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Re: What did you do to your bike today?
Posted: Fri Apr 23, 2021 3:44 am
by Warwick Biggs
I like the wheels Ashish, Where are they from and what size?
The shock looks like it bolts directly to the swingarm so how have you managed a progressive rate?
Re: What did you do to your bike today?
Posted: Fri Apr 23, 2021 10:06 am
by Syscrush
AshishNJ wrote: ↑Wed Apr 21, 2021 6:16 pm
Didn’t like the handlebar either.
What handlebar is it, and what don't you like about it? It looks great to me, but maybe I'm just happy to see someone else rockin' a fat bar. Mine's an LSL with the Superbike bend.
Re: What did you do to your bike today?
Posted: Fri Apr 23, 2021 10:09 am
by Syscrush
Warwick Biggs wrote: ↑Fri Apr 23, 2021 3:44 am
The shock looks like it bolts directly to the swingarm so how have you managed a progressive rate?
From that one photo it actually looks like he might end up with a regressive rate - but there could be something deceptive about the angles.
Re: What did you do to your bike today?
Posted: Fri Apr 23, 2021 1:40 pm
by AshishNJ
Syscrush wrote: ↑Fri Apr 23, 2021 10:06 am
AshishNJ wrote: ↑Wed Apr 21, 2021 6:16 pm
Didn’t like the handlebar either.
What handlebar is it, and what don't you like about it? It looks great to me, but maybe I'm just happy to see someone else rockin' a fat bar. Mine's an LSL with the Superbike bend.
I meant the older one I had was too high. I love these. These are rizoma drag bars. Almost straight. Don’t mind length in photo. I phone changes the angle somewhat. They will also be cut short
Re: What did you do to your bike today?
Posted: Fri Apr 23, 2021 1:45 pm
by AshishNJ
Warwick Biggs wrote: ↑Fri Apr 23, 2021 3:44 am
I like the wheels Ashish, Where are they from and what size?
The shock looks like it bolts directly to the swingarm so how have you managed a progressive rate?
It is a Frankenstein:). Front is 2008 r1. Rear is Ducati
Suspension is moved as is from 916. I won’t take any credit for rear suspension work. Someone else did that hard work.
Re: What did you do to your bike today?
Posted: Fri Apr 23, 2021 1:58 pm
by AshishNJ
Apologies for posting all this in wrong thread. I will update the project thread with some more pictures .
Re: What did you do to your bike today?
Posted: Fri Apr 23, 2021 9:29 pm
by wyly
happy to see it where ever you post it, love watching a great build.
Re: What did you do to your bike today?
Posted: Sun Apr 25, 2021 3:37 am
by Warwick Biggs
How have you assessed the affect of the change from 19"/18" wheels to 17" Ashish?
The R1 forks are fairly short compared to the CBX and by reducing the length you will reduce the trail. If you have also raised the rear with the Ducati bits this loss of trail will be exacerbated. Depending on how you have compensated for these factors, I would be looking closely at measuring trail and ground clearance. You don't want it to fold on you in the first tight corner. Also losing more than 2" of ground clearance at the front without other radical chassis mods to lift the bike up will have the crank end cases on the ground at even modest angles of lean.
From memory there were changes to swingarm length on the 916 compared with the 996 in your picture. Ducati have always had problems with their L twin rear ends because of the way the leading cylinder kicks out the front wheel. They had to keep their swing arms relatively short so as to keep the wheelbase within limits and to get the bike to turn like a sportster. This resulted in other problems and compromises so the other measurement I would be looking closely at is wheelbase.
Re: What did you do to your bike today?
Posted: Mon Apr 26, 2021 8:45 am
by EMS
The 916/996 had an adjustable front rake to consider different handling requirements
Re: What did you do to your bike today?
Posted: Tue Apr 27, 2021 11:14 pm
by AshishNJ
Warwick Biggs wrote: ↑Sun Apr 25, 2021 3:37 am
How have you assessed the affect of the change from 19"/18" wheels to 17" Ashish?
The R1 forks are fairly short compared to the CBX and by reducing the length you will reduce the trail. If you have also raised the rear with the Ducati bits this loss of trail will be exacerbated. Depending on how you have compensated for these factors, I would be looking closely at measuring trail and ground clearance. You don't want it to fold on you in the first tight corner. Also losing more than 2" of ground clearance at the front without other radical chassis mods to lift the bike up will have the crank end cases on the ground at even modest angles of lean.
From memory there were changes to swingarm length on the 916 compared with the 996 in your picture. Ducati have always had problems with their L twin rear ends because of the way the leading cylinder kicks out the front wheel. They had to keep their swing arms relatively short so as to keep the wheelbase within limits and to get the bike to turn like a sportster. This resulted in other problems and compromises so the other measurement I would be looking closely at is wheelbase.
Don’t have answers to many questions. The initial fab was done by someone who owned motorcycle shop and had done the needed calculations. I had the engine and delkevic 6-1 installed and there was plenty of ground clearance front and back. I would measure it once engine is back on the frame with the exhaust etc.
If you view this video, mine is very similarly setup (I can’t understand what he is saying though :) )
https://m.youtube.com/watch?v=a4IJVY56C10&t=60s
Re: What did you do to your bike today?
