Roadracing my CB1100F

Posted: Tue Jan 09, 2007 8:47 pm

With the wide motors in these things there is often a compromise between proper bike attitude and ground clearance. The short rear wheel coupled with the long front forks will actualy increase rear swingarm angle and should help you getting that thing to finish the turn. I don't like riding bikes with a nose high and saggy butt attitude, however. They generally dont turnin very well and don't steer that well especially on corner entrance thru mid turn. When you have time you can build a back half of the exhaust that will solve your exhaust clearance issues but you will have to route it thru the area of you current footpeg mounts. If you move the pegs forward, it will put your feet more underneath your butt and provide more leverage to hike that thing around. You would benefit from raising the rear and dropping the front, the bike will feel alot better than it does now and whatever you had to do with pegs, exhaust, and case covers to make it work would be worth the trouble. I am surprised you were able to hang with the modern 600's, The ama factory Honda's from 82 even with Spencer on board, would have trouble keeping a decent 600 supersport in sight. Please keep us informed of your performance in the upcoming race and good luck. Steve

Posted: Thu Jan 11, 2007 3:41 am

Yeah, Steve, it's always a question of which compromises you want to accept, isn't it?

The first corner at PI is hell fast - like flat-out in top on a TZ350 if you do it right - so I am prepared to muscle around the slow corners, where you make up bugger-all time, for the sake of stability and speed on the fast stuff where you make up lots. For everything other than the street meetings, this compromise works for me. In NZ, we still have some sanctioned meetings on closed-off town streets. There, they are almost all slow corners, and you really need fast turn-in, or a full motard-style back-in.

It's actually the 4 into 1 collector itself, rather than the tailpipe out of it, that is grounding. We modified the tailpipe, but the rest needs all 4 exhaust downpipes to be modified, and that was the time thing. In fact, with time, we'd design and make our own system for performance as well as the ground clearance issue.

But this is still all for the fun of the ride, and to decide whether we should go ahead and make a full CB-F racer.

Posted: Thu Feb 01, 2007 5:18 am

See post-race report on thread "Phillip Island Vintage race" from about Jan 29 '07.

This machine is going to be turned into a proper racer.

Even now, the motor is quite powerful compared with some of the worked Suzukis and especially the Team Glam Kawasakis, which surprised me. Haven't had it on the dyno yet, but it feels 125hp+ on the track alongside machines which I have seen on the dyno. Many of the competition in our class I have not seen on the dyno, but whose hp claims I have seen, seem to me to have power measured in My Little Ponies if ours produces about 125.

The general plan: Wiseco pistons to 1123, and we will do a bit more with the head, play very slightly with compression, build a stronger crank and put in stronger rods, leave the gearing as is in the gearbox (have a range of external sprockets anyway), but mainly concentrate on the chassis for ground clearance, compliance, and steering. Properly set-up Ohlins shocks and probably cartridge emulators for the front forks are on the menu. We have some thinking to do about engine width, of course, as I was scraping both sidecovers in the weekend, regardless of how far I hung off. Pipes have been mentioned in earlier posts. Camchain, CCT, primary chain and its tensioner need some thought, but it's what causes tensioners to fail that really interests us.

The brakes were fine until I binned it and we didn't really bleed them properly, so they were a bit spongy for our Sunday racing - I do not think that's permanent. Replacing the fluid will probably show some gunk from the crash.

I'll use the tyre warmers on it, too, now that we're going to be a little more than, "See: this is what my ride-to-work bike can do."

Posted: Wed Aug 29, 2007 4:40 am

OK, folks, reviving this thread now that we have got going with the 1100F race project again.

The chassis has been substantially modified: steering head angle brought in by some 2 1/2 degrees, and the frame made solid without the removable sections, and also braced. We will run with the stock swingarm until we know that it is a problem. I am expecting that it will be a problem, with a more rigid frame than the Flexoplus stocker, but it depends...development is much better a bit at a time, so you can work out what change is doing what, I have found. With Historics, you have heaps of time to find out, because they're already obsolete before you start. I have another swingarm lined up if necessary.

We have had a set of remote reservoir Ohlins made up specifically for the machine and my size and style (the NZ Ohlins guru, Robert Taylor, has worked with us before and knows what I like).

1123 motor, but have decided to leave the head pretty much as it was before, since the porting was done anticipating that it would become an 1123. We've just built a 140rwhp GSX1100 for a customer, so we're not allowed to exceed that. I think we will be close enough, probably 125-130 or so on a fairly flat curve from 8,500 on up (Dynojet dyno).

Proper race clipons, rather than repositioned standard ones, so I'm going to be more comfortable.

We'll still use an F bike fuel tank, and probably standard seat as well, but the full fairing is still planned.

(Chris 41, your end cover is on its way to you tomorrow. Thanks, mate.)

