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  #21  
Unread 01-04-2012, 08:32 PM
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ToraTora ToraTora is offline
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Wink Screen Play

Much like on the GPR with the new screen hardware I got the same kit from SF Moto for the Mito. Here's the bike with the gold screws that the PO had installed on it. A few of them had already vibrated off and since they didn't look right on this bike it was time to replace them with some proper blackness.



Here's the kit.



I like these kits however they do have some issues such as the plastic washers need trimming, and the rubber nuts are just long enough that you have to squish them to get them started on the screw.



Then they wind up and squish and are suppose to look like in this photo. However if you can't get your hand in the zone with enough force to squish the rubber nut then it wont start the threads. I had to pull the front piece off the Mito to get the front screw mounted.



The finished product–little soft on the focus so I'l have to get a better photos later.



A couple of good looking stallions.

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Now: '00 Derbi GPR 75, '87 Puch Monza Barcelona, '05 Wicked GPR, '95 Pika Mito, '07 Bol d'Or
Then: 1974 XR-75, DS-100, IT-175, MB-5(x2), CB400, CB750F, 750 Paso
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  #22  
Unread 01-07-2012, 04:38 AM
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ToraTora ToraTora is offline
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Wink Check the Clearance Clarence

I took the top end off the Mito today. All the parts look good–that was a relief. :P Once I had them out I fitted the wrist pin into the crank with the bearing and I couldn't feel any play ruling out that as the noise source. Then I got out the feeler gauges and pretty much convinced myself that I wasn't going to be able to properly check anything. Accepting that I packed up the cylinder and piston and took them to JP our local machine shop that understands strokers. He showed me some pretty interesting info about the Wiseco pistons. On what he calls the M-series pistons (what we buy for our Mitos and it would appear other stroker machines) have a code stamped into the top stating the bore in mm which the piston should run. In this case the piston I have has 853M05600. The 5600 translates into 56.00mm bore for this piston (I'd like to know what that 1290F indicates). Then if you are lucky enough to have the box (because they don't tell you this information on the piston specs page on their website) Wiseco lists the clearance between the piston and the cylinder. For this piston it is 0.051mm (most folks in the States still think in inches so the box actually lists that first 0.0020").

Checking the piston measured 90° off the wrist pin on the skirt and subtracting that from bore measured at the skirts (and well a bunch of places where he found that the cylinder didn't show much wear because it was the same at the lower skirts and other locations in the cylinder) there was a 0.2032mm (0.008") clearance. With feeler gauges I was only able to really get a .005" in there smoothly–I could get the .006" in and a .007" very tightly although it seemed more like a .005" showing to me that for this measurement feeler gauges are inaccurate and the wrong tool for the job (at least outside of just getting a ball park kind of check, and certainly not for a critical check).

Comparing this with what I found in the service manual where I read in a table that for a B cylinder (which mine is stamped) the proper piston size is 0.040 to 0.060mm with a wear limit of 0.100mm for the Mito EV, for the "racing" Mito (whatever that means) the numbers were slightly different with 0.038 to 0.062mm.

So doing a bit of math 0.060 plus 0.100 = 0.160mm, just a bit shy of the 0.2032mm measurement for my combo, and I think those numbers are for a non forged piston. Since the Wiseco is a forged piston that will expand more when warmed up having that 0.04mm of extra room should be okay. For the next test I'm going to put it all back together, let the engine warm up to operating temp and listen to what it does. If the sound goes away at operating temp then I'm going to run it. JP says that he's seen stroker engines with greater piston clearance run fine and that the forged pistons are strong pistons. Even still I'm finding the results of this math to be somewhat disconcerting. : /



