Xl600R/XR650L Hybrid


171 replies to this topic
  • Zombie_Stomp

Posted December 16, 2008 - 11:52 PM

#41

Another update: I might just go with the current xr600r bottom-end with the XL top-end. If I go over by 1 or 2mm, I get 628-653cc of displacement out of only an 80mm crank. The reason I've been thinking of going this route is that it's the simplest solution and the cheapest, involving the least amount of case splitting, etc. The reason for this recent idea is that I heard I may not be able to interchange the cranks sucessfully from the XR650L becase the flywheel end might be different. Plus the simplicity of the operation. So if I do the XR600R bottom/ XL600R top, what piston would be right?
Edit: this just in: a little more researching led to this discovery:
Model / Bore / Stroke / Compression Ratio
XL600/100/75/8.5:1
XR650L/100/82/8.3:1
XR600R/97/80/9.0:1

SO, if I used the XR crank for it's 628-650+ displacement (again, depending on how far overbored I go), I could use an 11:1 wiseco piston made for an XL and still have decent compression, given that the piston does not actually go above the cylinder, if that is even possible. Is that even a concern? It makes more sense to me that they all go the same height and the distance between the top of the piston and the piston pin is to make TDC within the same cylinder height, right?

  • zrxer

Posted December 17, 2008 - 05:29 AM

#42

I actually used an XL600 cylinder on a '96 XR600 that I bought new. I believe I bored it 1mm over which gave, as I recall, 654cc. The "correct" way would have been to dissassemble the engine and take the main cases in to have them bored. What I did was lay the XL600 base gasket into place and scribed a line around it. Then shoved rags in the crank area and went to town with a die grinder and carbide bit. It worked just fine. In fact that bike is still going strong somewhere in Oregon. Of course I had the head bolt threads and dowel holes enlarged for the 9mm hardware. If you do that, make sure you sink the threads deeper into the cylinder, there is a difference.

  • HeadTrauma

Posted December 17, 2008 - 09:20 AM

#43

So if I do the XR600R bottom/ XL600R top, what piston would be right?


Technically the piston needs to be matched with the crank. As you know, the XL600 has a 75mm stroke and the XR600 has an 80mm stroke. Both engines use the same connecting rod, so the difference is made up by the piston compression height. The easy way to get the right parts would be to get a 101 or 102mm piston for an XR600 and use the XR600 crank with the XL600 head and cylinder. You might be able to mix and match parts between the XL, XR, and 650L, but I don't have pistons/engines from all three that I could measure and mock up to verify.

  • Zombie_Stomp

Posted December 17, 2008 - 09:56 AM

#44

So the XL600 has bigger cylinder bolts than the xr600? You said in this case you did enlarge to 9mm.

Screw it, I might just add the dual-carb-head to the XR600 and add a slightly larger bore and high compression piston for the sake of saving money and time. If I think it out right, I could do the 100mm, but then again I could just go 2.41mm over with the XR Wiseco and be done with it, for no extra cost. I've got an extra black xr600 cylinder and getting it bored would make for minimal downtime.

So I guess the question then would be, this:
Posted ImageJE Pistons are crafted from 2618 T6 high-tensile strength forged aluminum for extreme performance, resulting in the ultimate durability. JE Pistons dirt bike and ATV piston kits include pins, pin fitment, lock and rings. FITS: Honda XR600R (1985-2000) PART NUMBER: JE-128995
ATV / MOTORCYCLE / MOTOCROSS / MX / DIRT BIKE / GEAR / PARTS PRICE: $179.95
QUANTITY:

Or this:

Posted Image
# Piston kits meet or exceed O.E.M specification
# Kits contains required Piston, Rings, Pin & Circlips
# Oversizes available 97, 97.5, 98, 100mm
$152.98
I kept imagining 3mm being taken off of one of the side walls of that thin cylinder skirt, then I got my spare cylinder out and remembered it would only be 1.5mm from the wall. Duh! :thumbsup:

  • HeadTrauma

Posted December 17, 2008 - 11:44 AM

#45

So the XL600 has bigger cylinder bolts than the xr600?


