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General Category => Tech Corner => Topic started by: Dash on June 30, 2017, 09:26:37 AM



Title: Need suggestions for new front end
Post by: Dash on June 30, 2017, 09:26:37 AM
Now that the rear is sorted, I wanna focus on the front of the bike.

The fork seals start sweating and leaking quite often because of small pits in the forks. This is a recurring and annoying issue. So I wanna solve this problem and use the occasion to swap in a different front end for a bit of an upgrade. Maybe even something with dual discs and calipers so I can brake even later  ::)

So please guys, shower me with your wisdom: what front ends can I fit on the standard triple clamp of the CB-1 without too much trouble? (Im thinking stuff like CBR 400, 600 F etc.)


Title: Re: Need suggestions for new front end
Post by: a_morti on June 30, 2017, 12:29:07 PM
How much upgrading do you want to do? 96-97 cbr900 forks fit easily, even the steering lock works with minimal filing. You do need to kludge a mounting for the headlight and clocks though, and the Cbr handlebars are below the triple. If not in to kludging, I got a custom cnc top triple with clock and headlight mounts built in. These accept the late Cbr calipers (see below).

As for stock triples, there is an amazing degree o parts interchangeability on Showa 41mm forks. I guess the top evolution is f3? You can fit them right in. They are longer so will protrude out the clip ons (guess not a big deal). If you want a 3 spoke twin disc wheel, look at early blackbird, vtr1000f, 400sf, nc23... Lots of options.

You'll need to work something out with mudguards, the brackets are different. Or you could fit the CB-1 lowers to those forks if you're ok with CB-1 brakes in the end. Perhaps a later 3 pot Nissin caliper helps, if you delink it?

If you want to get great brakes, I guess you need those f3 forks, but with vtr 1000f forks lower which should bolt right on. The vtr calipers are ok but with just a little filing they give access to 4 pot calipers such as the big nissins off a 929/954/600rr.
Bear in mind you also need the corresponding master cylinder.


Title: Re: Need suggestions for new front end
Post by: Dash on June 30, 2017, 01:48:37 PM
How much upgrading do you want to do? 96-97 cbr900 forks fit easily, even the steering lock works with minimal filing. You do need to kludge a mounting for the headlight and clocks though, and the Cbr handlebars are below the triple. If not in to kludging, I got a custom cnc top triple with clock and headlight mounts built in. These accept the late Cbr calipers (see below).

As for stock triples, there is an amazing degree o parts interchangeability on Showa 41mm forks. I guess the top evolution is f3? You can fit them right in. They are longer so will protrude out the clip ons (guess not a big deal). If you want a 3 spoke twin disc wheel, look at early blackbird, vtr1000f, 400sf, nc23... Lots of options.

You'll need to work something out with mudguards, the brackets are different. Or you could fit the CB-1 lowers to those forks if you're ok with CB-1 brakes in the end. Perhaps a later 3 pot Nissin caliper helps, if you delink it?

If you want to get great brakes, I guess you need those f3 forks, but with vtr 1000f forks lower which should bolt right on. The vtr calipers are ok but with just a little filing they give access to 4 pot calipers such as the big nissins off a 929/954/600rr.
Bear in mind you also need the corresponding master cylinder.

Something to keep in mind with my bike is that it has risers and handlebars fitted. So no clip ons. This makes matters a little easier in some aspects but complicates matters if the forks must protrude out of the triple clamp since the will get in the way of the handlebar.

Im not looking for massive improvements. In fact, Im happy with forks that fit without having to adjust or costumize half the front end. :P Keeping in mind what the bike's worth, I dont want to blow a lot of money and time on this. Its kinda like with the rear shock: Im looking for a cheap and easy replacement without expecting it to turn the CB into a motogp machine.

So, to be more precise what Im looking for is a new front end that:

- is relatively cheap & easy to find
- bolts right on without modifications to the bike
- allows me to keep my current brake setup
- -if possible- improves the front suspension a little (Note: I already have Hyperpro springs fitted, would like to carry these over)



Title: Re: Need suggestions for new front end
Post by: a_morti on June 30, 2017, 02:10:45 PM
Most forks with superior damping are longer than stock, so you will have an issue of them fighting your handlebar for space.

It sounds like what you really want is a pair of replacement legs. Perhaps made up to be shorter since you no longer have clips above the yoke.

Not sure they'll be any easier to find but maybe nc29 forks would be an idea? Again, can bolt your fork bottoms to those and keep brakes and mudguard.



