Topic: best handling

[wannabridin]

hey guys,

i've tried searching but i can't find what i'm looking for.  if someone has a link, feel free to post it, as i don't want to waste space!

here's my thoughts...  i'm wanting my 76 750k to be somewhat of a budget build, but i want it to handle about as well as it can.  i'm not going to go with a big bore kit, i just want to waken up the stock bore some with some porting and balancing and other tid-bits, just a good rebuild with room to grow in the future!  but i would like to build it to handle really well, at least as good as these old girls can.  here's my thoughts, and i already have some of the parts:

75 GL1000 front end with fork brace on the stock wheel (already have the forks and brakes)
fork tube emulators with constant rate springs(race tech)
IKON or progressive rear shocks, stock length or a tad higher
all balls tapered steering head bearings (already have)
new wheel bearings (already have)
hondaman swingarm bushings
steering damper (z1 enterprises)
rear sets and clubmans (already have both)

i'd rather not spend the money on shouldered rims w/ stainless spokes, but will this combination yield a much better result with everything mentioned?  or can i get by with just new spokes?  also, what's the deal with welding the part of the downtube coming from the steering neck?  i've read some posts here about doing this to help out, but what exactly is the benefit of this?  also, are there any areas of the frame that can really be strengthened by welding up a little extra material?  thanks for the help!!

[KRONUS0100]

I have the 76 gl1000 entire front end with dual brakes on my 76 Cb750f.....handles a heck of a lot better..although i have been unable to locate a fork brace.  you should also consider the braided brake lines..they make a world of difference.

[wannabridin]

well i'm just talking about pure handling.  i will get braided lines, that's a no brainer.

here's a website i found, and fishhead has confirmed that has great stuff, including quality fork braces:

http://www.randakks.com/Suspension%20Components.htm

and his master cylinder which i hear is 2nd to almost none:

http://www.randakks.com/Brake%20Parts.htm

browse around that site too, lots of cool crap!!

[KRONUS0100]

yeah...i forgot all about that site...i belong to the naked goldwing forum as well......DUH!

[MCRider]

The 2 downtubes from the steering neck to either side are pressed into their tubes that continue on down under the engine. At the point where they are pressed in, you can see the upside down shaped "U" gussets, they are rivoted in 3 places on either side.
While this is acceptable for production bikes it is below standard for performance.

AS you tighten up other areas of suspension, these joints loosen and wiggle at the extreme. I read up on this particular one and the protocol is to run weld down the vertical seams or the joints, but not the horizontal.

I have also gusseted the frame in other areas pinpointed as weak spots. I used to ride hard, but I doubt that I will ride the current project hard enough to care, but its good for bragging rights.   

[nobody]

http://forums.sohc4.net/index.php?topic=54052.msg581068#msg581068

[Big Bob]

I'm indifferent on clubman bars.  I've got a set on the race bike and like them for that application but for a real-worlf street bike you might want to consider a set of superbike bars.  But hey, bars are cheap.  Try a few different ones and run what you feel.

I'd strongly encourage you to build a set of wheels with alloy rims.  Less weight, less unsprung weight.  For bonus points go with 18 inch wheels front and rear.  You won't believe the difference in handling.

Steering dampers are another one I'm ambivalent on.  I don't have one on the race bike and that thing doesn't wobble even under the most ridiculous conditions.  Good bearings, shocks, etc. first.

[wannabridin]

http://forums.sohc4.net/index.php?topic=54052.msg581068#msg581068

ok, well i read thru hondamans posts tons of times, but i figured if i could compile a list together with a little more details and address other areas, it would be great.  thanks for the link though!

I read up on this particular one and the protocol is to run weld down the vertical seams or the joints, but not the horizontal.

I have also gusseted the frame in other areas pinpointed as weak spots. I used to ride hard, but I doubt that I will ride the current project hard enough to care, but its good for bragging rights.   

could you elaborate on the vertical but not horizontal weld?  i've seen both of these seams welded on various bikes before, but i would like to know why you've only heard of one.  also, could you go into a little more detail or link me some pictures of the areas you thought were weak?  i'm thinking that the upper shock mounts could use a nice little gusset, and that the area in the corner under the oil tank could as well, maybe a flat piece under the seat between the shocks since i'll be running my electronics and battery here and hence will be removing the stock horizontal support.

