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I wanted to post this as I found this also very informative. From powroll.


If you ride as fast as you type, you're probably maxing out that stock Warrior pretty quickly! Hit that 'enter' button a few times in between sentences, ok Rich?

From your description, it definitely sounds like you're definitely over-revving and floating the valves coming out of turns.

Yamaha didn't give the Warrior a rev limiter - the little 350 will basically rev until the valves float and break, or the rod lets loose. Because there's no rev limiter, proper gearing is vitally important to engine longevity and the fastest possible lap times.

If you look at a dyno chart on the Warrior, the peak horsepower occurs at about 7500 rpm, after that, power drops off dramatically. If you are revving the engine much past 7500, you will actually be losing power (and speed).

Flat Track racing is somewhat of a chess match - those who have proper gearing for a specific track will go faster. Install an inexpensive tachometer (they have a wire that wraps around the spark plug wire to give engine rpm readings) and do some testing. You want to reach peak rpm at the end of the straightaway. Gear up until you are in top gear at no more than 8,000 rpm at this point. This setup will give you maximum power and speed for the current horsepower of your engine – an added bonus is increased longevity!

Once you’ve got gearing set up correctly, if you still need more power, the 365cc kit is a very good starting point. Because it will increase torque and horsepower, you may be able to gear up even more once it is installed.

Cams can help or hurt the Warrior. Because of the two valve design, even a minor change in lift and/or duration on a cam can mean radical changes in how the engine responds. Always be very careful to match a Warrior camshaft to other engine modifications, and take the recommendations of the manufacturer as to the cam they recommend with whatever bore and/or stroke you’re running.

Purchasing a cam that is specifically designed for the engine displacement and compression ratio of your engine is vitally important to gaining the best power AND reliability.

We have not tested the Hot Cam for the Warrior. We do have camshafts that we grind specifically for our bore kit and bore/stroke combinations. With the Powroll 365cc kit, I usually recommend our 12742 torque grind camshaft. However, if you’re just using the engine specifically for Flat Track, I’d use the #12708 cam & #24028T springs for more mid and top end power.

This setup, along with new valves, a 3 angle grind on the seats and just a clean up on the ports, you’ll see at least a 40% increase in horsepower over what you have right now. Not bad for about $500 (with your core refund).

Exhaust systems are easy with the Warrior, since Yamaha gave the quad a HUGE stock headpipe that works great with the addition of a freer flowing muffler. We recommend the White Brothers E series or any of the Supertrapp lineup.

With all that added horsepower, you’ll need to gear up again!
 
I always read the White Brother E Series exhaust is the best exhaust for the Warrior. Even Mickey Dunlap told me that. I went with the Yosh because I like it. Not many people like the look or sound of an adjustable plate exhaust but they work the best for this motor.
 
Dave I've read and talk to a couple engine builders and they have all said they really like to use adjustable exhaust systems as they seem to make a very board power band. Supertrapps the one that I've heard the most on.
It's all about tuning the airflow so the engine doesn't have to work so hard to make hp/tq.
 
I wanted to post this as I found this also very informative. From powroll.



Cams can help or hurt the Warrior. Because of the two valve design, even a minor change in lift and/or duration on a cam can mean radical changes in how the engine responds. Always be very careful to match a Warrior camshaft to other engine modifications, and take the recommendations of the manufacturer as to the cam they recommend with whatever bore and/or stroke you’re running.

Purchasing a cam that is specifically designed for the engine displacement and compression ratio of your engine is vitally important to gaining the best power AND reliability.

We have not tested the Hot Cam for the Warrior. We do have camshafts that we grind specifically for our bore kit and bore/stroke combinations. With the Powroll 365cc kit, I usually recommend our 12742 torque grind camshaft. However, if you’re just using the engine specifically for Flat Track, I’d use the #12708 cam & #24028T springs for more mid and top end power.

This setup, along with new valves, a 3 angle grind on the seats and just a clean up on the ports, you’ll see at least a 40% increase in horsepower over what you have right now. Not bad for about $500 (with your core refund).

Exhaust systems are easy with the Warrior, since Yamaha gave the quad a HUGE stock headpipe that works great with the addition of a freer flowing muffler. We recommend the White Brothers E series or any of the Supertrapp lineup.

With all that added horsepower, you’ll need to gear up again!
Click to expand...

OK... well, I've got some issues with that response, but I dont have time right this moment to further comment.

I'm off to bed....
 
does $500 sound about right for a 366 cc setup? i am talking JE piston, bore, WEB .390 cam, KW valve kit, head job, lightened flywheel?
 
