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Discussion Starter #42
Yes, but generally speaking when creating a stricter engine the pin on the crankshaft is relocated. Outward for a longer rod. Inward toward for a shorter rod. The piston wrist pin is higher than a standard location for a longer rod and for a shorter rod the wrist pin is located lower.

Generally speaking, this means a short stroker uses talker pistons to maintain the same or larger displacement. The opposite is true - generally - for longer rod stroker engines.

I’m not making this stuff up. I think the last link posted spelled out some of this information. I e found other references to it too, but most of it is applied to cars rather than motorcycles and so the lines get blurred. From what I’ve found, motorcycles - in general - have a more pronounced visible change in rod/piston size for a stroker engine.

Hmm, that gives me an idea. I should check with Wiesco - I think that’s their name - about a piston for the KLR stroker project. I’ve used their products in the past and should of thought of them sooner. Maybe they can provide some insight or a kit (doubtful).


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ILove2Ride2Wheels,
To the best of my knowledge, most stroker kits use the stock piston pin position and a slightly shorter rod. The Powroll company used the simply heat the rod and compress it by half of the intended added stroke. (Created a bulge in the rod.) Then the oem size bottom crank pin was/is relocated an equal amount towards the OD of the crank flyweights.
This keeps the piston crown deck height in the cylinder the same as oem, but pulls the piston further down the cylinder bore at BDC.

There is only 1mm of material between the piston pin bore and the bottom oil rail of an Gen 2 OEM KLR650 piston and probably the EM JE brand and Wossner brand pistons also. No room to move the pin upwards.

https://www.openfos.com/supply/3194880-POWROLL-MOTOR-PERFORMANCE-in-CROOKED-RIVER-OR/
 
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Discussion Starter #44
That’s an interesting technique and now that you’ve mentioned I recall seeing a pic of something like that in my younger days. I’m in my late 50s. I think now days, the cut and weld, but I was looking to have a rod made. They only cost about $300 or so.

I checked the Wiesco web site. They don’t offer anything but an OEM replacement. I’d hoped they’d offer custom services as I know an OEM piston isn’t going to work.

I appreciate the information though. Maybe I’ll see if my Google skills can find a custom piston shop before I just give up and settle for the 719cc BBK. Although, my wife would be happier if I didn’t do the bottom end just because of the additional cost. :) the rest was already budgeted in to my purchase - new with minor farkles or used with complete engine rebuild. Either would get new shocks so those didn’t count. But the bottom end changes would put me over budget on the purchase.


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ILove2Ride2Wheels,
To the best of my knowledge, most stroker kits use the stock piston pin position and a slightly shorter rod. The Powroll company used the simply heat the rod and compress it by half of the intended added stroke. (Created a bulge in the rod.) Then the oem size bottom crank pin was/is relocated an equal amount towards the OD of the crank flyweights.
This keeps the piston crown deck height in the cylinder the same as oem, but pulls the piston further down the cylinder bore at BDC.

There is only 1mm of material between the piston pin bore and the bottom oil rail of an Gen 2 OEM KLR650 piston and probably the EM JE brand and Wossner brand pistons also. No room to move the pin upwards.

https://www.openfos.com/supply/3194880-POWROLL-MOTOR-PERFORMANCE-in-CROOKED-RIVER-OR/
In my youth, I remember when folks would stroke their HD Panhead and Shovelhead engines by moving the crank pin slightly further away from center. Then, to keep the piston from bashing into the head, they would install a "stroker plate" between the cylinder base and the engine cases.

Jason
 

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Discussion Starter #46
In my youth, I remember when folks would stroke their HD Panhead and Shovelhead engines by moving the crank pin slightly further away from center. Then, to keep the piston from bashing into the head, they would install a "stroker plate" between the cylinder base and the engine cases.



Jason


I’ve heard if that method too. Another old technique. But you have to have clearance for the engine to fit in the frame.

Don’t Harley’s attach on just the bottom and the KLR uses the top and bottom?

I did find a couple of companies that do make custom motorcycle pistons, but need to contact them about cost. Then I’ll need to figure out the bore size for the custom piston and stroke size as well. That’s going to take time working with the vendor and a possible tear down.

I’m not sure I’ll have enough time to do it though and keep to my schedule. Might just do it in two stages? If I’m not satisfied with the 719cc. Something tells me that if I rebuild it once with the 719cc kit I’m not likely to want to do it again. I mean, why toss a perfectly good 719cc kit just to upgrade it for a few more cc and some extra torque and hp beyond what a 719cc can provide. How much more would I get? Which is why if I do it, I want to do it the first time around.

Well it’s a good thing I have a side gig lined up for Christmas as I could use that money to pay for it all. Still be within budget for it that way.


