Mcm mod for comparison
#1
09-17-2018, 07:17 PM
Join Date: Jun 2008
Location: So Cal
Posts: 1,352
Mcm mod for comparison
I’ve asked more than one mechanic about retiming cams. They seem to be in unison on their thoughts of the mod. It’s not rocket science. Many have tried this before.
So im thinking if someone isn’t willing to go the distance I’ll try to see what’s up. My female friend has been bitten by the hp bug. Talking about selling her klx, she has my husky te450 now, and is eyeing the plated 05 Crf450x im working on getting a 08 R head & 02 R cam installed.
Im gonna do the mcm mod then find a piped, rejetted, identically geared klx250s to see if it’s faster stop light to stop light, on ramps, and 0-60 times. Let’s really see if this is what it’s touted to be.
The last time I helped someone stfu lol
So im thinking if someone isn’t willing to go the distance I’ll try to see what’s up. My female friend has been bitten by the hp bug. Talking about selling her klx, she has my husky te450 now, and is eyeing the plated 05 Crf450x im working on getting a 08 R head & 02 R cam installed.
Im gonna do the mcm mod then find a piped, rejetted, identically geared klx250s to see if it’s faster stop light to stop light, on ramps, and 0-60 times. Let’s really see if this is what it’s touted to be.
The last time I helped someone stfu lol
Last edited by RaceGass; 09-17-2018 at 07:23 PM.
#2
09-17-2018, 09:45 PM
When you start the modding on the girlfriends bike I'll help with the particulars.
You gonna build a TRQ monster (MCM, stock header+slipon+lidless) or an all-around screamer ( FMF system, MCM, lidless )..?
Done right, y'all may decide to keep the KLX..
Also, done right, it'll take a well sorted BB KLX to beat you. Wasting your time disgracing stockbore KLX's will become boring really quickly..
You gonna build a TRQ monster (MCM, stock header+slipon+lidless) or an all-around screamer ( FMF system, MCM, lidless )..?
Done right, y'all may decide to keep the KLX..
Also, done right, it'll take a well sorted BB KLX to beat you. Wasting your time disgracing stockbore KLX's will become boring really quickly..
Last edited by Klxster; 09-17-2018 at 09:55 PM.
#3
09-17-2018, 10:29 PM
You're taking this way to seriously, but since you are, did you also ask those mechanics what normal cam timing normally might be? They should know if they think the MCM is wrong.
You see that was what sold me on doing the MCM, both Marcelino and Joe Minton,very well known and very well respected in the motorcycle industry, both pointed out the optimum was nearer 100 degrees. Seems the Nighthawk was set at 133 and the KLX at around 110. Just sayin' Minton was pretty darn well known and respected up there along with Gordon Jennings, so some unnamed mechanics don't quite cut it like Joe.
I also did some more digging. Found that increasing the overlap as the MCM does is known to increase mid range power, sometimes at the cost of top end power, but clearly in Marcelino and other riders' testing, it doesn't.. I also found the numbers for the KX250F for comparison to a racing engine's lobe timing:
For the Kawasaki KX250F engine with the stock camshafts, the timing information is as follows:
Then there are the specs for the S4 Corse race cams in a Ducati
You see that was what sold me on doing the MCM, both Marcelino and Joe Minton,very well known and very well respected in the motorcycle industry, both pointed out the optimum was nearer 100 degrees. Seems the Nighthawk was set at 133 and the KLX at around 110. Just sayin' Minton was pretty darn well known and respected up there along with Gordon Jennings, so some unnamed mechanics don't quite cut it like Joe.
I also did some more digging. Found that increasing the overlap as the MCM does is known to increase mid range power, sometimes at the cost of top end power, but clearly in Marcelino and other riders' testing, it doesn't.. I also found the numbers for the KX250F for comparison to a racing engine's lobe timing:
For the Kawasaki KX250F engine with the stock camshafts, the timing information is as follows:
Intake Opens 40° BTDC (Before Top Dead Center)
Intake Closes 72° ATDC (After Top Dead Center)
Intake Lobe Center = ((40 + 72 + 180) ÷ 2) - 40 = 106° :
Exhaust Opens 69° BBDC (Before Bottom Dead Center)
Exhaust Closes 49° ATDC (After Top Dead Center)
Exhaust Lobe Center = ((69 + 49 + 180) ÷ 2) - 49 = 100° .