Title: Re: Need suggestions for new front end
Post by: Dash on June 30, 2017, 03:39:31 PM
Most forks with superior damping are longer than stock, so you will have an issue of them fighting your handlebar for space.

It sounds like what you really want is a pair of replacement legs. Perhaps made up to be shorter since you no longer have clips above the yoke.

Not sure they'll be any easier to find but maybe nc29 forks would be an idea? Again, can bolt your fork bottoms to those and keep brakes and mudguard.



Yeah, reading your replies I ve come to the same conclusion. What I need are new tops. the bottom legs seem to be fine. So either I need new CB-1 forks or just new upper forks that fit the CB-1 bottom forks. Which makes me wonder, which upper forks are as long as the CB's and fit in the lower CB fork apart from the NC29?

Id reckon upper Hawk forks would do the trick as well? Id need forks that are easy to find. CBR 400 and Hawk forks aren't...


Title: Re: Need suggestions for new front end
Post by: a_morti on June 30, 2017, 03:49:04 PM
You're in cz, is that right? Guess you're looking for any model which did well in Europe.

Rc42, perhaps?

Couple ideas from eBay Germany

http://m.ebay.de/itm/Honda-VFR-Rc-36-Gabel-komplett-/282549190192?hash=item41c93e7e30%3Ag%3AB6cAAOSw0j9ZOYfo&_trkparms=pageci%253Afc6d4393-5dcc-11e7-8b68-74dbd180e0a2%257Cparentrq%253Afa8b7de815c0abda6d44d90ffff7731d%257Ciid%253A4

http://m.ebay.de/itm/Letzte-Chance-Honda-NT650-Hawk-GT-RC31-GT647-Telegabel-komplett-/182637015818?fits=DEM_Make%3AHonda&hash=item2a8603b30a%3Ag%3A1d0AAOSwbtVZOWNj&_trkparms=pageci%253A20fb2cd9-5dcd-11e7-bf83-74dbd18077a8%257Cparentrq%253Afa8c6d7915c0abd99d190ac0fff85558%257Ciid%253A6


Title: Re: Need suggestions for new front end
Post by: Sugs on July 01, 2017, 01:21:29 AM
Gotta be someplace in Europe that can recondition, rechrome and repolish the upper tubes.  A few here in the U.S.  If your pitting isn't too bad, you can try a small fine diamond sharpening stone.  A buddy of mine turned me on to this and it worked great on my leaking forks, and so far no new leaks.  I just ran the stone up and down the fork tube over the pits until I couldn't feel them anymore.


Title: Re: Need suggestions for new front end
Post by: Dash on July 01, 2017, 06:56:31 AM
You're in cz, is that right? Guess you're looking for any model which did well in Europe.

Rc42, perhaps?

Couple ideas from eBay Germany

http://m.ebay.de/itm/Honda-VFR-Rc-36-Gabel-komplett-/282549190192?hash=item41c93e7e30%3Ag%3AB6cAAOSw0j9ZOYfo&_trkparms=pageci%253Afc6d4393-5dcc-11e7-8b68-74dbd180e0a2%257Cparentrq%253Afa8b7de815c0abda6d44d90ffff7731d%257Ciid%253A4

http://m.ebay.de/itm/Letzte-Chance-Honda-NT650-Hawk-GT-RC31-GT647-Telegabel-komplett-/182637015818?fits=DEM_Make%3AHonda&hash=item2a8603b30a%3Ag%3A1d0AAOSwbtVZOWNj&_trkparms=pageci%253A20fb2cd9-5dcd-11e7-bf83-74dbd18077a8%257Cparentrq%253Afa8c6d7915c0abd99d190ac0fff85558%257Ciid%253A6

Im in Holland. I was in CZ for the track ;)

So I understand correctly that the Hawk uppers will fit the CB-1 lowers? Would that also mean the uppers from the NTV (revere) will also work?

In that case the 2nd link might be worth a shot. Just need to be sure it will fit.


Gotta be someplace in Europe that can recondition, rechrome and repolish the upper tubes.  A few here in the U.S.  If your pitting isn't too bad, you can try a small fine diamond sharpening stone.  A buddy of mine turned me on to this and it worked great on my leaking forks, and so far no new leaks.  I just ran the stone up and down the fork tube over the pits until I couldn't feel them anymore.

No such thing near here. Besides, the pitting is pretty severe. Im not confident enough trying to patch them up will fix the issue. I do appriciate the suggestion though.