Posted: Wed Aug 29, 2007 9:34 pm

No worries mate with the cover mate, thanks . We will probably be at PI, 2008 but the Poms are not coming to this meet Team Glam has gone ICGP racing on TZ350s and Top Banana racing is skipping 08.
so I don't know how the program will run. Maybe just normal or I wouldn't mind seeing eastern states V southern V NZ
We may have the SOHC Sidecar fitted with a Hyvo stroker engine in it.

Chris

Posted: Wed Aug 29, 2007 10:13 pm

Yeah, heard about TG and looked at their website.

Makes me pleased I'm having a break from the TZs; their learning curve is depressingly familiar.

I'm not sure yet if I'll be at Phillip Island 2008 myself - there's a big adventure ride taking in all 26 of the major NZ South Island mountain passes in early February, and I'm itching to do that on the big trailie.

Cheers

Posted: Tue Sep 04, 2007 1:41 am

Side cover received Pete thanks. It will be a pity if there is a reduced international contingent in 08 but at least it will be more racing for us I am going to do the Thursday practice next time I cant get used to PI as quick as other tracks. I will reduce the fork offset before this months State titles to get more feel
and that should help at PI

Regards Chris.

Posted: Tue Apr 29, 2008 4:36 am

The project has been simmering away for the last few months, and we gave the machine the first run in its new guise 10 days ago.

Just a gentle jog at the track, at a training day I was instructing on, keeping it below 8,500rpm. It had to be a fairly gentle jog, as I still have the same tyres I crashed on at PI in January 2007. Obviously, new tyres are on the menu for soon.

The machine feels good and strong, sounds OK.

So what have we done since last report?

1. Solid mounted the engine - made up plates etc to mount into the welded-up frame;

2. Rebuilt the front suspension (did not go to emulators, as it probably did not need them once we'd modified the existing damping and adjustment; I am happy with its stock springs);

3. Fitted new Ohlins to our/Robert Taylor's specs at the rear;

4. Shortened the swingarm a bit;

5. Designed, built and fitted new 4-2-1 exhaust system with own design silencer, with varying diameters in each pipe but for the same lengths in each pipe. Inlets for the headers fabricated to fit the exhaust ports exactly, not an easy job just in itself. If we were to do this for a customer, the time taken would have been about USD3,000 worth;

6. Repaint - black, clear lacquered over the colour coat;

7. Did I mention we've braced the frame where it needs it? I know I did mention we've steepened the steering head angle a lot;

8. 1123 kit fitted;

9. Designed, made, and fitted our own camchain tensioner, along the same lines as one we make for racing GSX1100s;

10. Fitted the latest Dyna ignition system;

11. Installed a tacho; reset the limiter to 10,000, but I found starts on it were very difficult without a tacho (direct comparison with old Brit singles, where I seldom consult the tacho at all. It's highly embarrassing getting a great start and then bogging down when the thing hits the limiter just as you're about to change up, thus losing your great start.);

12. Sorted a new fairing, but didn't fit it for the training day for ease of access to everything.

Once we have it settled down a bit, dyno runs will be done to sort the final carburetion. It's a bit fluffy in the midrange, and this machine I want to get as close to perfect as we can. (Then I guess we'll have to find a better rider than me.)

Here are two pics, one of the bike itself and one to show some of the exhaust system.. I realised after taking them that the shiny lacquer reflected the paint on my son's 4WD. The machine is all black...better pics will follow some time.

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Posted: Tue Apr 29, 2008 2:02 pm

Looking good Pete! (gotta do something about that rear brake lever though!)

Posted: Tue Apr 29, 2008 7:45 pm

any detail pictures of the frame bracing?

Posted: Tue Apr 29, 2008 10:43 pm

MWis wrote:

Looking good Pete! (gotta do something about that rear brake lever though!)

The marks on the rear brake lever are where we heated it and bent it in and out again (gotta leave some soot on the alloy before heating so as to determine the right heat to bend); it now sits in closer than the gear lever.

Stout, the frame bracing is (a) down by the swingarm pivot; (b) from that area horizontally back to the rear subframe on each side; (c) at an angle one side to the other of the downtubes behind the engine; (c) between the top tubes above the engine; (d) around the steering head. No pics as completed, though somewhere (if I can find them) I have some of the work in progress once we'd got the frame back after crash straightening and steering head steepening on the jig.

You can count as frame bracing the full solid mounting system we made up for the engine, as well.

Posted: Tue Apr 29, 2008 11:19 pm

Ahhh....did not know that! my apologies!

Posted: Wed Apr 30, 2008 4:18 am

I would also like to see the steering head, top tube bracing.

Is the header a 4-2-1? Looks like 1,2 & 3,4 into 1.

