xr650L hotcam report

[martinfan30]

the green one on the shaft? no. i eyed it over and looked good. just lubed it and i have no leaks(x-fingers)!

[TDC71]

LOL I did the same thing and always keep lookn for a leak from it. Its been 2000 miles since I did it and its still good.......... but you know how that goes being a tech, .25cent part takes hrs to replace

[Bibleman]

Martinfan, I did not get a cam card with mine, but then again I bought it off a guy on ebay. It is brand new and in the box but the box was opened.

[tobinbakner]

Martinfan is the loss in the low end something you think you would have noticed if you hadn't ridden it back to back. In other words if I changed the cam now and didn't ride it all winter would I notice it in the spring when I got it out?

Thanks

Tobin

[Denn10]

MARTIN can you give the specs of the hotcam lift and duration vs the stocker????

[martinfan30]

LOL I did the same thing and always keep lookn for a leak from it. Its been 2000 miles since I did it and its still good.......... but you know how that goes being a tech, .25cent part takes hrs to replace

ya buddy! that is MURPHY!

[martinfan30]

Martinfan, I did not get a cam card with mine, but then again I bought it off a guy on ebay. It is brand new and in the box but the box was opened.

i contacted the guys at hotcams and they emailed me the cam card.

.15 mm intake and .2 mm exhaust (valve lash).

8.8 mm lift exh/int

258 duration exh/int. @ 1mm.

[martinfan30]

MARTIN can you give the specs of the hotcam lift and duration vs the stocker????

see the post above DENN. i havent found the stock cams specs yet, but still looking.

[martinfan30]

Martinfan is the loss in the low end something you think you would have noticed if you hadn't ridden it back to back. In other words if I changed the cam now and didn't ride it all winter would I notice it in the spring when I got it out?

Thanks

Tobin

i really doubt you would notice in that condition. i have been riding EVERY day so i could see the shift from low PUNCH, to ok low end and killer mid-top PUNCH.

i also know my jetting is spot on, so it is the nature of the beast. i would highly recomend doing the cam/hi comp piston at same time for this reason.

[crmc33]

If you want more midrange and bottom end also think about D shaping the exit exhaust ports. Gives better midrange with no loss of top end power. Dyno proven.

The guy who tuned my head also taold me not to grind the exh ports flush with the headers. A 1.5mm step out into the headers is ideal to stop gas recirculation.

This is why most modern race engines dont have round exhaust port exits.

To D-shape the exh port exit you have to weld the floor of the port exit. Doesnt need much. Then grind to a nice flat.

I have pics of mine if it helps anyone gain a few free HP!

[martinfan30]

If you want more midrange and bottom end also think about D shaping the exit exhaust ports. Gives better midrange with no loss of top end power. Dyno proven.

The guy who tuned my head also taold me not to grind the exh ports flush with the headers. A 1.5mm step out into the headers is ideal to stop gas recirculation.

This is why most modern race engines dont have round exhaust port exits.

To D-shape the exh port exit you have to weld the floor of the port exit. Doesnt need much. Then grind to a nice flat.

I have pics of mine if it helps anyone gain a few free HP!

love to see a pic! now you got me thinking about doing it. who did your's? cost? would it still be very streetable? im not racing, just a power whore!

[Denn10]

i contacted the guys at hotcams and they emailed me the cam card.

.15 mm intake and .2 mm exhaust (valve lash).

8.8 mm lift exh/int

258 duration exh/int. @ 1mm.

any idea what stock cam specs are??

[martinfan30]

any idea what stock cam specs are??

havent found em yet.

[tobinbakner]

The best I can find for the stock cam is in the Honda service manual. it say the intake valve opens at 5 degrees BTDC closes at 40 degrees ABDC. The Exhaust opens at 45 degrees BBDC and closes at 5 degrees ATDC. all at 1mm lift. There isn't any lift given If I understand how the numbers are derived the intake is open for 225 degrees. 5+180+40=225. the exhaust would be open 230 degrees 45+180+5=230. I wonder what the stock XR600R cam is? Unfortunately I don't have a Honda service manual for it.

Tobin

[crmc33]

Heres a link to my latest exhaust port shape;

http://www.motopike.com/images/pic_0072.jpg

other cylinder head images at the bottom of http://www.motopike.com/Supermono.html

HTH!

[martinfan30]

very nice headwork! that intake looks WAAAAY different than stock.

[Denn10]

oh well i guess it doesnt matter what stock lift is just curious as 8.8mm is pretty close to .340 lift

[flyin vee]

+1 on the power whore. I'm trying to imagine the power increase on my L if I added a Hotcam and a 10.1 comp piston. I already have an Edelbrock pumper, Uni and a high flow exhaust. You guys think running 15/48 3rd gear power wheelies would be possible? If so sounds like a good winter project. OZ:thumbsup:

[Denn10]

martin said his did and he doesnt have the hi comp piston so im sure youd be able to 3rd wheelie no problem

[martinfan30]

3rd gear right now for me no. no piston. 2ND GEAR can be done with a bar tug. 3rd gear may be poss. after a hicomp piston and a tug on the bar.