2009 Kawasaki KLX351F project bike - Page 2

SamM · 03-23-2011, 01:01 PM

I've dealt with Happy Trails before. Good people! I'll probably just order one of those. The engine is not worth taking chances with.

I haven't read any dB reading comparisons. FMF lists a 96dB maximum on the Q4, with most models coming in below 93dB. They report a 1.5 dB reduction and 3hp increase when using the MegaBomb header.

Quote:

Sweet ride!

Thanks RageHardIntoTheBendies!

SamM

[/quote]

FastDoc · 03-23-2011, 01:05 PM

That sounds too good to be true regarding the header...

I don't know the sound output of my TBR.

I'd estimate somewhere around a million db. :?

RageHardIntoTheBendies · 03-23-2011, 03:15 PM

I really wanted (still do) a KLX-SF due to the fact that the 300 barrel is a cheap upgrade and nets you about the same HP as the DRZ400 but with a lighter weight and a 6 speed

I also remember there being some other small KLX tweaks you can make, like drilling the vent hole for the crank case breather larger?

Also some carb adjustments for better response like drilling the slide, and removing a coil from the slide spring for less preload.

FastDoc · 03-23-2011, 03:38 PM

Also some carb adjustments for better response like drilling the slide, and removing a coil from the slide spring for less preload.

The DJ kit no longer calls for drilling the slide and comes with a shorter, lower preload I presume, spring.

The drilling the vent thing is a new one on me. 300, 331, 351 kits are inexpensive and install in a few hours from what I understand.

david3921 · 03-23-2011, 03:59 PM

Nice bike, Sam. I really, really wanted one of those when they first came out. I asked my local dealer to call me when they came in. They never did. I saw one at a dealer when I was visiting my children in Missouri. I just couldn't get over the asking price at the time...around $5300. Especially when I got my XF200 for just over $2000 (2 years ago). Now, I see they are going on Ebay for as low as just under $3400 for brand new 2009's. I saw a couple threads on them at Supermoto junkie where they hopped them up. You might want to look over there for some ideas.

RageHardIntoTheBendies · 03-23-2011, 04:35 PM

http://www.thumpertalk.com/forum/sho...ighlight=crank

SamM · 03-24-2011, 09:24 AM

Thanks guys! Great information! When I finally do decided to get into the mods, I'll probably replace the stock Keihin CVK with a Mikuni flatside.

I'll check Supermotojunkie.

SamM

suprf1y · 03-24-2011, 11:06 AM

I wouldn't.

Nothing wrong with that CVK carb. It's really good for the application. I'd go after a lot of things before I considered swapping it.

SamM · 03-25-2011, 01:12 PM

The Keihin CVK and CV are both very good carbs. None of my Buells were fast, until I replaced the 40mm Keihin CV with a Mikuni HSR42 flatside. My KLR650 came with a CVK. It will soon have fuel injection and I would never go back. The Keihin CV and CVK react too slowly to produce good power. They are best left for commuter bikes. Admittedly, that was my plan for the KLX but it's just too much fun. The Mikuni reacts much faster and makes more power. I'd like a little more power. My plan is to convert the KLX for use as a dualsport. The Supermoto wheels will only be used occasionally.

Today, I made the first purchase for my new KLX. It should be all I need to carry a small waterproof bag for light camping trips. My wife bought me a small Eureka personal bivy for Christmas and I already have lightweight gear from my rock climbing days. I've decided to make this motorcycle my new TAT bike. I'm a dualsport guy at heart. I really don't need a Supermoto bike.

SamM

FastDoc · 03-25-2011, 02:15 PM

That's the same rack I bought and I think it's the best.

I liked it because it allows the use of the factory tool kit pouch, has no sparp angles or edges, is strong, and powdercoated. It is also better looking, and cheaper than the alternatives. 8)

For me the jetted CVK carb seems fine.
:roll:
I was thinking about this philosophically.

Take a KLX. put in a 351 kit, pumper carb, and exhaust. Now you have the power of a DRZ (stock) and less weight. Same money.

On the other hand it may be better to buy the DRZ (or a Yamaha 250 WR-F) and leave it alone.

Because of this I will for the most part leave my KLX alone as far as performance mods are concerned at this point.

On the other hand a 351 jug sounds good....

RageHardIntoTheBendies · 03-25-2011, 03:08 PM

Dang it, local dealer now has new 250sf's on for $4500, sooo tempting!

SamM · 03-26-2011, 08:10 AM

Wow, I'm really flip-flopping about whether or not to mod this thing out or not. I went out to the garage yesterday and sat on it, since the weather is crappy again. This is one cool little bike. I called Light Speed and they no longer make all the carbonfiber parts for the KLX. All they have is the frame protects and the skidplate. I'm not sure about a cf skidplate. The Happy-Trail skidplate will protect the engine much better and for $87 is a bargain.

