My mechanic quoted me the S&S 106 kit to repair and upgrade my 2003 88b. A few weeks prior to this, he was suggesting a larger bore, and not too much more stroke, over-square I believe he called it. He explained that the shorter stroke would make less heat, and therefore last longer for the amount that I ride,around 7500 miles per year. I liked that idea, but he said doing it the first way would be a lot more custom of a build, and therefore harder to repair in the future if I ended up at a shop 5 states away with no clue what I have in there.

So, any constructive advice for either direction would be appreciated. The work being considered right now is to use the S&S 106 stroker kit, which will include a new crank(welded?), new heads, pistons and associated parts, and whatever cam we choose to go with it- I allready have gear drive, and I believe he suggested a 585. I will have the jugs and heads diamond cut, then he will bore the cylinders, and go over the heads- he said the S&S is good, but he can port and polish it a bit better than the standard production. He also said I will need a new carb to feed this thing, and since I want to retain my stock air cleaner cover, that it will need to be a Mikuni. Also, regardless of what else is done, the Timken tapered bearing kit is going in.

My biggest concern, even above cost, is reliability. I have seen some negative statements regarding the piston skirts on this kit, saying that they are too small so they wobble and use oil... For the money I am putting into this, I want to get at least another 50,000 miles out of it- my stock motor made it to 49,000 before the crank got ruined by the compensator and rotor loosening up.

 

from what I have seen the late 96 tc engine has shorter skirts VS the older 88.

i wouldnt be too concerned over that. Id be more concerned over WHO is setting the kit up.

I would NOT buy any aftermarket heads for a hot street engine, I would choose a proven cam/head comb, like Head-quarters, Hillside/Woods or T-man and have them set the compression, and match the cam with proper valve sizing and port work to optimize output.

I thinks all thees guys will do a 106-107 either way.

If I did the over-square way, with a stock crank, i would find one on Ebay used and have it sent to darkhorse and have the engine cases bored by my Indy. and then switch out the crank, then when the rest of the kit comes just finish the top end and ride.

Or, you could by the aftermarket 4 3/8 stroke crank, and from what I have seen most will need to be sent out and welded anyway. and of course put your bored OE barrels on with the ported heads, and cams.

with a twin cam i think either way you would be happy, both are very reliable.

over 100 ci a Mikuni 45 would be my choice, but with conservative cams and compression like 10 to 1 or less a 42mm would work fine.

 

So you don't think I should go with a kit that includes heads? I will have to ask my mechanic again, but I think he said something about the stock head being unable to accept an oversized valve guide or something- btw, I won't be doing any of the work myself- I am dangerous enough with a wrench, but I don't have the knowledge to get this deep into a motor on my own, and don't have the time to figure it all out right now. My mechanic is a pretty good I think- white haired old man that does most of his machine work in house.

I will go with the larger Mikuni I suppose- I don't think the engine is gonna shrink, so might as well go big...

 

well, if you choose a cam that comes "on" in the mid range like a woods 9 or Tman 625 the 45 would be better for bigger power.

for my current setup a 45 would hurt the setup cuz the cam comes on earlier and starts to fade at 5k rpms the torque is in the lower range and the 42 works better there for higher velocity though the ports.

there isnt anything that cant be done to stock heads that would persuade me to buy S$S heads over reworking some stock ones. put the money someplace else.

 

Well, then I will have to more thought into the carb too then- I would prefer my cam to come on at lower rpms- I like roll on power rather then dropping a couple gears- I don't really drive that hard most of the time- But I do tend to carry a lot of weight in the form of luggage, and occasionally a passenger- she doesn't weigh much but it all adds up. And I do want to climb mountains with it- I haven't made a trip out west yet..

I will have to talk to him more about the heads... This is why I asked on here- I just don't know all this stuff. He may start his time clock when he sees the list of questions I come back with... Just kidding- he is a good guy- likes to talk. A stop to buy an oil filter takes about 2 hours...

 

if you like roll on power, and it sounds like you after big torque and mid range, and your riding 2 up alot with gear, then this all must be taken into consideration before you start buying parts.

