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183 lb XR200

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Racetech did some work on improving rising rate on non linkage shocks by using a true progressive spring. The damping was compromised a bit but it did provide an improvement.

Packaging issues are easier to solve without linkage and an off center shock. I considered converting a XR to no linkage just to simplify, but too many things needed to be changed. With a modded, or different frame, the shock could stay in the center but attached further rear on the SA and the upper mount moved forward for more rising rate.

Edited by chuck4788

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Along the Freeride concept I did some out of the box calculations of using a XR200 engine in a Trials bike, since I have detail weights for a Montesa 315R I used it although some newer Trials bikes are up to 20 lbs lighter.

My 315R weighs 163lbs with no fuel. the power train weights are:

engine 50.75 lbs

exhaust 7.4 lbs

radiator w/ fan 3.05

coolant 1.2

total 62.4 lbs

XR200 engine 58 lbs

stock exhaust 7.7 lbs

aftermark 6.6 lbs

total 64.6-65.7 - lbs

Forks: 19.46 lbs (CR80/85/150R) minus 15.94 lbs (315R) = 3.52 lbs

Engines: 64.6 lbs (XR) - 62.4 lbs (315R) = 2.2 lbs

So a XR200 engine and CR80/85/150R forks will add 5.72 lbs to a Montesa 315R

Add 5 lbs for a seat and the bike will weigh 174lbs.

Assume ignition, carb, and airbox weights are equivalent.

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And all of this time I have been thinking that I could build a Freeride XR200-260 down to 165lbs...!! HA!HA!

:ride:

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And all of this time I have been thinking that I could build a Freeride XR200-260 down to 165lbs...!! HA!HA!

:ride:

You could if you used a chassis lighter than a Monty, but the Monty has a rep for a stiffer chassis than the newer light weight bikes, or maybe their engines are lighter than the 315R.

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Well I'm adding a long ride seat and tank to my 315R thanks to ChrisDB selling one on TT. But that won't make a sows ear into a silk purse because the seat is not high enough for trail riding and the suspension is still only 6" of travel, just makes the bike easier on trails because you can sit a bit. IMO all of this still makes my modded XR200 the ideal technical trail bike.

When I go riding I take both bikes and warm up for 30 minutes or so riding the 315R on tight technical trails, then ride the modded XR on regular trails for the rest of the day. Of course YMMV depending on where and how you ride.

Edited by chuck4788

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Follow up on Brent's mention of the KTM Freeride 350 here is a TT link to the conversation including Brent's comments on his test rides and a number of really nice videos to watch. As Brent says, probably not the ultra-bottom end bike but it shows some of its abilities in the videos.

Might have to build me an lightweight air-cooled XL/TL250 based 350 Freeride since I can't justify the $10,000 cost of the KTM! Neat bike though!

http://www.thumpertalk.com/topic/933784-350-freeride/

Edited by Swiss

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Ryder did you ever find one of the Yamaha Factory Ti shock springs on EBay for your Ohlins shock?

Swiss

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The stock yamaha TI spring was way too large for either the CR shock or the Ohlins,... not even close :( Can't remember if the spring rate was usable but I doubt it.

I ended up using an 8 inch spring length rather than the 10 inch stocker. This alone was a good weight savings but I forgot to weigh it. no problem with coil bind either. Most shocks can run shorter springs.

Edited by woodsryder

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Come on Guys, it can't be that hard getting under 200lbs... 

 

Borile evidently did it with a Chinese 230cc electric start engine!  Which would be the equivalent to the CRF230 Honda.  Of course his was using more street oriented suspension, but the CR85/CRF150r forks would be as light as the 40mm units that he used.  Same for the disk brakes off the small Hondas... 

 

http://www.twowheelsblog.com/post/10485/borile-multiuso-a-unique-multi-purpose-bike-from-Italy

 

Check out the offroad model with aluminum uni-body tank/frame in the photos.  Looks like maybe a bigger 250cc engine in that one.

 

Swiss

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Not much new except my muffler. The supertrapp was small but still heavy so I fabbed up an aluminum can silencer. I used a water bottle from the camping store and cut one end off. Its less than .030 thick and weighs as much as a couple beer cans. I just don't know how to go any lighter without using Titanium for the steel parts. Its got a unique sound with a distinct resonant frequency. Its very mellow at low through mid throttle, then it barks when you open it. The low end torque is also better. This little engine just keeps on giving!!

 

 

http://i116.photobucket.com/albums/o29/kayaker43/BBR218/7b5ca67a-e6d4-4649-9c94-7c185d04e163_zps3522c2c9.jpg~original

 

http://i116.photobucket.com/albums/o29/kayaker43/BBR218/PICT00032_zps23634cb9.jpg~original

 

Can't seem to get photos to post here from photobucket like they used to??

