Topic: 750F thread?

[Mandic]

Oh I know it could be good, unfortunately I don't even have the time for what I've done to it, haha.  So what it is, is what I get.  It is a lot better than the 33 year old paint peeling and surface rust spots I had.

[gearhead ed]

Here is a pic of my 78 F3 I picked it up a few years ago with 9k on and have put about 20k with no real problems. I put on the Kerker exhaust dyna ignition, accle coils, rejetted to 125's, tires, sprockets,chain,swing arm bushings,allballs steering head bearings I think some top end work is in my future but for now all is well.

Nice bike,do you know who makes the backrest?

Thanks!

[hesselfuzz]

Glad to find this thread. Was up way too late reading it last night. I am finishing up rebuilding a 73k right now and was intending to do the F2 next. After reading about some of the "issues" w/ the F2, I'm reconsidering. I know  those here love their SS's but what are their shortcomings? I have a whole other K I could build up instead.

What about those F2 heads; bigger valves (good?), retainers (bad)

The carbs; some say the K's are better?

What about the rear swing arm; I've some say it's longer but my sure doesn't look it?

I'm not into restoration freak (apologies to those of that bent). I spent less than $500 for the three bikes and want to do a cafe racer. Am willing to hybridize between the F and K's so what's the hot ticket.

Let the haggling begin.

[fatmatt650]

You should give up on that F right now and give it to someone who will properly appreciate it. Feel free to PM me for delivery instructions.

[hesselfuzz]

Ha-ha, everyone on here is a joker.

[Mandic]

Rear sets for an F2 are custom or nothing, so that is a big thing.  I want them on my bike but don't have the pegs and shifter arms to fab up mounts right now. 

Engine stuff is nothing but it is costlier. 

Honestly after getting my head overhauled with all Cycle-X parts, I don't see why the retainers would be week in an F2.  They are machine steel, not stamped steel like Cycle-X claims. 

Pistons are costlier and I don't think I've found a source for OEM sized ones at a reasonable price.  I'd like to have used lighter pistons in my rebuild but couldn't locate any that didn't rival the cost of 836 ones. 

Rear swing arm, I cannot verify but the service manual states that the wheelbase isn't any different on an F2 I believe.  I just bought a generic swingarm bearing kit and installed it.  No issues. The strut mount is on top of the swing arm for the caliper mount though.  So something like the Dresda arm from Carpy would have to be modified to work. 

Seriously if you don't want to bother with the F2 I am certain some folks here would gladly take it off your hands.  I lucked into mine and would gladly have another, ha. 

So honestly if it were me, and I had a pile of parts/bikes.  I'd consider a K frame with everything else F2 to get the bolt on Rear set and that is about the only reason.  Would still have to custom mount the rear master cylinder, but I feel that would be easier than locating and fabbing rear set mounts.  Would allow you to switch to a newer master cylinder off something else that maybe is cleaner looking or easier to get parts for. 

[Jerry Rxman Griffin aka MuthaF'er]

The one and only downside to the 750 with the most "tech of the day" F2/F3 is the valve guides wear quicker than all the other 750s due to a redesign of the head to accomodate larger valves. The valve angle in the head put more pressure on the guides apparently. If you have this issue APE has a stock non-porting rebuild service they do with better guides. Yes, a few parts are harder to come by just as they are with the F/F1. The bigger valves mean a little more HP. I never knew that to be a problem  My question would be how many miles does your head have on it or how many miles would you put on a rebuilt head. I've seen from all the posts 30,000 to 40,000 miles as the problem area. 

[MRieck]

Rear sets for an F2 are custom or nothing, so that is a big thing.  I want them on my bike but don't have the pegs and shifter arms to fab up mounts right now.  

Engine stuff is nothing but it is costlier.  

Honestly after getting my head overhauled with all Cycle-X parts, I don't see why the retainers would be week in an F2.  They are machine steel, not stamped steel like Cycle-X claims.  

Pistons are costlier and I don't think I've found a source for OEM sized ones at a reasonable price.  I'd like to have used lighter pistons in my rebuild but couldn't locate any that didn't rival the cost of 836 ones.  

Rear swing arm, I cannot verify but the service manual states that the wheelbase isn't any different on an F2 I believe.  I just bought a generic swingarm bearing kit and installed it.  No issues. The strut mount is on top of the swing arm for the caliper mount though.  So something like the Dresda arm from Carpy would have to be modified to work.  