The KX250F makes 34.8 hp at 11,850 rpm, significantly higher than the KLX's 19.5 @ 8310 rpm The results of most everything near the KLX performance I saw had the lobes nearer to 100 than 110. Intake Closes 72° ATDC (After Top Dead Center)
Intake Lobe Center = ((40 + 72 + 180) ÷ 2) - 40 = 106° :
Exhaust Opens 69° BBDC (Before Bottom Dead Center)
Exhaust Closes 49° ATDC (After Top Dead Center)
Exhaust Lobe Center = ((69 + 49 + 180) ÷ 2) - 49 = 100° .
Then there are the specs for the S4 Corse race cams in a Ducati
Exhaust lobe center: 107 degrees
Intake lobe center: 110 - 112 degrees
Seems Marcelino actually had something there. Time the cams for the engine specs and he tested his work. .
Intake lobe center: 110 - 112 degrees
#4
09-18-2018, 01:06 AM
WOrD for the DaY - "Generic"
RaceGass, since you do not personally understand the nuances of altering both camshafts' timings, and how doing so interacts with the existing intake and exhaust tracts, you are under orders to stop asking generic engine peeps about generic power differences with generic cam re-timing - As you should already know - all they can offer is generic responses for generic scenarios..
Let's get to work on Jill's KLX...?
RaceGass, since you do not personally understand the nuances of altering both camshafts' timings, and how doing so interacts with the existing intake and exhaust tracts, you are under orders to stop asking generic engine peeps about generic power differences with generic cam re-timing - As you should already know - all they can offer is generic responses for generic scenarios..
Let's get to work on Jill's KLX...?
Last edited by Klxster; 09-18-2018 at 01:10 AM.
#7
09-18-2018, 03:13 PM
WOrD for the DaY - "Generic"
RaceGass, since you do not personally understand the nuances of altering both camshafts' timings, and how doing so interacts with the existing intake and exhaust tracts, you are under orders to stop asking generic engine peeps about generic power differences with generic cam re-timing - As you should already know - all they can offer is generic responses for generic scenarios..
Let's get to work on Jill's KLX...?
RaceGass, since you do not personally understand the nuances of altering both camshafts' timings, and how doing so interacts with the existing intake and exhaust tracts, you are under orders to stop asking generic engine peeps about generic power differences with generic cam re-timing - As you should already know - all they can offer is generic responses for generic scenarios..
Let's get to work on Jill's KLX...?
Talk about generic, where did you do the math to find the exact lobe center angles for the KLX250?
There is no need to act the way you always do. Why don't you try to be decent instead of trying to indirectly insult others. Is it really that hard?
Last edited by klx678; 09-18-2018 at 03:18 PM.
#8
09-18-2018, 04:59 PM
Join Date: Jun 2008
Location: So Cal
Posts: 1,352
But after I get my hands on the low mileage klx250s, I’ll follow the procedure carefully to make sure it’s done as intended. Once completed I’ll find another klx to see if this mod does jump out ahead in a straight up drag test stop light to stop light, or will it run out of steam sooner and the non mcm bikes rev range overcomes the short shifting klx. Either way this has been a question in my mind since this was posted originally, as there was NEVER any real testing done ever like what I’m planning was there?
#9
09-18-2018, 05:24 PM
Join Date: Jun 2008
Location: So Cal
Posts: 1,352
Nothing is stopping either one of you from performing the tests I’ve come up with. You have a mcm modded bike to perform the tests I’ve asked about. It’s not like I want to do this, but the results have never been shown to my knowledge. I’m sure the valve cover gasket has shrank from heat cycles so that will be $41 right of the bat.
I’d rather see how using a thinner base gasket might increase mid range power or if a little removal of material around the valve guides could increase port velocity to improve top end power.
So you both have a window of opportunity to prove this mod. Or not...
I’d rather see how using a thinner base gasket might increase mid range power or if a little removal of material around the valve guides could increase port velocity to improve top end power.
So you both have a window of opportunity to prove this mod. Or not...
Last edited by RaceGass; 09-18-2018 at 05:46 PM.
#10
09-18-2018, 05:53 PM
Nothing is stopping either one of you from performing the tests I’ve come up with. You have a mcm modded bike to perform the tests I’ve asked about. It’s not like I want to do this, but the results have never been shown to my knowledge. I’m sure the valve cover gasket has shrank from heat cycles so that will be $41 right of the bat.
I’d rather see how using a thinner base gasket might increase mid range power or if a little removal of material around the valve guides could increase port velocity to improve top end power.
So you both have a window of opportunity to prove this mod. Or not...
I’d rather see how using a thinner base gasket might increase mid range power or if a little removal of material around the valve guides could increase port velocity to improve top end power.
So you both have a window of opportunity to prove this mod. Or not...