The Essential Trials Stickie

[mbalmer]

Dang it. This would be such an awesome way to spend the weekend. Probably another month until I can ride

 

[1brunoj]

should I put rim locks on front and rear. None there, 1st flat front

 

[seavoyage]

Rim Locks on vintage trials tube type tires

should I put rim locks on front and rear. None there, 1st flat front

Definitely use rim locks with any tube type trials tires to prevent pinch flats. Some recommend 2 rim locks in the rear, but I've also have seen the contrary opinion:

http://www.trialscentral.com/forums/topic/42873-rim-locks-tlr-200/page__hl__+rim++locks

http://www.advrider.com/forums/showthread.php?t=893125

Trials tires are designed to grip at 6-7 psi front (tube-type) and 3-4 psi rear (tubeless). Many riders that try Trials tires (D803, MT43, etc.) on their full size bike over-inflate their tires, but get pinch flats running at less than 15 psi. Imagine if they ran the more appropriate ~7 psi in the rear. On my GasGas EC300, I run 7 psi on my MT43 but I use the TUbliss® system (360 degree rim lock). On the front I just run a Bib Mousse which feels like 11 psi.

Consider using the MotionPro LiteLoc over the traditional rim locks. http://www.motionpro.com/motorcycle/partno/11-0060/

If the tire pressure is too high (i.e. above 7 psi) a trials tire just doesn't work as designed. Here's a video demonstrating how a trials tire works.

youtu.be/UythUroeHbQ​

 

[seavoyage]

Applying trials techniques to dirt bikes

The KTM Freeride 350 weighs more than a KTM200EXC/XC-W (appoximately 222 lbs. dry); imagine what you could do on a lighter 125/144/150cc bike using these riding techniques which are very different from the mainstream MX based techniques.You might compare the KTM Freeride weight to a 1974 Honda TL250 4-stroke trials bike which weighed 230 lbs. Hint: you'll have to change your suspension set-up: current MX/Enduro settings are over sprung; have too much rebound dampening; and tire pressures are too high.

youtu.be/pBm9aDqrw-o
youtu.be/y-jbJU9c8NQ
youtu.be/-20xs65ct7o
youtu.be/4On13H4Jpbo
youtu.be/_dNGG-ks0B0​

As you well know, the KTM Freeride 350 is not imported into the US, but lighter, more powerful bikes with aftermarket modifications to modify the powerband have been available for 2-decades in the US market.

These lighter dirt bikes are more than capable for competing in the Sportsman class and Intermediate lines at the local trials club, Sacramento P.I.T.S.

 

[mbalmer]

Link to event flyer: http://www.sactopits.org/wp/wp-content/uploads/2012/02/Kraut-Cup-Trial-13.pdf

Take the Eagle Lakes Road off ramp on Hwy 80, just east of Hwy 20 junction.

Any pictures from this event? I would like to have attended, but can't yet sit in a car for the long ride to and from the PITS property.

 

[seavoyage]

Any pictures from this event? I would like to have attended, but can't yet sit in a car for the long ride to and from the PITS property.

Courtesy of Hop-Sing: http://s229.photobucket.com/user/chickkebill/library/Kraut Cup 2013?sort=3&page=1

 

[mbalmer]

Thanks for the pictures. How did you do, Drew, Sid or whoever else was there?

 

[seavoyage]

Thanks for the pictures. How did you do, Drew, Sid or whoever else was there?

We decided not to go at the last minute, :mad it was too hot.

it was hot up there though a little cooler then the valley for sure. We swam in the river it was nice. The event was tough lots of rock(granite boulders) and I finished third while mark took second in the sportsman/intermediate class. Maybe we'll see you up there in two weeks at the next event. Take care and talk soon. Sid,

The_Toe_Cutter and undertheoaks 2nd and 3nd in Sportsman Intermediate. :thumbup Jim and Allison didn't attend.:wtf

 

[seavoyage]

Converting Honda XLs into Trials Bikes

Prior to 1969 trials bikes were any bike ridden in trials.

Here's a bad-ass conversion:

Before the 1974 TL250/TL125, Honda and Sammy Miller experimented with XL250 conversions. Cycle did an article on the conversion about 1 year before the TL was released: https://plus.google.com/photos/111541825671446218235/albums/5586264165949750033?banner=pwa

Here's the version built by Peter Gaunt and Alan Jeffries: http://www.twnclub.ch/classic_trial_files/honda_files/XL250/JeffriesXL250.htm The conversion modified the angle of the head, cut the bottom tube, put the engine higher in the frame, made a shorter new swing arm, replaced the 30mm carb by an Amal 26mm.