No, the '83-87 XL600 and '84-87 XR600 both have 8mm head bolts. I think the RFVC XR500 does too. All the '88-00 600s and '93-current 650Ls came with 9mm head bolts.

  • Zombie_Stomp

Posted December 17, 2008 - 12:30 PM

#46

I actually used an XL600 cylinder on a '96 XR600 that I bought new. I believe I bored it 1mm over which gave, as I recall, 654cc. The "correct" way would have been to dissassemble the engine and take the main cases in to have them bored. What I did was lay the XL600 base gasket into place and scribed a line around it. Then shoved rags in the crank area and went to town with a die grinder and carbide bit. It worked just fine. In fact that bike is still going strong somewhere in Oregon. [COLOR="DarkOrange"]Of course I had the head bolt threads and dowel holes enlarged for the 9mm hardware. If you do that, make sure you sink the threads deeper into the cylinder, there is a difference.[/COLOR]


No, the '83-87 XL600 and '84-87 XR600 both have 8mm head bolts. I think the RFVC XR500 does too. All the '88-00 600s and '93-current 650Ls came with 9mm head bolts.


The part highlighted in ZRXers's quote is why I asked. I meant to say head bolts I guess. Maybe he can clarify. My older XR cylinder (1985) that I got out appears to be the same as XL bolt holes and dowel holes.

Meanwhile, once I get the basement cleaning finished, I can begin to tear down the xl engine and clean the head. Then I can check those bolts with the XR cylinder I'll use and take out the XR engine from the bike and sell the head and carb to finance the cylinder bore and piston kit, and what few other goodies I might need, gaskets, oil seals, etc.

  • zrxer

Posted December 17, 2008 - 01:12 PM

#47

So the XL600 has bigger cylinder bolts than the xr600? You said in this case you did enlarge to 9mm.

Screw it, I might just add the dual-carb-head to the XR600 and add a slightly larger bore and high compression piston for the sake of saving money and time. If I think it out right, I could do the 100mm, but then again I could just go 2.41mm over with the XR Wiseco and be done with it, for no extra cost. I've got an extra black xr600 cylinder and getting it bored would make for minimal downtime.

So I guess the question then would be, this:
Posted ImageJE Pistons are crafted from 2618 T6 high-tensile strength forged aluminum for extreme performance, resulting in the ultimate durability. JE Pistons dirt bike and ATV piston kits include pins, pin fitment, lock and rings. FITS: Honda XR600R (1985-2000) PART NUMBER: JE-128995
ATV / MOTORCYCLE / MOTOCROSS / MX / DIRT BIKE / GEAR / PARTS PRICE: $179.95
QUANTITY:

Or this:

Posted Image
# Piston kits meet or exceed O.E.M specification
# Kits contains required Piston, Rings, Pin & Circlips
# Oversizes available 97, 97.5, 98, 100mm
$152.98
I kept imagining 3mm being taken off of one of the side walls of that thin cylinder skirt, then I got my spare cylinder out and remembered it would only be 1.5mm from the wall. Duh! :thumbsup:


No. The XL600 is 8mm. I used the XR600 head and head bolts (which are 9mm) so I had the threads in the XL600 cylinder enlarged to 9mm.

  • Zombie_Stomp

Posted December 17, 2008 - 03:58 PM

#48

No. The XL600 is 8mm. I used the XR600 head and head bolts (which are 9mm) so I had the threads in the XL600 cylinder enlarged to 9mm.

So since I'm using an '85 cylinder it'll probably be ok. If I were using the cylinder on the engine, a '98, it's 9mm bolts would have to be accommodated.

It would have been a 603.5cc if you bored 1mm over.

I found all kinds of displacement calculators to tell me what displacement is by plugging in the numbers, but it took some real searching to get the formula.

Something I didn't get an answer on, Bruce, was that raising link. I wanted to make sure I got the measurements of it before you reinstalled it since I am making one. Maybe you have it laying around and you can give me some rough measurements even if you don't have calipers.

Posted Image

Then when you reinstall it, I can see how it looks and how much it raises the bike before I commit my measurements to the aluminum. :thumbsup: I was planning on using the proportions of a lowering link to go by, but that varies based on preload adjustments. I guess there will be differences between ours nonetheless, I'm using a 1989 XR rear shock with a black Eibach spring and whatever preload the amateur that put it on decided upon.

