XR200 Auto-clutch

[Swiss]

Chuck,

 

Apparently EFM is doing custom auto-clutches for the XR400 and will do them for the XR200 also.  Interesting thing is that they use the stock number of clutch plates (could use a CRF230 clutch?) by adding the auto mechanism on the outside of the clutch pack.  They can get away with this by using a spacer plate to move the clutch cover out from the main cases.  The kit includes extended side cover screws etc...  Article in the XR250/400 forum located here:

https://www.thumpertalk.com/topic/1018788-auto-clutch/

 

This guy doesn't have his working yet but it is an option since a pumped up 200-218 engine wouldn't allow reduction of the number of stock clutch plates for performance.  Cost is said to be $695 and from the looks of it you could use the stock clutch lever and pieces.. 

 

Did you ever get the clutch basket checked out to see if you could machine the inner basket and add another clutch plate to the stock unit?

 

Swiss

[Chuck.]

I gathered up the various parts but got sidetracked by house issues, and I doubt that I will get to it before going south.

 

Some thoughts on the issue of auto clutch disengaging on decel braking.  The Honda ATC  centrifugal clutches are on the crank and are small because they deals  with  engine torque (about 1/3 the torque than at the clutch basket),  and include a sprague unit (#14 one way clutch) to provide engine braking. Pluses: still have manual clutch. Downsides: No oil filter, special right crank, need ATV side cover. Unknown: adapting kicker and compression release to the ATV side cover.

 

[Swiss]

According to the XR400 postings EFM is saying that their system only disengages at about idle speeds when slowing down and then a quick rpm snap and it engages again?  Will have to wait until one of these guys gets theirs running to see how they like it.  One concern is with the thickness of the spacer and the kickstarter spacing?  I know that there is some room there, but have to consider the decompressor mechanism also.

 

Chuck, if you wanted to send me the spare clutch I could look at it and probably find the time to modify it after your approval of what I find.  That would put you months ahead of where you will be when you get back from another winter in Sunny Arizona!  HA!HA!

Edited September 10, 2013 by Swiss

[Chuck.]

Well AZ is getting closer; can't decide if I take a bike down or buy one there. 

 

I did go on an interesting ride today in the Cascades that is causing me to rethink a lot about bike setup, including autoclutches.

One infamous trail climbs 4000 feet in a few miles with boulders, rocks, roots, stair steps, and switchbacks. I've ridden this before with a basically stock XR200 motor in a RM chassis, and while a major workout no unplanned stops all the way to the top.  Not today with my Powroll XR200, lots of flameouts and a rough ride over the rocks and debris.  A CR125 with auto-clutch just smoked up the hill, pun intended.?

 

A Montesa (Honda) 4RT also didn't have flameout problems.

 

So the questions are why the differences between then and now:  The near stock XR200 motor was geared lower and doesn't have a tendency to flame out. The RM chassis/suspension just sucks up the bumps and stair steps like the CR. Th XR wheelbase is shorter and the suspension not plush enough.  Traction has not been an issue because all bikes run radial Trials tires on the rear.

 

The Powroll motor has more than enough bottom end for the gearing used, just that if you let the rpm drop below a certain point there is no recovery and a stalled motor.  This motor with its gearing can lift the front wheel exiting a corner in third at 3000rpm, so the torque is there.  The stock motor doesn't seem to sign off as quickly at low revs.   Which suggests an autoclutch for the 218.

Gearing on the two bikes; 12/49 on the RM, 13/49 on the XR218, both with 4,00R18 rear tires.

[Swiss]

Well, if you are going to spend the big bucks. I am pretty sure that the KTM 350 Freeride has been released in the USA.  Might check to see if there are any in Arizona.  Of course that is just shy of $10k to pick one up.  Would be nice to have one set up with street tags!  That would weigh more than your XR200 but when you talk about 218 torque I don't think that you will be able to compare to the Freeride!  The Freeride would require minimal engine and suspension mods, just tuning for your weight.  One of the 350 Freeride guys upped the stock 24hp output to about 34hp with just an injection/timing curve mod.  You also need to open up the airbox which is severely restricted from the factory, at least on last year's model.

 

Will still be happy to look at and set up your clutch basket for the extra plate if it can be done.  When I did my XL350 it took less than an hour to do it.  I think that if you ran the auto-clutch you would need the extra plate set? 

