Bonneville America Forums Forums Technical Forums Performance Mods QUESTION REGARDING BIG BORE KIT

Let me first say that I dont' even have the permanent tags on my new toy, and I'm having plenty of fun with her as she is, but I can't help but wonder...

So I know some of you folks have put in big-bore kits. My question is how long have you had them, how reliable are they, and what have you heard about other long-term issues? I have no intensions of getting rid of this new scoot for a long, long time, but I'm going to want to squeeze a bit more juice out of here in a few years. Just looking to see what my options are.

Thanks! Rubber side down!

--Jaeger

Still waiting for someone to post an actual dyno result of a big bore installation.

I think we can count on Dinqua to do that at some point.

I am getting mine dyno'd on the 15th, I'll post the results then.
So far so good though. About 4k+miles on her now without a single oil drip or burp. Stronger for sure.

I dropped one in shortly after getting my Speedy...I think the biggest differnce was the amount of Torque...

At first I thought the Speedy, was a little weak for riding two-up (with me at 210 and my gf at 120)...but now it's well within the acceptable range.

Well, my concern/interest is long-term reliability issues. I dunno if the kits have been around long enough to really be tested properly, but... Well, it looks basically like the new 2005 SMs are simply upgraded 2004s with the big-bore kit. Hell, they're the same weight! I just want to know if the engine and frame will actually take that sort of "abuse" without reducing their ultimate lifespan.

That, of course, and I want to see some hard numbers (as well as anecdotes) regarding the improvements my $1k worth of parts and labor will bring!

--Jaeger

I put the BB kit about the same time as Dinqua and then blew a head gasket. Turns out it was my fault, missread the manual. No dyno results yet but will have them soon as I get a few things out of the way. I will say that the torque and speed out of it now is unbelievable. Dinqua knows and he's not kidding about crushing nads with the BB Speedy. I have shocked, smoked, embarrassed, surprised many and crushed nads myself. I have some leaks I'm screwing with(my fault) but ya know, I would do it again.

Well if it's any comfort to you, Wiseco has been making piston kits like this one since 1941. The kits for these particular bikes though haven't really been around long enough to have 50,000-100,000 mile longterm tests to determine actual reliability. But Wiseco is an easy company to trust when it comes to big bore kits. They would'nt have lasted 64 years if they weren't. They're definitely a well respected company.

I thought about doing it, but decided against it for now. I'll just wait till it needs it. Hopefully that won't happen for another 60-70,000 miles. Like you, I plan on keeping my bike for a very long time. I think they're going to have to pry it from my cold, dead fingers.

The only additonal recommended mod I've seen for the Wiseco kit is to improve the clutch with a Barnett(another respected company famous for their clutches), or to just put in heavier duty clutch springs.

There's been a couple of dyno runs on Bonnevilles that I know of. One reprot had 75 hp at the rear wheel, but that was with Mikuni carbs installed. Here's an actual dyno run that I got from the New Triumph bonneville forum on Delphi.

-----------------------------
The blue line is a '02 T-100 (reference curve form Dynojet)
= 53.08PS / 55.56Nm at the rear wheel.

The red line is my '03 T-100 before the installation. My setup: TOR's, Dynojet Stage2 Carb Kit (DJ114 main's), Snorkel removed and UNI.
= 52.34PS / 53.89Nm at rw.

As you can see, no remarkable difference (only the sound...)or a weak engine.

The green line is my T-100 after the installation. My setup is the same like above but DJ118 main's.
= 61.61PS / 67.79Nm (at 3300rpm) at the rear wheel.
Now I can feel the difference!

dyno 1

dyno 2

This was from a guy out of Switzerland running on a new dyno, so take it for what it's worth.

The dyno charts seem believable to me. Am I the only one who gets all emotional over the VERY FLAT torque curve these engines have? If only I could do that with my truck engine!

