CBX Racing

CBXs, new bikes, old bikes, cars, trucks, general chat, off topic, this is the place to post it.
Post Reply
User avatar
Syscrush
ICOA Member
ICOA Member
Posts: 1714
Joined: Fri Sep 14, 2012 2:29 pm
Location: Toronto, ON
Location: Toronto, ON

Re: CBX Racing

Post by Syscrush »

Warwick Biggs wrote:
Sat Jul 02, 2022 4:02 am
I'm wondering if it has some sort of ramp like a slipper clutch and whether it works the same way on down changes.
Looks like shifting is the same as with a normal clutch (PDF Link):

SHIFTING
1. Upshifting:
• For normal riding situations, upshift as you normally would.
2. Downshifting:
• For normal riding situation—including slowing down from a tall gear—downshift as you
normally would. Downshift if the engine is jerking or “lugging.”
• Downshift one gear at a time and allow the engine braking to engage like normal.
• When downshifting, apply a small amount of throttle then slowly release the clutch lever to
reactivate the clutch.
• If you are traveling at a high rate of speed in a tall gear, you MUST apply a small amount of
throttle to reactivate the clutch. If you pull the clutch lever or allow the RPM to drop to idle
without reactivating the clutch, free-wheeling occurs.
• Don’t ride in a gear higher than you need. Adjust your gear selection to match your ground
speed, engine RPM, and terrain.
• When you slow down to stop, you do not need to touch or modulate the lever. The EXP
disk will release automatically when you drop below the engagement RPM.
• Once you are stopped, shift into 1st gear using
your clutch lever before accelerating again.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

"• If you are traveling at a high rate of speed in a tall gear, you MUST apply a small amount of
throttle to reactivate the clutch. If you pull the clutch lever or allow the RPM to drop to idle
without reactivating the clutch, free-wheeling occurs."

That sounds potentially problematic. I still don't really understand how it works or how you set the engagement speed. Obviously it has to be above idle but if you have already set a relatively high idle speed (eg: 2,000 rpm) to make power shifting easier you would have to set the engagement at at least 2,500 rpm and in some circumstances that could mean you inadvertently lose drive if it drops below this speed, especially with reduced flywheel.

I guess you would need to test it and see just how problematic that might be.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

My enquiry with Rekluse has been referred to their R&D department so we will wait and see if they come up with something. In the meantime I have ordered a new set of Barnett steel plates to see if they help when attempting to select neutral.

I have fitted the larger slow jets (#62's in place of #60's) and the revs are no longer hanging. The off idle throttle response seems better, at least in the workshop and it immediately drops back to a normal idle. I will have to wait a few weeks for another track test but it looks hopeful and having a stable idle speed may assist gear selection too altho' Roly reckons he always had the idle on the Beast set at 2,000 rpm to make downshifts easier. This only applies to bikes with shaved cranks, however,

Of course, changing these very fine jets requires pulling the carbs off because it is a rather delicate bench job. Changing needle position is also a delicate bench job because the locating circlips are so tiny and have a tendency to sproing off into the ether never to be seen again. But I can extract the needles from above after removing the tank and top caps without removing the carbs from the bike. Nobody in their right mind likes fitting solid banks of 6 carbs to a CBX and CR carbs are even more fiddly.

Anyhow, I have done it so many times that I have developed my own technique, so this is how I do it:-.

First, copious quantities of rubber grease on both ends of the rubbers after carefully checking that they have not developed any splits.

Second, gently heat the rubbers for 5-10 minutes with a heat gun so they are nice and pliable.

Third, place the clamps loosely on the carbs out of the way behind the rubbers and in the order you want to tighten them (I always have the screws on the outer carbs facing outwards and at 12 o'clock and #'s 3 & 4 I place underneath at 6 o'clock, also facing out.

Fourth, line the carbs up with the inlet spigots on the head with the boots already mounted on the carbs but not clamped and try to push them all on evenly together. If you do one end first, when you try to push the other end in the first end will inevitably pop out again. After doing that half a dozen times you will appreciate the 'line 'em all up and give em' a single shove' technique. The recommended technique in the manual of tilting the motor is essentially the same but you do not need to drop the motor forward if you use my method.