It looks like I may just go with the FMF MegaBomb header and the Q4 muffler to start with. I'll rejet with the DynoJet kit and swap out the stock snorkel for one from a KDX. If there is a noticeable difference, I'll go to the next step and do this in progressive stages. That would be a carb swap to a Mikuni 36mm flatside. Headwork from M-Tech and a set of Web Cams would be the next step. If all this works to bring the bike up to a higher level of performance, that I am satisfied with I would stop there. If not, then a stock KLX300 cylinder and and an aftermarket Wiseco 300cc piston could be the next mod. If that wasn't enough I would spring for the 351cc kit from B&B.

As soon as the weather breaks and I can get some miles on it, I'll report my mileage and impression of the KLX.

SamM

FastDoc · 03-26-2011, 11:33 AM

I can't wait to hear your results, and I'm interested to see if you can stop short of a Stage 3+ modification. :P

I like your ideas for the mods but this is what I may be able to contribute.

I think the Q4 is the best choice in a quieter muffler, and the performance advantages of a more straight through design like my TBR are likely not worth the extra noise.

I have heard, for what that's worth that the Power Bomb does add some power for no more, and maybe even less noise

. Indeed I'd be interested if you could do an experiment for me if you go that route. I'd like before and after noise and SOP power evaluations of the jetted and piped bike before and after the PB if you were willing.

No need to go to the KDX snorkel. If you look at the geometry of the airbox the snorkel adds only a fraction of an inch to the top of the airbox to keep water out. If your crotch is dry on this bike so is your airbox. I can report no perceptable noise increase with the snorkel simply removed.

Some people remove the backfire screen. I did not.

Propperly piped and jetted I bet you won't see the need to change the carb. To get more power other than Stage 2 mods, the cheapest and best way is a 300, 331, or 351 kit. 8)

You will indeed NEED MPG's just to have the range to make it to the next gas station! My lawnmover has a farther range than this thing.

SamM · 03-26-2011, 12:35 PM

FastDoc,
I'm looking at the MegaBomb rather than the PowerBomb. There's about a $50 difference between them. The MegaBomb header is advertised to give a 1.5 dB decrease in sound. The PowerBomb add does not list a decrease in sound.

My thoughts on going with the bigger 351cc bore are that I would probably need a bigger custom pipe and muffler. The FMF MegaBomb is still sized for the 250cc bore. It's more than likely going to be the bottleneck with the 351cc big bore cylinder. There is not a big increase on power when going to the bigger bore over just a pipe and muffler. From 26 to 29.8hp isn't much. The FMF exhaust system would probably be a good match for the 300cc engine kit. That's my reasoning for starting with the smaller bore first. We'll have to see! I'd like to dyno the bike with just the exhaust mods first, then with the headwork and cams. Once I see how this effects mileage, I would go forward.

I just don't want to have the bike down for any length of time.

SamM

suprf1y · 03-26-2011, 07:28 PM

I've had my KLX for 3 years. I do a lot of fairly fast single track, and always ride the bike there.
If I can offer any insight, it would be this,
I did the jetting, and carb mods first, including drilling the slide, a 300 needle, and removing the lid. This helped a lot. Next I did a Muzzy can, and that made a big difference. Removing the backfire screen made a far bigger difference than I expected. I'm not sure why, but maybe the air signal is stronger, and the slide opens faster, or maybe my jetting was a little off, and the extra airflow corrected it, but it was one of the mods that made a very significant difference. If I bought another one, it would be the first thing I did. The FMF header, and muffler were icing on the cake. I'm quite happy with the power now, but since the stock cams are quite mild, when i go after more power, cams will probably be next, followed by a 300 barrel, and piston.
With my bike, the way it is now, I was able to beat (barely) a KLX 300 with carb mods and FMF muffler in a drag race.
I am very happy with the bike.
My mods now

FMF Powerbomb header, and Q4 muffler
132 Main, N1TC needle, drilled slide
Airbox lid and backfire screen removed

03-23-2011, 01:05 PM	#17
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	That sounds too good to be true regarding the header... I don't know the sound output of my TBR. I'd estimate somewhere around a million db. :? __________________ Happy to serve.
	0

03-23-2011, 03:15 PM	#18
RageHardIntoTheBendies Join Date: Oct 2010 Location: Victoria, BC Posts: 114	I really wanted (still do) a KLX-SF due to the fact that the 300 barrel is a cheap upgrade and nets you about the same HP as the DRZ400 but with a lighter weight and a 6 speed I also remember there being some other small KLX tweaks you can make, like drilling the vent hole for the crank case breather larger? Also some carb adjustments for better response like drilling the slide, and removing a coil from the slide spring for less preload. __________________ Saga 250 Enduro
	0