Meister Jeager,
Sal has already hit upon the Wiseco reliability overall so I won't add to that. However, jojje, the Wild Swede, has been running them in his 100hp turbo bonnie for a couple years and I don't think he's really blown one up yet. And he beats the dog meat out of it on the drag strip on a regular basis.
I see absolutely no reason there would be any issue with frame strength or torque issues either.
The new 2005s with the "900" motor IS NOT the same. Not even close. It is merely a slightly bored 790cc made to be an 865cc motor. The Wiseco is a real 904cc kit. So with Triumph math that makes it a 950, right? Also, with the wiseco sleeves you install, I bet you have room to go another 10-15% over in the future if needed.
I have done many big bores in the past, mostly MX bikes mind you, and have always used Wiseco producst, never had to replace them twice. Never had one blow up, leak, rattle, implode or anything else happen to the bike or framework. Just my experiences though.
I would never have done this if there was even the slightest chance of it being harmful, especially in the long run, as this is a mod you cannot just remove and go back to stock. Well, not without buying a complete new head and cylinder assembly.
No worries friend, I believe it is as safe as can be and well worth every penny and minute of time it takes to do the job.

SalMagie & Dinqua (and everybody else)--

Wow. Ok, y'all have pretty solidly convinced me, both in terms of history and anectodal evidence. I suppose that answers my question as fully as can be!

Basically, I know I'll want to upgrade to a literbike (or equiv) sometime in a few years, but I really, really REAAAAALY like ny new baby... and rather than having to buy a whole new bike, it's nice to know that I'll be able to modify the engine to get the power I'll want. Furthermore, I don't want to get a physically bigger bike -- I LIKE to corner, quite a concept to some I guess...

Dude, I gotta tell ya, the thought of spanking a Magna is enough to get me a little excited -- like, in that kind've unsavory, filthy way that bikers get about motorcycles. Tee hee.

Thanks for the input, and rubber side down, folks!

--Jaeger

My biggest question with the Wilde Swede, is how the nuts did he get his ignitor to spin higher?? He sent me some pics where he'd moved his ignitor pick-up (inside the RH engine cover) over about an inch to advance his ignition curve, and I read his post on his forum, that'd be something that I'd still be interested in! Same thing with the 989 tracker on the bonnevilleperformance website, the guy's quoting an HP value @10,000 rpm. While that sounds a little TOO high, wish I knew how they did it!

Besides the increase in displacement, a Wiseco big bore kit gives you a cast iron sleeve, and foreged pistons! That's a win-win deal.

I've read somewhere that, over in the States, there some people making 920 & 950 BB kits. Sorry I can't remember where I got that from. Ooh, that's very nearly a litre. Should be realy cooking!

Matt Capri and his group at SouthBay Triumph (SouthBay Moto) make their own kits. If you do some research you will find out how "superior" they are as claimed.
I've only ever heard of one person with one and it blew up. Hm, that must have been rider error.
If you call SB they will tell you what crap the wiseco kits are and how the ALL leak and explode.
I guess if you can't tell folks how good yours are, just tell them how bad the competition is instead. Besides, what could Wiseco know? They have only been making high performance pistons for 40 years. SB has been doing it for many months!
This is just my opinion as I have discussed this with SB a few times and am given the same line of BS every time I talk to them.
You can make your own decision though.

I fully agree with your comments about Wiseco; brilliant kit. I too, never trust any bugger who slags-off the competition instead of proving their own product.
Just looked up & found a mention in Torque #33, page 17: RR Performance in Quebec built an SM running 920cc @ 10.5:1, as well as modded cams & porting. There are no details as to sources though so, you'd have to contact them direct. No good to us in UK though as the duty would buy a house.

The 10.5:1 ratio is a dead giveaway that it is a Wiseco kit, that's what theirs put out.I bet they even took a bit more out of each cylinder to get the little extra 18cc's. I also had my head done, but no cam work....yet. Gotta save somnething to do for the wintertime.

Its the 16th... The results of the dyno test are...?

I'm thinking once again the dyno did not produce the anticipated results.

It was pouring rain and I did not go to the dyno dood, sorry, I will get it done asap and post results. Even if they're not what I anticipate, I still post them, no worries.