Edited by woodsryder

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Finally found out what gas caps fit the BBR tank. The BBR billet cap is a shameful half pound of bling but luckily an XR80 plastic cap fits right on.

 

It was the easiest half pound savings ever.

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Finally found out what gas caps fit the BBR tank. The BBR billet cap is a shameful half pound of bling but luckily an XR80 plastic cap fits right on.

 

It was the easiest half pound savings ever.

Thanks.

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Hi Woodsryder,

I'm Chuck's riding buddy [since 1966]. Been following thread. Got a BBR. Had S.A. lengthened and put 21/18 wheels on. Love the handling. I'm 130 lbs with 30 in. inseam, and need to do the peg relocate. Would you post a close picture from behind and above of the right peg folded--and details of how to make it? Same for left. What holds the peg up when kicking? What is the carb to airbox hose and what is it connected to at the box? How do you adjust the idle speed? BBR frame to engine clearances are most annoying. I appreciate all the creativity you've brought to this most worthy project. Thanks, W

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Woodsy, more questions. Did you have to bend the kickstarter? If so, how much and where? How much clearance to frame and folded peg. I studied your peg work on page 8.

Chuck and I are building a 218 based on a TLR crankcase and a stock cammed XR200 top end. We're hoping that the TLR flywheel with the stock cam will give a softer extreme bottom end than his torque cammed 218. Our riding often has challenging uphill rock-strewn switchbacks. The bike has a BBR exhaust system with the round-section muffler, w/o baffle. I'm a noise weenie and would like to baffle it. Have you used the BBR baffle, and if so, is it significantly quieter? I'm unconcerned about power loss.

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 We're hoping that the TLR flywheel with the stock cam will give a softer extreme bottom end than his torque cammed 218. 

That's pretty close to my combo but without the stroker. Stock XR piston, cam, ATC185 head, carb, TLR crank, flywheel in a TLR frame. It's still a bit harsh right off idle. Novice riders don't like it. I set it up with cam advanced 4 degrees but haven't played with ignition timing much. Less ignition might soften it enough to make it more friendly. Point being the TLR flywheel doesn't make much difference from an XR flywheel.

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I did some tests on initial timing with my 218 (11:1, Torque cam); It would run ok at 0 degrees BTDC and didn't get good low end throttle response until 5 degrees BTDC.

Powroll recommends limiting total to 29 degrees, which results in 9 degrees initial with a stock spec advancer.  I've run stock motors up to 34 total with good results on pump premium so there is a range depending on engine mods.

 

So with some mods to the advancer I could detune the bottom end. 

 

Published advance curves for the CRF230F show more aggressive initial timing but that engine has a 9:1 CR, then max advance at  3900rpm vs 3500rpm for the XR, and then a series of reduced total advance to 10k.  With an electronic rather than mechanical advance we could could do the same on the XRs. If I knew the advance curves used by other XR CDI boxes it could be plug n play using the crank position sensor on the TLR flywheel.

 

I sometimes detect ping at about 3000-3200rpm so a slower advance rate, or less initial could help. 

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willyobe, sorry I never responded. TT never notifies me even though I subscribe to posts.

 

My BBR is being transported to Florida by a friend so I won't be able to access it for a couple weeks. My footpeg brackets come off the stock mounting points down and rearward. There is a thinwall tube running across between them to stabilize things. I fabbed the mounting points and modifed some CR85 pegs to fit. There is no return spring and a tiny rare earth magnet on the right side to hold up the peg. Its not ideal but works pretty good, once a year the peg flips up while riding and stays there but i just kick it back down. I use the stock kick lever with no mods, the TLR lever sticks out way farther and makes kicking awkward. The shifter angle and length is extreme but still works OK. The peg to engine relationship is always a problem with XR conversions and usually requires a flip up peg. 

 

Very important note. The stock  XR uses the peg to stop the kick lever. There is also an internal stop inside the cases but it will break off if you don't have an external stop. I found this out the hard way and grenaded a motor. If you overtravel the kickstarter you will immediately break the internal stop and jam the kickstart mechanism into a transmission gear. That went unnoticed for a while until the loose chunk of aluminum got wedged against the cylinder liner bottom edge and broke off a piece. My overbored cylinder had a thin 1mm sleeve so it didn't stand a chance. The piston jammed and bent the rod,.. goodbye stroker crank!!

 

Always provide an external stop for XR200 kickers. Not sure if its in my pics but my kicker now hits a stop I added.

 

I had the original BBR pipe with D shaped silencer. It sounded nice but wasn't super quiet and was very heavy. Went to a supertrap and it didn't sound as good but same noise level. My new lightweight muffler is even a touch louder but with an awesome tone. None of them are anywhere near stock quiet but are all reasonable for trail riding. Quiet mufflers are always large and/or heavy

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