Went to the dealer today to order the 300 stuff (cylinder, piston, etc, ) The guy raised some questions. He said the exhaust valve and possibly the exhaust cam were not the same. Any comments. The head parts guy is going to talk to the head mechanic tomorrow about this. Have you guys looked into this. He didn't say it wouldn't work but wanted to have more info before ordering, and I agreed with him. Another question was exhaust flow out of the exhaust valve.

 

I don't see why that matters... Unless he thinks the valves are going to protrude into the combustion chamber more on a 250 than a 300 (which I highly doubt)... Don't worry about it dude. It's been done already. As soon as I find a 2nd hand jug I'm all over it.

 

+1 on what Kawiwawi said.

You have been wringing your hands over this for no realreason. There are companies in Japan that offer complete overbore kits for the the KLX250. Mind you, the KLX300 is not even sold here anymore, so there's no way they could be confusing the two. No where in the literature for these kits does it say you need to modify the valvesor head in any fashion.

My dealer installs stock KLX300barrels/pistionsroutinely onnothing butKLX250's. He offered it as an option when I bought the bike and was ready to cover it with the full warantee.. I'd be willing to bet my dealer in Japan knows a bit more about these bikes and engines thanmost stateside dealers, because he's been working with them since waaaaaaaay before 2006. There has been no break in production of the KLX250 in Japan, since 1998. Your guy isworking fromlittle more than one year worth of experience.

Add the fact that I know of at least 4 people who have been riding D-trackers with the 300cc jug for years and I can say with complete confidence that you will have no problems related the the KLX250 exhaust valves or head. The difference in part numbers might be as simple as a difference in ACR timing...i'm not sure, but it's definitely nothing to lose sleep over.

 

I wonder if the 300 cam is more agressive than the 250? Dean how do the 300 d-trackers run. Are they close to a stock drz400sm?

 

I've never ridden a totally stock 400SM. A friend of mine has onewith a Yosh slip-on and appropriate jetting. His still has more noticeable low-end grunt.The 300cc jug makes a very noticable improvement though. Also, the D-trackers are easier to fling around in the really tight stuff and I prefer the lower seat height.They can run with the DRZ unless you get a long, sweeping uphill section. Wouldn't want to part with the6 speedgear box either.

 

Thanks for your input.

 

Dmar,

This just in:

Further investigation reveals that, in 2003, the KLX300 ACR timing was changed to make it easier to kick start. Prior to that change, the KLX300 had the same PN of exhaust can we have in the KLX250s today.

We don't have kick start so we don't have to worry about it. Lift, duration and everything else that matters is exactly the same.

 

looks like the 300 kit is a go. After lots of research and feedback I got all the answers I was looking for.