RE: Thumper Racing 340cc upgrade costs and options?
 

OUCH! I see what you mean. I know Kustom-kraft does cylinder repair, but I doubt they repair anything that extensive.

RE: Thumper Racing 340cc upgrade costs and options?
 

I think you will be real happy with either big bore kit. One thing about the KLX-s is that the cam is "de-tuned" from the -r engine.
A performance cam would also bring in more ponies.
I don't think I'll go with acam at this point as the 340 is meeting my needs. Plus the broke-in motor is giving me better mileage. Broke 50 on last fill up.
Frank

RE: Thumper Racing 340cc upgrade costs and options?
 

Not so, the cams are identical.

RE: Thumper Racing 340cc upgrade costs and options?
 

+1. There is no difference is camshaft specs. The PN on the exhaust cam is different, but I suspect that is due to an ACR timing change. CDI timing is different, so maybe thatis what Frank is thinking about?

RE: Thumper Racing 340cc upgrade costs and options?
 

While cams are on the topic, does anyone think that a set of cams that make power in the lower to mid rpm range but don't fall off on the topcould stand up to a bike that has the 300 kit installed in terms of torgue and power?

RE: Thumper Racing 340cc upgrade costs and options?
 

Cams are a give and take thing. If you move the powerband down lower you won't get top end gains as much, and same thing for upper power your going to lose some bottom end.
The problem with are bikes is that are cdi pulls timing out of the top end that why it feels flat after 8000 rpm. I've been trying to move some power up in the rpm range with cam selection but its a work in Progess!

Kevin

RE: Thumper Racing 340cc upgrade costs and options?
 

Can you clarify/elaborate onthis?

Maybe I'm tired and not grasping the statement but it seems to me that you need a ecu (computer related brain) or something similaronboard to "pull timing". It's my understanding thatthe KLX isnot quite that adaptive and is preset within certain parameters.

RE: Thumper Racing 340cc upgrade costs and options?
 

That can be offset somewhat with more advanced cam timing, though not completely. Here in Japan, they offer a kit that adapts the old KLX250R CDI into the KLX250 wiring, but it's big bucks for just wiring. The old CDI gives you 40 degrees BTDC by 5000 RPM wheras ours only advances to 25 deg BTDC.Big difference!

RE: Thumper Racing 340cc upgrade costs and options?
 

The old 250 is bdtc 5deg. @1700rpm, to 40deg. btdc@3000rpm ours on the other hand bdtc 10deg. @1300rpm, bdtc 35deg. @5000rpm, there is the problem we have more timing down low but 5 deg. Less and later in the powerband. You can only make up so much with camshaft advance, your still losing power due to timing being pulled out.

Kevin

RE: Thumper Racing 340cc upgrade costs and options?
 

No,thosenumbers are for the KLX300R CDI,which would go nicely with a large bore setup. The 250R is as I stated. It doesn't advanced to 40BTDC until 5000RPM in order to maintain better low-end torque with the smaller displacement.

I agree with most of that. That is whyI said you can compensate for SOME of that with cams, as I've shown in another thread with dyno charts entitled 'Dragone #19.' Check it out. Your numbers are still off though. Your figure at 1300rpm is correct, but 35 deg @5000RPM is for the models prior to incorporating what they call an 'advance limit'our bikes (the H6 and H7 series) will only advance to 25degBTDC. It has to do with emissions. That is why it is advantagous to install the KLX300 CDI if you go large boar...and they also will comliment after-market cams very nicely;)