Jim

Posted: Wed Apr 30, 2008 10:39 pm

The bracing around the steering head is not all that extensive. We just beefed up what was there already and added one tube, as we could see no need for more. Most of the bracing effort has been at the back and top of the chassis.

The four pipes feed into two pipes that then feed into one. The junctions are all under the motor. The calculations just ended up that way.

We designed the exhaust to help give us a good wide spread of power, and that's the way it seems so far; pulls like a traction engine from about 5,000rpm, so I am anticipating being able to operate anywhere from there to 10,000. Luxury.

Posted: Thu May 01, 2008 4:31 am

The bike looks great! I have a question about the cam chain tensioner you designed and built. Do you have any pics and can you make more? Cool

This part alone may make you a fan favorite around here. Good luck on the track and dont forget about the tensioners! Very Happy

Posted: Thu May 01, 2008 9:41 pm

Larry, I do not have photos of the CCT, but in general terms we have dispensed with the Honda spring and adapted a semi-solid arrangement that we have had in customers' Suzukis for some years. We made a similar one that has been in the CB400F racer (now nearly a 600, running on methanol at about 13.5:1) since 2003.

Obviously, the CB1100F camchain runs present a design difficulty. I would not like to suggest our design as a solution for other owners until we have actually tested it in roadracing for at least a season. The chain layout is sufficiently different from the Suzuki one that we are not absolutely confident as yet.

BTW have also designed but not yet fitted a primary chain taming device, too.

If we were to make either of these for other owners, they would be pretty expensive.

And a final BTW: every Honda discussion forum I have seen - CB1100F, Firestorm, Varadero, CB400F, CB77, XL250 - has a repetitive litany of CCT problem reports. And yet, though I have had broken tensioner blades once or twice, I have never personally suffered a complete failure in ten or a dozen OHC Hondas, maybe 400,000 road miles on them, and maybe 7,000 road racing miles. I wonder if I am just lucky, or if the problem is not so real after all. In the trade, my business partner and I over the last 30 years have noticed that what could have been described as a CCT problem/disaster/result could most often be equally described as some other problem, with the CCT being only a symptom.

Posted: Tue Aug 19, 2008 4:47 am

Next step: the race 1100F has been on the dyno (latest Dynojet) for 9 hours of setting up in the last couple of weeks.

Then the bloody dyno broke (bike running at 250kph at the time). Sheeeyit. Apparently some bit of tortured metal flew out through the casing of the dyno, and the shop concrete wall, and embedded itself in a passing rubbish truck. Obviously knew where it was bound, anyway.

My business partner has a couple of printouts at the shop, and I'll scan and post them here when I get them.

Peak power is in the early to mid 130s, relatively fat flat curve (ie just what it feels like through the seat); in fact, it looks as if it makes more and better power in the midrange than most of the race GSX1100/1135s down here.

Some worries about the ignition with total loss/battery system and no charging; we suspect the system is actually designed to run at 14.4 volts and not a basic 12. Nothing's ever simple.

We're aiming to be racing it the last weekend in September. It's still wintry down here right now, so that's soon enough for my old thin blood, thank you.

Posted: Sun Sep 28, 2008 11:12 pm

First, a photo or two:

So that's how it looks, faired, polished, prepared, tires being warmed.

Funny how once you are on racing pace, rather than just bimbling around at trackdays and the like, handling really shows up.

We have the motor dead right for what we wanted, with usable power over about a 4,500 rpm range, but we have clearly been too radical with steepening the steering head angle. Turn-in to faster corners under brakes is mighty scary, sorta like a tankslapper. It's manageable at slower corners, where you just have to hold it up, but anywhere near the end of a fast straight is just diabolical.

If we rake it back out a bit more, we can still tune the angle with the ride height at the rear and by dropping the forks in the triple clamps, anyway.

At present, you can't even stabilise it with the rear brake all that well, because of lockup whilst heading sideways. (So as well as pulling out the front by maybe 1 1/2 degrees, we'll be cutting down the effectiveness of the rear brake, too...)

It's good in a straight line, though, and accelerating out of corners is OK but a little weavey. So maybe it will be time to reconsider the steering damper and swingarm bracing questions as well as steering head (ie admit we didn't get it right.)

It's times like these I am so glad that I build Historic race bikes that by definition are already obsolete, so you can develop them over as much time as you like.

Posted: Mon Sep 29, 2008 1:46 am

I'd ride it!

Cool

Posted: Mon Sep 29, 2008 4:46 am

Stout, you're a good friend.

I don't know that my conscience would allow you to race it, but, yeah, come on over for a track day.

I've been the development rider on a lot of race bike projects over the years, and this is as bad as I've ridden under brakes, ever. It's clearly the steering head angle, because it steadies up once you are in corners and get power back on, and the forks lengthen out again.

