Modern Penton questions

[johnacapp]

Hi To All,
I was wondering if anyone could help me with a modern penton problems?
I bought a 2006 sx 525 from a private owner that is street legal.
First let me give you a quick background, I bought the bike at good price, it's way more machine then I need. Just can't pass on a good deal!
I wanted to set it up to ride a few of the AMA dual-sport rides, back roads and trails around my area.
Ok here's the issues that I need help with.

First, The suspension needs lowered about 2". Has anyone out there had any experience in doing this? I would like to keep it as econmical as possible.  

Second, Is there any way you can remap the computer to be a little less aggressive? The bike backfires and denotes, it also very loud, I know I am making a race bike into a trail bike not what it was intended for but a milder quieter bike would be less offensive to others.

I'm hoping someone out there can help me with these questions. KTM sites have a lot of people that want to give you advise but not very helpful or practical.

74 Penton 250 owner
John

[brian kirby]

Hi John,

Your suspension can be lowered, but because it will require complete disassembly of both the fork and shock it will be expensive. Based on strictly rebuild prices I'd say $180 each end, shortening may add a little more. The ignition on your bike is fine, the low flywheel mass on the SX is what makes it so aggressive and abrupt. Several companies make flywheel weights, I recommend the largest one you can find. Lastly, many aftermarket exhaust companies make FIM/Forest Service legal quiet mufflers.

Having said all that, the biggest problem with that bike is the 4 speed gearbox. That really limits the bikes usefulness in anything but MX. I know this is probably not what you want to hear, but you would really be better off selling the bike and getting something more suitable to your intended use.

Brian

'72 Berkshire

[johnacapp]

Brian,
Thanks for the information.
Just for the record the bike is a six speed not a four.
I contacted the local dealer who originally set up the bike to be street legal, stated that his shop could lower the bike at reasonable price. But as I got into some of the minor issues to get it inspected I saw firsthand an example of his shops sloppy wiring work and I'm very reluctant to let him touch it.
I'm looking for a good mail order place or someone in our group that has firsthand experience lowing a KTM.
The flywheel weight is a great idea; But, I think I might be drawing air in on the exhaust, causing the extreme backfiring issue. Didn't seem to be a problem when I parked it for the winter? Again hoping someone out there can give advice?
John

[Gary Roach]

Hi John,

Another thing that might help to make the bike less aggressive is to replace the throttle tube with one that opens the carb up slower. I put a G2 Ergonomics throttle tube on my wife's 200EXC, and it helped take out that intial "hit" from when you first roll on the throttle. The G2's come with 3 cams that are all different ratio than stock.
 
G2's website:
http://g2ergo.com/shop/catalog/G2-Throttle-Cam-System-for-KTM-242.html






I'm not sure how much the back can be lowered, but if it can't be lowered as much as you want, Synergy Seals offers an item called an "X-Bushing" that goes between the shock and swingarm, and they claim that it will lower the back as much as 7/8".

Synergy Seals website:
http://www.shop.synergyseals.com/product.sc?productId=42&categoryId=13




Gary

[Mike Horton]

The backfiring problem may be a leak at the header pipe, but I guessing it lean jetting causing decel popping. Need to richen up the jetting. Check out ktm.com site 4 stroke and jetting sections - good info.

[Larry Perkins]

Might check valve adjustment too.  That backfire and popping can come from too tight on the valves.  Lots of things on the modern fourstroke that seem to be carb things are actually too tight on the valves.

Larry P

[brian kirby]

If the bike is a 6 speed then you have no obstacles you can not overcome. Gary is absolutely right about those G2 throttle cams, they are a simple idea and they really do work. That and a big flywheel weight will turn that bike into a rideable dualsport.

Brian

'72 Berkshire

[johnacapp]

Thanks To all!

I have seen the bushing that lowers the back end in dirt bike mag. about 5-6 months ago,It's neat but I really need more.
I have taken all the preload out just to play with. I need to lower.
 
Yes I think it needs to be leaned out. I will check out the site.

PLEASE help with any info on lowing!

[johnacapp]

Mike,
Please explain "ktm.com site 4 stroke and jetting sections"
Once I go to ktm.com how do I get to 4 stroke and jetting?
Thanks
John

[Mike Horton]

John
Sorry about that. Site is ktmtalk.com This is a great site for ktm's. Good luck !
Mike

[Kip Kern]

John

I own a "08" TE 250 Husky and had it lowered 2" front and rear.  Hall's Cycles did the lowering as Brian talked about.  While in the shock and forks, Jay revalved the suspension and not only can I touch the ground with both feet, but the bike handles fantastic in the woods now.  I won't buy another new bike unless it is lowered and will also stick with fuel injection, no more messing with carbs, simply change the Map on the system to your liking and have fun!

[wfopete]

Also consider throwing on a bigger counter shaft sprocket to kill the hit. If your on the roads you will probably want it anyway.

Pete Petrick
175 Jackpiner
Slow but Good

[Jeff D]

For suspension on my KTM I used Works Enduro Rider (WER) in New Jersey.  Run by 20-time ISDT/E rider/former US Team Manager Drew Smith and younger brother Chris, also ISDE rider (1st US Vase win since Dalton if I recall correctly.)  Well-versed in KTM and great customer service.  Ask to speak to Drew and tell him I sent ya.  

For exhaust, stock EXC exhaust on my 400 is very quiet, and the current models are even quieter.  Don't know about SX exhaust but suspect it is not as muffled and more suitable to closed course/motocross track sound levels.  See if you can find someone with an EXC and compare.  The quieter the better...less sound = more ground!


Jeff DeBell