What are the break in recommendations (jasonP and Dave)? I just put in a 366 and web390 and looking for others suggestions.
 
What are the break in recommendations (jasonP and Dave)? I just put in a 366 and web390 and looking for others suggestions.
Click to expand...

run a break in oil that is non synethic.
No idling for long periods.
Heat cycles are good.
No constant throttle.
Don't hold it wide open very long with the first tank of gas.
Don't lug the engine hard.
Change the engine oil at least after the first 10 hours.
Make sure to check to see if you have oil pressure at the plug in the top of the head..
 
Ok....this was coming........make it as simple as you can for noobie engine guys.....what is a great all around rebuild? Need specific part names and numbers if possible. Along with what to do to the head. What to buy? Still lost and don't want to waste my money. Gas upgrade not a problem and Edle carb is going in. What piston, gasket, and cam should I buy. (I really dig jasonp's set up)

Thanks.
 
deadlastracing said:
Ok....this was coming........make it as simple as you can for noobie engine guys.....what is a great all around rebuild? Need specific part names and numbers if possible. Along with what to do to the head. What to buy? Still lost and don't want to waste my money. Gas upgrade not a problem and Edle carb is going in. What piston, gasket, and cam should I buy. (I really dig jasonp's set up)

Thanks.
Click to expand...

I think it would be pretty sweet to see a 366cc 12:1 compression JE piston with a .450" Megacycle cam. Just have the head freshed up with a 3 angle valve job and you are good to go. Maybe the alba kit would be the way to go.
You would get the torque from the piston and the top end from the cam also might be able to run on high test as the cam will bleed some compression off. You could also try runing one colder numbered plug to help this.
After riding with both cams a web .390 and Mega .450 I would choise the .450 for the fun factor. Doesn't have quite the low end of the .390 but the mid and top end is really fun!
This is if your not looking to do a stroker.
 
Ive got the stock bore with the JE 12.1 comp piston, 3 angle vavle job and a little port work. No Cam stock crank and rod. Pulls good down low, but a little lacking up top
 
"You could also try runing one colder numbered plug to help this." Lost me one again?

So far i have planned.....85.00mm boar, JE 366 12.1, .450 Mega cam, 3 angle valve job, HD kw springs. Good start?
 
deadlastracing said:
"You could also try runing one colder numbered plug to help this." Lost me one again?

So far i have planned.....85.00mm boar, JE 366 12.1, .450 Mega cam, 3 angle valve job, HD kw springs. Good start?
Click to expand...

Yup, 85mm bore is 366cc. Remember to that once you go this far boring the cylinder (sleeve/jug) you will have to have a new one pressed in if anything happens to the top end where a hone job won't take care of freshing up the cylinder. Also Hotrods stroker works off 84mm bore piston so again just thinking ahead. FST and CWR both send a new sleeve with so no worries if you are going that route.
I think this is a really good start. If fuel is more of a concern then I would stay with the 10.5:1 piston. I like it because I could play with the deck height and still be within reasonable compression.
Yeah so you run a cooler plug to help pull heat from the combustion chamber and out to the head. When running a lot of compression it makes tons of heat and this being a air cooled engine make it even easier to have detonation (knock or ping). Thats why on hot days you hear people running these pistons have to put 100 octant fuel in as it is less volatile and has a higher ignition temp then low test fuel.
Anyway, 12:1 JE 366cc. Mega 450" cam, Kibblewhite HD springs, 3 angle valve job and stock Yamaha gaskets should work great for you.
So if you are running a DR8 NGK plug go to a DR9 one cooler after the mods.
 
surftouch said:
Ive got the stock bore with the JE 12.1 comp piston, 3 angle vavle job and a little port work. No Cam stock crank and rod. Pulls good down low, but a little lacking up top
Click to expand...

If you look under the camshaft spec thread in this under this section you this will help you pick one.

I would say something like a web .430 or Megacycle .450 if you are wanting a mid to top end horsepower cam. But again it all depends on what you want.
 
Also Hotrods stroker works off 84mm bore piston so again just thinking ahead. FST and CWR both send a new sleeve with so no worries if you are going that route. FST and CWR are what/who?

Is it a necessary to get a new sleeve after the boar? Most machine shops will be able to do that bore and 3angle job no prob right? Does the shop also have to install the cam and springs? Or can I/should I do it? Trying to save what money I can.

So with the mods I have planned I will have to run high octane fuel? should I stick to a 10.5:1? Will that have a different effect on the power. I'm Running an IMS tank so that should help with this gas issue, less fill ups, and hold more of what ever fuel I'm running.

