Bonneville America Forums Forums General Motorcycle Forums Vendors Only Wiseco 988cc Big Bore 1/4" Stroker Kit

Now in stock!
More Info Here

-brent

OH
HOT
DAMN

Soon. Lemme get the bike paid off.

--Jaeger

Curious, Wouldn't you need different rods if your changing the stroke?

We just got these in today. I have a lot of ?'s that will be answered Monday when I can speak to someone at Wiseco. Details to follow...

-brent

Kerby, your question is a common one. Ford did just that when they changed the stroke on some of their car engines: used shorter con rods (352s and 390s in particular). Chevy did it when they enlarged the 350 V-8 to 400 cubes.

However, hot rodders for years have been stroking all kinds of engines, and the common way to compensate for the increased stroke is to move the piston pin location upwards - half the amount of the stroke increase. So, a 1/4" stroked Triumph crank will have pistons with the pin moved 1/8" higher.

There's a name for this distance, by the way. It's called compression height. The distance is measured from the flat portion of the top of the piston (NOT the top of any dome) to the middle of the pin hole.

Since the raw forging blanks that the piston manufacturer uses are unfinished when they come from the aluminum company (I think Alcoa does most of them), the piston company can put the pin location just about any old place it wants to.

Also, the piston company supplies new piston pins with their custom pistons. These pins are almost always shorter than stock, made of tougher material, and have a thinner wall section. Lightness is what they're after.

Remember, guys: to do a stroker motor requires you to get your crank stroked. For that, you'll need to remove it from your engine and ship it off to Falicon so they can weld the rod journals and then offset grind them for the 1/4" stroke increase.

You will also need to send them both pistons w/pins, at least one set of rings, both con rods and at least one set of rod bearings. This is so they can balance your rotating assembly. You absolutely need to have your crank assy. balanced after stroking!

One last blab on this subject, and then I'll "take off". In building a larger engine, especially with higher-than-stock compression ratio, a person really needs to consider installing bigger cams (longer duration).

The reason for this is that the smaller stock cams will be choking that larger engine. You don't need bigger cams so that you can rev your engine like a Suzuki Pro Stock drag bike; you need them to help that large engine breath.

I see by Brent's website that he now stocks those nice Thunderbike cams. While they seem a little "pricey" to me, if you've dropped the bucks on the big bore/stroker kit, you need to spend some more to do the job right.

Not putting in bigger cams will probably result in your getting serious ping in your engine, even on good gasoline. (An inexpensive work-around would be for you to install a water injection unit.)

Wow, three posts and I've not said anything about porting and big intake valves. Having done a fair amount of flow bench work in my younger days, I know the value of big valves, especially the intakes. In fact, bigger intake valves are more important than port work, especially for street vehicles. Yeah, I know - where does it end? (It ends when your billfold goes flat....)

You just saved me from a lot of typing PD, good description.

Thanks PD, I knew that something more was gonna need done. I might have gotten all giddy when I saw that post.

Ok let me ask the stupid question. Is this new larger displacement kit for use in either the 790 or 865 or is for the 865 only?

well now, i love the idea of a bigger motor was thinking of doing the 994 kit from BC. but could not find any info on this kit except from BC. the 988cc sounds good and you don,t have to cut the case.

Reading through the posts here, and seeing the complexity of the operation, it seems to me that someone could make a pot of money building these engines and selling entire long blocks with a core trade in.

It is mighty tempting. Enought to make one evaluate just how much Id like to experience the new bike with nearly 200 cc of displacement and the loads more torque and horsepower.

I suspect that this would then make our bikes.....ideal. No need to trade up for an eventual new model Triumph cruiser just upgrade to a bigger, better, stronger Speedmaster.

Its a fair investment but still lots less than a new bike.

Larry... I was thinking the same thing. It would make things soooo much easier. I know I would order one.

finally!

One of my favorite quotes: "There is no substitute for cubic money."
Mike Sr.