Fifth, finally make sure the clamps are all correctly seated in the grooves in the rubbers otherwise you will end up with splits and the rubbers not sealing properly. The motor will then run unevenly and usually the headers on those cylinders will either run too hot (lean) or too cold (not firing at all).

On CR's you also have to be careful with the position of the drain screws too because #4 has to be carefully measured with a micrometer and filed down so that it does not end up resting on the primary chain bulge in the cases. This also enables you to loosen all the drain plugs to drain the carbs between runs otherwise the additives in the PULP will, if left long enuf' for the fuel to evaporate, gum up the jets.

Whenever, I hear stories about CBX carb problems the first thing I would visually check is the condition of the rubbers and whether they are mounted properly. I think this applies to CV's just as well as CR's.

The second thing I would try with CBX carb problems, especially if you have lengthy lay ups during winter, etc. is spaying some carb cleaner down the fuel line. Modern unleaded fuels go off and gum up the works very quickly and a can of carb cleaner will often cure poor running problems on bikes that have been sitting around unused for a while. :twocents-02cents:

User avatar
Syscrush
ICOA Member
ICOA Member
Posts: 1714
Joined: Fri Sep 14, 2012 2:29 pm
Location: Toronto, ON
Location: Toronto, ON

Re: CBX Racing

Post by Syscrush »

Warwick Biggs wrote:
Mon Jul 11, 2022 2:09 am
the locating circlips are so tiny and have a tendency to sproing off into the ether never to be seen again.
My uncle was a mechanic for years then a fleet manager, and a hobby mechanic at home, taking care of his own vehicles and helping out friends and family. He said that in the shop they'd call those circlips "Jesus clips" because whey they sproing off into the ether you shout "Jesus!".
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Your uncle was a more polite gentleman than moi, Phil. Luckily, I don't have any close neighbors because my expressions when working on the lump are a lot more colourful.

Louis has come up with a new old stock Barnett clutch so I might bite the bullet and grit my teeth (don't you Iove mixed metaphors?) over the rampaging US $ and lousy exchange rate and try that. James Fisher tells me he has no problem selecting neutral with his racer fitted with a Barnett clutch.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

My Barnett clutch is stuck in a Miami dispatch center so I won't have it in time for my track test this w/e. I have re-jetted the carbs tho' and am hopeful that I've eliminated the horrible hesitation coming off a closed throttle. You really can't safely ride a 140 hp race bike with that sort of problem. As you try to gently feed in the power to drive thru' the apex there is nothing. Then just when you have minimal traction you get a bucket load of hp causing the back to either spin up or step out. Hopefully, it is cured.

Here is the lump ready to go.
You do not have the required permissions to view the files attached to this post.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

A-ha! The problem with my pics loading strangely appears to be related to the aspect ratio and the conversion of pics taken with my mobile phone and then emailed to my Zenbook. If I edit it to landscape it seems to load correctly. Here, I'll try again...

In this pic you can see 2 things. First I have re-positioned and repainted my front number plate/nose fairing. It gets peppered with stones in close combat and helps to save my visor from chips but regularly needs re-painting. You can also see where I have narrowed the Rickmans seat immediately behind the tank and profiled it with a hump so that I can more easily slide off the seat on each side and use my body weight to turn it and stand the bike up a bit more in the corners - not my natural style I might add but needs must.
You do not have the required permissions to view the files attached to this post.

User avatar
bikeymikey748
ICOA Member
ICOA Member
Posts: 496
Joined: Tue Aug 30, 2011 2:52 pm
Location: Montreal, Canada
Location: Montreal, Canada

Re: CBX Racing

Post by bikeymikey748 »

That’s a SERIOUS looking bit ‘o kit !

