Some major upgrade advice - Page 9 - Kawasaki KLR 650 Forum
2008+ KLR650 Wrenching & Mod Questions For repair, maintaining or modifying discussions related to the newly updated 2008 and beyond, Generation 2 KLR650 Motorcycle.

 17Likes
 
LinkBack Thread Tools Display Modes
post #81 of 147 Old 11-03-2019, 08:06 PM
5th Gear
 
Join Date: Jan 2011
Posts: 4,390
Quote:
Originally Posted by Norton 850 View Post
Just for clarification, you do not change the stroke with a longer piston rod. A longer piston rod decreases the thrust angle.

Jason
You're absolutely right, I stand corrected.

Deck height was raised in pdwestman's Harley example above to allow standard piston-pin--to-piston-top height pistons, and perhaps stock connecting rods, to operate with a stroked crankshaft.

Thanks for the correction!

ďYou better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, youíre gonna be dead.Ē "John Russell" (Paul Newman), Hombre

Last edited by Damocles; 11-03-2019 at 08:33 PM.
Damocles is offline  
Sponsored Links
Advertisement
 
post #82 of 147 Old 11-04-2019, 11:38 AM
4th Gear
 
Join Date: Aug 2010
Location: Kelowna, B.C.
Posts: 2,398
Quote:
Originally Posted by Norton 850 View Post
Yes, but the long stroke motor makes more torque at lower RPMs. Look at any statistics on long stroke motors, they make gobs of torque down low, usually much more than their over-square counterparts. The disadvantage is that the long stroke motors typically cannot produce as much h.p. as short strokers, without undo piston speed, which translates into excessive heat and wear. If you ride an old BSA or Norton or any long-stroke British bike you can feel it making gobs of torque seemingly right off idle. That's a feeling that I miss in the KLR and other shorter stroke motors, even though they make more h.p.. Longer stroke = more leverage = more torque = more energy that you can feel. It's simple physics and not a myth.

Jason
All I'm telling you is that isn't what the comparative testing showed.

Dave
DPelletier is offline  
post #83 of 147 Old 11-04-2019, 11:40 AM
4th Gear
 
Join Date: Aug 2010
Location: Kelowna, B.C.
Posts: 2,398
Quote:
Originally Posted by ILove2Ride2Wheels View Post
So, really what you are saying is ... any engine of the same displacement will produce the same power at the same PSI - flow through the head I am assuming - regardless of the stroke. More or less.

So, a short stroke engine, a standard stroke engine, and long stroke engine all of the same displacement will produce the same torque at the flywheel - not wheel?

Just trying to clarify here. Assuming this is correct, then it definitely makes sense to strike an engine to a larger displacement regardless of a short or long stroke method.

The only real difference as I understand it is a short stroke creates its maximum power over a higher RPM range than a long stroke. A long stroke creates its maximum power in a lower RPM range. If this is the case I can see why you reference the flywheel rather than the rear wheel. The flywheel being the torque sink so to speak.

The flywheel weight would need to be increased to hold the torque to be released. While a log stroke could use a lighter flywheel. Both methods would then be able to maintain a similar acceleration curve.



Sent from my iPhone using Tapatalk



Correct: regardless of how you get there, the increase in displacement is all that makes a significant difference (again, all else being equal)

Dave
DPelletier is offline  
 
post #84 of 147 Old 11-04-2019, 03:23 PM
OverDrive
 
Join Date: Nov 2009
Location: Lander, Wyoming
Posts: 5,611
Quote:
Originally Posted by ILove2Ride2Wheels View Post
Okay, you know my mind is going to mush over this concept, but let me see if I have this right because Iíve been thinking way to much about it.

1) Shorted the connecting rod.

2) Increase the pivot pin on the crankshaftís orbit the same amount as you decrease the connecting rod.

3) Stock piston - no change in wrist pin location.

So, at top of the stroke the piston is at the same deck height as a stock configuration. At the bottom of the stroke the piston is whatever change in length you make for the crankshaft pivot point/connecting rod change. So displacement change is Pi/4 x bore squared x (stock stroke + pivot point or rod length change)?

As an example the rod is shortened 6mm. The pivot point is moved outward 6mm. The stock stroke is 83. The stock bore Iím using is 105.

.785 * ((105) * (105)) * (83 + 6) = 770.65

That right?



Sent from my iPhone using Tapatalk
Yes, the rod is shortened by HALF of the Total change of crankshaft stroke increase. I posted that way earlier.

6mm of rod pin relocation = 12mm of total stroke increase, I doubt if that is even possible with this engine.
Do you think that there is even enough clearance around the crankshaft? Look here, https://www.klrforum.com/1987-2007-w...rank-case.html

Why would any company build a bolt together rod to fit this engine? Wouldn't that increase rotational rod weight and weight is already your enemy. Wouldn't the rotational weight Increase the vibration of your engine?

Quote:
Originally Posted by Damocles View Post
You're absolutely right, I stand corrected.

Deck height was raised in pdwestman's Harley example above to allow standard piston-pin--to-piston-top height pistons, and perhaps stock connecting rods, to operate with a stroked crankshaft.

Thanks for the correction!
That was not my "Harley example", Damocles.
But I did explain it is easier to purchase longer push rods for an HD engine than to purchase a longer cam chain for a KLR.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
pdwestman is offline  
post #85 of 147 Old 11-04-2019, 03:40 PM
2nd Gear
 
Norton 850's Avatar
 
Join Date: Sep 2013
Location: Houston, Texas
Posts: 161
Quote:
Originally Posted by pdwestman View Post
That was not my "Harley example", Damocles.
But I did explain it is easier to purchase longer push rods for an HD engine than to purchase a longer cam chain for a KLR.
Yeah, that was me.

