xr650L hotcam report


101 replies to this topic
  • tobinbakner

Posted November 11, 2007 - 03:19 PM

#61

Just found my XR600 OEM manual. It has the exact same numbers for opening and closing for both intake and exhaust.

It seems strange that they are the same. The Honda part numbers are different.

Cool. Thanks for looking that up. I believe the part numbers are different because the L uses the automatic decompressor and the R doesn't. You lose the automatic decompressor when you put in an after market cam. I've also checked on the valve sizes for both bikes. According to this website they are the same. http://bigborethumpers.com/valves.html So it looks like the only performance differences between the two is the lower weight of the XR600R, A higher compression ratio (The R is 9:1 and the L is 8.3:1), the ignition curve (which I believe is used because of the higher compression ratio), charging system, and possibly a lighter flywheel. Can you tell me what the ignition specs are for the XR600R? The L's is: advance start 8 degrees/2300 RPM stop at 28 degrees/4000 RPM. There has been a lot of speculation that an XR600R CDI will help performance on an L. I think it will but only with a High compression piston. It would be nice to know what the start and stop are so you could duplicate it with an after market programmable ignition system when you go with a higher compression piston.

Thanks

Tobin

  • cleonard

Posted November 11, 2007 - 04:00 PM

#62

Cool. Thanks for looking that up. I believe the part numbers are different because the L uses the automatic decompressor and the R doesn't. You lose the automatic decompressor when you put in an after market cam. I've also checked on the valve sizes for both bikes. According to this website they are the same. http://bigborethumpers.com/valves.html So it looks like the only performance differences between the two is the lower weight of the XR600R, A higher compression ratio (The R is 9:1 and the L is 8.3:1), the ignition curve (which I believe is used because of the higher compression ratio), charging system, and possibly a lighter flywheel. Can you tell me what the ignition specs are for the XR600R? The L's is: advance start 8 degrees/2300 RPM stop at 28 degrees/4000 RPM. There has been a lot of speculation that an XR600R CDI will help performance on an L. I think it will but only with a High compression piston. It would be nice to know what the start and stop are so you could duplicate it with an after market programmable ignition system when you go with a higher compression piston.

Thanks

Tobin


I think that the weight is the main difference. The only other thing that you didn't mention is the carb. The 600 has a "normal" birt bike non-CV carb.

I think that the 600 has the same decomp mechanism as the 650L. Perhaps it is tuned to different RPMs though as I'm sure the starter motor must turn the engine faster than a kick.

  • crmc33

Posted November 12, 2007 - 05:02 AM

#63

The main crankshaft webs are also lighter on the XR600 and XL600
The XL crank has narrower wasted webs near the big end pin.

Just building another tuned engine with one in at the moment.

Have replaced the Honda rod with a 'hot-rod'. I hope its up to the job!!

  • Frank ZX

Posted November 12, 2007 - 08:11 AM

#64

did you pull the cover cuz the chain came off of the crank sprocket ?


No,I mean the head cover.I could not get it off,so I took out all motor mount bolts,and it came out easy.Also the allen head that holds the chain tenisoner was very tight.I tapped the head with a hammer about 10X to shock the bond loose,then twisted right out.Now I have done it,next time would be a breeze.

  • martinfan30

Posted November 12, 2007 - 08:22 AM

#65

ya the v/c was syuck on mine too. really stuck! with the carb and intake boot off it came right out .

  • FZ1426

Posted November 12, 2007 - 05:22 PM

#66

This post has helped me make the desision not to do a Hotcams install on my '96 and just do a piston instead.

Years ago I put an Arias 97mm 10.5/1 piston in a '93 600 and it tranformed the bike completely. They don't make them anymore.

I've got my '96 apart at the moment for a high comp piston installation.
The only two choices I'm seeing available now are Wiseco and JE.

I can get a Wiseco in (stock) 97mm and 11/1. But I would prefer a 10.5/1.

JE has a 10.5/1 but only in a 100mm or larger size which requires a new sleeve. Don't really want to go that route.

Any others available? Also, could someone throw out the head and cylinder bolt torques?

Not looking forward to that PITA cam chain tensioner...Thanks.

  • stepho

Posted November 12, 2007 - 07:25 PM

#67

Hey Frank that bolt on the chain tens. does not need to be real tight.Just a little blue and there is a web in the rocker cover that prevents the bolt from backing all the way out. That bolt can break off in there and really put a crapper on your day. Especially if you love to tinker and are playing with the motor constantly.

  • martinfan30

Posted November 12, 2007 - 08:04 PM

#68

This post has helped me make the desision not to do a Hotcams install on my '96 and just do a piston instead.

