Author Topic: ScooterBob & GHG's C-5 Cafe Racer project  (Read 155300 times)

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gremlin

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Reply #285 on: May 19, 2015, 01:26:43 pm
  Unfortunately Gremlin,  this first go 'round of pistons are spoken for.  However..... I know a guy who lives out on the permafrost of the Tundra who MIGHT could possibly have one ?   Wears glasses this guy, very cerebral at times yet down to earth.   Good with motorcycles and Hot rods and such .  And if you could catch him.... or pry it out of his hands before he puts it in an AVL .... Maybe ?    Just sayin' !

The Tundra is a wonderful place, I think I know of whom you speak.  He may actually have the fingers that placed my AVL piston in B5 year before last.

Last time I was down at Marty's shop - he mentioned that B had not been spending as much time as he would like there, so, who knows?

The piston I currently have is performing well (a blustery 36 degree ride into work this morning was an easy 70 mph - indicated) without a PC-V so .....  I can be happy waiting for the next batch - just curious.

p.s.  have you had to do any power-commander tuning after the change ?
1996 Trophy 1200
2009 Hyosung GV250
2011 RE B5


gashousegorilla

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Reply #286 on: May 19, 2015, 04:08:46 pm
 Yes I'm sure it was he , who put that slug in yours as well. I can certainly get in touch with him and pass on the info if you like Gremlin. With this first run of pistons  .. four in total, minimum order.  We just wanted to get a feel for how it is.  Then if it's good ?  And it sure seems to be so far. We will order another run of them provided there is enough interest.

  And yes, I am sure it is fine with the stock ECU.   We found the same with a much higher compression increase.  And I would imagine your TPS might have been bumped up a wee bit ?   The only point in which we needed to use a PC-V, was when we went to Cams and to increase the rev limiter.... A must really.  The Cams make too radical of a change. Radically pulling fuel out down low, then radically adding fuel as the revs come up as you could imagine with more lift and duration.  But prior to that ?  Not an issue with the stock EFI and  TPS adjustment.  The first time we put a PC-V on  before the cams.... It made a 1 HP difference and slightly better throttle responce.  The bike had a freer flowing filter and silencer on it at the time , with the much higher compression of the different .... smaller.... chambered head we were using. And have been using up to now.  So, prior to the tune on the PC-V we were fine with our AFR's.

  Now with the tune on the PC-V ?  And remember, the bike is set up the same except for the head and piston.  It "feels " fine. Plug looks perfect.   I am not concerned, It may need a tweak ? And I intend to get it on a Dyno to take a look at it and see how it does, but I want to break it in first and get a better feel for it on the road first.   I have played with the fuel a bit at idle. But I'm back to where I was and it's fine.  I started with a colder plug... an 8.... for safety with the higher compression, and I'm moving the heat range hotter. I'm at a 7 now and it is good. But I intend to try a 6 today.   This stock chamber, because it is larger then what we have been using seems.... Lazy-er at low speeds as far as the mix.  But may flow better at higher speeds. So it seems to react better at idle with a hotter plug. 

 
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gremlin

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Reply #287 on: May 19, 2015, 06:53:46 pm
.....We just wanted to get a feel for how it is.  Then if it's good ?  And it sure seems to be so far. We will order another run of them provided there is enough interest........

The line forms here:

1.  Gremlin Bulletman
2.  Gremlin
3.
4.
5.
6.
« Last Edit: May 19, 2015, 07:25:16 pm by gremlin »
1996 Trophy 1200
2009 Hyosung GV250
2011 RE B5


dginfw

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Reply #288 on: May 20, 2015, 02:22:58 am
 GHG, Just a quick question, as my mind tends to wonder about such things:
Am I correct in assuming that if NO other changes are made to intake/exhaust, that a slight bump in compression would not need additional fueling because the amount of air being sucked in isn't being changed?... but rather, it is being made more efficient with the air volume that IS going in there? (by efficiency I mean a bigger 'bang' with the same amount of fuel)  everything I've read or heard is that a slight compression bump (assuming low compression to start with) is a win/win: more power and efficiency
of course there are other factors, but I'm speaking in general terms like on a stock bike
Dave in TX:   '01  W650- keeper
                    '12 C5 military -sold
                    '14 Continental GT-  sold
                    '06 Iron Barrel Bullet- Ace Clubman mods


SteveThackery

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Reply #289 on: May 20, 2015, 02:53:19 am
Am I correct in assuming that if NO other changes are made to intake/exhaust, that a slight bump in compression would not need additional fueling because the amount of air being sucked in isn't being changed?... but rather, it is being made more efficient with the air volume that IS going in there? (by efficiency I mean a bigger 'bang' with the same amount of fuel)  everything I've read or heard is that a slight compression bump (assuming low compression to start with) is a win/win: more power and efficiency

I realise the question wasn't addressed to me, so I hope you'll forgive me for joining in. 