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Re-ground crankshaft (moving main journal center outboard of crankshaft center line), shorter rod, stock (or big-bore piston) . . . oughta work, no?
 

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In my youth, I remember when folks would stroke their HD Panhead and Shovelhead engines by moving the crank pin slightly further away from center. Then, to keep the piston from bashing into the head, they would install a "stroker plate" between the cylinder base and the engine cases.

Jason
That is fairly simply done with longer push rods or tappets on a push rod type engine.

I dare one to ask DID or EK chain company the price to make a 2 link longer camchain for a 1 off project. And two links might be too long for the existing guides & tensioner to function properly, And one had better plan on using degreeable camshaft sprockets to dial-in the camshaft lobe centers as per camshaft manufacturer specs, regardless of other parts.
https://www.klrchris.com/klr650-adjustable-cam-gear/

Details! It's all in the details.

Defeet of deduck went under defence before detail!
 

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Discussion Starter #49
Re-ground crankshaft (moving main journal center outboard of crankshaft center line), shorter rod, stock (or big-bore piston) . . . oughta work, no?


I don’t think so, but possibly. I’d have to see the measurements and compare them to stock to know for sure.

There’s no reason for me to do it that way though if the displacement doesn’t increase as well. The whole point of a stocker IMO is to increase displacement, increase torque, and increase horse power.

I was running some calculations and just a 6mm longer stroked increased the CCs significantly. A stick is 651.88cc. Up the stroke 6mm and it’s up to 699.01. Use a 105mm piston (aka EM) and it’s 770cc. I’m not sure what piston size Mike was using for his 762cc stroker, but it might be close to what I’ve posted.

Honestly, I don’t know how much room there is to relocate the crankshaft pin. It has to be done in such a way that it does not hit the cylinder skirt and still have a relatively shallow enough angle to push/pull the piston without too much resistance. Plus, you need to keep in mind to maximize the displacement increase the wrist pin needs to be closer to the piston dome. Usually this means a thinner piston. Sometimes with only two rings instead of three. It can be complicated.

I really wish Mike had a spare piston he’d sell me. Or would do the work for me for a stroker kit. I’d drop of my motorcycle in a heartbeat if he would. It’s his & Sam’s project though and I can respect his choices for it.

One thing I’m sure of ... whatever I wind up with will perform better than stock. Plus, I’ll still have to finish up the build with carburation, exhaust, and possible FI mapping or customized CDI - I know that’s not what it is, but what else should I call it - unit. If I could only get that Czechoslovakia company that makes them respond to my email I might be able to get a programmable CDI unit.


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I don’t think so, but possibly. I’d have to see the measurements and compare them to stock to know for sure.
It's pretty simple, the stroke is elongated by twice the distance the main journal center is offset from its original location. e.g., offset the center by 3 mm and you'll get the 6 mm stroke increase in your example. If using a stock piston, you'd need a 3 mm shorter connecting rod (measuring from piston pin center to crankshaft center, piston at TDC).
There’s no reason for me to do it that way though if the displacement doesn’t increase as well. The whole point of a stocker IMO is to increase displacement, increase torque, and increase horse power.
You're entitled to your own definition of "as well." Re-grinding the crank and installing shorter rods permits use of stock or essentially stock-geometry pistons (as in existing big-bore kits).
I was running some calculations and just a 6mm longer stroked increased the CCs significantly. A stick is 651.88cc. Up the stroke 6mm and it’s up to 699.01. Use a 105mm piston (aka EM) and it’s 770cc. I’m not sure what piston size Mike was using for his 762cc stroker, but it might be close to what I’ve posted.

Honestly, I don’t know how much room there is to relocate the crankshaft pin. It has to be done in such a way that it does not hit the cylinder skirt and still have a relatively shallow enough angle to push/pull the piston without too much resistance. Plus, you need to keep in mind to maximize the displacement increase the wrist pin needs to be closer to the piston dome. Usually this means a thinner piston. Sometimes with only two rings instead of three. It can be complicated.
Au contraire on any necessity for moving the wrist pin closer to the piston dome with the re-ground crank/shorter rod stroking technique.
I really wish Mike had a spare piston he’d sell me. Or would do the work for me for a stroker kit. I’d drop of my motorcycle in a heartbeat if he would. It’s his & Sam’s project though and I can respect his choices for it.

One thing I’m sure of ... whatever I wind up with will perform better than stock. Plus, I’ll still have to finish up the build with carburation, exhaust, and possible FI mapping or customized CDI - I know that’s not what it is, but what else should I call it - unit. If I could only get that Czechoslovakia company that makes them respond to my email I might be able to get a programmable CDI unit.
Methinks you enter the domain of, "diminishing returns," assuming carburation, FI mapping, and a programmable CDI increase power significantly. As mentioned, the same air/fuel ratio from whatever source (trick carb, FI, etc.) yields from a normally aspirated engine essentially the same power potential, given the Laws of Conservation of Energy. "Customized CDI?" "Progreammable CDI?" The ability to advance the spark, using high-octane fuel, offers marginal power increase--significant, maybe, in wheel-to-wheel competition (not the KLR's long suit).