Seriously if you don't want to bother with the F2 I am certain some folks here would gladly take it off your hands.  I lucked into mine and would gladly have another, ha.  

So honestly if it were me, and I had a pile of parts/bikes.  I'd consider a K frame with everything else F2 to get the bolt on Rear set and that is about the only reason.  Would still have to custom mount the rear master cylinder, but I feel that would be easier than locating and fabbing rear set mounts.  Would allow you to switch to a newer master cylinder off something else that maybe is cleaner looking or easier to get parts for.  

The keepers have a shallow angle plus the keeper hole in the retainers is thin at the bottom with a sharp lip. It can crack and split. You have to look at at early system vs later K/F2 system to appreciate the difference. The best F2 set up was the the Yoshimura spring/retainer/keepers package. Ken uses R/D which beefs up the bottom of the retainer. That should end problems especially if loading more spring into it. If you are serious about the F2 I'd recommend using the Kibblewhite 5mm set up with the 32mm amd 34mm intake valves. It is not cheap but the 34 intake valve, for example, is over 15 grams lighter than the stock F2 piece

[mick750F]

Rear sets for an F2 are custom or nothing, so that is a big thing.  I want them on my bike but don't have the pegs and shifter arms to fab up mounts right now.  

Engine stuff is nothing but it is costlier.  

Honestly after getting my head overhauled with all Cycle-X parts, I don't see why the retainers would be week in an F2.  They are machine steel, not stamped steel like Cycle-X claims.  

Pistons are costlier and I don't think I've found a source for OEM sized ones at a reasonable price.  I'd like to have used lighter pistons in my rebuild but couldn't locate any that didn't rival the cost of 836 ones.  

Rear swing arm, I cannot verify but the service manual states that the wheelbase isn't any different on an F2 I believe.  I just bought a generic swingarm bearing kit and installed it.  No issues. The strut mount is on top of the swing arm for the caliper mount though.  So something like the Dresda arm from Carpy would have to be modified to work.  

Seriously if you don't want to bother with the F2 I am certain some folks here would gladly take it off your hands.  I lucked into mine and would gladly have another, ha.  

So honestly if it were me, and I had a pile of parts/bikes.  I'd consider a K frame with everything else F2 to get the bolt on Rear set and that is about the only reason.  Would still have to custom mount the rear master cylinder, but I feel that would be easier than locating and fabbing rear set mounts.  Would allow you to switch to a newer master cylinder off something else that maybe is cleaner looking or easier to get parts for.  

The keepers have a shallow angle plus the keeper hole in the retainers is thin at the bottom with a sharp lip. It can crack and split. You have to look at at early system vs later K/F2 system to appreciate the difference. The best F2 set up was the the Yoshimura spring/retainer/keepers package. Ken uses R/D which beefs up the bottom of the retainer. That should end problems especially if loading more spring into it. If you are serious about the F2 I'd recommend using the Kibblewhite 5mm set up with the 32mm amd 34mm intake valves. It is not cheap but the 34 intake valve, for example, is over 15 grams lighter than the stock F2 piece

   The Devil speaks his mind. Hi Mike...whaddup? We should talk soon, I sense important work in your future...important to me anyway.

Mike

[cafenut]

heres todays  $100 find.   http://www.photoshop.com/users/myhondas/assets/38d0b57458614d3b853a50e047f177f2http://www.photoshop.com/users/myhondas/assets/cd73c37e7c454a54881a0f01cae83584http://www.photoshop.com/users/myhondas/assets/f42c616114534bcaadb839fb3aab0c07http://www.photoshop.com/users/myhondas/assets/082eeab4ac1144f696812eecf08a8c49

[MRieck]

Rear sets for an F2 are custom or nothing, so that is a big thing.  I want them on my bike but don't have the pegs and shifter arms to fab up mounts right now.  

Engine stuff is nothing but it is costlier.  

Honestly after getting my head overhauled with all Cycle-X parts, I don't see why the retainers would be week in an F2.  They are machine steel, not stamped steel like Cycle-X claims.  

Pistons are costlier and I don't think I've found a source for OEM sized ones at a reasonable price.  I'd like to have used lighter pistons in my rebuild but couldn't locate any that didn't rival the cost of 836 ones.  