But, yes, in a word.  Increasing the compression ratio increases the thermal efficiency of the engine (for reasons to do with the laws of thermodyamics and lots of maths).  In simple terms, this means that you get more energy into the piston and less down the exhaust pipe.

There is no downside per se, except one: the engine becomes less tolerant of low octane fuels.  Here in the West we've got consistently good fuel (in terms of octane rating) so the Bullet engine will easily cope with - and benefit from - an increase in CR.

I should add a big caveat: if you are making other substantial changes - such as supercharging, for example - then it's all a lot more complicated and you can't just assume more CR = better.  But we're talking about the real world here. 

In summary, a bump in CR should result in a wee bit more torque through the range, and/or a small improvement in fuel economy.  The downside will be more of a tendency to detonation if the fuel has an excessively low octane rating.
Meteor 350

Previous:
'14 B5
'06 ElectraX (Good bike, had no trouble at all)
'02 500ES (Fully "Hitchcocked" - 535, cams, piston, etc - and still a piece of junk)

...plus loads of other bikes: German, British, Japanese, Italian, East European.


gashousegorilla

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Reply #290 on: May 20, 2015, 04:14:17 am
The line forms here:

1.  Gremlin Bulletman
2.  Gremlin
3.
4.
5.
6.

  Got it  ;)

  Also, A little time on the highway today.... I little early with the miles on the piston ?   But .... ::)    It does have a bit better bit better top end.  Cruising at 75-80 is effortless. A quick shot to 86, again easy.   Until I came to my senses and backed off,  and let reason get the better of me.  I did also have a potential too hot of a plug in there.. A 6.  But it turned out to be fine.  I think I will stick to a 7 for more spirited riding and peace of mind  :o.   My speedo does match GPS  btw.


 
GHG, Just a quick question, as my mind tends to wonder about such things:
Am I correct in assuming that if NO other changes are made to intake/exhaust, that a slight bump in compression would not need additional fueling because the amount of air being sucked in isn't being changed?... but rather, it is being made more efficient with the air volume that IS going in there? (by efficiency I mean a bigger 'bang' with the same amount of fuel)  everything I've read or heard is that a slight compression bump (assuming low compression to start with) is a win/win: more power and efficiency
of course there are other factors, but I'm speaking in general terms like on a stock bike

I realise the question wasn't addressed to me, so I hope you'll forgive me for joining in. 

But, yes, in a word.  Increasing the compression ratio increases the thermal efficiency of the engine (for reasons to do with the laws of thermodyamics and lots of maths).  In simple terms, this means that you get more energy into the piston and less down the exhaust pipe.

There is no downside per se, except one: the engine becomes less tolerant of low octane fuels.  Here in the West we've got consistently good fuel (in terms of octane rating) so the Bullet engine will easily cope with - and benefit from - an increase in CR.

I should add a big caveat: if you are making other substantial changes - such as supercharging, for example - then it's all a lot more complicated and you can't just assume more CR = better.  But we're talking about the real world here. 

In summary, a bump in CR should result in a wee bit more torque through the range, and/or a small improvement in fuel economy.  The downside will be more of a tendency to detonation if the fuel has an excessively low octane rating.

   I couldn't have said it better myself Steve. ;)     And I do have a sneaking suspicion that I will find I am a bit over fueled now.  Particularly in the low to mid range.
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dginfw

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Reply #291 on: May 20, 2015, 04:59:21 am
Thank you Steve.  I kinda had a general understanding but that helps me make more sense of it....I know forced induction is a whole other ballgame because more air increases the need for fuel, and I'm a fan of normally aspirated motors myself. I like it simple
Dave in TX:   '01  W650- keeper
                    '12 C5 military -sold
                    '14 Continental GT-  sold
                    '06 Iron Barrel Bullet- Ace Clubman mods


gremlin

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Reply #292 on: May 20, 2015, 08:44:56 am
We eagerly await the result of your dyno testing !

Will the system respond to a reduction in spark advance? (due to the quicker burn and optimum angular timing stuff?)  If so, how much?

torque on par with a BMW Dakar ?

Magic !
1996 Trophy 1200
2009 Hyosung GV250
2011 RE B5


gashousegorilla

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Reply #293 on: May 20, 2015, 04:11:44 pm
We eagerly await the result of your dyno testing !

Will the system respond to a reduction in spark advance? (due to the quicker burn and optimum angular timing stuff?)  If so, how much?

torque on par with a BMW Dakar ?

Magic !