Title: Re: Need suggestions for new front end
Post by: a_morti on July 01, 2017, 03:09:30 PM
Yep. All period honda showa 41mm damper rod forks use the same fitting to attach the top and bottom as far as i have seen.


Title: Re: Need suggestions for new front end
Post by: Dash on July 06, 2017, 08:34:54 AM
Im told the NTV (Revere), which also has 41mm forks, has slightly shorter forks.

Are Hawk and CB-1 top forks the same lenght?


Title: Re: Need suggestions for new front end
Post by: Pod70 on July 07, 2017, 06:36:52 AM
Hello Dash,
If you're looking to stick with 41mm Honda forks then the following might help:
CB-1 Forks 615mm long
NC23 (CBR400 Tri-arm) forks 598mm
NC29 (CBR400 Gull arm) forks 572mm - This would bring your front end back to around stock height allowing for the dropped forks due to the handlebar conversion.
NTV650 REVERE 88-92 600mm

If you want to swap in a CBR400/ NVT650 front, I probably have a spare left hand fork leg, caliper & NC23 wheel (3 spoke) which I could sell.
The problem I have found with buying 2nd hand forks is that generally the chrome on the stanchions is as pitted as the ones you are looking to replace but you can buy new stanchions from http://www.allbikeengineering.co.uk/forks.php. I bought a set for the race bike with seals and bushes and it came to around 220.

If it helps I'd be happy to get new stanchions delivered to me and send them on with the other parts. You will need to play around with the length of the spacer tubes but I've got a friend who races an NC29 so we could measure his as a start point.


Title: Re: Need suggestions for new front end
Post by: spacetiger on July 07, 2017, 10:49:41 AM
A few rambling thoughts since you will stay with a damper rod setup.

- trying to match fork lengths with thought of swapping "new bits" from "new fork" to cb lowers might not produce results you are looking for. The damper rod varies in length. It sets the suspension working range so you need to know what length you have. You could take a shorter fork and use longer damper rod to lengthen the fork - or other way around. Try cross referencing part numbers if needed.

- fork spacer length important to set prepare distance. That means it is unique to you and is determined by setting rider sag.

With slightly longer rear shock for the rear be mindful of your changes so they work together


Title: Re: Need suggestions for new front end
Post by: Dash on July 07, 2017, 11:36:46 AM
Thanks for the input guys.

I found some decent 2nd hand Hawk uppers. They re the same lenght as the CB-1s uppers, I believe. So nothing should change... I hope :o


Title: Re: Need suggestions for new front end
Post by: ptlcb1 on July 09, 2017, 08:51:52 AM
In case you havent noticed, i raced my CB-1 with a great deal of success. Just my 2 cents, but not really a need for a dual disk set up on the front.  I added stainless steel braided brake line, heavier fork springs  and a heavier fork oil, and Gold Valve Fork Emulators. I always used the stock brake pads. My front end performance has been spectacular! I constantly kept moving my brake marks deeper and deeper!  I never experienced the faded that others have spoke about...


Title: Re: Need suggestions for new front end
Post by: Dash on July 10, 2017, 05:13:34 AM
In case you havent noticed, i raced my CB-1 with a great deal of success. Just my 2 cents, but not really a need for a dual disk set up on the front.  I added stainless steel braided brake line, heavier fork springs  and a heavier fork oil, and Gold Valve Fork Emulators. I always used the stock brake pads. My front end performance has been spectacular! I constantly kept moving my brake marks deeper and deeper!  I never experienced the faded that others have spoke about...

Yeah. Im sticking with my normal front end. Right now the plan is as follows:

- Hawk uppers
- CB-1 lowers
- CB-1 brake
- cintered pads
- Hyperpro progressive springs
- SAE 15 oil (thicker than the SAE 10 that Hyperpro prescribes)


Title: Re: Need suggestions for new front end
Post by: a_morti on July 10, 2017, 09:10:04 AM
Just need to adjust preload spacer length and you're good to go. Maybe a good time to fit preload adjustable caps (lots on china ebay, or used frim vfr800 or vtr1000f etc).


Title: Re: Need suggestions for new front end
Post by: ptlcb1 on July 10, 2017, 09:30:58 PM
Steel braided brake line?


Title: Re: Need suggestions for new front end
Post by: Dash on July 11, 2017, 02:52:22 AM
Just need to adjust preload spacer length and you're good to go. Maybe a good time to fit preload adjustable caps (lots on china ebay, or used frim vfr800 or vtr1000f etc).

preload spacer? Whats that? :-*

Steel braided brake line?