Rear swing arm, I cannot verify but the service manual states that the wheelbase isn't any different on an F2 I believe.  I just bought a generic swingarm bearing kit and installed it.  No issues. The strut mount is on top of the swing arm for the caliper mount though.  So something like the Dresda arm from Carpy would have to be modified to work.  

Seriously if you don't want to bother with the F2 I am certain some folks here would gladly take it off your hands.  I lucked into mine and would gladly have another, ha.  

So honestly if it were me, and I had a pile of parts/bikes.  I'd consider a K frame with everything else F2 to get the bolt on Rear set and that is about the only reason.  Would still have to custom mount the rear master cylinder, but I feel that would be easier than locating and fabbing rear set mounts.  Would allow you to switch to a newer master cylinder off something else that maybe is cleaner looking or easier to get parts for.  

The keepers have a shallow angle plus the keeper hole in the retainers is thin at the bottom with a sharp lip. It can crack and split. You have to look at at early system vs later K/F2 system to appreciate the difference. The best F2 set up was the the Yoshimura spring/retainer/keepers package. Ken uses R/D which beefs up the bottom of the retainer. That should end problems especially if loading more spring into it. If you are serious about the F2 I'd recommend using the Kibblewhite 5mm set up with the 32mm amd 34mm intake valves. It is not cheap but the 34 intake valve, for example, is over 15 grams lighter than the stock F2 piece

   The Devil speaks his mind. Hi Mike...whaddup? We should talk soon, I sense important work in your future...important to me anyway.

Mike

I don't know Mike...Glosta is soooooooooo far away from me. I'd be more than happy to a have conversation. 99%  of the New England guys get togethers are on the 3rd Wednesday of a given month and I have prior commitments. Hopefully we'll see each other soon....always a pleasure speaking with you Mike.

[spencepop]

Let's hear it for the EFF.  I'm redoing a '75 that I'm about 80% done with.  Where can I get some help on wiring?  I have 4 wires by the battery that I cannot find connections for.  I have yellow/red female coming off the selenoid.  I have a yellow/red female coming out of the wiring harness (original Honda harness). That's ain't gonna work.  There's a black male coming off the selenoid along with the yellow/red...cannot find anything to connect it to.  There's a green/red male coming from the wiring harness with nothing to connect to.

Please help.

[hesselfuzz]

Let's hear it for the EFF.  I'm redoing a '75 that I'm about 80% done with.  Where can I get some help on wiring?  I have 4 wires by the battery that I cannot find connections for.  I have yellow/red female coming off the selenoid.  I have a yellow/red female coming out of the wiring harness (original Honda harness). That's ain't gonna work.  There's a black male coming off the selenoid along with the yellow/red...cannot find anything to connect it to.  There's a green/red male coming from the wiring harness with nothing to connect to.

Please help.

Spencepop,  The black and yellow w/red from the starter solenoid should plug to the harness. On my solenoid the yellow/red is female and the black is male with corresponding plugs on the harness. The two should come out of the harness together right there at the solenoid. Hope that helps.
Greg

PS- After looking at the wiring diagrams more I would guess you have a K solenoid. The black on the solenoid should attach to a green w/ red stripe wire on the F harness. The yellow/red's go together.  G

[Mandic]

Where would the casting number be on an F2 cylinder head? 

I fear I have discovered I have a bastard motor in my bike.  Which is odd because it is all black and looks to be factory paint.  But the block number is CB750E-2608451 - which according to Z1's listing is a 76k bike engine. 

However I just had the head rebuilt with a Cycle-X F2 rebuild kit and it all fit as it should have.  The pistons in my engine are domed and I had about 120psi of compression before tear down.

However the rings that I got for my engine, are not right.  They are too thick.  My ring lands are 1.2/1.2/2.8 measurements.  The rings I was sent by Total Seal are 1.5/1.5/2.8.  Which the only reference I can find to sizing for an F2 says that it should be these sizes. 

So I am in a really tough spot right now as I NEED my bike back together, like last week, and I cannot figure out what rings I need now.

[Vinylwasp]

Where would the casting number be on an F2 cylinder head? 

I fear I have discovered I have a bastard motor in my bike.  Which is odd because it is all black and looks to be factory paint.  But the block number is CB750E-2608451 - which according to Z1's listing is a 76k bike engine. 

However I just had the head rebuilt with a Cycle-X F2 rebuild kit and it all fit as it should have.  The pistons in my engine are domed and I had about 120psi of compression before tear down.