"This kit requires boring of the cylinders and pressing in the sleeves as well as additional engine work. Check with Wiseco for specifics."

I sent Wiseco -2- seperate e-mails anking to define "additional engine work" and got no response... can anyone help?

Robert in Utah

Here's what PapaDean posted on another forum about the stroker kit:

------------------------------
Just a quick note on the Wiseco stroker piston kit. It only contains the same parts as the regular big bore kit, except that the pin location has been moved (up) to account for an extra 1/4" stroke length.

"YOU MUST GET YOUR OWN CRANK STROKED TO MAKE THIS WORK! You can send it to Falicone Cranks back east/down south for this proceedure. (They weld up the rod journals and then offset regrind them.) You'll also have to send your pistons w/pins, con rods, one set of rings and one set of rod brgs, so they can balance your rotating assembly.

While not a cheap project, it's at least less expensive than buying a new, larger engined bike.

Oh, one also ought to get a new pair of cams to let those big cubes breath. Those aren't cheap, either.
---------------------------

I'd also add that it might be a good idea to get some larger valves put in, which can be done through Bonneville Performance. Better carbs would also be wise.

You can send an e-mail to Bill Gately at bgately@bonnevilleperformance.com . I'm sure he can answer any questions, but it might take a bit for a reply since it's still racing season.

Found some more info for you Robert on a Delphi forum.

This post from Bill Gately:

"For everyone's information the 989cc Wiseco stroker kit requires not only boring and sleeving your barrels but stroking your crankshaft 6mm--the piston kit and the bore and sleeve will run about 771.00. This of course also requires the complete disassembly of the engine, new bearings as well as a set of Carrillo rods. The cost above the Wiseco kit in parts alone is 540.00 for the rods, 180.00 for the main and rod bearings, 850.00 to stroke, straighten, polish and nitrate the crank and another 400.00 to balance it. Then there is the labor to tear down and rebuild your engine if you are not qualified to do it yourself. There is a solid 15 to 18 hours involved in this endeavor--and I am certain your local Triumph dealer will take substantially longer than that to do this job."

And the next post from another member:

BALANCE TWIN CYLINDER 600-302 $249.00
STROKE TWIN CYLINDER 600-402 $585.00
HEAVY DIRT TRACK TWIN 600-580 $795.00
SUPERCRANK MODIFICATION TWIN 600-502 $449.00
BLUEPRINT TWIN CYLINDER 600-702 $295.00
LIGHTEN & BAL ALL TWIN CYLINDER 600-652 $369.00
INSPECT, MAG, STRAIGHTEN, POLISH 600-001 $122.00

Bill, $1250 is a lot of loot for an extra 84cc, above are cut and pasted quotes for crankwork by Falicon. How are the balance shafts addressed when a crank is stroked and balanced?

I think I read in one of your posts, that your race bike crank is dynamically balanced and the balance shfts are replaced with dummy shafts?

Have you built up a stroked street motor? 270 or 360 deg? Dummy balance shafts?
-----------------------------

Bill's reply:

I agree--if you measure the work by the cc's. The additonal engine performance is significant and necessary for my purposes on the track--the street kit emulates the race engine at a lower compression--13.5:1 race vs 10.5:1 street. Either way it is what it is--expensive. The very reason I made this post. I have received several inquiries from customers who think that other people are selling this kit at a very reasonable price --but the whole story is just not being told--probably out of ignorance--or to keep the customer ignorant until they are confronted with the truth after they have made a purchase. This kit is only for those few people like myself who want to get maximum gains--100 rear wheel HP--from there normally aspirated 790 or 865 engine. Of course this 100 HP number also includes the head work, carburetion and exhaust system modifications--also very expensive.

The balancing process we use is better than most and is the same used by the NASCAR engine builders---in fact a retired NASCAR engineer does the balancing not the crank people.