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Yes, by crikey Mikey 'tis built to a purpose to be sure. Not for show but for go and here are the specs (put together in case I'm not around anymore):-
Classic 1982 Honda Prolink CBX 1170cc Log Booked Period 5 Historic Racing Motorcycle
The last and most outrageous of the production air cooled superbikes, the Honda 6 is the icon of excess but in this bike it has been carefully honed into a well-developed, reliable and competitive historic racer. One of only a handful in the world still regularly racing at national level, this is a genuine original matching numbers machine that has been sensitively modified to retain it’s revolutionary classic features. It is not another faux replica but the real (slightly modified for racing) deal.
Chassis modifications include head stem pulled back from 28 to 24 degrees, de-lugged but retained original alloy Prolink swing arm and linkage modified to accept lightweight 17” wheels (120 front, 165 rear carrying new Bridgestone Battlax slicks). Fully adjustable Wilbers suspension re-valved front and rear by multi Oz champion Trevor Manley (recently refurbished) and lifted with a selection of custom dog bones for enhanced ground clearance and contemporary lean angles available with modern race tyres. Front 39 mm forks retain original air caps. Sprung for 85 kilo rider. Fully Computracked and perfectly straight.
Original stock sliding 4 stainless piston front brake calipers with HH sintered pads, period disguised floating VTR rotors, braided lines and Brembo radial master cylinder. Single piston rear.
Quad cam 26 valve motor re-sleeved from 1050cc to 1170cc. Head conservatively ported with 2 mm o/size valves, Waggot cams, sturdy custom balanced Chromalloy rods, MTC 10.6:1 forged pistons, lightened fully balanced crank to Honda Racing Corporation specification, extended sump and larger capacity oil cooler, Barnett heavy duty clutch, gears undercut and cases modified to carry 20 tooth countershaft sprocket with a variety of alloy final drive sprockets, 520 chain. Lanyard plus manual kill switch.
Tuned 6 into 2 stainless db compliant race exhaust by Ken Onus.
Ignitech fully programmable TCP4 digital ignition with rev limiter, alternator removed and custom race loom running total loss off 2 ‘switchable on the fly’ 20 cell Antigravity lithium batteries
Bank of 6 Jyo Bito finely engineered ‘V’ mounted 31 mm CR Special smoothbore race carbs with Venhill quick action throttle with various cams, choice of jetting. Motor built and dyno tuned by Roly Skate and then refined at the track.
Rickman seat, and nose fairing, Raasq period rear sets, fully adjustable levers, lever protectors, engine protectors Colin Marley billet crank end caps, etc.
Front and rear paddock stands and digital tyre warmers.
Extensive list of spares including clutches, master cylinders, levers, sprockets and all original road gear, loom etc. including spare set of sought after 18" Boomerang mag wheels with custom cast iron disks. W/shop manuals. The bike still has a compliance plate and could be re-registered as a roadster.
Weight: 198 kgs half wet
Power: 140+ hp depending on state of tune estd. value in 2022 - one of a kind and $Priceless.
Possible future improvements would be light weight carbon wheels, titanium valves, collets and gear, fitting Lambda sensors to individual exhaust headers and balance straws to alloy inlet tracts and properly flow testing the cylinder head. Perhaps another few thousand rpm and 20 hp could be found altho' I'm guessing because it is uncharted territory. A six speed gear cluster would be great and electronic throttle, up and down quick shifter, slipper clutch and mechanical fuel injection are all allowable under the rules but currently well outside my budget. My pick would be the carbon wheels but I'm just dreaming.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

The best laid schemes o' mice an' men gang aft agley an lea'e us ought but grief an pain. Or, so Robbie Burns wisely confided to a mouse he had rudely disturbed.
The lump did not make it to the track because even raw ether could not raise it from it's slumber. That is what comes from unnecessary fiddling with 6 air screws on the smoothbores. I absent mindedly lost track of all my quarter turns despite meticulously writing everything down. Doing everything 6 times begets boredom and mistakes follow in gay profusion. Back to square one with that then.
The GSXR had not had a canter for 6 months or more and had a flat battery so it got the guernsey after a charge up but has now been sold. So much time languishing under a sheet is inexcusable for such a great bike. I had it set up for racing but after deciding I was getting too old to try to race with the super keen, super fit ASBK youngsters on their superbikes it became a little used track bike. It deserves better. Here are some last picks of it... bye bye dark horse gixxer.
You do not have the required permissions to view the files attached to this post.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

While at the track I had the opportunity to try something diametrically opposite to the lump - a modern high tech single no less! Any less and it would not have an engine at all but the Svartpilen 701 has 75hp in a super light chassis with multi access imu traction control, 2 way quickshifter, topline Brembos and a featherweight chassis that you can split hairs with.

