I am looking for a big bore kit for my 93 fxr. It has an 80" now w/ ev-27 cam (probably going to change out for something a little larger), aftermarket ignition (can't remember at the time which one it came with from the previous owner). The carb on it was in definate need of a rebuild but I had a Weber DCOE 40 laying around from a previous bike that I will toss on it.

I am new to HDs but have built a bunch of import bikes/motors, twins/4 cylinders...choppers/streetfighters... whatever I can get my hands on.

1. On a stock evo case how big of bore cylinders can I run? 3 5/8?
2. Whats a reasonable price to pay for case boring?
3. Does the case need to be completely stripped bare to be bored?
4. What are some good vendor reference sites for pistons, cylinders, cams etc.
5. How high of compression can I run on 92? 11.0:1?

 

You might have a problem trying to bore those "suspect" year factory HD cases out. If you are definately sold on a stroker then aftermarket cases already set up for what you are looking for would be the better way to go.

The other alternative is the way I'm going. That is a Revolution Performance 85" big bore kit that is a direct bolt on. The compression ratio was set up specifically for my combination at no extra charge. I'm using ported SE heads, so the compression ratio on the pistons were dropped from the standard 10.5 to 9.5. This combination will work with the EV27 that you already have and that I am also running. I'll jetmy S&S Super E and set the Dyna 2000 ingintion for this setup as I have some competent help.

If this option might interest you, check out the RP website or call Andrew at 1-866-892-2109. He will be able to answer any questions that you may have and can work with you on your preferred combination. The kit BTW, has a lifetime warranty if installed as directed.

 

What is wrong with hte cases that year? I am not sold at all on stroking it. I never mentioned stroking, just boring for larger cylinders. I know the ev-27 will work but I am looking for something with some more lift and duration for a higher rpm powerband and higher HP. It looks like the RP 85" is $900, the revtech 88" kit is $500. As for questions 1-5, answers to those would be very helpful.

If I do go with an 85" RP would be where I shop though... seem to know there stuff and have a ready to go kit.

 

There were several years from the early to mid 90's where Harley had case casting problems. Many of the original cases cracked and had to be replaced. Were yours replaced? Perhaps you'll never know, but the added stress of boring the cases out larger can cause problems with stock cases.

I'm pretty positive that 3 5/8" is the largest a factory case would go. You are then limited cubic inch wise by the lenghth of thecrankshaft throw selected.

Yes, the engine has to be torn down and the cases split to remove the flywheels. The case halves a reassembled and then the cylinder holes are bored. Aftermarket cases eliminate this problem, are strongerand can be had in sizes larger than 3 5/8". They are also clearanced for stroker flywheels. Your stock cases would have to be clearanced as well for some longer strokes.n

Far a prices to do the work on your cases, that varies by geography, the shop involved and perhaps shipping charges both ways.

You can check with S&S, Zippers, Delkron, Ultima, Recktechand others for parts vendor sources.

What are you going to do about head work?More cubes means more air and abigger cam will require bigger springs. All these factors including the compression ratio come into play when deciding on a combination. What kind of ignition are you using and will it have to be changed? If I had to change cams with my RP combination, I would look at the Woods W6 based onAndy's recommendation at RP. I might also look at the V-Thunder 3020 and 3030.I have a Dyna 2000 adjustable module on the shelf, so I have the ability to change the ignition curve and timing if needed.

Best advice I could pass along is to buy the best highest qualityparts you can. I will not run any parts in my engine or transmission unless they are made by a reputable US manufacturer. If you check and ask around, you will find that it is very difficult to get any kind of warranty out of Revtech. After checking around on prices, I decided to go with the RP kit as being the most cost effective for my needs, see I'm using stock 93 cases too [:@]!!

One of my RP cylindersarrived with a gouge in one of the polished fins. It was not shipping damage as the parts were packed very well. RP immediately offered to send me a replacement cylinder and pay the shipping both ways. How's that for customer service? Call Andy and he can answer more of your questions on the technical end.

 

It might be a crane ignition. The receipts are at my dealers and the bike is at my shop so I can't check it at the moment. 900 seems like a lot for 4.5 CI. I will probably just go with some high comp. pistons and port the stock heads until I can get a 127" or something.. The case has 80,000 mi on it but it has 5,000 on the stockish rebuild. So it may have been changed out at some point or it may not be one of the "bad" cases if it has lasted this long.

 

Ive got a 97 wide glide that i had stroked last year. It has the ultima 89" crank in it with Ross ceramic coated pistons bored.030 over. The heads are worked S/E's with big valves and springs.Im running a S&S 520 cam with the crane ignition.I tell ya this thing rocks. I have smoked 2 96 inch bikes already and the 88's cant even compete. Feels good to have the ole EVO walk on the new stuff.Total rebuild cost including parts/labor was about $2000. I would definitly recommend the ultima kit!

 

In 1984 I had an FXR EVO, just milled down the stock heads .050, oversized valves ported, S&S carb, S&S cam Sporster ignition. Left the stock flat top pistons this was a budget build but really screamed. Beyond that it makes better sense to just change out the complete motor, 3800 for a 113 then sell the old motor usually 1500- 2000 depending on condition. I put in the 127 but kept the old motor as it's a 110" S&S (collectors item only 400 made) the 127 was about $4000. Really happy with it.

 

I have a 1990 bike and have also been thinking of a big bore kit for it. I already have a 89 inch stroker kit installed. Unfortunately we both have crank cases that are suspect! There are three issues I have found so far: the crankcase walls around the front cylinder are thin, so it is not a good idea to bore them out; a tuned motor may pull the cylinder studs out as there is very little metal around them; but worst of all is the drive side main bearing can shake itself loose in the crankcase, especially if the engine is tuned.

So in summary it is not wise to fit a big bore kit and the only way ahead to increase capacity is to fit a stroker kit, but even that has its possible problems. I have reluctantly given up all ideas of making further mods to my engine.

To answer your questions, you really need a 1994 or later engine to bore the factory cases out. The engine would need to be removed from the bike and stripped completely to bore it (as it will to fit a stroker kit). I have JIMS flywheels and am running around 10:1 compression ratio. You could consider after market cases? There are two options available: some will give you a 3 5/8 bore, others 313/16 bore. Sputhe even make cases and cylinders that will take a stroker crank and give you 104 inches, but the cost starts adding up. I havelooked down that route, but am now thinking of a new motor!

 

Had a problem with my 85 WG. When I had the jugs bored the sleeve in one spun.

 

Yo, Buddy! How did your 85" big bore kit work out? Truely bolt on? I have seen an 83" kit also.