Here's Andre Praverts version mentioned in the previous article:

More info: http://www.honda-trials.com/_sgg/m1ma_1.htm

 

[SACTOPITS]

Trials in Norcal - Near junction of Highway 80 & 20

Time for the Hard Rock Trial, July 13 & 14, 2013
This year held in conjunction with the Geritol Trial on Saturday

Saturday Vintage Beginner & Geritol Trial
Signups start at 11AM, Riders meeting at Noon, trial starts 12:15
Signup for PITS VB, Geritol, or both
Geritol line = 2 line, Whippersnapper = 1 line
Bring out your vintage bikes and have a ton of fun
4 line friendly loop

Sunday Class A Trial
Signups start at 9 AM, Riders meeting at 10 AM, trial starts 10:15

Weather should be dry and in the mid 70's to mid 80's

Checkers needed for both events

Flyer
http://www.sactopits.org/wp/wp-content/uploads/2012/02/Hard-Rock-Trial-13.pdf

 

[undertheoaks]

Time for the Hard Rock Trial, July 13 & 14, 2013
This year held in conjunction with the Geritol Trial on Saturday

Saturday Vintage Beginner & Geritol Trial
Signups start at 11AM, Riders meeting at Noon, trial starts 12:15
Signup for PITS VB, Geritol, or both
Geritol line = 2 line, Whippersnapper = 1 line
Bring out your vintage bikes and have a ton of fun
4 line friendly loop

Sunday Class A Trial
Signups start at 9 AM, Riders meeting at 10 AM, trial starts 10:15

Weather should be dry and in the mid 70's to mid 80's

Checkers needed for both events

Flyer
http://www.sactopits.org/wp/wp-content/uploads/2012/02/Hard-Rock-Trial-13.pdf

Should be another awesome and fun event and a lot cooler...whew!arty

 

[seavoyage]

GasGas Pro clutch tuning

Many GasGas Pro owners experience clutch drag. The GasGas Pro clutch is very sensitive to the 'finger height' and the currently available complete clutch pack is too thick resulting in noticeable drag - the slave cylinder 'top hat' can't engage the 'shallower' finger height to hold tension or complete disengage. If a 2.00mm steel plate is replaced with a 1.30mm-1.50mm steel plate, the finger height will be too high resulting in slip - top hat stays engaged.

The GasGas Pro uses a Diaphragm clutch design similar to an automobile, and different from mainstream motorcycle wet clutch design.

I recently replaced my Pro clutch pack and discovered the following:

GasGas only sells the complete clutch pack MT280232055 : 3 Friction plates MT280232051 and 2 steel plates.MT280232050 . See note below..

Each steel plate in the complete clutch pack is 2.00mm thick.

2002-2003 clutch packs were different MT280432055 . Early 2002 friction plates MT280232051 were prone to swelling; current friction plates do not swell in ATF.

The 1.50mm MT280232050 , 1.40mm MT280232050/4 , and 1.30mm MT280232050/3 steel plates are no longer available. If used with the current clutch pack to replace one of the 2.00mm steel plates, the overall thickness will be too thin.

If, post 2006 model, both steel plates measure 2.00mm and the friction plates vary in thickness: one friction plate is 2.20mm and the other two 1.80-1.85mm for a overall thickness of 10.00mm? ( I realize the math doesn't add up from the factory specs)

AND

The correct specification is: No less than 9.75mm and not more than 10.05mm

How do we build a clutch pack that measures 9.75mm +/- 0.1mm to acheive the desired 17mm +/-1mm 'finger' to inner hub depth?

I ended up going through all my old friction discs to build the appropriate clutch pack.

I had trouble reverse bleeding the clutch and discovered one of the two orifices in my AJP master cylinder (small reservoir) was blocked. I couldn't clear the blockage; so I replaced the master. I discovered that the master cylinder bore and stroke was relatively the same between the AJP long and short reservoir styles.

Replaced the O-rings in the slave cylinder for good measure. The GasGas Pro Technical Bulletin (10/2006) updated 10/2012 http://www.trialspar...ober_2_2012.doc recommended conversion from DOT4 to mineral oil. We since converted back to DOT5 by replacing the slave cylinder O-rings with MT280432047..

We found the Carquest part number CTC407008 for Viton® O-rings for the slave cylinder a bit tighter than the OEM MT280432047

Note:

2006 and newer model Installation note: The clutch fiber and steel discs were changed in the 2006 model year. The three fiber discs have a variation in thickness and the two steel discs are thicker than the previous models. There may be slight variations in thickness of the fiber discs, this is done at the point of manufacture to ensure precise total pack width. The total pack width is 10.0~10.01mm – The two steel discs measure 2.0mm each – Two of the fiber discs measure approximately 1.80~1.85mm thick and the third one is 2.2mm thick. All steel and fiber discs are symmetrical (there is no specific front or back side)
IMPORTANT: Of the three fiber clutch plates, one is noticeably thicker. (about 2.2mm thick) This thickest plate MUST be the one that is placed into the engine first. (Farthest into the interior and against the rear surface of the center clutch driven hub.)

 

[SVJ]

So, no more slippage?

 

[seavoyage]

So, no more slippage?

The clutch and transmission is finally sorted out. We rode Knoxville last weekend... rocks, single track, along the creek bed, and to the waterfall for a swim!

 

[seavoyage]

OKO Carburetors

youtu.be/tAUr9b5h0Fk​

More info: http://www.mid-atlantictrials.com/OKO.html

 

[mc1hd]

Video no workee for me.

 

[undertheoaks]

http://www.youtube.com/watch?v=y700zd7TC7M&feature=player_embedded

Man Ryan is awesome ! On teaching he explains things so well, at least for me. I have to get the whole video for sure.:thumbup

 

[The Toe Cutter]

Do it, it's a great investment!!

 

[mc1hd]

Have all videos, watched too much. Riding is kee, no exception for riding. Skill's come from riding - meth lamb obstacles with balance could be beneficial.

 

[undertheoaks]

Are we practicing tomorrow ? I will be there around 10ish, I have a test with the city of Berkley at 8am but free after that.