03-23-2011, 03:38 PM	#19
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	Also some carb adjustments for better response like drilling the slide, and removing a coil from the slide spring for less preload. The DJ kit no longer calls for drilling the slide and comes with a shorter, lower preload I presume, spring. The drilling the vent thing is a new one on me. 300, 331, 351 kits are inexpensive and install in a few hours from what I understand. __________________ Happy to serve.
	0

03-23-2011, 04:35 PM	#21
RageHardIntoTheBendies Join Date: Oct 2010 Location: Victoria, BC Posts: 114	http://www.thumpertalk.com/forum/sho...ighlight=crank __________________ Saga 250 Enduro
	0

03-24-2011, 09:24 AM	#22
SamM Join Date: Feb 2007 Location: West Virginia Posts: 1,194	Thanks guys! Great information! When I finally do decided to get into the mods, I'll probably replace the stock Keihin CVK with a Mikuni flatside. I'll check Supermotojunkie. SamM __________________ 2013 Jeep Wrangler Sahara MOAB 2005 BMW E53 X5 2011 Schutt Industries LTT-HC LQG trailer 2017 Coleman CT200U 1978 Yamaha SR500E 1979 Yamaha XS650 Special II
	0

03-23-2011, 03:59 PM	#20
david3921 Join Date: Feb 2009 Location: Michigan Posts: 1,030	Nice bike, Sam. I really, really wanted one of those when they first came out. I asked my local dealer to call me when they came in. They never did. I saw one at a dealer when I was visiting my children in Missouri. I just couldn't get over the asking price at the time...around $5300. Especially when I got my XF200 for just over $2000 (2 years ago). Now, I see they are going on Ebay for as low as just under $3400 for brand new 2009's. I saw a couple threads on them at Supermoto junkie where they hopped them up. You might want to look over there for some ideas.
	0

03-24-2011, 11:06 AM	#23
suprf1y Join Date: Oct 2007 Location: SW Ontario Posts: 408	I wouldn't. Nothing wrong with that CVK carb. It's really good for the application. I'd go after a lot of things before I considered swapping it.
	0

03-25-2011, 01:12 PM	#24
SamM Join Date: Feb 2007 Location: West Virginia Posts: 1,194	The Keihin CVK and CV are both very good carbs. None of my Buells were fast, until I replaced the 40mm Keihin CV with a Mikuni HSR42 flatside. My KLR650 came with a CVK. It will soon have fuel injection and I would never go back. The Keihin CV and CVK react too slowly to produce good power. They are best left for commuter bikes. Admittedly, that was my plan for the KLX but it's just too much fun. The Mikuni reacts much faster and makes more power. I'd like a little more power. My plan is to convert the KLX for use as a dualsport. The Supermoto wheels will only be used occasionally. Today, I made the first purchase for my new KLX. It should be all I need to carry a small waterproof bag for light camping trips. My wife bought me a small Eureka personal bivy for Christmas and I already have lightweight gear from my rock climbing days. I've decided to make this motorcycle my new TAT bike. I'm a dualsport guy at heart. I really don't need a Supermoto bike. SamM __________________ 2013 Jeep Wrangler Sahara MOAB 2005 BMW E53 X5 2011 Schutt Industries LTT-HC LQG trailer 2017 Coleman CT200U 1978 Yamaha SR500E 1979 Yamaha XS650 Special II
	0

03-25-2011, 02:15 PM	#25
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	That's the same rack I bought and I think it's the best. I liked it because it allows the use of the factory tool kit pouch, has no sparp angles or edges, is strong, and powdercoated. It is also better looking, and cheaper than the alternatives. 8) For me the jetted CVK carb seems fine. :roll: I was thinking about this philosophically. Take a KLX. put in a 351 kit, pumper carb, and exhaust. Now you have the power of a DRZ (stock) and less weight. Same money. On the other hand it may be better to buy the DRZ (or a Yamaha 250 WR-F) and leave it alone. Because of this I will for the most part leave my KLX alone as far as performance mods are concerned at this point. On the other hand a 351 jug sounds good.... __________________ Happy to serve.
	0

03-25-2011, 03:08 PM	#26
RageHardIntoTheBendies Join Date: Oct 2010 Location: Victoria, BC Posts: 114	Dang it, local dealer now has new 250sf's on for $4500, sooo tempting! __________________ Saga 250 Enduro
	0

