I need your advice! I am having some work done on my quad, a 98 300EX. I was going to have a shop put in a new piston, rings, cam, and rocker arms. They suggested that since I needed a new piston, and if I wanted a little more power, I could go with a Wiseco 11.1 High Performance piston and cam. If I do this, will I still be able to run well (keyword here is well)with the stock carb with regular gas? The shop says that it should be no problem, but I want some real world opnions. Slapping on a new (larger) carb is not possable at this time so it is either the Wiseco piston and cam or go with the stock 8:9.1 Honda piston and cam.

Everything on the quad is stock except the pipe. It is a DG pipe with Supertrapp exhaust and spark arrestor(12 rings). The shop is also rejetting all the jets for the pipe.

Thanks.

 

Although the stock 300ex carb is very restrictive, you an still run it. I am guessing the cam is just a mild grind, and you are probably not going to port it, so you should still be fine. 11:1 is not considered high compression in an ATV engine, and 93 octane should run without problems. For you to need all of these parts already, what happened? Usually lack of changing oil is the only thing that would make these parts wear this quickly. Just wondering so you aren't charged for something you don't need.

 

Thanks for the info. I am glad to hear this. A friend of mine thinks I will have to change out the carb and run racing fuel if I put in the 11.1 piston. By the way, will I notice the increased power or will it just be very slight?

since you asked, here is my story;

Well, it was a combination of heat (way, way too lean) and dirt. I bought the bike used from a local dealer, and it already had the pipe on it. I did not know too much (anything actually) about jetting at the time so I didn't worry about anything. About a year ago,(I had the bike a year already) I was out at a place called Ocotillo Wells and I guy I was talking to said I was running way too hot. The pipe is all rainbow blue at the head, but it was that way already when I got it so I figured the guy was crazy. This got me thinking though and I started checking into it and that's when I started learning all about jetting and such. Pipe was glowing, it was that hot.

The top end also needs rebuilt because my filter came 1/2 way off out on a dry lake bed and I was riding in this stuff that was like silt / baby powder (I have heard it reffered to as pucker dirt)for about an hour. I was having a great old time kicking up major dust clouds. Well engine dies and I can't get it restarted. After about a 10 min. rest it starts and I haed back to camp and find the filter off the air intake about half way. The next trip or two out all of the sudden it starts stalling for no apparent reason, and then it starts to make a loud knocking noise.

So between the heat, oh by the way, the jetting was still at all the original manufacture settings, and all the dirt that got in there. I F****d it up good. At least know I have learned a lot about the dangers of heat and dirt. Boy, dirt really kills an engine fast.

There is my expensive story. here is what I am having done,

New...

Piston, rings, cam, valves, and all the assosiated stuff that goes with those parts like gaskets and such.
Clean out the carb, airbox, intake, rejet the main, needle, and idle jets.

Thanks

 

Compression=horsepower
All a blower (supercharger or turbo) does is increase compression. Escentially, nitrous works the same way. As long as detonation (spark knock) is not occuring, high compression is not hard on an engine. Although I think the idea of forged pistons is overrated, the wiesco should last longer than the cast honda replacement. Plus, the wiesco is probably cheaper. Have a good shop perform the work. I had a cylinder bored at a local machine shop since FTZ was 2-3 weeks out. They bored it 2mm more than was needed, and also bored it at an angle. After the exchange of many words, they only paid half on a new cylinder.
I had a '91 250x with stock piston. I rebuilt it with a 12:1 (250x has smaller combustion chamber and that increases compression) wiesco. The difference was night and day.

Don't feel bad. You aren't the first to experience the harmfull effects of dirt.

 

Don't be dead set that a 11:1 won't need race fuel. The decission on race fuel or no race fuel is the relationship of the piston dome to the head. My guess is no that you won't. It is nice to splash a lil race fuel in now and then to help cool the cylinder.

You may also view the option of a powroll 297 kit, it's a bore in kit that comes any way you want between 13:1 to 10.5:1 (cost about 212)

Unless your going with porting and a top end cam, DON"T change that carb. The stock carb flows much better than any other with a mid, mid to top cam with higher compression.

Remember when you raise the compression with slight boring the jetting will actually go down.