However the rings that I got for my engine, are not right.  They are too thick.  My ring lands are 1.2/1.2/2.8 measurements.  The rings I was sent by Total Seal are 1.5/1.5/2.8.  Which the only reference I can find to sizing for an F2 says that it should be these sizes. 

So I am in a really tough spot right now as I NEED my bike back together, like last week, and I cannot figure out what rings I need now.

Hey Mandic, those generic Engine and Frame number lists are pretty inaccurate in my experience. The carb lists are even worse.

Here's where I go: http://www.cmsnl.com/honda-cb750four_model14344/, for a full parts list and microfiche of every CB750 model in every market Honda ever shipped them too. Cool eh? Here's your engine number from the CB750F 750 SUPER SPORT 1977 USA special offer page here: http://www.cmsnl.com/honda-cb750f-750-super-sport-1977-usa_model491/partslist/, and it looks like you have a 77'. The serial numbers are at the bottom of the list as flash image for this model



The really interesting thing that I've learnt from looking this up is that both the 77 and the 78 in the US are designated F, and not F2 even though they appear to have the Black F2 engine. I'd be interested to compare the head part numbers between these and designated F2 models below. Might let you do that. 

For anyone else who's interested here's the rest of the list with starting serial numbers for each F2 model and market:

CB750F2 SUPERSPORT (AUSTRALIA).
Frame # CB750G-1000020 ~
Engine # CB750E-2610038 ~

CB750F2 SUPERSPORT (GERMANY).
Frame # CB750G-1002412 ~
Engine # B750GE-1002134 ~

CB750F2 SUPERSPORT (FRANCE).
Frame # CB750G-1000016 ~
Engine # B750GE-1000014 ~

CB750F2 SUPERSPORT (GENERAL EXPORT MPH).
Frame # CB750G-1002957 ~
Engine # CB750E-2612339 ~

CB750F2 SUPERSPORT (EUROPEAN DIRECT SALES).
Frame # CB750G-1000018 ~
Engine # B750GE-1000018 ~

CB750F2 SUPERSPORT (GENERAL EXPORT KPH).
Frame # CB750G-1001962 ~
Engine # CB750E-2612041 ~

CB750F2 SUPERSPORT (CANADA).
Frame # CB750F-2101415 ~ 2109050
Engine # CB750E-2601712 ~ 2609080

CB750F2 SUPERSPORT (ENGLAND).
Frame # CB750G-1000014 ~
Engine # B750GE-1000016 ~

There's a complete parts list for each model off the start page.
Note these are all designated F2.

Cheers from way way down under.

[Mandic]

Awesome, yes when I was looking at parts breakdowns last night the Honda Fiche numbers seemed to say I have an F motor as well.

I am both very happy and AMAZED that someone put a 77F motor back in my bike.  The engine was replaced 3 or 4,000 miles ago and for someone to have gone out and found the exact right engine and not just grab the first K motor they came across amazes me.

[Freaky1]

Glad to find this thread. Was up way too late reading it last night. I am finishing up rebuilding a 73k right now and was intending to do the F2 next. After reading about some of the "issues" w/ the F2, I'm reconsidering. I know  those here love their SS's but what are their shortcomings? I have a whole other K I could build up instead.

What about those F2 heads; bigger valves (good?), retainers (bad)

The carbs; some say the K's are better?

What about the rear swing arm; I've some say it's longer but my sure doesn't look it?

I'm not into restoration freak (apologies to those of that bent). I spent less than $500 for the three bikes and want to do a cafe racer. Am willing to hybridize between the F and K's so what's the hot ticket.

Let the haggling begin.

I went and put earlier model carbs on my 77 F right off the bat and now that The Beast is in rebuild stage I'm going back to the stockers. I'm looking forward to an accelerator pump and I think the carbs are just a tad bigger also. Compared to the earlier ones, pulling the newer ones apart looks to be quite a project, am I wrong?

Non F pistons will drop your compression to unfavorable levels and the selection of sizes for the proper F ones are somewhat limited. My F has ballpark 30k miles and during this rebuild I will be doing a full head rebuild and POSSIBLY lower end also.

If your thinking rear sets then by all means go with the K frame, '77 & '78 frames are not conducive to rear sets because of minor things like passenger peg setups and major things like nowhere to pivot the rear brake arm from.

My opinion, K frame with an F motor, I've always been a fan of the odd ball and in this case that would be anything F, especially '77 and newer.

