I had a NRHS 1250 conversion done on my 05 883C and here is the dyno sheet for it.




I liked the power and it felt like it had plenty but I hated it using about a quart of oil every 500 miles. The oil temps shot up to 250 also. Quite a few people with 04 and up sportys with this conversion have experienced the same problems and a solution still has not been found. Still there are others with no problems.
The local indie who installed it for me went ahead and took it apart again and installed new valve seals for free but it still drank oil like crazy.
It seems like it would be something simple to figure out and some people refuse to believe this is a problem but if it was so simple thenI ask them why has no solution been found to this day? I didn't want to dump anymore money into it just hoping to stumble upon the solution while all the time pouring $8 a quart oil in every 500 miles of riding so I got rid of the Sporty. Still I loved that bike except for that problem.

One of the posters on here (I forget his name) a while back posted instructions on how to do this conversion yourself. He took pics while he did it and posted them all up here. Well after all that he ended up having the same problem I did and he got sick of it and put the 883 cylinders and pistons back in and bingo, no more excessive oil usage.

Just be warned if you try thisconversion that there is a chance you may be in for some disappointment and waste of perfectly good money.


Also that dyno chart OFG posted doesn't say it on the pic but on the website where it comes from it says in small print that the bike they tested had on it the following...

HurricaneFlow Air Cleaner, Mikuni HSR42 carburetor, SE .536 cams, Supertrapp exhaust system, and Daytona Twin-Tec ignition.

 

Some stock 1200's will have oil consumption issues (typically 04-05), but that's a different issue from the NRHS oil consumption issue. First, the stock 1200's that do use oil do not use anything close to what the NRHS engines use (some report as much as 1 quart per 500 mi. on NRHS). Second, the stock 1200's oil consumption issue is caused by the valve seals they used in 04-05. Since then the valve seals have been revised. With my stock 1200 I used 1 quart in 5K mi. and had oil going down the valve stem (only found out going into the engine). With a modified version of the new seals there is no oil consumption 6500 mi. later and no oil going down the valve stem. My oil temperature has also dropped (probably a result of the oil leaking).

The NRHS valve seal/valve train change to ported heads is a totally different setup from stock. What has been found is excessive valve to guide clearances on the headwork (and sometimes the valve seal not even seated). Like .005 clearances where the service wear limit is .0038. What NRHS has done in the past is deny that running .005 is a problem. Then it denied that the heads coming from them are setup so loose. Another possibility for the high oil consumption is that they may use total seal low tension rings, which burn more oil in exchange for more horsepower. Finally, their 1250cc kits that are iron-lined are just V-Twin 1200 cylinder bored out to 1250cc's (their aluminum and cast iron cylinders are axtell though). They claim that the V-twin cylinders have a thicker iron liner in them so they can be bored out to 1250cc's where they say a stock 1200 cylinder cannot be bored out to 1250cc's. However, another issue is that the V-Twin cylinders are made in Taiwan. Could some of them be of questionable quality?

There are two people getting their engines redone at other shops. The first has gotten his valve train redone and set the valve to guide clearances from .005 to .001 Intake and .0015 exhaust. This took his oil consumption down from 1 quart per 500 miles to 1 quart per 800 miles (still too much). Now he is investigating the rings/cylinders to see if he can stop it. Another person had his heads redone and reported by someone else (found additional 15 CFM flow from Stage 3 NRHS heads). So far he doesn't notice any oil consumption, but it is too soon to tell. I think it only have 300 miles on it so far. Stay tuned.

Now what NRHS will say in their defense is that there are people with 1250 cc kits and STOCK heads that also have oil consumption problems. If it was a problem with their headwork, then why would those people with stock heads also have oil consumption problems. One possibility is the stock valve seals from 04-05, which also caused problems on stock bikes. However, some of these bikes had no oil consumption problems as 883's and then as 1250's had oil consumption problems. That question yet hasn't been answered because those people either decided to return their 883 to stock (oil consumption stopped again) or sell the bike. If it was me, then I would look at the cylinder/rings. My opinion (and it's just that) is if an engine is eating that much oil there are only two ways it will do it. 1) Through the valvetrain and 2) Through the cylinders/rings. I guess the question I would ask them is if it wasn't a problem with the 1250 kits, then why did the bikes stop using oil again when they were returned to 883's?

What upsets me the most is that other pe

 

That's some good info. 1200C. I've read a number of similar complaints about the NRHS 1250 upgrades on the 04 up motors but have never heard any explanation as to the cause of the problem. I guess if I was in the market for an upgrade, I'd be talking to Zippers.

 

"You get what you pay for", and with Zippers you are sure to dent your bank account. On the other hand, I don't think I've ever heard anyone complain about motor work performed by Zippers...

 

What do you pay for Zipper's? Can't find prices on their web site..

 

Why do you think that is? No seriously, I don't know what they charge specifically for a 1200 or 1250 conversion, but their motor work is generally a substantial amount higher than what NRHS charges.

 

If you want to go 883 to 1200, then my suggestion is the SE 1200 kit for '07 sportsters. Just use different intake flanges to make them fit the 04-06 rubbermounts.

Just buy it from a place that sells for 20% off like Chicago Harley. It comes with 1200 heads, which are also the same heads the XB buells use.

 

Anyone have a dyno sheet on a stock 1200c (2004-2006)?

 

here is a stage one dyno of my2004 1200r cycle shack slip-ons and screaming eagle a/c and dyna-jet kit installed I have since changed a bunch of stuff and ifyou notice it is not sae corrected. I am going to go a different route I bought a set of screaming eagle heads that are suppose to raise compression to 10.5-1 , all I need to do now is figure out what cams I want to use . I also have a mikuni 42 flat side carb already installed , sowe wil see how this all turns out. I know I have heard all the dirt I should let nrhs do my heads ,forget the screaming eagle they are just decked 04 heads blah blah blah yet I havent sen anybody complain about oil consumption using them. and does it really matter what route I take to get the higher compression as long as I get there?