 

I agree that when you geared it up for the increased power, you dropped the bottom end rpms below where your reliable ignition level works.  That means that you get those flameouts because you lack a strong ignition pulse and the engine is turning so slow.  Heavier flywheel "Might" help it but you still need a good hot spark to light it off at near zero rpms.  I think that you are already running the heavier choice of factory flywheel on it if I remember your old postings.  You run into two issues with the ignition, first the stored energy in the cdi isn't very large and second the trigger pulse starts to become unreliable.

[Chuck.]

Honda uses a crank position sensor on other XRs but in the 200cc two valve world only on the TLR200.  I will check the CDI Sensor clearance to make sure it is still at the minimum. I'm running an irridium plug which helps in marginal situations.

 

My concern with the crank position sensor systems is the advance curve is in the CDI box and I don't know what curves different models use.  There are some custom programmable boxes out there that could also provide a stronger spark. 

Of course an autoclutch would also solve the problem.

[brent j]

Well AZ is getting closer; can't decide if I take a bike down or buy one there. 

 

I did go on an interesting ride today in the Cascades that is causing me to rethink a lot about bike setup, including autoclutches.

One infamous trail climbs 4000 feet in a few miles with boulders, rocks, roots, stair steps, and switchbacks. I've ridden this before with a basically stock XR200 motor in a RM chassis, and while a major workout no unplanned stops all the way to the top.  Not today with my Powroll XR200, lots of flameouts and a rough ride over the rocks and debris.  A CR125 with auto-clutch just smoked up the hill, pun intended.?

 

A Montesa (Honda) 4RT also didn't have flameout problems.

 

So the questions are why the differences between then and now:  The near stock XR200 motor was geared lower and doesn't have a tendency to flame out. The RM chassis/suspension just sucks up the bumps and stair steps like the CR. Th XR wheelbase is shorter and the suspension not plush enough.  Traction has not been an issue because all bikes run radial Trials tires on the rear.

 

The Powroll motor has more than enough bottom end for the gearing used, just that if you let the rpm drop below a certain point there is no recovery and a stalled motor.  This motor with its gearing can lift the front wheel exiting a corner in third at 3000rpm, so the torque is there.  The stock motor doesn't seem to sign off as quickly at low revs.   Which suggests an autoclutch for the 218.

Gearing on the two bikes; 12/49 on the RM, 13/49 on the XR218, both with 4,00R18 rear tires.

 

 

 

 

 

 

On topic but different bike/clutch.

 

Your comments on how your bike stalled sound similar to the Freeride. It got better as I got used to the different style of motor but I recently fitted a REKLUSE clutch to the Freeride and I can't speak highly enough of it. It's transformed the easiest bike in the world to ride into something even easier to ride. No stalling at all! Easier to get the power on or off on a steep rock hill and far more control. Hill starts are now a joke!

The downside is getting used to having no engine braking at idle. The clutch engages about 200rpm above idle and drops out about the same. I can blip the throttle at the top of a downhill and it will usually stay engeged. If the speed drops too much and it drops out I just blip it again.

 

I have set up a left  hand side rear brake using the clutch master cylinder through the rear foot master cylinder. I'm in the process of setting up a valve to be able to use the LHS lever for clutch or rear brake as I select.

 

 

Edited September 13, 2013 by brent j

[Old School Al]

 I can't help but wonder why Old School Jeff hasn't experienced these "flameout" problems (or clutch problems either) with his XR218R?  His favorite element for the 218 is the tough, technical, low speed trials type conditions.  Hills, creeks, stair steps, boulders, loose shale, roots, angled downed trees, snow/ice, slimy mud, etc., etc..  These are the conditions where he has many,many times pulled away from much younger riders on larger and way more modern machines. ?   Any idea why he hasn't had these problems........?

 

Old School Al

[Swiss]

Probably more aggressive riding and better clutch work. 

[Old School Al]

He's somewhat aggressive, but not wild at all............he's a "old guy" (can get his senior discount at some places now)! ?   He puts a lot of thought into his riding and caring for the bike, and is very smooth.  I didn't mention his 218 has a lightened flywheel also...............can't really tell any difference from stock weight though.

 

Old School Al

[Chuck.]

 I can't help but wonder why Old School Jeff hasn't experienced these "flameout" problems (or clutch problems either) with his XR218R?  His favorite element for the 218 is the tough, technical, low speed trials type conditions.  Hills, creeks, stair steps, boulders, loose shale, roots, angled downed trees, snow/ice, slimy mud, etc., etc..  These are the conditions where he has many,many times pulled away from much younger riders on larger and way more modern machines. ?   Any idea why he hasn't had these problems........?

