440/450 Stroker Owners

[jalexa77]

I am seriously considering building either a 440/450 stroker w/all the goodies.

Buying a new quad is not an option, and I'm not looking to build the fastest quad. All I'm looking for is a reasonably fast machine that is reliable.

Are the small displacement strokers worth the money? Any reliability issues? Good power? Or should I simply go with a high compression 416/426 w/HD con-rod?

The cases on my machine are already split (replacing third gear).

Thanks for the replies

Jeremiah

[UglyMotha™]

i'm running a 450 stroker i built the engine but my machining and parts came from lazarus at gt thunder my engine has a 416 bore and a 7mm stroke

i prefer it over the big bore strokers small light piston so she revs quick but can still lay down the torque

give this guy here a call he can tell you what you want 330-674-7122 thats the num for gt thunder

[hondaracer31]

I have a 440, 416 bore with a 4mm stroke. I love it, it'll run with piped 450's. They have more on top, but for MX it's more than enough.

[NacsMXer]

I have the same stroker kit as UglyMotha. All the accompanying goodies are in my sig. I had Laz at GT Thunder personally build the entire motor last time around. No reliability issues what so ever so far, it has been every bit as reliable as stock. I uses a long +7mm stroke with a custom short skirt 87mm (416) piston so it still revs hella fast for such a long stroke. Strokers have always been notorious for being slow-revving motors, but this kit breaks all the rules! I am very pleased with this setup, it was either buy a new 450 quad (out of the question), or rebuild a competative motor to compete.

This is the answer to keeping the 400EX on par with the new 450's. It is a completely custom kit, no other stroker kit will compare except for the big bore 465 and up kits, which are not AMA legal by the way. If you plan to build yourself, you need to send in your crank to be stroked and beefed up. The lower cases will also need to be machined for proper crank/rod clearance.

[jalexa77]

I will probably end up sending the crank and cylinder to Powroll.

Hondaracer31--Did the 4mm stroker require any case work?

For those w/the GT Thunder kit--what was the approx cost for the crank, crankcase, piston and cylinder machining?

Thanks for the replies.


BTW--Anyone running a lightened flywheel w/the stroker?

[NacsMXer]

For the prices from GT Thunder, email Lazarus directly, he always gets back to you promptly if you contact him during the work week. Lsommers@bright.net

I would tell you the price, but I paid for all the motor work at once so I don't know the exact prices of each component.

Oh, and no cylinder machining required, the kit uses a 87mm (416) bore, so the stock jug will handle it if you haven't already bored beyond that. The crank is the only thing that needs to be machined to clear the crankcase.

[underpowered]

on a +4 stroke, the only mods we had to do on my buddies is trim the counterbalancer and part of the skirt on the piston. we built a 460 stoker, 440 bore with a +4 stoke. very fast quad. for being a big bore, high comp(13:1), stroker motor it is one of the quickest reving motors i have seen. it even revs faster than one of our other friends YFZ. it is a mean machine and has not had any problems out of it yet.

[hondaracer31]

Mine is all Powroll and there's no machining needed. They have a new rod designed just for the stroker so clearance is not an issue. Everytime I ride this thing, I'm impressed with how well it runs. I don't need a new 450 as long as I have this.:devil:

[jiffers]

i have just built a gt thunder 452 stroker that laz kindly sent to the uk for me and the was no machining to the cases to except the crank and it came with a modded counter ballancer just need to ride the damn thing now

[UglyMotha™]

Originally posted by NacsMXer
The lower cases will also need to be machined for proper crank/rod clearance.



Laz machines the counterbalancer not the cases the cases are fine the way they are


also i'm running a a lightened flywheel with my stroker its the ultralight mod from rocky ridge racing and she revs unbelievably quick

[NacsMXer]

Gotcha, I had it mixed up there. Which cam are you running in yours?

[underpowered]

When we built my buddies stroker motor, we had a hard time finging pistons for it. everywhere we checked wanted us to buy 4. luckily we found someone on here that had a spare and let us buy one off of them for a great price. Where di you guys get your stoker pistons at? i would like to build a stoker but dont want to have to buy 4 pistons or spend almost $300 on one piston.

[hondaracer31]

The pistons for mine cost $280 each. If you find a good one cheaper, let me know.

[NacsMXer]

Most stroker kits use a custom piston so the added stroke doesn't cause the piston to ram into the head. Laz had JE pistons custom make the piston for the GT Thunder kit. It has a short skirt and a relocated wrist pin hole to bring it back to the correct deck height.

[underpowered]

yeah, it took us a while to find a piston with the wristpin hole moved up 2mm. i was just wondering if anyone stocked them or knew of a cheaper one. a CP piston from parts unlimited is $255. we paid $150 for one from a member on here because it was a spare from when he special ordered some.

[stalefish_132]

mine is a 87mm (416) piston with +4mm stroker crank. with porting and XR400 cam, FCR39mm carb, full exhaust man it goes.
the guy who built the engine says its around 48hp range but man its got torque. i would recomend this combo but what others have posted is good to, you cant go wrong with a stroker:devil:

[NacsMXer]

Originally posted by stalefish_132
mine is a 87mm (416) piston with +4mm stroker crank. with porting and XR400 cam, FCR39mm carb, full exhaust man it goes.
the guy who built the engine says its around 48hp range but man its got torque. i would recomend this combo but what others have posted is good to, you cant go wrong with a stroker:devil:

Man if yours is 48 fwHP, then mine must be to the moooon! :blah: I'd say I would be lucky to produce that with the setup in my sig :uhoh: Then again, i've never got it dynoed before so you could be right :chinese: I do know that HP doesn't come easy.

[modracer5]

I had the same problem finding pistons for my 465. 89mm X +4mm stroke. what I did was take an off the shelf 11.5/1 wiesco piston and cut .100" off the top then recut the valve reliefs. Piston is still close to .200" thick in the dead center witch is the thinnest part. the removed weight off the piston really helps this motor to rev even faster. I raced 9 gncc races on this setup year before last plus all kinds of local stuff, 5 gncc races last year and motor just got freshened from top to bottom.

[UglyMotha™]

Originally posted by NacsMXer
Gotcha, I had it mixed up there. Which cam are you running in yours?


stg II, i'm thinking bout switching it up to a hrc

[jalexa77]

Thanks again for the replies.

I have contacted each Powroll and GT Thunder, now it's time to decide whether to go w/a 4mm or 6mm stroker....:confused:

[Jonesy]

My friend has a 400ex with a 440 cylinder and a 4mm stroker crank and rod. So technically it's a 460ex. Sure it has a 42mm carb, larger intake valves, cam, msd ignition, stroker cam, and a 13 to 1 JE piston. But let me tell you this. For a bigger bore, there is NOTHING slow reving about that quad. It revs to 10grand literally before you can snap your fingers. If the motor is built right, it will rev quick. Promise you that. Dependability wise, the motor has been together for over 6 months and hasn't had a wrench turned on it yet. He does less work on it now than when it was a 406. If you want it done, call Walton Universal Performance at (859)-485-1100. He can set you up cheaper than anyone I know.