Posted: Mon Sep 29, 2008 6:21 am

She looks wicked!! Twisted Evil

Posted: Tue Sep 30, 2008 3:42 am

Looks like the fun is just beginning!

I have re-read your post, is this the correct summary of the "diabolical" suspension changes?

-900F frame stiffened
-17" rims
-tucked steering head 2-1/2 degrees
-shortened swingarm. How much?
-Ohlin shocks. What lenght?

Have you measured the rake and trail?

I've had a similar ride off fast straights into turns. It sure tucks up the twins.

The set-up is:

-900F frame stiffened
-17" rims with BT-090 Pro's
-braced swingarm 3/4" shorter than stock
-14-1/2" shocks, Vipex with soft Icon springs
-GL fork 1" shorter than stock, .85 kg Race Tech springs with emulators

I haven't measured the rake/trail but I will before any changes are made.

Has anyone checked into HRC geometry?

Good luck with your race season.

Posted: Tue Sep 30, 2008 9:27 am

Yeah, we're the same as HRC but with 1 degree less rake. Wrong....now back to 26 degrees.

The frame was originally stock Euro CB1100F, so geometry was near as dammit the same as HRC Superbike, I believe.

Posted: Mon Nov 17, 2008 3:58 am

So now we had a full day at the track yesterday - a race rider training day at which I was instructing, so I had twelve 15-minute riding sessions, 4 of them on the 1100F. Vince Sharpe, of Torbay Hotrod fame, did another 4 or 5 sessions on it, and his feedback and suggestions have really helped out a lot.

1. Frame steering angle moved out a bit beforehand (as hinted before), so we had a better baseline before we got to the track;

2. but we've now, during yesterday's testing, changed the trail as well by dropping the forks in the triple clamps again to standard Euro/Oz/NZ CB1100F setting (standard, they have clip-ons above the top triple clamp); and

3. backed off the preload on the shocks and also put in a softer set of springs from the suspension specialist's recommendation.

Each stage gave us a move in the right direction.

By the end of the day, it felt as if I was riding a little bike, and we were getting up to a good competitive lap time when I went for a hard ride in the last session.

Vince is really keen that I run it unfaired. I like the "free horsepower" aspect for the straights, as I like the idea of a free ride whilst I have a rest. He makes the points - and I agree - that the look is more in keeping without the fairing, and you can move around more on the bike without it. (Refer to my immediate preceding comment about resting - do I really want to move around more?).

Anyway, heading in the right direction: more to go, but we're getting there. And, though I've fitted a steering damper, it was loosened off all day. (Just have to take care not to get into the run-off soft stuff.)

When I think it is as good as it can be for the moment, I'll post up some of the measurements.

Posted: Tue Jan 20, 2009 10:33 pm

And now the 1100F racer has had its first real race day.

I started at the back of the 22-bike grid each time, as I'm still setting it up.

2 fourths and a fifth. That's OK. Some more suspension setting to do, but we are getting there. Running it unfaired at present until more fully sorted.

Frame dimensions are now back to standard CB1100F, though the shocks are longer and the forks are lowered in the triples.

Here are a couple of pics, the second taken whilst I was in company with Vince on the Torbay Hotrod:

Posted: Tue Jan 20, 2009 11:50 pm

AWESOME!! Neat to see someone racing an F in actual events.

Interesting that you ended returning to the 1100F geom. Was this a re-re-baseline thing or is this where you're going to start your fine tuning from now?

Good luck!

Posted: Wed Jan 21, 2009 7:41 pm

Yeah - re-rebaselining; fine tuning is settings for forks and shocks from here.

Posted: Thu Jan 22, 2009 1:50 am

PJay wrote:

Stout, you're a good friend.

I don't know that my conscience would allow you to race it, but, yeah, come on over for a track day.

I've been the development rider on a lot of race bike projects over the years, and this is as bad as I've ridden under brakes, ever. It's clearly the steering head angle, because it steadies up once you are in corners and get power back on, and the forks lengthen out again.

As I have not had a bike to ride for almost 2 years I want to ride anything with two wheels...

Posted: Fri Jan 23, 2009 3:16 am

stoutblock wrote:

PJay wrote:

Stout, you're a good friend.

I don't know that my conscience would allow you to race it, but, yeah, come on over for a track day.

I've been the development rider on a lot of race bike projects over the years, and this is as bad as I've ridden under brakes, ever. It's clearly the steering head angle, because it steadies up once you are in corners and get power back on, and the forks lengthen out again.

As I have not had a bike to ride for almost 2 years I want to ride anything with two wheels...

OK, mate. The machine's much better now.

So get your ass down here to NZ and you can get to ride it at a trackday.

Cheers

Posted: Fri Jan 23, 2009 3:25 am

Great photos Pete - which track were you racing on?