Years ago I put an Arias 97mm 10.5/1 piston in a '93 600 and it tranformed the bike completely. They don't make them anymore.

I've got my '96 apart at the moment for a high comp piston installation.
The only two choices I'm seeing available now are Wiseco and JE.

I can get a Wiseco in (stock) 97mm and 11/1. But I would prefer a 10.5/1.

JE has a 10.5/1 but only in a 100mm or larger size which requires a new sleeve. Don't really want to go that route.

Any others available? Also, could someone throw out the head and cylinder bolt torques?

Not looking forward to that PITA cam chain tensioner...Thanks.


i hate to give anyone the wrong impression of the hotcam. after riding it for several days in a row i have realized that it made a nice power increase across the board.

i only would have done a hi comp piston with it next time.

the tensioner can be dealt with easily by the special tool in the honda manual or as frank did, compress the spring and tie it with bailing wire. then install and cut the wire off. just dont let it fall into the case or you'll have to pull the right side cover!

let us know what you do and how it goes! i will be ordering a hi comp piston for my L soon too.

  • absynth01

Posted November 13, 2007 - 07:05 AM

#69

I don't know what my 650L was before I got it, but it is worthy. The higher comp must do dramatic changes with everything else in-line. As I said before, An uncorked 650R is about even. It won't pull from me, but I can't catch it. It will run in front , but not obvious. We roll all day front to back, 650R basically stock, mine heaviy modded. The only diff-E-START. And yes, the 650R pisses me off because my dealer could not sell me a "road legal" bike. Even modified here, a 650R is rare. I chose to play the game, and kill them with charm. My 04' title states"X6L". Funny my buds 650R is "650R". Hate to be there in a gov sweep.

  • Frank ZX

Posted November 13, 2007 - 02:49 PM

#70

The Hotcam is awesome in my book.I would recommend it to everyone!

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  • martinfan30

Posted November 13, 2007 - 07:40 PM

#71

The Hotcam is awesome in my book.I would recommend it to everyone!


engine sounds different too i noticed.

  • Frank ZX

Posted November 15, 2007 - 03:28 AM

#72

engine sounds different too i noticed.


Yea,Mine sounds different too.I think some people are afraid the cam will make there bike less relilable,or loss in low end power.I'm very pleased with mine.

  • nascardave

Posted January 18, 2008 - 04:28 PM

#73

My friend got a Hot Cam I read the instructions It said you can't use the Automatic De-Compression Do you have to put a manual one on or can you run it without one

  • stepho

Posted January 18, 2008 - 10:32 PM

#74

I run a megacycle camshaft with a very agressive grind and i run without it. never had a problem. I also grinded off the tab that rubs on the decomression unit so it does not touch the lobe. you can remove the decompression mechanism from the camshaft if you weld up the holes so you dont lose oil pressure in the cam. or machine a sleeve to cover it if you cant weld.

  • dldavis_66

Posted January 19, 2008 - 04:53 AM

#75

Been thinking about putting a HotCam on both my 650Ls. One thing kinda bugs me though. You can't reinstall the Decompression mechanism with the HotCam. Plus, I'll be upgrading the pistion to 10.5-1. Not having any Decompression sounds like trouble for the electric starter.

  • dldavis_66

Posted January 19, 2008 - 05:08 AM

#76

What kind of filler rod was used to weld the ports??? Since the heads are cast aluminum and cast aluminum is not very weldable with standard filler rods. Aluminum-Bronze maybe?? Could you find out and let me know please???

Also, I am assumming that you know longer have the smog pump on the bike.

  • nascardave

Posted January 19, 2008 - 03:50 PM

#77

Thank you for the information I will get started on the bike

  • martinfan30

Posted January 20, 2008 - 08:42 AM

#78

Smog equpiment is the first thing to go on a new L in my opinion. The Auto decompressor is not needed at all IMHO. I run a hotcam with no problem starting, even cold. I know of some guys who run cams, high compression pistons AND a smaller capacity battery(to save size/weight) with ZERO issues.

  • zodran

Posted January 20, 2008 - 12:12 PM

#79

Been thinking about putting a HotCam on both my 650Ls. One thing kinda bugs me though. You can't reinstall the Decompression mechanism with the HotCam. Plus, I'll be upgrading the pistion to 10.5-1. Not having any Decompression sounds like trouble for the electric starter.


Nope, you aren't raising the compression THAT much. I still have the decomp with my megacycle but I don't think it's necessary because of the overlap between intake and exhaust. Even with the mild grind I have it gives the engine an exotic sound, definitely not stock. :cool:

  • martinfan30

Posted January 20, 2008 - 05:28 PM

#80

You are right Zodran. A performance cam actually drops the compression slightly due to increased overlap/duration.





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