  You know Gremlin ?.....  You got me thinkin'. Looking at the specs of that bike?  It does bare SOME similarities ?  I never rode one.   Ours is a bit lighter.... ?  Depends on if those numbers are at the crank or not?  If so... we were close with Torque  with the last configuration.   That bike has slightly higher compression, revs a bit higher ?  Duel rate springs ?    Ummmmmmm.....  No STOP !  :o  I wanna try it the way it is .  ;)

  And yes , I can adjust ignition timing to were ever I want.   As you know , what the stock timing curve looks like, is a bit of a mystery on these bikes. And it's blind adjustment the way it stands.  And I do believe is can and should be optimized. What is going on in that head of yours ?

An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gremlin

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Reply #294 on: May 20, 2015, 05:32:20 pm
......... What is going on in that head of yours ?

Insanity, mostly.  ;)

I was just wondering if a higher compression engine would "need" less spark advance - all other things being equal.

In other words, once its on the dyno, it would be interesting to see if the torque curve responds positively to a slight decrease in advance.
1996 Trophy 1200
2009 Hyosung GV250
2011 RE B5


gashousegorilla

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Reply #295 on: May 20, 2015, 05:47:42 pm
  It's a very good point actually......And with a rich AFR?   Faster burn speed..... Ummmmmm?  I was in the neighborhood of 13.2 last time.....  Ummmmmmm ?! Very good point !  The bike does run flat on a zero ignition map, no changes over stock.  But there is a bit more timing on the caned map.... I could play with them on the road first.  Might be fun.......
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ace.cafe

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Reply #296 on: May 20, 2015, 05:57:34 pm
It is possible that it might be better with less spark advance. But it is not something that is guaranteed. Theoretically, with all other things being equal, there is a reasonable expectation that it might, but it might be so little as to not be noticed. It can lose power from retarding the spark, if it doesn't need it.
It really should be tried out on the dyno, to see where it wants the advance to be.
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gremlin

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Reply #297 on: May 20, 2015, 08:45:40 pm
This is an interesting, and easily digestible webpage --> http://www.daytona-sensors.com/tech_tuning.html

I'm withdrawing my previous suggestion  :o

This is a slower read for us slower readers .....  http://rescomp.stanford.edu/~efroeh/papers/RDH_Engine_Performance.pdf
« Last Edit: May 20, 2015, 08:47:57 pm by gremlin »
1996 Trophy 1200
2009 Hyosung GV250
2011 RE B5


gashousegorilla

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Reply #298 on: May 20, 2015, 11:26:32 pm
This is an interesting, and easily digestible webpage --> http://www.daytona-sensors.com/tech_tuning.html

I'm withdrawing my previous suggestion  :o

This is a slower read for us slower readers .....  http://rescomp.stanford.edu/~efroeh/papers/RDH_Engine_Performance.pdf

  Good stuff ! ;)   A bit of after diner reading for sure.
Another decent one....
http://www.innovatemotorsports.com/resources/myths.php



   With a little less Timing, the bike is still a Torque monster on the hills and in 5th on the highway from, 3000 rpm's to 5000 and beyond it seems.   Plug appears a bit cleaner.... timing marks on the ground strap look "safe". Maybe a bit close to the outer ring at full advance......
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gashousegorilla

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Reply #299 on: October 15, 2015, 04:22:36 am
  Tune and flog the piss out of it !  ::).....  Gitter' Dunn as usuall  ;)


I gotta say - if a part will survive the eternal dyno flogging and riding the mean streets of Gorilla Land - no mortal man can break it. Gashouse Gorilla is almost as hard on sh!t as I am .....  :o


 And it has !  You know, like we do. ;D  ;) 

   A little update after a summer full of Street flogging , and some Dyno flogging and tuning earlier today.  On the same Dyno we have been using from the start. ... Thanks again Shawn, around the corner at JDS Cycle !

   The motor has performed great over the summer without any issues...... except for a roll over sensor acting up for a little bit that is ! >:(    So after a season of fun on the bike, I put it on the Dyno to see what it is doing and for a tune on the map... bit of a tweak really as we were close with the fueling.   I am very pleased and happy with the results.  We did a little better then the previous set up. The Domed piston we came up with, combined with the stock chamber does better in the mid range and at peak..... really across the whole range.  The bikes revs freely, smoothly and routinely  up to 64-6500 rpms.  Although not quite yet needed .....it's good to see the stock bottom end taking the abuse so well.   BTW, which was ONE of the reasons why we decided early on, to stick with the stock 500 cc piston size.

   The Dyno results are 34.83 HP, and 35.47 ft lbs of torque at the wheel...  With as nice fat 3-4  gain in the mid-range.   I thought I was feeling that all summer ? And sure enough I did...

 
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.