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Now: '00 Derbi GPR 75, '87 Puch Monza Barcelona, '05 Wicked GPR, '95 Pika Mito, '07 Bol d'Or
Then: 1974 XR-75, DS-100, IT-175, MB-5(x2), CB400, CB750F, 750 Paso
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  #23  
Unread 01-07-2012, 01:12 PM
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trevorparscal trevorparscal is offline
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I'm running the same piston with the same clearance, and had the same issues trying to measure the exact amount of clearance. My stock piston actually had more clearance than the Wiseco, our worry was initially that the Wiseco would be too big. My bike is running well so far, but I'm going to have Carlos inspect it after break-in to make sure we have the timing and jetting right (2 things we adjusted to fix my detonation issue)
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  #24  
Unread 01-07-2012, 07:37 PM
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twinturba twinturba is offline
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Pretty sure I mentioned this to you guys before, I installed and ran this piston in my 1995 mito years ago without any issue. The bike had a B cylinder.
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  #25  
Unread 01-10-2012, 10:32 PM
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ToraTora ToraTora is offline
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Cool

I put the top end of the Mito back together today, and it seemed like I should put up some photos of the PWK in its now home. I've run the bike through a few heat cycles and then off for a ride. Still no wide open action until I get the new piston run in a bit more. At that point I'll do some plug chops and HFFS action to tune the carb. For now the stock Kawasaki tuning seems to make the bike quite happy. The throttle response is snappy and the bike accelerates smoothly up to around 8K or less where I shift since I'm still running in the carb.

Since the intake manifold was cracking on the outside I massaged in some silicon sealer into the cracks, and then set for a layer all around the outside surface–hopefully it will help.



nicely dressed tubes











__________________
Now: '00 Derbi GPR 75, '87 Puch Monza Barcelona, '05 Wicked GPR, '95 Pika Mito, '07 Bol d'Or
Then: 1974 XR-75, DS-100, IT-175, MB-5(x2), CB400, CB750F, 750 Paso
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  #26  
Unread 01-11-2012, 08:09 PM
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ToraTora ToraTora is offline
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Cool The Fork Up

Yesterday when taking the Mito out for a test ride it was noticed that the forks were engaged in a lock out. That's right–riding a hard nose. :P Which translated into "What will Wednesday's project be–taking the forks apart?" And that's what happened today. After much figuring and a false hypothisis I finally determined that it was the order or sequence of the bits that needed shuffling.

The forks in lock out mode


The fork components


Proper assemblage–start with a fork sliding tube


Insert the inner spring bushing with the angled end pointed down (this photo shows it incorrectly pointed up)


Add the spring tension space–this has to be inserted below the spring or it will get hung up on the internal stationary tube insert


Add the spring (this can be added from the top later


Then pull up the sliding tube rod (this will actually be through the spring


Slide on the disc and insert the half moon pieces (the spring needs to be compressed in order to achieve this step


With both half moon clips


Then put in some fork oil and put the caps on and ready to test.

Here's a look see down the stationary tube where the spring spacer gets hung up.


In addition to sorting the forks I check on the plug to see how the jetting is set. It looked pretty good however I've yet to run it WOT as the bike is still having the new piston run in. This was with a 138 main jet so I decided to richen it up a bit and put in a 140.


Kind of hard to see this one however with a quick loosening of the intake manifold and air box clamps, and releasing the choke cable the PWK nicely tilts to the side where a 17mm socket can get in and remover the access port to the main jets. Then a 6mm socket to pull out the jet for replacement. One of the cleanest setup I have to jet changing only out done by access on the Monza. :P Oh and remember to turn off the petcock.


Additionally I needed to figure out why the speedo wasn't working. Since the front wheel was already off I inspected it, then I had a look at the stock wheel to see what might not have made the transition. It turns out there is a clip that was needed.






And there you have it a solid six hours worth of wrenching activity.
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Now: '00 Derbi GPR 75, '87 Puch Monza Barcelona, '05 Wicked GPR, '95 Pika Mito, '07 Bol d'Or
Then: 1974 XR-75, DS-100, IT-175, MB-5(x2), CB400, CB750F, 750 Paso
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  #27  
Unread 01-14-2012, 03:13 AM
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ToraTora ToraTora is offline
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Cool It's all about the flow

Stopped by the Treats to pick up some jet action. I've been working on tuning the Mito with the PWK. A 138 comes in the carb that seemed lean. I then tried a 140 which comes in the KX85 version. That too was lean. Next was a 145 that I picked up from Scuderia the day previous, and that too seemed lean, and I've got a 150 installed and the bike is getting closer. The needle is still at the second slot from the bottom and seems a bit boggy so I'm going to drop it down to the third from the bottom.

