HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
CheGuevara

650L -big bore and cam

14 posts in this topic

I'm a bit of a mechanical newbie and definitely lazy, but I've finally managed to nearly complete a total rebuild of this motor (bought it completely buggered -replaced every bearing inside (that wasn't cheap), new rod, had it bored for the 10.25:1 675cc Wiseco , mild port job by Jay Wright (BareBones Machine) and plan for the Hot Cams stg1 cam. I'm replacing the entire rocker arm assembly, have installed new stock valves and springs etc... basically an all-new motor.

My question is to those who have the same cam/piston combo. Is it necessary to mill the piston crown or is there sufficient clearance?

I haven't installed the cam yet and I'm hoping to get this thing together without having to clay the head as I've never done it before, and as mentioned previously I'm lazy and don't want to put it together, take it apart and reassemble again. Once assembled I plan to spin the motor by hand of course to make sure I don't feel contact, but I'm aware this may not be a good predictor of what will happen while the motor is spinning at speed.

Thanks in advance,

-Mike

Share this post


Link to post
Share on other sites

It is major important to check the valve to piston clearance. I know that is not what you want to hear. Need to check the spring bind on the valve springs and degree the new cam is a good idea. Lot's of money riding on doing these checks. You sound like you like to go to Vegas :D

Sounds like you built a 50hp XR650L!!! :) With header/muffler, Uni air filter, and a pumper carburetor that is what you should have. A 48% increase in power over a Stock XR650L :):D That will be a awesome jump in power. Did you ride the bike before you started the rebuild?

Share this post


Link to post
Share on other sites

Nope, never ridden it - in fact I don't own a 650L, just the motor & electrics. All this stuff is going into my '92 TZ250 chassis :D (I've already built the mounts and test-fit the motor) and it'll be getting a full custom exhaust (reverse-cone meg) and probably a TM42 over the winter -just wanna get it running right now tho so I can register it for the street :)

I've also been told about 4 degrees advance on the cam is a good starting point for a street bike.

Thanks for the info! In the end what must be done must be done I s'pose. Any good online info for the claying procedure? Pics are good, if possible :)

50HP and I'll be well happy as the bike should weigh in around 250lbs (up from 220 with the TZ motor).

cheers,

-Mike

Share this post


Link to post
Share on other sites
Nope, never ridden it - in fact I don't own a 650L, just the motor & electrics. All this stuff is going into my '92 TZ250 chassis :D (I've already built the mounts and test-fit the motor) and it'll be getting a full custom exhaust (reverse-cone meg) and probably a TM42 over the winter -just wanna get it running right now tho so I can register it for the street :)

I've also been told about 4 degrees advance on the cam is a good starting point for a street bike.

Thanks for the info! In the end what must be done must be done I s'pose. Any good online info for the claying procedure? Pics are good, if possible :)

50HP and I'll be well happy as the bike should weigh in around 250lbs (up from 220 with the TZ motor).

cheers,

-Mike

I saw a 2002 TZ 250 and that was quite a bike... and 230 pounds dry weight. That sould be a fun bike with the 650 motor.

Share this post


Link to post
Share on other sites

Hey Motorcycle diary dude!

There was a guy here or on the XR650L yahoo group who has the same sort of ride (actually race only I belive) Very good info from him in setting up my 41FCR.

Good luck!!!

Travis

Share this post


Link to post
Share on other sites

Ya I've seen a few around the web. I drew my initial inspiration (and some hard-won knowlege) from a fellow named Randal Zempell who used the same vintage frame ('92) and a 600 motor. I went with the 650L motor due to the electric start and the fact that I want to put this bike on the street (didn't want the trouble of trying to fit the kicker around the huge frame spars).

It's a VERY tight squeeze in the frame -less than 1cm on either side of the barrel to the frame spars and vertical placement is restricted by the starter motor/starter clutch cover. After much measuring, pattern making and re-measuring, I've finally sorted a set of motor mounts that should work out OK.

Now I just need to find room for an oil resevoir and battery :)

-Mike

Share this post


Link to post
Share on other sites

You may want to seriously consider going with a stock HRC racing cam. Service Honda. com has it for around 240$. It is more $$$$ than the hotcam but the metal compound of the HRC matchs the stock rockers. The hot cam is a softer compound with a hardened surface. Which means one tiny blem in the surface and the hotcam will eat your new rockers alive. I put a bigbore kit in my 600, all new rockers and subs, port and polished the whole 10 yards and i did a lot of research on the cams and the HRC was the way to go if you are looking for dependability+performance. not to mention all the mods made such a difference the bike performed like it was 80 lbs lighter.

Good luck and i am sure your prototype will kick some but.

Share this post


Link to post
Share on other sites
You may want to seriously consider going with a stock HRC racing cam. Service Honda. com has it for around 240$. It is more $$$$ than the hotcam but the metal compound of the HRC matchs the stock rockers. The hot cam is a softer compound with a hardened surface. Which means one tiny blem in the surface and the hotcam will eat your new rockers alive. I put a bigbore kit in my 600, all new rockers and subs, port and polished the whole 10 yards and i did a lot of research on the cams and the HRC was the way to go if you are looking for dependability+performance. not to mention all the mods made such a difference the bike performed like it was 80 lbs lighter.

Good luck and i am sure your prototype will kick some but.

Is there an online supplier of HRC Parts. (I haven't found it on honda.com)

I am really getting tired of having to deal with the local honda sales monkeys

thanks

Rob

Share this post


Link to post
Share on other sites
Is there an online supplier of HRC Parts. (I haven't found it on honda. com)

I am really getting tired of having to deal with the local honda sales monkeys

thanks

Rob

if you have the part # servicehonda.com can get it for you at a discount even

Travis

Share this post


Link to post
Share on other sites

try a search of this section I think I posted it here a month or 2 ago

Travis

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0