I want to do the engine mod so that I dont have to worry to much about how its runnin do to certain weather conditions. Also with all that done what will the new HP and cc be, roughly?

Sorry for the questions but thanks a ton for the help.
 
deadlastracing said:
Also Hotrods stroker works off 84mm bore piston so again just thinking ahead. FST and CWR both send a new sleeve with so no worries if you are going that route. FST and CWR are what/who?

Four Stroke Tech (aka Mickey Dunlap) 446cc stroker kit
Cycle Works Racing (aka Greg) 460cc Stroker Kit

Is it a necessary to get a new sleeve after the boar? Most machine shops will be able to do that bore and 3angle job no prob right? Does the shop also have to install the cam and springs? Or can I/should I do it? Trying to save what money I can.

No they bore the sleeve then hone it to the size piston you have.
I'm just saying that 85mm is the largest bore you can go on the stock sleeve...
Yes most machine shops should be able to freshin up the head with a 3 angle valve job and install the springs. Also should put new Yamaha valve stem seals in.
You could instally the cam your self but you have to press a bearing on the end of the cam, if you neverous about doing that then I would have them do it.

So with the mods I have planned I will have to run high octane fuel? should I stick to a 10.5:1? Will that have a different effect on the power. I'm Running an IMS tank so that should help with this gas issue, less fill ups, and hold more of what ever fuel I'm running.

Honestly it is hard to say what type of fuel you will have to run as there is a lot of things that can effect what octane you have to run. I believe it is around a 2-3 hp difference going up to 12:1. Again I'm just taking a good guess. If you can find 93 octane with a one colder plug with a good oil cooler you should be ok with a big cam. Might have to jet it a little richer to help cool the engine as well. I would consider a rev limiter as it is really easy to over rev the engine after doing this. Also want to gear up one tooth on the front sprocket to keep the engine in the "meat" longer.

I want to do the engine mod so that I dont have to worry to much about how its runnin do to certain weather conditions. Also with all that done what will the new HP and cc be, roughly?

366cc and around 29-34 hp per given engine tune and intake and exhaust mods.

Sorry for the questions but thanks a ton for the help.
Click to expand...
 
i almost have the exact set-up that jason has except i did not go with that .450 cam. i have the cam and thought of putting it in but for some reason i dont feel safe doing it. but i like the setup i have now. great torque but top end isnt quite as strong as my old setup but doesnt really fall off at all. i have 13-40 sprockets on 22" tires and it will now pull the front end off the ground in first gear if rpms are just off idleand if you can get traction. before it would never do that.

when i still had my stock carb on, there was a spot in the mid range that would hit and it would just take off and was unreal. i loved that. but it also had a spot that would miss and carry on in the rpms and i could barly ride it. so i bought an edelbrock. it does not have that hit anymore but i havent adjusted the carb at all since i put it on so i think if i spend some time with it, it will come alive even better.

but i do like the setup, great for woods and ripping around. i would like to try megacycles mid-range cam because i dont want all my power in the top end for i do just creep through woods a lot. i like my power where from idle it just pulls hard and you dont have to be in the mid-range or higher for the power to come on. hope this helps a little, sorry for being so long
 
91warrior said:
i almost have the exact set-up that jason has except i did not go with that .450 cam. i have the cam and thought of putting it in but for some reason i dont feel safe doing it. but i like the setup i have now. great torque but top end isnt quite as strong as my old setup but doesnt really fall off at all. i have 13-40 sprockets on 22" tires and it will now pull the front end off the ground in first gear if rpms are just off idleand if you can get traction. before it would never do that.

when i still had my stock carb on, there was a spot in the mid range that would hit and it would just take off and was unreal. i loved that. but it also had a spot that would miss and carry on in the rpms and i could barly ride it. so i bought an edelbrock. it does not have that hit anymore but i havent adjusted the carb at all since i put it on so i think if i spend some time with it, it will come alive even better.

but i do like the setup, great for woods and ripping around. i would like to try megacycles mid-range cam because i dont want all my power in the top end for i do just creep through woods a lot. i like my power where from idle it just pulls hard and you dont have to be in the mid-range or higher for the power to come on. hope this helps a little, sorry for being so long
Click to expand...

Yeah when picking a cam it basically is up to what you really want out of the engine and where you want the power. Where you ride the most and what RPM do you want.
I found the web .390 is a great cam. Great all around power and fun. I found after switching to the .450" Megacycle I wouldn't go back. I just love the hit of the mid and top-end. It does give up a little on the bottom. But it is always a trade off.
 
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