| Author | Message | ||
     12mpghwy |
I diagnosed a bad head gasket, and decided to rebuild the top end. The bike has around 18K miles. The cyl bores look good as do all the other components at least to the naked eye. So I'd like to get it back together for less than 1500 bucks with best bang for the buck performance. Cheaper is obviously better. So what is the consensus on top end work? Basicly I want a little bit more power than stock (stock new and perfect) and to buy the cheapest upgrades first. I was thinking of having someone or some shop rebuild the heads with light port work, bore the stock cyl's once over and use some properly matched pisons with the right squish band and all that. Idea's? Thanks | ||
| Phelan |
Who's putting it together? You or a shop? | ||
| Nallac |
wouldn't a 1250 kit be a good start?. | ||
| 12mpghwy |
I will be putting it back together. I don't know about a 1250 kit being cost effective. I don't have allot of experience with this but my guess is the extra 30 something CCs vs a once over stock cyl with the same change in compression from new after market pistons would probably not make a cost effective difference. I don't have much in the way of good measuring equipment but If I can find a local shop that can check my cyl for round and then hone and ridge ream them as nescisary, I could re ring the stock pistons and spend more money on head work were I think it would make more difference. Basicly I will probably have to choose between stock cyls and some shops "stage 2" head work or 1250 kit and some shops "stage 1" head work or even just a basic valve job, to stay within my budget. (Message edited by 12mpghwy on March 30, 2010) | ||
| Mmmi_grad |
I can rebuild the heads and the top end for 1500 with nice parts. Introducing a 1250 kit......aint going to happen. Buy a race ecm, muffler and air filter. stick a fork in it. | ||
| Mmmi_grad |
hahah we both posted at the same time. Before you take it apart do a compression test on the good cyl. If you got really good compression then I would just install new rings after haveing the piston and cyl clearance double checked. But hell if you have great compression, odds are new rings will be ok and you can go crazy on the heads only after good advice from cycle rama and a conversation about what you want to do with the bike. Throwing big mony in head work might not be a worthwhile idea either. | ||
| 12mpghwy |
I do have a race ECM, a muffler and an air filter. Also would consider cams that would compliment the final setup, as I have to take the cam cover of to replace the oil pump drive gear. If its a cost effective change. The compression is a bit low, around 110 front 100 rear, the crappy gauge I have tends to read about 10-15 PSI lower than my friends snap on. For refrence I believe the manual calls for work if there is less than 130 PSI, and its allready apart. This engine is easy to work on, I was actually able to get the top end off on my one hour lunch break. (Message edited by 12mpghwy on March 30, 2010) | ||
| Preybird1 |
LOL HA ha are you ready for this..... I Wanted to do the same thing you did and beef it up a "little" and ended up spending $11,000 and 131+hp @ the motor and i am still counting........to be continued  | ||
| Dinuns1 |
11,000 only 131 wat the hell did you do ? | ||
| 12mpghwy |
nice bike Preybird1... I would be happy to make 100 whp which I think is possible on stock cyls with a small bump in compression and some head work in combination with some ecmspy tuning on the race ecm and the intake and exhaust parts I already have. If I wanted to go crazy I have a spare haltech ecu with all the sensors from a project car that now dead, it would have no problem running this engine with a small turbo. And then the head porting would be less critical. I wonder what the limits of the stock rods and crank are? | ||
| Pkforbes87 |
For just a hair over $1500 you could have a 1250 kit with 10.5:1 pistons, stage II headwork, and .536 cams. Of course that means installing it all yourself and there's no room in the budget left for tuning.. You might be able to save some money by using your stock cylinders with a slight overbore and using new higher compression pistons. I really think that the higher compression of my 1250 kit is where the extra power came from.. not from the extra 50cc's. I had compression tested after finishing the build.. 230 PSI rear cylinder, 200 front cylinder. The rule of thumb I've heard is that a >10% difference is not desirable, but with both numbers being so damn good, I'm not too worried about it. With the way the engine weight "hangs" on the front head, lower compression doesn't surprise me and the bike has run like a champ for about 7000 miles since the rebuild. | ||
| Preybird1 |
I bought every after market mod i could get and they were all expensive! | ||
| Phelan |
