The only problem I have with boring stock cylinders to 107 is a problem I see in the future. As emissions change the bikes are going to be running leaner, leaner = hotter. And with the minimal wall clearence I see a potential warping problem if these bikes are tuned to lean. Maybe it's just me. We do bore work at our shop as well, but if you factor the cost for boring versus the cost for the new thicker cylinders it not that huge of a difference. If you pieced together a 107 you'll have $370 for the pistons, $55 for the base and head gaskets plus whatever your shop gets to bore your stock cylinders out. Say $100 bucks a hole?? That comes to $620. So you would be paying another $380 for the thicker cylinders. Not to mention you still have your stock equipment if you want to trade your bike in and re-sell your 107 stuff. It's all a preference.

 

I'll just try to be happy with my stock "96" motor w/a decent set of cams and a good tune for 2 up riding and call it good....I think...
Maybe freshen up the heads down the road.
I don't know if bigger is always better..

 

You are right in that the leaner these new engines run, the more heat they put out but it can be corrected, and should be with a good tune. If not tuned properly, most any engine can and will have issues.

As you stated, it is personal preference, but I would prefer to take that $380 and buy a good tuning system if there is not already one on the bike.

We could debate this to death as there are people on each side of the fence on this issue.

 

I agree with you, but with the people that are auto tuning these days, I don't know. Fuel prices continue to rise and will continue to do so. The autotune people that leave the target AFR's high to get the best fuel economy out of it are the ones that might have issues, or the tuners that tune to lean, or the people that do a download. There is alot of variables to consider. The problems will occur when people get caught up in traffic, or leave the bikes idle for extende periods of time. We can make them as rich as we want, but they still need that air flow. Like I said, it's about personal preference and budget. Just because it works today doesn't mean it will work in the long run. Things change, and I think emissions will have alot to do with it. How many tuners have you heard about that just tune high TP's and hope the MAP takes care of the cruising ranges? Alot of the "canned" MAPs already seam to be lean in these ranges. It could result in trouble. And at the point (warped cylinders) that $380 a guy saved wasn't worth it. Like I said, boring stock is working fine today, and I have only heard of a few issues, but who knows what the future will bring. Personally, i'd rather spend a few extra and not cut any corners from the start. But that's just my opinion.

 

HarleyTuner,

What are your numbers on your build and do you have a chart posted on the forum?

 

I'm changing cams again, but here it is currently.

 

You make some very good points harley tuner, THANKS. One of MY main reasons for going with the heavier cylinders is the relatively small difference in overall cost between the two. When looking at a cross section of a bored cylinder vs. an after market heavy wall cyl. theres a huge difference. Another reason is I'd like to reduce friction. friction = engine heat and faster wear to the cylinders. Revolution Performance, with their nikasil technology is suppose to have about 1/10th the friction. If anyone has some before and after heat numbers, I'd like to hear from them! Their clearances are also very tight, .0015. I like a tight hole, it lasts longer.

 

I will let you know after I've installed them. they should arrive late next week sometime. what do you think of them since you're already using them.?
Did you do any head work at the same time ?

 

Impressive horse power on a 110". Many thanks!

 

Thanks, but I think there's still more in it, I plan on doing new cams and TB & injectors before Spring.