While opposite in many ways it is also apposite on the track. It was easily the fastest thing out there in my group and had more grunt out of the corners that a Testastretta that briefly impeded my way. Place it anywhere millimetre accurate. Trail brake hard to the apex and it is telling you exactly how close you are to the limit or stand it up on it's nose with 2 fingers. This Sveedish black arrow is a real track weapon. In fact the dosh from my dark horse may find it's way into an even more modified version with more hp and even better chassis. Stay tuned folks. There is something appealing about a modern Manx Norton as stablemate to the icon of excess. A single and a six has a certain 'je ne sais quoi' about it.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Don't you love the way Microsoft inserts words that it thinks you should use when you type something it doesn't like? It SHOULD have read multi axis inertia measurement unit, just in case you didn't know. Lean angle slip sensitive traction control to be less prosaic.

User avatar
Syscrush
ICOA Member
ICOA Member
Posts: 1714
Joined: Fri Sep 14, 2012 2:29 pm
Location: Toronto, ON
Location: Toronto, ON

Re: CBX Racing

Post by Syscrush »

As the former owner of a KTM Duke 690, I'm here to say that I 100% understand the appeal of the 701. Probably the best bike I'll ever own.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Funny you should say that Phil. Great minds obviously think alike. This is the probable gixxer replacement. Almost brand new apart from Marchesini light weight wheels, adjustable triple clamps, plus a host of other track refinements.

The 701 negotiations got caught up in complications associated with arrangements for next year's Manx GP and 2 701 owners trying not to offend each other. Geez! Some of these sensitive new age racers are just so damn nice to each other that it makes me nostalgic for the good old bad old days. Anyhow, the Super Duke R was the compromise. It doesn't have a QS but other than that is more or less the same bike. It is even lighter than the 701 and better suited to my purpose as a practice bike, albeit ugly as sin to my eyes. Plus, it has all the road gear so I can even register it and ride it on the public roads.

And it costs around half what the gixxer will realise and the difference can go towards my search for a larger enclosed 2 bike trailer so that I will always have a back up bike if the Lump becomes indisposed. So we will indeed have a single and a six. A bit of synchronicity there if you consider diametrically opposed extremes to have something in common. Plus the V4, of course. Is that too many bikes? We will have to wait and see.

People say racing is expensive and that is true but the reality is that there are some great opportunities and deals done at the track, often on a nod and a handshake that might surprise other motorcyclists and that help moderate those costs. You certainly don't have to be a works rider or professional racer and even a septagenarian clubman on a modest income can enjoy this sport - even if you do have to put up with so many damn nice people!
You do not have the required permissions to view the files attached to this post.

User avatar
Syscrush
ICOA Member
ICOA Member
Posts: 1714
Joined: Fri Sep 14, 2012 2:29 pm
Location: Toronto, ON
Location: Toronto, ON

Re: CBX Racing

Post by Syscrush »

That's the same as my bike - the '08-11 model. At a KTM track day with a ton of RC8's and 2 690's, they had to have a waitlist for the little bikes.

Mine had a Galfer wave rotor, EBC HH pads, the KTM Ergo seat, taller touring windscreen, and a custom rack for a set of 3 Givi hard bags. I did commuting, touring, runabout/errands, mountain riding, and track days on that bike. Amazing brakes and suspension, funny engine, nice light weight. Always a winner.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

Post Reply

Return to “Daily Discussion: By, For & About CBXers”