http://www.nrhsperformance.com/pictures/mikemccambridgebeforeandafter.gif

2004 XL883-1250 Conversion owned by Mike McCambridge
Blue: after conversion
Red: before conversion

Modifications:
NRHS/Axtell 1250 kit w/flat tops
NRHS competition valve job on stock 883 heads and valves
NRHS chamber relief work to get CR down to 10.5:1 with flat tops
SE .536 cams
SE air cleaner
SE slip-ons
(Stock carb & ignition)

Mike rode out here from Milwaukee on his XL883 for the NRHS July 4th shindig. We did the conversion here, modified the heads, and installed the cams, and this is what he's riding back with
Congratulations Mike!

...you really like making me drool!!!

Thats kind of the same thing I was thinking about doing, until I can afford to get some XB Stage 2 heads. What all was involved in the competition valve job on the 883 heads. How much more involved is it than cutting the squish band? Do you just do the valve seats? How much does that part run and would I be able to use the .575 cams with the setup instead?

So, what would you get with the heads ported. Those are very respectable numbers for a 1250 conversion with basicaly stock 883 heads with a nice valve job.

Wow, awesome! I have a question...
is Mike an XLF member, and if he is, do you
know what his username is here?
Just curious.

Wow, what an improvement. How many extra H.P.'s does that 1250 kit put out over a regular 1200 conversion bike w/ NRHS Stage II heads? (like the one in my sig)

Aerosport, a competition valve job opens up the seat i.d. to roughly 90% of the valve diameter, and puts our special radius cuts onto the seat (different cut for intake vs. exhaust, intake is maximized for flow, exhaust compromises some flow for heat dissipation and wear). We also blended his seats into the bowl. We didn't cut the squish band, this used flat tops. The competition valve job runs $137.50 per pair and the chamber work is another $137.50, so this was $275 worth of head work. 575's take a better spring pack, this was done with his stock springs (and valves, and guides, we put new seals on is all).

Ralph, on my 883-1250 running the same cams, but with Stage 1 on the heads (which includes that valve job) and reverse dome pistons (10:1, the above is 10.5:1) and no chamber work, the bike made 85hp. I was surprised by the above result. I told Mike to expect around 75.

Michelle, yes he is, but I'll have to ask him his user name.

OCD, the 1250 kit is normally, by itself, good for 5-7% more hp, assuming all the other components support it. Power tends to be defined by the part that's holding the motor back, as opposed to being defined by the sum of the go-fast parts. One part that's holding the bike back can negate everything else you do.

So does that mean that the two guys on the forum that got 80-84 hp from their 1212 conversion were where they should be?

Awesome! Can't wait to get some miles on my bike and post up my new dyno numbers with the updated top end. Gonna be SICK! Congrats, Mike.

--Sean

Howdy All - the bike is mine. I'm coming to you live from sunny CO, planning on heading back home to Milwaukee tomorrow.

The bike is SICK. These guys are the real deal, I am really impressed. Words can't describe how different the bike is... more on that later.

When I get back home I will post some pics of the conversion and our nice ride in the mountains.

Thanks NRHS!!!! :D

Congrats Mike, have a safe ride home and take lots of pics on the way.

Aaron what does the torque curve look like for this combination? Could you please post a dyno run with it included?

Also what are the jet sizes that he was using? Again a post with the AFR?

Did you do any tuning to this combination after the "breakin"?

Thanks for the post, it shows the potential of that 1250 kit has verses the 1212 kit.

http://www.nrhsperformance.com/images/drmikemccambridge.gif
Here it is with torque. He had a 180 main and a 48 pilot for this pull and a/f was about right, in the low 13's (don't have a sheet handy with a/f and I'm not at the shop right at the moment). But Milwaukee is lower so he may need a little more jet there.

We rolled it on the dyno with the intent of tuning it, but this is how it was, I just did three or four pulls and got this. AFR was OK and no way to adjust the timing, so I just rolled it off.

I'm impressed with the torque curve - 70 ft*lb at 2200 RPM or so.... good stuff. :tour

Very impressive, that torque curve makes that bike a dream to ride. I'm sure that when Mike gets back to Milwaukee it will completly broke in and the fun should really start at that point. Keep the front end down Mike.

I really appreciate you posting the dyno curve. I now have something to compare mine with. And as I have suspected my curve has a low spot down low. It has a very pronounced dip down low actually. I seem to think it is those damn V&H Straightshots, I have since change to the SEII's and the bike feels much more responsive, only a dyno will tell.

