bigger cams.

Lots to do, but i want the wife happy before i start on my own toys. Happy wife, happy home. The reality is, if she's excited about racing again with the new bike, i get to come out and play too. Lol. Method to the madness fellas.

Happy New Year to all. !!!!!   

Offline Medyo Bastos

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Re: 76 F model project
« Reply #15 on: December 31, 2014, 11:59:12 pm »

Offline Bill/BentON Racing

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Re: 76 F model project
« Reply #16 on: January 01, 2015, 04:55:10 am »
Yeh, I wasn't sure what year. It s a 1100 or 1200. Got a $20.00 paperweight! Haha. Now I get GL1000 one!  ;D Bill
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Offline Bill/BentON Racing

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Re: 76 F model project
« Reply #17 on: January 01, 2015, 09:14:43 am »
Just got one on fleabay 1975 GL1000 $29.95 + $12.95 to ship, Bill ;D
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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: 76 F model project
« Reply #18 on: January 01, 2015, 12:16:23 pm »
You guys have a final drive shaft from an earlier one for the 78 engine? Not sure how much earlier but I'd like to avoid the chain oiler shaft. I compared the fiche for my 75 F and everything appears to be the same except the shaft. A complete 'unit' vs just shaft would be easier. Thats one option I have or maybe just use the original and find the conversion sprocket if anyone knows where they can be found.

Parts are here from Japan and more coming  ;D  The Yamiya order only took 5 days and it was placed on Christmas. The US orders placed on the same day are, well......... hey, at least I got an email from Pat saying the case studs were out of stock. The Tsubaki camchain off Amazon and the cam from 'Texas' will show up next week. 

OK just checked. It is found ONLY on the 75/76 F and the 76 K. Gotta put the 78 K engine in a 75 F frame so it needs to line up and not have that damn chain oiler.
« Last Edit: January 01, 2015, 12:20:58 pm by Jerry Rxman Griffin aka MuthaF'er »
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Bill/BentON Racing

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Re: 76 F model project
« Reply #19 on: January 01, 2015, 12:51:49 pm »
You need an output shaft for 75/76F ? I should have one, Bill
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 76 F model project
« Reply #20 on: January 01, 2015, 02:58:02 pm »
Yeah, that would help. Let me know if you have the whole unit with good bearings and what the tooth count is on the gear. I'll need to decide which way to go. I can either swap that or find a conversion sprocket and a seal since the part numbers for the seals are different. 
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Bill/BentON Racing

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Re: 76 F model project
« Reply #21 on: January 01, 2015, 03:37:20 pm »
This one welded! K.  ;D 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 cbr954

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Re: 76 F model project
« Reply #22 on: January 01, 2015, 03:47:30 pm »
This one welded! K.  ;D Bill
  RC welded them to I believe?  What is everyone doing nowdays for this part?  I was thinking about welding mine too unless there is a better alternative
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Offline dragracer

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Re: 76 F model project
« Reply #23 on: January 01, 2015, 05:50:44 pm »
This one welded! K.  ;D Bill
  RC welded them to I believe?  What is everyone doing nowdays for this part?  I was thinking about welding mine too unless there is a better alternative

Mine is not welded. Never had an issue with it up to now. Not to say it won't explode the next time i go racing. Maybe Billy has his done.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 76 F model project
« Reply #24 on: January 01, 2015, 10:23:25 pm »
Who is it/was it that was doing the bolt kit for them? Flush hex head I believe? Mark McGrew? The German guys that are/were making the cush rubbers? Classic City?

I wonder how far off original balance those welds are?

I just suggested to Elan to consider making new cush rubbers for these since he has a handle on the oil stopper seal rubber component.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

 

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