[wohali]

Hi Mandic,

I feel a bit guilty - because I think i suggested you call Total Seal - it does seem there is some confusion on the ring sets.

What I've learned from measuring my own F2/F3 is that the compression rings are indeed both 1.2, not 1.5. You have two options:

1. Call Total Seal and ask them to trade the 1.5 rings for 1.2 ones. They may charge an extra fee for this as I've heard talk that they don't stock the 1.2 rings except for the 836 Wiseco kit (1.0 1.2)
2. Find a local machine shop willing to increase the groove size to 1.5 for you, so that you can get the rings you just bought to fit correctly. This may be the easiest; others have said this is about $25/piston, and in the future it means you can use regular Honda K0-K6 rings which are in plentiful supply from dealers, eBay, etc.

Still trying to decide which I do myself. Since I have to bring my crankcase in for some welding to repair a crack from a broken chain, I may very well just hand over the pistons and ask for the grooves to be enlarged as well to save time.

Good luck!

[Mandic]

No big deal man, I'm not angry about getting the wrong rings.  I jumped the gun and got the parts before I disassembled the motor.  I shouldn't have. 

I spoke to Keith at Total Seal this morning.  They no longer have the 1.2 rings.  He said no one makes them.  I contact Wiseco, Hastings, and Total seal.  None could help me.

With that I am on a MAJOR time crunch so I went the one route I knew I could get done asap.  I called Cycle-X and have an 836 kit on the way.  They are sending me their pre-bored cylinders, F2 pistons, and a set of heavy duty studs.  I didn't want to go this route but it was the one way I know I can get the job done this week.

I contacted 4 local machine shops.  2 weren't willing to do it.  1 didn't call me back when they said they'd check into it.  And the 4th said they couldn't do it for at least 2 weeks.  I leave for my new home in Texas on Monday.  So Thursday night will be an all nighter of engine rebuild/reinstall and firing.

[Mandic]

With that, has anyone installed a Cycle-X 836 before?  Just curious if there are any things I need to consider during the process. 

Ken at Cycle-X recommended I scribed the head with the bigger head gasket and feather out the chamber a bit to reduce the hot spots that the old chamber edges would create.  I was considering doing that anyway. 

[wohali]

F2/F3 owners: See this thread about Total-Seal rings for our bikes.

I'm coordinating a group buy of custom rings from Total Seal. We need just 64 rings (8 full sets) to have Total Seal custom make the 1.2mmx61.01mm compression rings we need for the stock F2/F3 pistons. (The oil rings he has on the shelf already.) If we manage to do this, they'll start stocking them on the shelf too!

[Freaky1]

Wohali ~ I'm all for the ring set as I don't think I'll have the money to go the same route Mandic is and even if I don't use them this time around I would like to have a set on MY shelf, I'll PM you.

[wohali]

Thanks Freaky1! I've added you to the list. Just need 6 more orders to be placed to make this happen now!

I encourage everyone to respond over on the Group Buy thread instead to keep this thread clean.

-Joan

[Mandic]

Yea if I didn't have the money set aside for buying a new vehicle when I move, I'd be up a creek with no paddle or canoe right now, haha.

[Mandic]

Exhaust opinions:

OK guys I am thinking about my bike.  Due to some issues I have a little more time to get it together and was planning to put on a new exhaust later anyway.  So with that, what exhaust should I get? 

I want a 4-1 configuration on my 77 750F.  With the new 836 motor I'd like something that breaths a little better than the stock 4-1-mac muffler I have.  And something a bit louder.  Texas laws won't be an issue as far as noise, though I don't want my neighbors hating me at all hours of the morning. 

The options I considered are Carpy's Yoshi replica and the Cycle-X 4-2-1 setup.  I love the look of the Cycle-X double megaphone muffler, but I think the way Carpy's sounds may be a bit more what I'm looking for(with the baffle in). 

If you have another option let me know.  If you have either of these exhaust I am curious how you mounted them to your bike.  I've long since lost the factory exhaust mount, and modified my right side brake/foot mount so I'm curious as to how I will go about mounting these.  The other things is I don't even see any mounting tabs on these exhaust for back mounts.

Any input?

Cycle-X:


Carpy Yoshi Replica:




Either way I think I will get them ceramic coated silver.  My bike has enough black black and black going on, a nice bit of shine wouldn't hurt anything.