 

Old School Al

Oh the torque on the bottom is very impressive and addictive.  For all of the riding you described I prefer it over a stock motor. 

This engine pulls like gang busters most of the time but if the Rs get too low it will flame out. It is also a very easy engine to start, often feeling like half a kick; but it needs to be a more aggressive kick than a stocker with the kick starting at the top so the compression release works.  Classic flameout is at the top of a stair step just as the rear wheel reaches the top.  

I've replaced the needle set, fussed with mixture screw, checked and fussed with float levels several times (now at stock), Irridium spark plug, idle at 1500rpm. 

So I'm open to ideas.

[Swiss]

Chuck,

 

A quick video shot would tell it all.  Can you have one of your riding buddies shoot it and you set up the problem on a ride, before you head south!

[KTM520EXC]

Chuck,

 

I would increase the idle speed by ~ 100 rpm's+ to see if they does not help your problem. Kind of like when you have a vehicle with an automatic transmission in park and when you engage it, it drops ~ 200 rpm.  The same principle applies if you engage your clutch "with a load" it drops your rpm.

 

just my .02 worth.

 

Auto Clutches solves the problem and makes it way more ridable.

 

My experience with auto clutches are 75% positive and 25% negative.

 

They are certainly an improvement, but don't solve everything, i.e. like free wheeling, or being in the wrong gear, which can be abusive to your whole power train. The smaller the motor and transmission, the more abusive, especially with an air cooled motor.

 

Something to consider.

 

Michael

 

BTW, if you want someone to donate a clutch for mods, I have one I can offer.

[SteveThe Snakes]

  Possibly in the past more clutch use worked, trails also get drier and more difficult.

 

I wonder if your having a carb problem off idle. The Kehin 28mm PWK carb I am using on the 230 has an unbelivable pull at and above idle.  It also seems nearly impossible to stall at very low rpm in very tall gears.  I think it atomizes the fuel much better at just above idle.  The slide appears to direct air right into the needle jet it also uses the bleed style needle jet.

[Chuck.]

Please tell more about the PWK carb, I have one I was planning to use on a Montesa 315R as a solution to Delorto problems. 

 

Yes a good test would help, I have a fast responding multi channel recording air/fuel ratio meter I thought might also help id any mixture issues.  It currently also records rpm  but I thought adding throttle position would help, just need an easy way to install one on the bike. One thought I had was fuel surge in the float bowl when the rear wheel climbs the stair step, I use to run the float level almost .5mm low but found it was easier to jet running stock height. Maybe a faster idle will help as I used that on stock motors for years to reduce rear wheel lock up, and dead engine, while braking on downhills.

 

Maybe the air/fuel with rpm and a video might do it. 

 

We are only 4 weeks away from leaving and I have a bunch of higher priority items to finish. Next problem is recreating the obstacles and PNW weather.

[SteveThe Snakes]

Chuck,

Look at the slide and needle jet on the PWK carb. It appears it directs air right into quick atomization of the bleed style needle to perfume fuel into the motor. I can p.m. you the jetting I am using and also a needle jet modification that seems to work well.

One of the only drags is reaching up into the bbr frame to put the chock on. They do however make a remote choke cable kit.

You'll have to make a manifold as it is a spigot mount. A cb500 four rubber works well from the carb to manifold connection.

Steve

[Chuck.]

I have a manifold from another XR200 carb project, but my concern with the PWK is it uses a  primary type needle jet and the high vacuum of the 4Ts do better with a bleed type needle jet.  So although the FCR carbs use primary type needle jets I have some reservations about using a PWK on a 4T. Any advice would be appreciated.

[SteveThe Snakes]

I have a manifold from another XR200 carb project, but my concern with the PWK is it uses a  primary type needle jet and the high vacuum of the 4Ts do better with a bleed type needle jet.  So although the FCR carbs use primary type needle jets I have some reservations about using a PWK on a 4T. Any advice would be appreciated.

 

 

The PWK you have has a primary type needle jet?

The CR85 or KX100 28mm PWK use bleed type as far as I know.  Both of the ones I bought are bleed type that came stock on a KX100.

[Chuck.]

I made that statement because I didn't see any air jets on the inlet side and the carb was from a 2T KX85.  I bought the carb for use on a 2T over a year ago but never got around to doing the install and tuning.

I pulled the carb from storage and removed the needle jet holder and it has air bleed holes, so it is a bleed type. 

[SteveThe Snakes]

Yes it's kind of funky. It looks like they used the same hole for the pilot air screw as it passes through in the back of the carb.