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carb help
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Posted by: dsaint77

I have an 87 250r, it is stock except for LRD adjustable pipe. I am going to build up the motor prolly going with a PV type engine, I would like to get a new carb for it and was wondering what I should be looking at? I see a lot of people are using Air Strykers and I wondered what you guys thought.

Most kits do not come with a carb so I will have to pick one up seperate.

Adam

Posted by: zedicus00

depends on the engine size and powerband you want... give us more details an we will help you out. do u want top end, low end or midrange power, how big of CC's are you wanting to run, etc?

Posted by: dsaint77

well about all I know at this point is that the stock 250r is decent, but im looking for white knuckle power that I can ride on the track, or ride in the dunes.

maybe the carb isnt exactually what I am looking for but a direction to go to get this power. I think that I will go with a Powervalve motor, but LRD website is messed up and I havent been able to get ahold of them. I havent contacted CT yet but I was thinking about their 350PV. ESR just dosent look like a good option to me for some reason.

Adam

Posted by: wilkin250r

Sand likes high horsepower, but it also likes high revs. For some reason, a 60HP engine at 10,000rpm seems to do a little better in the sand than a 60HP engine at 7000rpm. However, regardless of how you get it, high horsepower is key. A 60HP engine does better than a 50HP engine, regardless of the rpm range.

If you also want to race, you'll want a smooth powerband. That 60hp 7000rpm engine would do MUCH better on the track (generally speaking).

So for your type of riding, it looks like a big-bore (330+) would be your best bet. It will give you the horsepower you need for the sand, with the powerband that you want on the track. As long as you don't run into problems with displacement limits while racing...

Posted by: zedicus00

find the biggest carb you can. sumthing like a keihin 40mm atleast. airstrykers work great on like 265 national engines. but even then my engine builder is running a 42mm on a 265 national. if you dont mind doing a bit of work find a newer kx500 carb, or various snowmobile carbs, they are mostly keihin PWK carbs an can be had for lots cheaper then a standard large bore PWK. they take a bit of work to convert to quad use though. anyways these bigger carbs will let yur engine run out all the way to peak power, and with a good set of reads and good port work you wont loose all the bottom end.

o and wilk always recomends around a 330 cc engine, with good reason. its the best performing you can get while still maintaining some sence of reliability. theres even a 330 kit that doesnt require case machining. though u still need to make sure yur bottom end is up to it.