Yup, fitted to the front and back


Title: Re: Need suggestions for new front end
Post by: Pod70 on July 12, 2017, 07:59:42 AM
Just need to adjust preload spacer length and you're good to go. Maybe a good time to fit preload adjustable caps (lots on china ebay, or used frim vfr800 or vtr1000f etc).

preload spacer? Whats that? :-*

The metal tube that sits in the fork tube on top of the spring. Adding stiffer springs will mean that the front end will compress less under the weight of the bike & rider. You may have to trim a bit off the tubes to get the correct sag settings on the front end. typically you will be looking for around 10mm with just the weight of the bike. Adding the Pre-load adjusters above means that it is easier to tweak this.


Title: Re: Need suggestions for new front end
Post by: ModerateFkr on July 12, 2017, 11:44:55 AM
This guy seems to be doing for front end suspension what Jerry Spacetiger is doing for the back end, albeit on a different bike. They're clearly brothers!!

http://www.peterverdone.com/archive/05fork.htm


Title: Re: Need suggestions for new front end
Post by: Dash on July 12, 2017, 01:17:40 PM
New front end fitted.

Hawk uppers
CB-1 lowers
SAE 15 oil, 420 ml per fork
Miele Suspension Mod fitted






















I cut off 2 230mm lenghts of vacuum cleaner pipe and used those as spacers ;D

Less sag and improved dampening what Ive noticed so far. Still need to test it more thoroughly though.


Title: Re: Need suggestions for new front end
Post by: spacetiger on July 12, 2017, 08:18:57 PM
This guy seems to be doing for front end suspension what Jerry Spacetiger is doing for the back end, albeit on a different bike. They're clearly brothers!!

http://www.peterverdone.com/archive/05fork.htm

LOL

MF, I hope one day some of my work might be thought of the way Peter's work is viewed.  We do think along similar lines but he is far advanced than me; but I am a quick learner and do have some tools he does not have.

With photobucket charging a steep cost per year to host pics, I have to think about how to best post results to share with other riders.  At $400/year, you could be looking at $4,000 in 10 years... thats a lot to pay.  I may start my own site and post links to my site.  Since I have a variety of bikes, I can post work on trikes (currently on my 2nd Can Am Spyders), scooters, and a variety of different bikes.  I'll do a little searching this weekend to figure out what I'm going to do.

Now, back to the OP...  On the front end, there is much to consider when making changes in the rear.  I have decided to to swap the CB-1 front to cartridge set up using Honda (Showa) components from other Honda bikes.  Right now I have VTR1000 fork lowers so I can use two fixed 4 pot calipers.  The cartridges I will put inside the VTR lowers will come from a CBR 600 F4i because it was set up to limit front suspension travel to match up with the rear suspension travel I'm going with.  I'll use RT gold valves to set up the damping on the 22mm cartridges.  A lot of people use RT springs, I found the Penski springs to be as good, but are shorter than RT springs (260mm vs ~360mm OAL difference).  That shorter spring gives you more options to manage the air volume to negate the air spring affect near or at full fork compression.  I have started to pull together the front components because this does affect the rear set up.  The shock I was pursuing will not be the best shock after all.  I was trying to get a 2" shock working range  but that will have the rear suspension moving over too large a range compared with the front I am going with.  With the F4i cartridge, I will only need a rear shock (longer than the CB-1 shock) with about a 1.3" working range.   So, I will use the CBR900 shock as it has plenty of usable stroke.  This will save me from having to drill and tap the shock for the remote reservoir.    

Jerry


Title: Re: Need suggestions for new front end
Post by: ModerateFkr on July 13, 2017, 12:02:30 AM
We already hold you in very high regard Jerry.

I like your ideas. The server idea is good too. It's all about affordable server bandwidth. This is a small forum, so you should be able to do it on a decent unlimited broadband package and an always on server running unix (Ubuntu is free) - which you can build from an old PC. Your end should be minimal to zero cost.

Photobucket is probably getting hit by Pinterest (Fugly name - nearly as bad as yahoo!) and it's shareholders are demanding a business model upgrade. Time for that Carly woman to wade in. Sorry, this may only make sense if you read ZDNet - which I don't anymore.

Bikers are much nicer than techies. I once (in 2005) blogged they Apple should launch a phone with a cutdown version of iOS onboard. I was castigated like Copernicus... Because I was less than two years early - but 100% right. That's precisely what Apple did in 2007.