03-26-2011, 08:10 AM	#27
SamM Join Date: Feb 2007 Location: West Virginia Posts: 1,194	2009 Kawasaki KLX250SF 'Supermoto' Wow, I'm really flip-flopping about whether or not to mod this thing out or not. I went out to the garage yesterday and sat on it, since the weather is crappy again. This is one cool little bike. I called Light Speed and they no longer make all the carbonfiber parts for the KLX. All they have is the frame protects and the skidplate. I'm not sure about a cf skidplate. The Happy-Trail skidplate will protect the engine much better and for $87 is a bargain. It looks like I may just go with the FMF MegaBomb header and the Q4 muffler to start with. I'll rejet with the DynoJet kit and swap out the stock snorkel for one from a KDX. If there is a noticeable difference, I'll go to the next step and do this in progressive stages. That would be a carb swap to a Mikuni 36mm flatside. Headwork from M-Tech and a set of Web Cams would be the next step. If all this works to bring the bike up to a higher level of performance, that I am satisfied with I would stop there. If not, then a stock KLX300 cylinder and and an aftermarket Wiseco 300cc piston could be the next mod. If that wasn't enough I would spring for the 351cc kit from B&B. As soon as the weather breaks and I can get some miles on it, I'll report my mileage and impression of the KLX. SamM __________________ 2013 Jeep Wrangler Sahara MOAB 2005 BMW E53 X5 2011 Schutt Industries LTT-HC LQG trailer 2017 Coleman CT200U 1978 Yamaha SR500E 1979 Yamaha XS650 Special II
	0

03-26-2011, 11:33 AM	#28
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	I can't wait to hear your results, and I'm interested to see if you can stop short of a Stage 3+ modification. :P I like your ideas for the mods but this is what I may be able to contribute. I think the Q4 is the best choice in a quieter muffler, and the performance advantages of a more straight through design like my TBR are likely not worth the extra noise. I have heard, for what that's worth that the Power Bomb does add some power for no more, and maybe even less noise . Indeed I'd be interested if you could do an experiment for me if you go that route. I'd like before and after noise and SOP power evaluations of the jetted and piped bike before and after the PB if you were willing. No need to go to the KDX snorkel. If you look at the geometry of the airbox the snorkel adds only a fraction of an inch to the top of the airbox to keep water out. If your crotch is dry on this bike so is your airbox. I can report no perceptable noise increase with the snorkel simply removed. Some people remove the backfire screen. I did not. Propperly piped and jetted I bet you won't see the need to change the carb. To get more power other than Stage 2 mods, the cheapest and best way is a 300, 331, or 351 kit. 8) You will indeed NEED MPG's just to have the range to make it to the next gas station! My lawnmover has a farther range than this thing. __________________ Happy to serve.
	0

03-26-2011, 12:35 PM	#29
SamM Join Date: Feb 2007 Location: West Virginia Posts: 1,194	2009 Kawasaki KLX250SF 'Supermoto' FastDoc, I'm looking at the MegaBomb rather than the PowerBomb. There's about a $50 difference between them. The MegaBomb header is advertised to give a 1.5 dB decrease in sound. The PowerBomb add does not list a decrease in sound. My thoughts on going with the bigger 351cc bore are that I would probably need a bigger custom pipe and muffler. The FMF MegaBomb is still sized for the 250cc bore. It's more than likely going to be the bottleneck with the 351cc big bore cylinder. There is not a big increase on power when going to the bigger bore over just a pipe and muffler. From 26 to 29.8hp isn't much. The FMF exhaust system would probably be a good match for the 300cc engine kit. That's my reasoning for starting with the smaller bore first. We'll have to see! I'd like to dyno the bike with just the exhaust mods first, then with the headwork and cams. Once I see how this effects mileage, I would go forward. I just don't want to have the bike down for any length of time. SamM __________________ 2013 Jeep Wrangler Sahara MOAB 2005 BMW E53 X5 2011 Schutt Industries LTT-HC LQG trailer 2017 Coleman CT200U 1978 Yamaha SR500E 1979 Yamaha XS650 Special II
	0

03-26-2011, 07:28 PM	#30
suprf1y Join Date: Oct 2007 Location: SW Ontario Posts: 408	I've had my KLX for 3 years. I do a lot of fairly fast single track, and always ride the bike there. If I can offer any insight, it would be this, I did the jetting, and carb mods first, including drilling the slide, a 300 needle, and removing the lid. This helped a lot. Next I did a Muzzy can, and that made a big difference. Removing the backfire screen made a far bigger difference than I expected. I'm not sure why, but maybe the air signal is stronger, and the slide opens faster, or maybe my jetting was a little off, and the extra airflow corrected it, but it was one of the mods that made a very significant difference. If I bought another one, it would be the first thing I did. The FMF header, and muffler were icing on the cake. I'm quite happy with the power now, but since the stock cams are quite mild, when i go after more power, cams will probably be next, followed by a 300 barrel, and piston. With my bike, the way it is now, I was able to beat (barely) a KLX 300 with carb mods and FMF muffler in a drag race. I am very happy with the bike. My mods now FMF Powerbomb header, and Q4 muffler 132 Main, N1TC needle, drilled slide Airbox lid and backfire screen removed
	0