Sorry to have high jacked this post but this post has been very informative to me and probably to Shamdog also. Mike's combination is very similar to both of our bikes. All our results are in the same general HP area, that seems to indicate that that's the result of this type of conversion. Or do you think there is something still in Mike's after some further tuning?

Thanks again NRHS guys and to you especially Aaron.

Mike used the all aluminum cylinders in his build but this same kit can be done with the cast iron cylinders. HERE IS THE GOOD NEWS!!

Cast iron engine kit: $750
883 flat top conversion headwork: $275
SE 536 cams: $275

TOTAL: $1300!!!

Guys,
I was there at NRHS to witness the little "upgrade" mike had done on his 883. Aaron, John, and Dan have done extensive research on how to make your XL go faster, and their work is nothing short of impressive. Mike's bike has so much power that he literally didn't know what to do with it - but I'm sure he can tell you all about that!

IF YOU'RE IN THE MARKET FOR A 1200 SPORTSTER: Don't buy it. Buy an 883 and spend all the money you saved at NRHS. (My stock '04 1200 with K&N air filter and SEII pipes peaks at only 72 hp). I wish I would have known all of this before I bought it. Dan - correct me if I'm wrong, but couldn't you get 100 hp out of an 883 by spending less than $3000 total on a 1250 kit, heads, and some other stuff?

later,
Nic Van Engen

I am quite confident we could turn an 883 into a 100 hp beast for under $3000

Mike's bike has so much power that he literally didn't know what to do with it - but I'm sure he can tell you all about that!

Haha! Yes, indeed it does...

First time I gave it a good bit of throttle in 1st gear at a stop sign it stood STRAIGHT UP. I'm talking one of those "Stunt Video" wheelies, witnesses claim I damn near broke the tailight...

Yea, it's got some power now. Very easy to lift the front wheel or break traction with the rear... :D

Ha, my very first (and second) wheelies came on accident after my conversion! The first one was extreme, a CBR rider saw it and told me the front tire was a full 20-inches off the ground. Fortunately I handled it seemlessly, hit the ground straight and shifted like a pro. Then went home and didn't ride for a few days. Haven't done any since, or on purpose.

--Sean

First time I gave it a good bit of throttle in 1st gear at a stop sign it stood STRAIGHT UP. I'm talking one of those "Stunt Video" wheelies, witnesses claim I damn near broke the tailight...



Yeah I saw it! I thought he was going to flip it over or dump it. I did not expect that! Wow! that was awesome to see.

Okay, so the $575.00 question. I have been putting my nickles away for the 1212 conversion and Stage 2 on my 883 heads. How close to these numbers would the 1212 get you compared to the 1250 with the same head work? I really want to use the stock HD cylinders on my conversion.

bwheeler,
You should be in the same ballpark as long as your exhaust is up to it. We are finding over and over again how critical exhaust designs are especially to top end hp.

bwheeler,
You should be in the same ballpark as long as your exhaust is up to it. We are finding over and over again how critical exhaust designs are especially to top end hp.

I've been looking at a couple of different exhaust. Which of these two would give better results on the 1250 kit: supertrapp 2-1 or V&H SS2R? Or do you have any other recommendations?

bwheeler,
You should be in the same ballpark as long as your exhaust is up to it. We are finding over and over again how critical exhaust designs are especially to top end hp.

I understand that. Here is my dilemma. I do not like the look of the Thunderhearder or the Supertrapp. I am thinking about ordering a Rinehart 2-1 today. I think it is the best looking 2-1 I have seen. The Bassani isn't too bad looking either. I just prefer the shorter look of the Rinehart- but the rear pipe is not of equal length to the front on the Rinehart as it is on the Bassani. In your OPINON what do you think about the Rinehart and have you dyno'ed anything with the Bassani 2-1 on it?

bump bump....

The Rhineharts have shown to be very good pipes. They also have one of the best 2 into 2s we have tested. Unfortunately we have not tested the Bassanis so I cannot testify to how good they are. I do know that Predator has them on his 88" monster.

The Rhineharts have shown to be very good pipes. They also have one of the best 2 into 2s we have tested. Unfortunately we have not tested the Bassanis so I cannot testify to how good they are. I do know that Predator has them on his 88" monster.

The Bassani or the Rinehart? It would be pretty tough to compare a 1212 conv. to that beast of his anyway.

