Bonneville America Forums Forums Technical Forums Performance Mods Big Bore or Out

I can't deny it anymore. I need more power, but not Rocket III Power! Like many of us, I love my TBA but she's just lacking the oomph I desire. So I've spent time thinking of selling her and getting a Sprint ST, ZRX1200, or even the true dark-side for a Harley.

But then I thought, why give up my baby and several more thousands of dollars when I can bump this baby up from 765 to 904!

The hesitation is anyone who was at the Georgia rally has seen what can go wrong with performance mods. That would be the worst nightmare imaginable.

So here is my question. I'm looking for a turn-key solution, which can take her apart, bore her out like a $20 New Orleans ******, put her back together, and have her back to me with carbs jetted, tuned, and running like the bike I want. The caveat is that I would prefer someone who has done it before with a TBA, the WiseCo kit, and knows the ins and outs.

I've heard some suggest WiseCo themselves to do it, which seems like a decent option? But then I still have to find someone to take her apart and put her back together.

I'll talk with Triumph and WiseCo as well (being in Georgia you would think TNA would have someone in mind), but like all things I figured best to check here first.

So any advice?

You probably won't get any advice from Triumph North America, that would be like them endorsing the work. Start with the dealers and the local independant bike shops.

Be patient,
We here at Triumph will deliver, soon.

My two cents worth, you'll be wasting your time trying to talk to Triumph NA about it, they won't even go near what might be a quasi-endorsement of such a performance upgrade. FWIW, my dealership (D&D Cycles in Pensacola, FL) markets their own line of re-ground camshafts, their own proprietary 904 Big Bore kit (costs about twice as much as the Wiseco Kit), and they also sell and install the Keihin CRS carburetor sets. Take a look at their website:

www.danddcycles.com

they list their prices for the BB kit, Carbs, and Camshafts, they will install all of the stuff, and would probably be as close to "turn-key" as you can find, although, I personally wasn't all that impressed by their jetting of my carbs when I bought my bike.

So, what you do is buy the Wiseco kit, load your bike with large amounts of exotic beer, and head for Dinguas house. He's got a lot of experience with that stuff.

I got my bike serviced (1 yr.) at D & D in Pensacola. Dink (owner/head of service dept.) showed me their big bore set up. They have a stock of 790 cylinders and take yours as a trade on a bored one. They do not use steel sleeves in the aluminum cylinders as the Wiseco kit. Their cylinders are re-bored and re-nickeled to accomodate the 904cc heads. So, you have a bigger, higher torqued engine made exactly like the factory with the same anticipated lifespan. No dissimilar metals, etc. It costs more but seems like a much better way to do it.

I'm not making any drastic changes for awhile. I'll see if anything new comes out next year. I might let them redo the carbs, needles, slides, etc. first.

That's exactly the kit that my ride is getting, I think the alot of the cost difference between the D&D kit and the Wiseco, is the cost of the nikasil plating, and the fact that you're kind of paying for the cylinder block labor upfront. Also, FWIW, he offers two sets of pistons to accommodate either 10.25 to 1 or 12.25 to 1 compression ratio; I gather he uses the 12.25:1 set-up on their dirt-tracker. On the plus side for me, since my engine is already in pieces because of the oil pump gear fiasco, I won't have to pay for that much labor for him to do the Big Bore kit.

Michael, I would definitely add D&D's big bore kit if my engine had to come apart. I didn't know about the two compression ratios - I would have to stick with the 10.25. All that extra torque sure would be nice. The total cost for me from scratch is over $1100. I'm probably ok now, have to wait and see.

Since my engine was coming apart anyways for Triumph to decide if they were going to give me a warranty extension, I figured what the heck, it was my way of making lemonade out of the lemons that those stupid nylon oil pump gears gave me! The dealer offered me the choice of the two piston sets, I told him that I'd be more than happy with the 10.25:1 set, don't see the reasoning behind running the 12.25 compression on an air-cooled daily commuter. My costs for the big bore kit will run just under a grand because the engine is in pieces, and the dealer included the big bore pistons when he sent my crank and rods to Falicon in Clearwater, so that they can be balanced with the crank. Can't wait!

So sounds like Dingua's the man in regards to these mods. The question is this: Do I spend the money for the WiseCo + Cams (that's what $1,200) plus labor (So maybe $2,000+) to build a Triumph 900? Or do I throw in the towel on waiting for Triumph to EVER come out with normal sized cruiser?

I guess the question is 1) Do I give up reliability with the wiseco kit, based on the Georgia Rally, I'd have to say yes. and 2) Assuming everything else is working well does the added 105 cc's make enough of a difference that I'm happy long-term, or will I still want a bigger bike.

Here's my thought. There is simply NO substitute for a V-8. Supercharge/Turbo Chare, DOHC's, anything on a 4 or 6 will pull like a V-8. Is that what the Big Bore kit will do?

Do I give up reliability with these mods?

Personally, I'm waiting to see if Triumph comes out with their rumoored 2/3rds Rocket. I went to a local bike night yesterday and parked next to a Rocket III. My bike looks small next to it, and much better IMO. But I need a slightly bigger bike anyway to haul around my wife and I. Still refuse to give up the Speedmaster though, it's just too fun to ride.

Hard to say yet on the reliability of the Wiseco kit. There just hasn't been enough bikes done, and more importantly enough miles on them, to gauge just how reliable they are. Jaymo's bike did throw a wrench into making this mod, but if you look at the history and reputation of Wiseco...a company that's been around for over 60 years...that's a big plus.

IMO, if you can't suffer the consequences of a Jaymo-like failure, then don't do the big bore.

I think Pat told me that Wiseco wasn't doing the machining work anymore and that is why he is now using a local machine shop. Initially I think it was that their cost went up but now I don't think they are doing any of the machining at Wiseco. I am the only one that currently has had catastrophic failure and I would point out that it was largely due to the break in and blowing oil without realizing it. I made the trip to GA 2 days after the install and we were doing a constant 90+ not a great way to break in you would have to agree. Matt was blowing oil too and re ringed and broke in properly and is now living large with the big-bore Wiseco with no issues whatsoever and Pat's bike has been flawless for 2 years running now. I wouldn't have any reservations with the reliability of the Wiseco stuff personally and I have been to the dark side - truly!!!

weisco uses liners, but you also get a forged piston which imho is the way to go

Frank

Man runner, it's like you're speaking greek to me. I really need to stop working so much and learn more about the inner workings of my bike.

I rode her in this morning and I just can't see giving her up. I'm going to have to go for the WiseCo Big Bore. I'll run that a while and then move to the cams later. That way if there are any problems I'll be able to isolate.

Jaymo, I appreciate the advice. You truly have been to the dark side and that scares the heck out of me. There is a nice shop up the road who builds custom bikes. Although they're kind of a harley crowd, I've got to believe that they have a good machine shop. I'll talk with the dealer about down in Newnan about doing the work.