In mappable FI and programmable ignition, do you not enter somewhat the "high-tech" arena you previously mentioned you wished to avoid? Not a problem; if you want these features, and you're wedded to the KLR platform, good for you! You defend the honor of the venerable KLR.

Owning both a KTM 690 and a KLR, the KTM has about 70 hp out of the box, a suspension beyond a KLR's, even with the truly excellent Cogent makeover, and vibrates less than the KLR; even has programmable ABS, and weighs less than a KLR (about 315 lbs dry, per KTM). Yet, I still love, and ride, my KLR. But . . . I'd stop short of trying to make the KLR650 into a KTM690!

:)

Again, best wishes on your planned hop-up; look forward to words and pictures of your progress.
 

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Discussion Starter #52
Just as an FYI, being that I’m not an engine builder, when I say I’m not sure it would work without the measurement and better understanding, well I mean just that. So, I’ll stick with what I know and understand. Nothing against your methodology, just not sure it would obtain the results I want. Since I only get one real shot at it, if I build a stroker it’ll be one with a longer rod and piston with a wrist pin located further toward the piston dome. Just because I know that method will provide the results I want.

In regard to FI, pumper carb, lectins carb, I agree that I don’t really want to get into programming the mapping of a FI system to get what I want out of it. Might be needed, but then again it might not. I may be able to achieve my end goal with a slightly larger diameter carb and just stop there. Can’t really say right now.

Nor am I 100% sure if the options for the programmable CDI unit. I only saw a posting about it for a 2008 KLR on another forum. So, that posting did mention timing advance. It’s not about using higher octane fuel though for me. It’s more about being able to tune the CDI system for better functionality/efficiency for the engine upgrade. It’s not about getting massive amounts of power, just fine tuning. Any carburation system I’ll install will require tuning. If I can adjust the ignition system as well, it’s just a better option. Once set, it’s done. I doubt I’d ever touch it again.

There are times I’ve wondered if an nine swap might be a better option though. I’d consider one that was fairly plug and play, but I doubt one exists or I’d see references to it in the forums. I did see one reference to swapping a Versys engine, but doubt it was a plug and play install. I might look into a swap though a bit more before purchasing any engine upgrades. If you have a reference, please do let me know.

As for a KTM, not interested in the least. I looked at it. Nope. Not for me. It’s not a KLR. Zero wind protection. Not really set up to carry luggage. Or a passenger occasionally. Great for the dirt. Bad for the street. Not what I want or need at all. Yet, I still get people pushing it instead of a KLR, but only the KLR IMO fits my basic requirements.

FWIW, I also don’t want an adventure style motorcycle. If I did, I’d buy a BMW. But all the adventure motorcycle I’ve looked at are really geared for the street and dirt roads. Wallow in sand. Or too heavy. Or all three. Just not interested. Best I can do - and am doing - is the KLR with modifications. Even with my modifications, it’s still less expensive than another motorcycle that I would still have to outfit with accessories and upgrades.

I may have missed the perfect motorcycle that would suit my needs, aside from the KLR, but it’s also what I have now. So there are no plans for me to change platforms. I’ll just do the best I can with what I have. No disrespect intended, just letting you know how I think and feel about the issue.


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As mentioned, the same air/fuel ratio from whatever source (trick carb, FI, etc.) yields from a normally aspirated engine essentially the same power potential, given the Laws of Conservation of Energy. "Customized CDI?" "Progreammable CDI?" The ability to advance the spark, using high-octane fuel, offers marginal power increase--significant, maybe, in wheel-to-wheel competition (not the KLR's long suit).
At the risk of getting slightly off topic, I run into this constantly from people claiming 5,10 or even larger hp increases from a carb swap, Lectron, EFI or whatever the latest flavor of the month fuel system is and that's just not how it works. ......the engine is an air pump and it's output is largely based on flow....it doesn't care where the air/fuel mixture comes from, only that there is enough of it and it is in the right ratio. Now the only fly in the ointment is that max power is at a richer ratio (around 12.5:1)and max efficiency is leaner (at 15-16:1) so you can tune for one or the other but you need a more complex system to alternate between both and THAT's where a computerized EFI system has an advantage, mileage.....but if you jetted properly for max power, there is NO hp increase available going from a carb to EFI all other things being equal.