Another thing I want to address is the spring in the carb. Because it is set up for a bike that is premixed when combined with the spring of the oil injector it is a little stiff and I want to get a softer spring installed.

Interestingly the stock Mito throttle that comes with a TM35 equipped bike becomes a 1/4 turn throttle with the PWK28. Performing HFFS is somewhat interesting with such a small range of motion.

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Now: '00 Derbi GPR 75, '87 Puch Monza Barcelona, '05 Wicked GPR, '95 Pika Mito, '07 Bol d'Or
Then: 1974 XR-75, DS-100, IT-175, MB-5(x2), CB400, CB750F, 750 Paso
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  #28  
Unread 01-15-2012, 07:05 PM
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ToraTora ToraTora is offline
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Cool Checking the Plug

After a 400km ride chasing the liter bikes around the SC mountains I pulled the plug and took a look see. The bike ran well with good pull and quick reving.

This is with a #150 main, NAPF needle set to the third position from bottom, and a #45 slow jet. I'm still thinking to run a #48 slow jet because I have the idle screw cranked down pretty tight.

Over all there is power through most of the throttle, I've yet to spend time in WOT as I wanted to get the top end run in first. Now I'm ready for some WOT and plug chops.

One thing I've noticed is that there is no point where it feels like it has gotten on the pipe. It will rev into and beyond redline (again without WOT), and it does pull hard all the way through, there just isn't the feeling of a large increase of power.

__________________
Now: '00 Derbi GPR 75, '87 Puch Monza Barcelona, '05 Wicked GPR, '95 Pika Mito, '07 Bol d'Or
Then: 1974 XR-75, DS-100, IT-175, MB-5(x2), CB400, CB750F, 750 Paso
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  #29  
Unread 04-11-2012, 02:12 PM
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ToraTora ToraTora is offline
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Wink Shocking!

Oh my! Something sexy this way comes...

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Now: '00 Derbi GPR 75, '87 Puch Monza Barcelona, '05 Wicked GPR, '95 Pika Mito, '07 Bol d'Or
Then: 1974 XR-75, DS-100, IT-175, MB-5(x2), CB400, CB750F, 750 Paso
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  #30  
Unread 07-01-2012, 01:02 AM
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ToraTora ToraTora is offline
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Bat 2 Damping the Rear

With the last post we saw the RS250 shock. I had a chance to install tho shock on the Mito only to learn it isn't quite as easy to install as I had expected.

Pretty much everything on the Mito is decent quality. The rear shock has preload adjustment on the spring, but it doesn't have either rebound or damping adjustment. The trick I had read was to pick up a shock from the Aprilia RS250 which features all of those goodies. I was told that these could be found for around $50. I suppose that was some time ago since I watched for one of these for over a year and the only one I saw come up was this one for $100, which of course I paid.


To get at the shock it because easier if the tank, seat, and air box are removed. Here are some shots of the stock shock installed. The lower bolt and nut are 14mm heads. The upper is an 7mm allen head special bolt with a 14mm nut.









The stock shock out of the bike.


The RS and Mito shock side by side.


Measuring the upper mount of the stock shock--22mm.


Measuring the upper mount of the RS shock--almost 30mm for a near 8mm disparity.


Measuring the lower mount of the stock shock--again 22mm.


Measuring the RS lower shock mount--just over 25mm for a 3mm disparity.


Some comparison photos.










Interestingly the RS shock has a threaded end. Unfortunately even though it is the same size the thread pitch is different.




So the shock is going to take a bit more machining action than presupposed, thus back in the box until it can be properly modified.


__________________
Now: '00 Derbi GPR 75, '87 Puch Monza Barcelona, '05 Wicked GPR, '95 Pika Mito, '07 Bol d'Or
Then: 1974 XR-75, DS-100, IT-175, MB-5(x2), CB400, CB750F, 750 Paso
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