You're not only a quick learner Jerry, you're an empirical learner and you get stuff done. Plus you can teach. That's a great combination. Add some tech to that mix.



Title: Re: Need suggestions for new front end
Post by: Dash on March 28, 2018, 04:16:44 AM
Returning to this topic at long last, sadly.

The damn seals are still sweating. Ive already replaced the uppers and the lowers seem to be just fine. Im at a loss what's causing this recurring leaking seals issue.

So Im once again considering swapping the entire front end. Maybe even do a bit of an upgrade.

Anyone know which front ends will bolt right in the CB1's triple clamp? Im told the CBR 600RR 2007 model front end will fit?
It will have a snowball effect to mount a different front end though, need new discs, calipers and master cilinder etc.

Anyone have any cheaper alternatives?  ;D



Title: Re: Need suggestions for new front end
Post by: a_morti on March 28, 2018, 04:46:15 AM
Did you ever replace the fork bushes? If those are worn they'll give the seals a hard time.

96/97 cbr900 is a very easy fit. The triples work and five minutes with a file will even give you a steering lock. However there is nowhere to fit the headlight and clocks, and the OEM handlebars are too low for my comfort.

If you like the idea I can try to get the CAD drawing for the CNC top yoke on my bike.


Title: Re: Need suggestions for new front end
Post by: Dash on March 28, 2018, 05:03:30 AM
Did you ever replace the fork bushes? If those are worn they'll give the seals a hard time.

96/97 cbr900 is a very easy fit. The triples work and five minutes with a file will even give you a steering lock. However there is nowhere to fit the headlight and clocks, and the OEM handlebars are too low for my comfort.

If you like the idea I can try to get the CAD drawing for the CNC top yoke on my bike.

No, I never did change the bushes. That would be the cheapest (attempted) fix I guess...
Completley forgot about them. daayyumm.

How can you tell if they re worn?


Title: Re: Need suggestions for new front end
Post by: a_morti on March 28, 2018, 08:34:22 AM
If you get them in your hand you'll see if they're worn as the Teflon coating on the wear surface... Wears.

To test on the bike, jack front end up securely, and grab the fork legs tight. Try to rock them back and forth. If there is noticeable play in the legs when rocking, or a knocking sound, the bushes are probably worn. Sometimes you'll notice a knocking noise under braking, and even when the steering bearings are eliminated it's still there.


Title: Re: Need suggestions for new front end
Post by: Dash on March 28, 2018, 12:31:29 PM
If you get them in your hand you'll see if they're worn as the Teflon coating on the wear surface... Wears.

To test on the bike, jack front end up securely, and grab the fork legs tight. Try to rock them back and forth. If there is noticeable play in the legs when rocking, or a knocking sound, the bushes are probably worn. Sometimes you'll notice a knocking noise under braking, and even when the steering bearings are eliminated it's still there.

Ok, thanks. Hopefully, if the weather is compliant, Im making a trip to the local shop. See if they can help me test that.


Title: Re: Need suggestions for new front end
Post by: cbx1260cc on May 03, 2018, 07:25:02 PM
Read this thread with much interest as I have a parts bike I'd like to return to service--BUT--it has NO FRONT FORKS.

How about this idea?

Use CBR600F3 Wheel / discs / calipers and forks and slid them into the CB1 triples. This gives dual discs.

BUT

As the CBR600F3 has a WIDER wheel vs the CB1 this will also mean that the forks are spaced farther apart to accomodate the wider wheel. Is that CORRECT??

Is a solution then to use the CBR600F3 complete front end with upper and lower triple trees??

Does this in turn necessitate pressing out the "stem" from the CB1 unit and "inserting" it into the F3 setup??

Also with a wider spacing of the fork tubes will this not also reduce the Left to Right handlebar movement with a resultant "lengthening" of the turning radius??

Written another way.

IF the CBR600F3 fork tubes slide up into the CB1 triples all would be good until one tried to fit the front WIDER F3 wheel and one would find the fork tubes were not spaced far enough apart to allow the wheel / brakes to fit.

Is this correct??

If someone who has tried this could give us the benfit of their experiences it would be much appreciated.

Thank you

Rick

 



Title: Re: Need suggestions for new front end
Post by: a_morti on May 04, 2018, 03:10:54 AM
Thw wheel width is bigger but the spacing is identical. I've had an f3 wheel with holes drilled to m8 for a stock disc mounted in stock forks just to use the wider lighter 6 spoke.