I'm indifferent on clubman bars.  I've got a set on the race bike and like them for that application but for a real-worlf street bike you might want to consider a set of superbike bars.  But hey, bars are cheap.  Try a few different ones and run what you feel.

I'd strongly encourage you to build a set of wheels with alloy rims.  Less weight, less unsprung weight.  For bonus points go with 18 inch wheels front and rear.  You won't believe the difference in handling.

Steering dampers are another one I'm ambivalent on.  I don't have one on the race bike and that thing doesn't wobble even under the most ridiculous conditions.  Good bearings, shocks, etc. first.

18's front and rear?  i've considered matching rims, as i feel it would really help the handling from having the the same gyroscopic forces acting on both ends equally and the looks.  could you explain in a little more detail what your thoughts are regarding this?  what width and what size tires are ideal? 

now for the clubmans, i feel they're just spot on for cafe, and since i'm only 25, to hell with the comfort for a little bit!  if i didn't do these, i'd do some dirtbike style flat bars, as i feel they are pretty badass looking, much like a flat track style bar, and they're pretty comfy.  the steering damper is another area where i think it's just pretty badass.  i don't feel they do too much until you reach speed, and they shouldn't be necessary with a properly set up front end, but hey, if i can do it and everything works well, why not???   

[MCRider]

I'll post some pictures. They are scattered throughout my build thread (link in my signature) but I'll get 2 or 3 for your thread.

In the meantime, if you click the "home" button above,then search on Frame Gussets you'll find the previous discussion. Also buried in those threads is the article by Tony Foales frame guru. You could search his name as well.

Hint: yes a triangle gusset in the "V" above the swingarm pivot (under the oil tank) is important.

[wannabridin]

i found some of your pics mcrider, so i'm going to post them up first :-D

but if you don't mind some closer up pictures?  also, what'd you use, 1/4" plate?  and what's this i hear about double wall frame construction, how difficult is the frame to weld on, i'll be doing it from home with my hobart handler 140, thanks!!

[MCRider]

Those are good, don't know if I have any closer up. It is 1/8 in plate. I have a machine shop doing my work for me and there equipment, welders etc are top notch. Can't comment on how hard it was as i didn't do it, but they've never given me any feedback that it was a problem.

The 2 obvious triangles in the pictures should have been swapped, in that a larger one should have been used by the swingarm pivot. Anything is better than nothing there though.

Tony Foales commented in his article that reinforcing the swingarm is misguided. The swingarms are fine the frame is weak. In his example he bolted a frame down to a platform and ran a lever thru the steering head. By levering it, he could get the swingarm pivot to deflect and vice versa. Very enlightening.

Some of the 750 frame is double walled I think. but not for performance purposes and don't quote me on that.

The only double wall i know of is this keen motor mount bot from our own Rob (voxonda.com). One must modify the brakelight switch mount to use it on a street bike. Rob supplies SS thru bolt as well.



Motor mounts are a weak link, again in the extreme, and Rob has addressed the front and rear removable ones. I can't use his front one as I am running a reinforced engine guard which will double as the front motor mount.

The other long bolt motor mount holes I had enlarged, both the frame and the engine cases, and had new stainless steel thru bolts made which are press fit rather than sloppy fit.

[MCRider]

I'm just scrolling thru my pictures at photobucket to get some samples. Close up of the rear, below tank gusset.

[Don R]

The frame tubes are not as thick as you might expect when you weld be careful with the heat. As old as they are some have internal rust also, so it is easier to burn through. As for the slpice on the frame tube risers under the fork neck, I tried to drill the spot welds and take one apart to do repair once. I never did get it apart, the double tube extended up beyond the bend and was stuck together so hard I would have destroyed the tube seperating the joint. But welding it properly can't hurt either. Have fun.

[ColinMc]

Yeah I need to get my bike into rolling chassis form before I paint my frame, I plan on going the same route...along with shaving any unneeded brackets and whatnot.

[MCRider]

Close up of the steering gusset weld. Note the weld goes up and down. It does not cross across the horizontal bottom of the gusset. i do not know why this is done this way, I read it somewhere here, FunJimmy I think and somewhere else as confirm.

It couldn't hurt to leave that weld off, so we did. When i asked my welder to do it that way he did not hesitate or look at me funny.  On other welds my welder has made suggestions to do it this way or that, that i would never thought of. So i just go with the flow as long as it isn't obviously outrageous.

