engine mods worth the $$???

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  #11  
Old 03-04-2015, 02:56 PM
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Originally Posted by Subasaki
the reason im semi willing to spend on things in addition to the BB kit is because i had a bigger bike,DRZ400. i was fine with the power stock but disliked everything else about the bike.(height,weight,top heavy,5 speed).
Yeah I'm finding that out on my E model, great power, decent suspension, but pegs are so high that it feels like standing on a skateboard, not very confidence inspiring.

Originally Posted by zomby woof
I think you got that backwards. It's a 4V motor with relatively large valve area and extremely mild cams.
Yes but the cams seem to improve the top end performance, if I were using the klx for a motocross machine and was running it at 6000-9000 rpm all day on the track I would agree; however, using the bike as a single track bike, I'd be more inclined to say cleaning up the head and making it flow better would be better suited. Porting is cheaper any how
 
  #12  
Old 03-04-2015, 04:56 PM
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Originally Posted by taxonomy
Just do the kit. I would have done and have done the 351 kit. The bike will be amazing compared to the old 250. Then, in a year or so decide if you need or want more power. It's not an all or nothing deal.

Who is doing port and polish for $250?

Part of the attraction of the KLX is you can mod or not. You can build the bike over a long time. Adding a new part once in a while makes the bike exciting again.

Once the 351 kit is in I would look at your suspension, be sure it's sprung right, especially up front. Getting spring rate right is worth more than any post big bore power gains you'll get from a pumper or cams.
I havent bought the BB kit yet...between 331 and 351...havent people overheated with the 351?
 
  #13  
Old 03-04-2015, 05:08 PM
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A decent cam grind will improve power everywhere. Porting on a head like this isn't worth much.


Yours truly, professional head porter and cam grinder
 
  #14  
Old 03-04-2015, 05:19 PM
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Originally Posted by Subasaki
I havent bought the BB kit yet...between 331 and 351...havent people overheated with the 351?

The 351 is dead reliable under all normal circumstances. There isn't a problem with that kit. People have many, many thousands of miles on them. You may be able to find some ancient example of an overheated 351, but it will be just that, one old example.

A KLX250 and a KLX351 are different bikes. The 351 kit changes it so much. If you've ridden your KLX for a while you will notice a big, big difference. Just put the kit in, change the jetting and keep the rest of your money in your wallet. Don't forget to invest 10% of your income for retirement.

If you want more power after that you can add a pumper carb. I spoke to one very reasonable sounding guy in person and he said the pumper made more power bit it made the bike a bit less ride able in the New England woods.

So, you know, just cool off and do one mod at a time. Get the 351 and install it properly, rejet your stock carb and go from there. Don't get ahead of yourself.

Call Moto-Pro and get the right springs for your weight and then ride the bike.

As a woods bike I do not that that the KLX351 needs more power. It makes nice useable power off the bottom, it's very predictable.

This path has been taken by many before you. One step at a time.
 
  #15  
Old 03-04-2015, 05:53 PM
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Reviewing the data and information every time it comes up - I can't see where a BB kit offers the most bang for the buck. It's $534 and makes just a little more power than a DGR+DJ kit ($215) - TRQ: 18.7 vs 16.3 HP: 22.24 vs 21.52

You add a slipon and DJ kit to the BB and you make 26 hp - but now you've spent $750 (DGR)- $900 (PC4) AND you'll be adding in the cost of a clutch upgrade at those power levels - either sooner or later..
 
  #16  
Old 03-04-2015, 06:13 PM
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^It's not all about peak power production. Only a fraction of us make the best use of, and spend a lot of riding time at, peak power. We're not all racing.
It's where the power is.
The big bore transforms the KLX into a trail tractor with low-end grunt.
A pipe and jet kit alone won't do that.
There are many 351s running around out there on stock clutches.
 

Last edited by IDRIDR; 03-08-2015 at 04:55 PM.
  #17  
Old 03-04-2015, 06:42 PM
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It's just that when you remove the subjective opinions and look only at the data - I can't see the benefit per dollar between a MCM, DG-R, and DJ kit ($215) and a stock + BB kit ($534).. The Barnett clutch upgrade is not optional on BB351 with slipon and pumper carb, from my research in here. Unless you ride like granny..
 
  #18  
Old 03-04-2015, 11:57 PM
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[QUOTE=Klxster;518827The Barnett clutch upgrade is not optional on BB351 with slipon and pumper carb, from my research in here. Unless you ride like granny..[/QUOTE]

Not true from my experience- I ran the oe clutch for over a year of slogging through the woods here. When I decided to put in the EBC kit I found that the clutch is still in good working order-it's sitting in a zip-loc in my tool box waiting for another chance...
 
  #19  
Old 03-05-2015, 12:04 AM
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so with the 351 i may need a new clutch?
 
  #20  
Old 03-05-2015, 01:46 AM
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Originally Posted by Subasaki
so with the 351 i may need a new clutch?
How hard do you flog it and slip the clutch?
 


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