Posted: Thu Apr 29, 2021 11:43 pm
by Warwick Biggs
I don't want to sound alarmist Ashish but what you have here is a radically altered suspension and I would try it out on a track b4 taking it onto the public road. Otherwise you are placing a lot of trust in the fabrication without fully understanding the process.
It might be fine if the fabricator has followed the basic rules of motorcycle suspension geometry but we see a lot of cavalier DYI modifications to bikes where the result is simply to undo all the good engineering that the manufacturer has built into their machine.
If you have insufficient trail as a result of shortening the forks then the front can 'fold'. That is, when you tip into a corner the forks will want to suddenly snap around onto full lock, usually causing a high side crash. It can also lead to high speed instability.
I have seen people playing round with rake and trail in quite radical fashion at the track and it can be done fairly safely. For example, reducing trail by pushing up the front forks in the triple clamps until the front starts to fold in corners and then backing off a bit in order to achieve maximum 'flickability' and to speed up the steering to the maximum. However, these are experienced A grade racers who know what to expect and can take counter measures. If they do crash it is in a relatively safe environment.
I hope you have better luck with the Delkevic 6 into 1 than I had. It looks good, is light and fits around an extended sump OK but it absolutely destroyed my mid range. On a tuned engine it caused a big dip in measured power from 3,500 - 8,000 rpm. The strong mid range is one of the best features of the CBX engine which was designed as a 6 into 2.
Re: What did you do to your bike today?
Posted: Fri Apr 30, 2021 5:28 am
by aahrens1
@Warwick Biggs: What muffler did you use on your Delkevic?
Re: What did you do to your bike today?
Posted: Fri Apr 30, 2021 9:15 am
by AshishNJ
Warwick Biggs wrote: ↑Thu Apr 29, 2021 11:43 pm
I don't want to sound alarmist Ashish but what you have here is a radically altered suspension and I would try it out on a track b4 taking it onto the public road. Otherwise you are placing a lot of trust in the fabrication without fully understanding the process.
It might be fine if the fabricator has followed the basic rules of motorcycle suspension geometry but we see a lot of cavalier DYI modifications to bikes where the result is simply to undo all the good engineering that the manufacturer has built into their machine.
If you have insufficient trail as a result of shortening the forks then the front can 'fold'. That is, when you tip into a corner the forks will want to suddenly snap around onto full lock, usually causing a high side crash. It can also lead to high speed instability.
I have seen people playing round with rake and trail in quite radical fashion at the track and it can be done fairly safely. For example, reducing trail by pushing up the front forks in the triple clamps until the front starts to fold in corners and then backing off a bit in order to achieve maximum 'flickability' and to speed up the steering to the maximum. However, these are experienced A grade racers who know what to expect and can take counter measures. If they do crash it is in a relatively safe environment.
I hope you have better luck with the Delkevic 6 into 1 than I had. It looks good, is light and fits around an extended sump OK but it absolutely destroyed my mid range. On a tuned engine it caused a big dip in measured power from 3,500 - 8,000 rpm. The strong mid range is one of the best features of the CBX engine which was designed as a 6 into 2.
Thanks for providing the input. I always take advice coming from knowledgeable folks serious. This is one of them. As of now, my engine and wheels are off for some work. Once they are back on, I will take all the measurements and share for some more good advice. After that, I intend to find an empty parking lot and do some test runs to get some idea on general stability and go from there .
Did you think it was the slip-on or the mid pipes that were causing the issue with delkevic?
Re: What did you do to your bike today?
Posted: Fri Apr 30, 2021 9:04 pm
by Warwick Biggs
No, Ashish I removed the muffler altogether and ran multiple tests. It is the way the 6 into 1 works. The original designer of the CBX Irimaji San commented at the time that the 6 cylinder was particularly sensitive to exhaust resonance or back pressure. I believe this is because of the firing order.
In the end I had two 3 into ones fabricated by an expert to go back to the original design (see pic). James Fisher, another CBX racer with a lot of experience swears by his 6 into 2 into 1 - again custom made.
The issues associated with fitting 17" wheels and suspension to a CBX have plagued race tuners for decades and are not simply resolved. The two most common approaches are to lift the motor in the frame or to lift the entire bike on much longer suspension. Both involve major chassis modifications. If your guy has succeeded I will be very keen to see how he has done so!
Re: What did you do to your bike today?
Posted: Sat May 01, 2021 2:27 am
by Warwick Biggs
To clarify:- I used the short straight Delkevic muffler that came with the kit. On the dyno I lost around 10 hp up top compared with my previous Pipemasters 6 into 6 but the loss of mid-range was where the greatest impact was felt, particularly on the track.
I tried removing the baffle, then removing the muffler altogether with little improvement other than a lot more noise. I then had a custom set of 3 into 1's made retaining the Delkevic headers cut and shut just to the rear of the collector. This immediately restored my mid-range altho' I'm yet to get it back on the dyno. However, seat of the pants at the track it is much much better.
I should also point out that my motor is modified with ported head and bigger valves sucking thru' 31 mm Bito CR Special smoothbore carbs and fired by a total loss digital ignition. The Delkevic 6 into 1 may have a less noticeable impact on a typical stock CBX making around 80 rwhp.