[img]
Modifications:
NRHS/Axtell 1250 kit w/flat tops
NRHS competition valve job on stock 883 heads and valves
NRHS chamber relief work to get CR down to 10.5:1 with flat tops
SE .536 cams
SE air cleaner
SE slip-ons
(Stock carb & ignition)


Excellent work, by the way. Aaron or Dan, I have a question about this build since I may start something similar. I have an '05 1200 that I am researching some mods for.

I was thinking of using .536s (since they work with the stock heads) and 10.5 pistons, then doing the heads later.

This bike you did still has the stock ignition. I was under the impression that if you altered the CR you needed an adjustable ignition. Of course, correct me if I'm wrong.:frownthre

Originally Posted by NRHS Sales:
The Rhineharts have shown to be very good pipes. They also have one of the best 2 into 2s we have tested. Unfortunately we have not tested the Bassanis so I cannot testify to how good they are. I do know that Predator has them on his 88" monster.

Do you have any dyno plots showing how the Rhineharts compare to the Supertrapp?

Broclee,
The 536 cams are great and will bolt on with your stock o4 and up 1200 heads. Just be sure you check valve to piston clearance if using pistons other than Hurricanes. With your heads an ignition modue will be a benefit since your valve sizes can benefit from more rpms. On Mikes bike his 883 heads have small valves so more rpms would not have given more power. His bike is basically at the limits of his valve size.

Ivan
No we do not. Tests like that require a dedicated bike that the only thing we are changing is exhausts during the same day. We are not in the exhaust business so that just is not practical for us to do tests like that. It is hard enough for us to do testing of our products much less somebody elses. Maybe call Rhinehart and see if they have done any tests like that.

Broclee,
The 536 cams are great and will bolt on with your stock o4 and up 1200 heads. Just be sure you check valve to piston clearance if using pistons other than Hurricanes. With your heads an ignition modue will be a benefit since your valve sizes can benefit from more rpms. On Mikes bike his 883 heads have small valves so more rpms would not have given more power. His bike is basically at the limits of his valve size.

Thanks again for the advice. It's a big help.:clap So if I understand this correctly, It's not neccessary to change the ignition, but it helps because the .536s make power past 6k. And of course, I gotta check the piston to valve clearance.

That is correct

r the 536 cams bolt in on a stock '04 1200?

I spoke to Dan earlier this week and will be sending in my heads for the work. I have a question, have you duplicated this performance more than once with this set up?

aka_Matt,
... SE slip-on's/no baffles, Ness BS, 79hp/75tq...

I have an 04 1200 and with SE slip-ons, and I have found that without the baffles my torque (and hp) drops considerably (compared to with the baffles) whenever I'm below about 4000 rpm. Above 4000 with no baffles it makes great hp (i think). In other words, they act like drag pipes. Is this how you're getting 79 hp, or have you done other mods as well?

nic

P.S. - your .536's question has already been answered in the above posts.

diesel, only other mod i have is the SE ignition... my tq peaks early, 74@3000, then drops to 69@4000, and peaks again at 75@5000, with 79hp@5900, 75hp from 5500-6500... and about the cam question, he said:
"...The 536 cams are great and will bolt on with your stock o4 and up 1200 heads. Just be sure you check valve to piston clearance if using pistons other than Hurricanes."
well, i'm using stock pistons, not hurricanes... so r they bolt in with the stock pistons?

Matt, I've never tried it, but personally I wouldn't do it without making the measurement. That grind has a lot of TDC lift on the exhaust side and that's what compromises the clearance.

How did he manage to ride home on the new engine?

I'd love to spend the extra money to get the 88" kit but instead of sending in the cases I'd love to set aside a couple or more weeks to ride up there and have you guys work on it then right it back. Assuming that's even possible of course. I'm just not sure if a long ride would be such a good idea before it's broken in.

Matt,
It looks like your torque peaks are running about the same as mine, just about 500 RPM later. My highest torque is 76@4250, by the time I get to 6000 (redline for me) its down to 60 ft/lbs. When you say no baffles, do you mean the pipes are completely hollow? I have removed my packing and put the baffles back in b/c it seemed like I couldn't make any low end power without them.

Nothing like praise! Glad all is well and the ride is sweet. Be careful with all that new found HP! Maybe next year I can scrape up some HP money! I'm almost jealous!
Dave
Live to Ride!

Open highway riding in 5th gear is about the best way to break in a motor after a conversion. The rpms are kept nice and low.

Have these results been replicated on anything else yet?