Dave
 

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As for a KTM, not interested in the least. I looked at it. Nope. Not for me. It’s not a KLR. Zero wind protection. Not really set up to carry luggage. Or a passenger occasionally. Great for the dirt. Bad for the street. Not what I want or need at all. Yet, I still get people pushing it instead of a KLR, but only the KLR IMO fits my basic requirements.

FWIW, I also don’t want an adventure style motorcycle. If I did, I’d buy a BMW. But all the adventure motorcycle I’ve looked at are really geared for the street and dirt roads. Wallow in sand. Or too heavy. Or all three. Just not interested. Best I can do - and am doing - is the KLR with modifications. Even with my modifications, it’s still less expensive than another motorcycle that I would still have to outfit with accessories and upgrades.

I may have missed the perfect motorcycle that would suit my needs, aside from the KLR, but it’s also what I have now. So there are no plans for me to change platforms. I’ll just do the best I can with what I have. No disrespect intended, just letting you know how I think and feel about the issue.


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I think we have similar thoughts; I'm fortunate enough to be able to afford any bike I want and my selection of the KLR wasn't about the expense. I chose it for the things I think it does better than any other bike at any price; longevity, reliability, simplicity/ease of repair and availability of parts. The bad things (suspension brakes, bars, pegs, handguards and to a lesser extent weight and power) all have solutions available.

I've spent a significant amount of money on my KLR's but I have them pretty much exactly as I want them. The 690 is a great bike but the fuel capacity is limited and the weight advantage comes at a cost of decreased longevity IMO. Ergos felt weird to me too. All the ADV twins = too heavy for where I like to ride. All the "dirt bikes with lights" - not comfortable enough on the pavement and aren't as good for long distance travel due to increased maintenance and inferior longevity...... I could go on and on but you get thte idea.

The KLR is an old, outdated, butget based dual purpose motorcycle......but it's also one of the most versatile dual purpose bikes on the planet with unrivaled longevity and parts availabiltiy owing to it's exceptionally long production and solid sales history. All weak areas have been documented and solutions have been provided decades ago....

Dave
 

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Discussion Starter #56
A.the engine is an air pump and it's output is largely based on flow....it doesn't care where the air/fuel mixture comes from, only that there is enough of it and it is in the right ratio.

Dave

Well that’s the assumption I’ve been working on too. Which is also why I’m not sure what would be best for my project. I’m looking at higher displacement, higher flowing head, and then something to feed that input flow and provide sufficient exhaust flow so the input flow is not restricted. If it’s all done right then I’ll have maximized the engines capabilities. Whatever that winds up being.

My basic understanding is the engine can be considered an air pump. The cylinder head design is one of the critical components to the pumping action. Valve size. Port size & shape. Cam shaft lift & duration. All contribute to the flow capabilities of the air pump.

So, I’m basing my choices on knowledge gleaned from others that have already done it. I’m just trying to put together a package from off the shelf parts as much as possible. EM’s 719cc BBK, web Cams 163 grind camshaft & high performance spring kit, Schnitz Racing’s SS oversize valves, and Race Tech to do the machine work.

If I can find a stroker kit or parts at an acceptable price point I’ll use that instead of EM BBK, but everything else would stay the same.



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Discussion Starter #57
The KLR is an old, outdated, butget based dual purpose motorcycle......but it's also one of the most versatile dual purpose bikes on the planet with unrivaled longevity and parts availabiltiy owing to it's exceptionally long production and solid sales history. All weak areas have been documented and solutions have been provided decades ago....

This is one of the main reasons I choose the KLR platform too.

I’ve explained my choice to my wife & a few friends using the older VW Beetle/Bug as a comparison. Under powered. Old technology. But a wealth of spare parts and third party upgrades. With some money, some time, and some effort you can modify a bug to do almost anything you want it to do. It’s such a customizable platform.

I don’t know exactly where my journey will end with this project, but I expect it will be fun getting there and I’ll enjoy the end result.

By the way thanks for the link. Way more than I want to do to the KLR. Way to far outside my capabilities. Figured that out the minute I read “tubing bender”. :)


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There are times I’ve wondered if an nine swap might be a better option though. I’d consider one that was fairly plug and play, but I doubt one exists or I’d see references to it in the forums. I did see one reference to swapping a Versys engine, but doubt it was a plug and play install. I might look into a swap though a bit more before purchasing any engine upgrades. If you have a reference, please do let me know.
https://advrider.com/f/threads/versys-motor-in-2008-klr-frame.504693/

I see DPelletier posted an ADV link also.
 

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Discussion Starter #59
Yes, and both are interesting but well outside my skill set.

I can rebuild the KLR motor, but cut/weld the frame? Not a chance. If I did, bet the first bump I hit would cause it all to fall apart. It’s an awesome build project though.


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