  • zrxer

Posted December 17, 2008 - 05:32 PM

#49

Oops, sorry about that Joel! It's in storage right now. I'll see if I can dig it out this weekend. :thumbsup:

  • Zombie_Stomp

Posted December 17, 2008 - 06:18 PM

#50

Oops, sorry about that Joel! It's in storage right now. I'll see if I can dig it out this weekend. :thumbsup:

Great, thanks!

Meanwhile, anyone have a preference between JE and Wiseco? I only heard that Wiseco had a bad rap from a bad batch of pistons in the 80's, but is really good. I haven't heard anything about JE. I like Wiseco because of the overall good reputation and lower price in this case.

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  • zrxer

Posted December 17, 2008 - 07:12 PM

#51

Both great pistons. JEs are lighter and have an excellent reputation. I have used tons (well maybe not TONS but you get the idea) of Wiseco pistons over the years and have never had any problems. I have a JE in the hybrid engine and a Wiseco in the other XR600 project I have going on. Can't go wrong with either in my opinion. Just make sure if you get a Wiseco, it is truly the compression ratio as advertised. :thumbsup:

  • zrxer

Posted December 20, 2008 - 07:23 AM

#52

A few more pics of the rod.

Posted Image
Posted Image
Posted Image

  • HeadTrauma

Posted December 20, 2008 - 08:53 AM

#53

It pains me to look at that. I gotta say, though, If you're going to blow an engine up, do it like that!

On more reason to shell out for a Carrillo or Falicon rod, I suppose.

  • Zombie_Stomp

Posted December 20, 2008 - 12:36 PM

#54

Just when I thought I couldn't think of any more questions about the Frakensteinization of these two engines, one came up.

Which valve clearance specs do you go by? .004 intake/.005 exhaust (XR600) or .002in. intake/ .004in. exhaust (XL600)? I guess that this gets down to the question of whether the valve timing is affected most by the head you are using, or the crank/piston/cylinder you are using. And I've never seen the clearances for the XR650L engine either since I don't have the book for that bike. If those are a third, different set of specs, that would lead me to believe that the crank/piston make the difference, since the stroke is the one thing that is different about all 3 engines, whereas the heads on the XR600 (single-carb, cam-auto-decompress-equipped, anyway) and xr650L very similar.

When in doubt, I'd go with the looser specs, as this would open the valves less, leaving less chance of valve/piston clearance issues, and if it gets too clack-y, move to the tighter specs.

  • zrxer

Posted December 21, 2008 - 09:56 AM

#55

Joel, I would run the looser specs for lubrication reasons. With tighter clearances you don't get enough of an oil film between the cam lobe and rocker; that's critical on these engines. Don't ask me how I know. :smirk: :thumbsup:

  • zrxer

Posted December 21, 2008 - 10:00 AM

#56

Here's a couple pics of the raising link. Looks to me like it's a home made thing. A couple of heim joints screwed together.

Posted Image Posted Image

  • Zombie_Stomp

Posted December 21, 2008 - 12:07 PM

#57

Thanks, man. :thumbsup: Looks like I could just obtain a stock link and cut it and tig weld it together shorter if that one is only held together by those few threads. Looks like it's about 2-3/4" distance from center to center of the bolts, I had figured on about 2-3/8" originally. We'll see what I come up with.

  • EarlT

Posted January 08, 2009 - 04:35 PM

#58

Which cam Chain did you use?
XR600 or XRL650?

  • zrxer

Posted January 10, 2009 - 06:59 AM

#59

The XR650L chain.

  • handirifle

Posted February 03, 2009 - 08:38 PM

#60

Hi, new on this forum but have been reading this thread with interest. The last page has me confused. Did the hybrid engine blow up? I do not remember reading that in the thread.

Would an XR650L stock engine have been a successful swap into the XL600 frame? Just wondering in case my '83 XL600 engine ever takes a dump on me. I dont want to spend the bucks for a whole nuther bike, and just swapping over to a newer engine and gaining electric start to boot, would sure be nice.





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