The extra 50cc, according to my friend Dan, gives ~5% increase in power. Good if you have the extra ~$300 to get the cylinders with the pistons, but not too necessary. I personally would save more dough to do it, but that's just me. Otherwise, just get stage II headwork, 10.5 or 11:1 pistons (depending on quality of gas in your area), and .536 cams. I would also get the NRHS billet pushrod bases (available through Al at American Sport Bike) to prevent leaks and add a little bling. | ||
| Texastechx1 |
if the pistons and cylinder walls are in good shape you can just do a simple de-glaze and re-ring with a top end gasket kit and save some SERIOUS $$$. i've done it to everything from weedeaters to trucks, as long as everything is within spec, you're in the clear. just an option and my .02  | ||
| Preybird1 |
i had to buy new jugs also as they were damaged when the valve went the top end was $3000 alone. | ||
| Pkforbes87 |
wow $3k for a top end seems a little steep. I bought Betty with a dropped exhaust valve. Front head, cylinder, and piston were all beyond repair. (quarter-sized hole in the piston!) A pair of 1250 cylinders and 10.5:1 pistons cost me $600. Rebuilt heads from a '99 M2 cost me about $150 from eBay. I don't remember the exact price but they were less than $200 and came with two stock pistons that I didn't need. I didn't have headwork done, only smoothed the exhaust ports a little on my own using a dremel. | ||
| 12mpghwy |
So here are the options I am considering: Cams: it has been recomended to me that if I want to stick with fuel injection and plan to do my own tuning that I should do cams later, first do heads and cyls and get it all tuned out and then do cams. That makes sence to me especially since everyone says the stock SE 536 cams are good for maybe 5 more hp than stock X1 cams. Heads: "Stage 2" head work 750-850 depending on where I get it from + shipping Cyls/pistons: Around 150 dollars parts + labor to have a local shop strip the paint of my stock cyls, chean them, measure them in torque plates, hone the cyls clean the stock pistons, flaten the flanges if nescisary, re ring the stock pistons and install them in the cleaned up cyls + buy new gaskets etc. I could save money by doing some of this myself but don't have a hone or proper measuring tools. Total $1050 Option 2: have stock cyls bored, for use with once over pistons for 1212cc at 10.5 compression, cost is 420 dollars plus head and base gaskets and shipping and aditional 50 bucks or so to have them set the ring gap and install the pistons. So total of about 500 less shipping. Total $1450 option 3: axtel iron lined 1250 cyls pistons, preped for instal are like 750 dollars + shipping Total $1550 option 4: rev performance 90 inch cyls, with them offering free case boring this month. 999 dollars. I split cases on an XB to do tranny work, it was time consuming to put back together but no big deal. Thing is if I am spliting the cases I would kick myself every time I rode it for not balancing and lightening the crank, and since I have a 99 with a bolt together crank its $420 to have them knife edge lighten and balance the crankshaft. At that point I would need some more cost in stock parts but would have fully rebuilt the engine. Total @ $2250 + alot of shipping what at least $150 shipping + 100 or so more worth in stock parts to finish up the bottom end. | ||
| 12mpghwy |
Question to all you folks, what else would I need to do with the bottom end if I wanted to do the 90CI options. Would the stock rods and crank assembly lightened and balanced be ok with that? Would I need new rods? Also looking at the above, option 2 fell off the table, it wouldn't make sence to bore the stock cyls when for 100-150 dollars more I could get the 1250's. | ||
| 12mpghwy |
I talked to Brian nallin and he has convinced me that if I am replacing the cyls I should get nikalsils for the heat rejection. So with that and them doing the heads and free case boring it comes down to a difference of about 50 dollars aditional shipping. And about 600 for the crank balance knife edge race window and re assembly with new bearings and having them set the play. Which constitutes a top end a bottom end rebuild. I think I shall go with this even though it blows the budget by about 1000 dollars | ||
| The_italian_job |
I've just bought my 1250 kit from NRHS and discussed with them the option of buying nikasil or not and they highly recommended not to buy nikasil cause they are exposed to breakage. not my words... | ||
| Bads1 |
Those would be Dans word. I'd go with the Revolution performance Millennium cylinders. Dan I think is just one opinion. | ||
| Phelan |
Yeah, people have different experiences with each and develop different opinions on them. To each his own IMHO. It's bot my money being spent. | ||
| Firemanjim |
Look real hard at your stock cylinders as we are seeing a bunch recently of the stock liners lifting and causing the head gaskets to blow. Common problem with the iron cylinder/aluminum liner of stock cylinders. If you can run your fingernail across top and feel any ridge,the cylinder is toast. 1250 kit is a great way to go, and Nikasil has been in the dirtbike market for years with excellent service.Would not hesitate to put them on any of my bikes. |