For sure, id use stock heads, and id keep the compression conservative.
the cams im using now are "hot" bagger cams, the come on quick and pull really well, the heads have been ported to match the cam profiles.

I recommend that if you do head work, have the cam designer do the port work or have the cam manufacture recomend a shop that knows how to match the porting to the cam grind.


my guy is a talker too, I feel bad for him cuz i come in to BS and it is seems like the last 3 times ive been by ive been the only one in there, no bikes to work on and the phone isnt ringing much.

i try to do some biz there when i come by to BS. last time in i bought some Tman performance cams.

I like to work on my bike alot, but if i had more cash than time id let him do it all.

 

Another option to consider. Axtell 107" cylinder/piston kit, TMan heads with his 555 or 590 cam. You are going into the bottom end anyway, have the indy pull the lower unit and sent to Hoban Brother (Darkhorse) for fore case boring, true, balance, plug/weld your stock crank. They will also check rods to see if all is within spec.

I would let Hoban take a look at your crank before assuming it is junk. If you need another, I have seen stock TC crank assemblies on Ebay from the salvage vendors for $250-$300. The "oversquare" (more bore than stroke) is a great configuration for easy torque.

Talk to TR at TMan about what you are building and how you intend to ride it. Two up, loaded and up in the mountains, I doubt that he would recommend the 625. The 625, 590 555 and 525 are basically the same profile, just more lift. IIRC, the 590 intake close is 44* ABDC and the others close at 41* and the 590 duration and lobe centerlines are just a tad different. He can match up the heads with the cam of your choice and the results will be predictable.

CArb doesn't need to be a Mikuni; I run a CV44mm on my 107" and she runs fine; easier to tune as well IMHO.

You haven't mentioned ignition but you will nee an adjustable unit, like the DTT unit for the TC.

Good lick.

 

I was told the crank is junk because of damage to the spline end, and that this type of damage can not be repaired... Are you saying that might not be true?

I allready have an adjustable Screamin Eagle ignition, but I will be looking at changing that as well if needed.

What does DTT stand for? Is the CV44 the screamin eagle carb?

 

I don't know the extend of the damage and it very wll may be that it is beyond repair. All I am saying is let the Hoban techs take a look; send them a picture. If you do need to replace the crank, check Ebay as I suggested. If you are sending the lower unit in for case boring and Timken conversion, talk to John Dahmer at Hoban; they have cranks coming out of their ears and can probably make you a fair deal on a reconditioned, trued and balanced stocker; you don't need more than that.

DTT = Daytona Twin Tec.

The CV44 is the SE carb. You can also have your stock CV40 modified by Dakota Kid. They will bore to 42mm and make some other mods that make the carb a better performer for a larger displaementl, cammed engine. However, the cost is about $325 and, if you are looking at at Mikuni anyway, that's about the same price as the HSR42mm. I am must partial to the CV carb for a touring bike. search this an other forums on Mikuni carbs and see how many threads come up about fitment problems, rattling slides, tuning difficulties, etc. IMHO, there is nothing to gain with the Mikuni except the potential for issues that would be self inflicted. Believe me, there will be other issues you would rather be dealing with on a new build; why add to the list. If you must have a Mikuni, set the CV40 up for the new build, get her running good, road tested and road worthy and then make the carb swap.

Most guys tend to generally go over board, like you said "might as well go big". Just build the engine to meet your needs.

If I were you, I would consider a 95" or a 98" package on top of your rebuilt lower unit; cheaper, better fuel economy and it will get the job done nicely.

 

Yup, My mikuni slide rattles, i dont mind it much, it dosnt effect the way it runs.

Tuning is easy, but there is a design in the carb that dose not like the Harley v twin.

it usually shows it self as a hugh sag on a dyno curve, it could be an exhaust, but in the Mikunis case its the Needle jet, the tube that the main jet screws into, and those peski jet needles live in.

the needle tube out of the box is usually too large for most HD applications, and switching the jet needles makes the thing too rich or too lean either way and its never right, so I got a smaller Needle jet and run the needle that the bike comes with and it runs great!

What ever carb you get, its good to become a student of the design and understand how to adjust it.