Personally after Falicon trashed one of my crankshafts, during the 2005 race season, I do not use them for anything. Falicon turned a perfectly usable crankshaft into a paper weight with no refund or even an apology for screwing us in the middle of a race season.. I have 3 other sources--one is APE in Los Angeles. The problem seems to be that the crank set up is unique and because of that tooling is necessary and the labor time is excessive for these peple to make it as profitable as their in-line 4 crankshaft work. We are now considering machining billet crankshafts--and may do so in the off season.

Let me add one more thing--performance modifications are always expensive especially for a motorcycle like the modern Bonneville series that has limited potential in the aftermarket--so if anyone is not interested in performance they should not even read this post--however, if you are please note that these mods are completely in line with big bore/stroker kits, high performance head work, flatslide carburetor kits or custom exhaust systems offered for any other motorcycle.

We have built 2 stroker engines to date--one is my street Bonneville and the other is for a customer--both are 360 engines. We have of course built 2, 270 stroker engines for the track.

The counter balancing weights are removed from the shaft and the shafts are put back in place in the engine case--if you do not do this or replace the shafts with 4 slugs the cases will flex when torqued to spec.
--------------------------

Here's a dyno run of his flat track race bike:



Nice power from one of our engines, but it's going to take a lot of money to get it there.

Yikes.

And that's with 13.5:1 compression vs the 10.5:1 compression of the regular stroker kit. So you can expect less hp and torque if you have it done. IMO the cost isn't worth it, but a lottery winner might go for it. Looks like us commoners will just have to be satisfied with the 904 Big Bore.

Yes the surfs will "only" get the 904 THAT is still way out there on the atainable list... But my bike is paid off now.... Hmmmmm "Sorry hun, we can't have a photographer at the wedding, poppa needs a big bore." No I don't think that will fly....

SalMaglie, definitely appreciated reading the posts you posted, I also wasn't 100% satisfied with my Falicon experience. Turns out that they won't knife-edge these cranks, for whatever reason, so the line item that the 2nd guy posted about the Supercrank Service doesn't apply, since the knife-edging is the meat and potatoes of that service. So when they didn't knife-edge my crank, I basically paid for the 2 cylinder blueprinting, plus about $50 each for each rod to have them reconditioned and polished, then more money for the cryogenic treatment. I was disappointed about not getting the knife-edging, and then when all of the shipping, shipping insurance, and FL state tax got levied, I ended up paying $786.37 for what was basically reconditioning work. Even the Lady at the Dealership was cracking jokes about me paying almost 8 bills for a couple of lousy falicon stickers. Ah well, that stuff really oughtta hold up though.

What is knife edging?

The Falicon Supercrank is the “ultimate” crankshaft modification for knife-edge performance. The OEM crankshaft is blueprinted to the best combination of oil clearance and precise tolerance for your specific application. The crank throws are contoured and polished to a mirror finish, improving oil flow and reducing crankcase turbulence. Each crankshaft is custom balanced to the reciprocating weight and intended rpm range, for use with or without the OEM counterbalance (on some models).

That's a quote off their website.

OK so they mean it more metaphorically...

Thanks for the quotes from gately. Intresting stuff, I felt foolish for spending the extra money on the BC version of the 904 kit but rationalized that the nicasil liners were worth it.

I feel somewhat better now

Benny, I realize I really didn't answer your question, Knife Edging is actually machining the crank throws so that instead of a square leading edge, the throw is tapered and polished, so instead of slamming through the oil, it's more like cutting through the oil. Also has the effect of lightening the crank, so the thing revs more freely, and reduces the flywheel effect.

Ahhh now that makes sense

Out of all the things I was wanting done to the crank, this is probably the one that I wanted the most, next to the micropolishing of the journals. It would have definitely altered how the engine reacted to throttle, so I was pretty disappointed that they wouldn't do it to the Triumph Crankshaft. Though in retrospect, it would have cost even more money than the $786 that I did spend, so it was nice to not spend the dough.