[MCRider]

Last one: removable front frame gusset.


I had to make this one removable as it bolts to the APE style removable frame tube kit. If you're not using a removable frame tube kit, you can weld this one in place.

I think Gordon's frame tube kit would allow a welded gusset here, but it would have to be smaller. Mine is bigger than it needs to be.

[MCRider]

OK this is the last: steering damper mount. They make some perfectly usable clamp on mounts, which i used to run. But on this project i wanted it part of the bike.


The steering damper should only be insurance agaisnt a perfect storm of negative suspension inputs. Not a bandaid over a problem that should be otherwise fixed.

It does help in crosswinds however.

[wannabridin]

hey Big Bob, can you give me a little more insight on the 18's front and rear?  or can anyone else give me a little info?  thanks guys!!!

[wannabridin]

bump for some info on equal sized rims and their effect on handling?  anymore info would be great!!!  thanks guys

[MCRider]

bump for some info on equal sized rims and their effect on handling?  anymore info would be great!!!  thanks guys

You have 19" front now and 18" rear?

I have a 75F rolling chassis with 18s but I've never ridden it. Expect it to feel great. Expect from 19 to 18 front, you'll perk up the steering, its very common for sport bike types to slip the forks up the trees a tad to perk up steering so that's where tha comes from. Though there are differences in rake and trail .

Lose a little unsprung weight. The brake may feel a little perkier too as it does not fight as big a lever. Though i may be misguided on that idea.

other gains assuming slightly wider rims are slighter wider tires, which will gain some ground clearance at full lean. But you'll also be losing a little ground clearance in the front so it may be a wash.

Keep in mind that by 1988, virtually all sportbikes and most standards were 17s front and rear. My current project CB750K2 standard is shod 17 fr and rr but is a ways from completion.

My riders 1988 HawkGT and 2003 FJR1300 are both 17 f & r so you're going in the right direction I think.

There are some compromises with older suspensions so 18 f & r is probably best. Modern Smaller tire sidewalls contribute less to the suspension than in the old days. This is all IMO and YMMV

[tinyrobot]

I am currently running 18s front and rear on alloy rims.  Two things were noticeable right away from the switch much like MCRider listed.  The smaller front wheel changes your forward lean angle (down .5" in radius)?  It quickens the steering.  The alloy wheels definitely felt to spin up faster and lean quicker.  The bike feels like it want to turn more now than before.

here is a pic from Acetoberfest here in Chicago

[Ecosse]

i am very interested in this but wonder how much the speedo reading would be affected. or is that effected? i can never get that right. 

18" certainly doesn't look out of character 'robot. sweet machine.

[MCRider]

i am very interested in this but wonder how much the speedo reading would be affected. or is that effected? i can never get that right. 

18" certainly doesn't look out of character 'robot. sweet machine.

I had forgotten (or more accurately never thought about it) about the speedo error. On a 19 to 18 I'd probably figure it out and live with it. The 18 looks good i agree.

Someone pointed it to me on the Phaedrus thread, with my 17" wheel it will be way off, spinning faster and giving an optimistic reading. That same person pointed me towards some in line speedo ratio adjusters, which appear that they would work, though add about 2" to the cable length.

Also, the folks I'd expected to do my instruments ouit in CA said they can make the adjustment in the head itself, i have to give them some readings like the rolling circumference of the new wheel etc.

[MCRider]

If I ever get to building the rolling chasis i spoke of, it'll have a digital combo instrument which can be tuned to any wheel.

It appears tinyrobots bike doesn't have a speedo.

[Ecosse]

I had forgotten (or more accurately never thought about it) about the speedo error. On a 19 to 18 I'd probably figure it out and live with it. The 18 looks good i agree.

Someone pointed it to me on the Phaedrus thread, with my 17" wheel it will be way off, spinning faster and giving an optimistic reading. That same person pointed me towards some in line speedo ratio adjusters, which appear that they would work, though add about 2" to the cable length.

i'm blushing... 

Also, the folks I'd expected to do my instruments ouit in CA said they can make the adjustment in the head itself, i have to give them some readings like the rolling circumference of the new wheel etc.

huh... that is very interest piquing.  i'll need to keep my eyes peeled for that.

It appears tinyrobots bike doesn't have a speedo.

that's one way of fixing the problem.