But I'm not a typical HD guy, so don't roll your eyes! In fact, I don't have ANY HD decals, or Eagles, or any HD memorabilia of any kind, promise!

Jason
Norton 850 is offline  
post #86 of 147 Old 11-04-2019, 04:30 PM
5th Gear
 
Join Date: Jan 2011
Posts: 4,390
Quote:
Originally Posted by Norton 850 View Post
Yeah, that was me.

But I'm not a typical HD guy, so don't roll your eyes! In fact, I don't have ANY HD decals, or Eagles, or any HD memorabilia of any kind, promise!

Jason
Please accept full credit for your Harley example, Norton850!

And, I take you at your word: You have no handlebar grip tassels!

pdwestman likes this.

ďYou better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, youíre gonna be dead.Ē "John Russell" (Paul Newman), Hombre
Damocles is offline  
post #87 of 147 Old 11-04-2019, 05:21 PM
2nd Gear
 
Norton 850's Avatar
 
Join Date: Sep 2013
Location: Houston, Texas
Posts: 161
Quote:
Originally Posted by Damocles View Post
Please accept full credit for your Harley example, Norton850!

And, I take you at your word: You have no handlebar grip tassels!

Or conchos, or black leather fringes, or anything!

Jason
Norton 850 is offline  
post #88 of 147 Old 11-04-2019, 08:15 PM Thread Starter
2nd Gear
 
Join Date: Oct 2019
Posts: 117
Some major upgrade advice

Quote:
Originally Posted by pdwestman View Post
Yes, the rod is shortened by HALF of the Total change of crankshaft stroke increase. I posted that way earlier.
I just wanted to be sure I understood it properly.

Quote:
Originally Posted by pdwestman View Post
6mm of rod pin relocation = 12mm of total stroke increase, I doubt if that is even possible with this engine. Do you think that there is even enough clearance around the crankshaft?
I canít really tell. It looks tight, but there is no crankshaft to look at so I donít know how much room is actually available. Iím not saying you are wrong, Iím just saying I canít tell from the picture. Maybe I can find one on eBay to look at.

This entire project would be a lot easier if EMís kit was available. Or if his numbers were available, but Iíve been unable to find any to date. So just kind of guessing.

I did find a reference - donít know if itís true - that the 672c. Stroker was based on the same bore as the 685cc piston. Using that as a base figure - 102.5 mm so I rounded it up to 103- I calculated the stroke at 92mm. That provided a 767.57cc. Just playing a bit with the numbers to get close. What I got out of it was the stoke stroke of 83mm changed by 11-12mm.

If I bump - just plugged in the numbers - the piston bore up to 105mm - same as the 719cc BBK - then the stroke drops to 88mm with a change of 5 mm. With the 105mm piston and 88mm stroke that is 762cc. Based on that, itís more likely a 5mm stroke change would be used and the pivot pin would only need to be relocated by 2.5mm. Using a shortened connecting rod - someone posted a reference of 139mm, but later posted an EM measurement of 138mm - of 135.5 to 136.5 would appear to be correct.

Going with a lengthened rod and relocating the pivot pin inward by the same 2.5mm might be a safer/better choice.

Unless my numbers are completely wrong. If so, some experienced advice would be appreciated.



Quote:
Originally Posted by pdwestman View Post
Why would any company build a bolt together rod to fit this engine? Wouldn't that increase rotational rod weight and weight is already your enemy. Wouldn't the rotational weight Increase the vibration of your engine?

I get what you are saying and it might be better to have a one piece connecting rod. Itís a trade off between ease of use - no need to split the crank - and a bit of extra weight. Honestly enough, I just planned to ask Crank Works Inc. about it and follow their advice.

As for why a company would build it, well itís not difficult. I was planning on purchasing a custom connecting rod anyway as Iím just not that much of a fan of cutting & welding or smooshing/stretching the connecting rod.

While weight might increase, I doubt it is a major issue as if I have Crank Works Inc. do the work theyíll be balancing the entire assembly anyway. I also planned to follow their advice on choosing the type of connecting rod so it could be a moot point.



Sent from my iPhone using Tapatalk
ILove2Ride2Wheels is offline  
post #89 of 147 Old 11-04-2019, 10:03 PM
5th Gear
 
Join Date: Jan 2011
Posts: 4,390
A custom one-of connecting rod might set your net worth back a bit ILove2, IMHO. However, cost doesn't enter into your plans and ambitions significantly, from your posts.

What does your calendar for boring/stroking/camming/exhausting/intaking/carburating/porting-and-polishing/dynamic balancing/larger valve installation/etc. look like, Ilove2?

Looks like your research is essentially complete, awaiting design decisions.

ďYou better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, youíre gonna be dead.Ē "John Russell" (Paul Newman), Hombre

Last edited by Damocles; 11-04-2019 at 10:06 PM.
Damocles is offline  
post #90 of 147 Old 11-04-2019, 10:14 PM
OverDrive
 
Join Date: Nov 2009
Location: Lander, Wyoming
Posts: 5,611
This thread reminds me of last years member who wanted to or did load his freshly resurrected KLR onto a sailboat and head for the Mediterranean Sea.

I wonder how he and his wife are doing? Excellently, I hope!
roadrash83 likes this.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
pdwestman is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki KLR 650 Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome