Gilera DNA 50 RST 2006 Build

Discussion in 'Scooter Projects' started by TeeZer, Jan 24, 2016.

  1. TeeZer

    TeeZer Member

    Messages:
    124
    Rides:
    R1, DNA 50
    Hi all,

    I thought I would start a post on my build. Some background...

    My bike has 150 miles on the clock, being practically new, the plan was to store the original min engine and replace it with a completely new tuned build.

    So the past couple years, I have been collecting new parts and trying to source some decent second hand crankcases.

    Firstly, after purchasing what I thought to be a couple of suitable second-hand crankcases and an additional complete motor, I realised that if this project was to turn out as pristine as I wished it to be, I would have to get brand new crankcases. The second-hand crankcases were simply too far gone, seized bolts, corrosion, and everything else that goes with second-hand alloy 5 years plus parts. After some patience I managed to source two brand new crankcases (aiming to use one of them) for a reasonable price. So recently, having now gathered all the parts, built my new engine.

    So that were collected and fitted...

    • Cylinder kit: Stage 6 Racing MKII cylinder kit
    • Crank: HPC crankClutch: Stage 6 Torque Control MKII Clutch & R/T CNC Clutch Bell
    • Induction: Stages 6 R/T Intake manifold, V-Force 3 reed block
    • Water Pump: Stage 6 R/T water-pump
    • Air Filter: Stage 6 Double foam
    • Carb: Dellorto VHST 24mm carb
    • Exhaust: Yasuni City C16
    • Gearing: Malossi gear-up (only one available for the Gileran DNA 50)
    • Transmission: Malossi Over-range torque driver
    • Variator: Malossi MHR variator
    • Belt: Malossi X Drive 619830 (rather hard to decide on with over-range setup, Kevlar belt is way shorter)
    The idea on further posts to this thread will be to catalogue each stage and the problems encountered in a hope that it will help someone else with their build.


     
  2. TeeZer

    TeeZer Member

    Messages:
    124
    Rides:
    R1, DNA 50
    Some major parts

    20151206_094419 (Custom).jpg
     
  3. TeeZer

    TeeZer Member

    Messages:
    124
    Rides:
    R1, DNA 50
    Cylinder Matching

    The first step was to do some cylinder matching, for this I need a tool, some accessories and some steady hands. Having never done this, and having to work on brand new crankcases it was scary.

    The Tools
    The only viable option for me was to use a Dremel. The main deciding factor was that I did not at the time have a compressor and still do not have the space for one with the capacity needed to run air tools. After much research I found that there were very mixed views/feelings on using a Dremel, but I also know that there are old-school Dremels and the new ones which are way better. I purchased a Dremel 4200 kit (4200-4/75).

    dremelĀ®4200-10567.jpg
    Next was the choice of bits to do the job, I saw some guy had great success on YouTube using the small sanding bands, as noted, they are really cheap and disposable on eBay. Having not tried anything like this, I decided to get some as a backup but also knew I would require something slightly more industrial (as much as can be fitting a Dremel) like some tungsten burrs. I got these also from eBay too.

    Dremel Burrs.jpg

    Approach - Practice makes perfect
    As mentioned, I had purchased some second-hand crankcases and a second-hand engine which I was hoping to use for the build, but then found some affordable new crankcases online. This turned out fine as I now had something to practice on, this is very IMPORTANT as you will get a feel for how the tools cut, the speed they work, the difference between the different bit and how/when they could dig going around the corners that you are required to do so.

    Having got some practice under my belt I decided to go for gold on the new crankcases. I did a lot of research on the web and would advise everyone to be very certain on what needs to be done. I started by marking out the relevant areas that needed work. The cylinder and base gaskets were used as a template, I had the metal spacer Stage 6 base gaskets which worked great.

    Whilst practicing I noticed that it was extremely easy to nick surfaces with the burr and so decided to duct tape the sensitive areas just in case, up to you, but it take next to no time and thought it could only help. I also taped and bagged the areas where there were bearing fitted as the new crankcases came with gearbox bearings and cylinder studs installed. This would have been easier without the cylinder studs in, but I was not going to chance removal.



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    End Result
    The Dremel and burrs worked perfectly, sure it did not give the most unbelievable mirror finish that you see in some professional jobs but there is also a debate on how smooth this surface should actually be.

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    Whist I had the Dremel out I decided to just polish the exhaust port too

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  4. TeeZer

    TeeZer Member

    Messages:
    124
    Rides:
    R1, DNA 50
    Crank Install


    Once we had installed the Stage 6 water pump, it was time to install the crank.

    After much research on the web I decided on the hot/cold technique, bearings in crankcase first. The main reasoning behind the choice was why use pressure when you can just slide something together. So the night before I put my crank and crank bearings in the freezer. I then set about heating up my crankcase deciding to heat the entire crankcase and then further heat the area with a heat gun. Once the first side was to temperature I took the first bearing out the freezer and dropped it in perfectly. The second one did not go that well, I dropped it in and it would just not go in straight no matter what I did. On further inspection of my crankcase I realised that there seemed to be a slight flaw to the machining where the upper edge of the bearing housing was slightly raised compared to the rest. This left me no choice but to resort to using my mate's fly press. A week later I managed to get to my mate for another attempt. The idea this time was to use a combination of the hot and cold method and the press. I did the same as the first bearing, paying extra attention to sitting the bearing as square as I could and eased it in with the press. All went well this time. Next the crank.

    The next weekend I decided to put the crank in, once again all went well with the first side. I heated up the bearing race and dropped the crank, straight out the freezer, straight into the bearing of the small half. I then put the small crankcase half with crank into the freezer for half a day. Applied the sealant and then went for it.

    Despite doing the same thing as the first side, the crank halves just would not go the last few millimetres. As I have seen many do, is quickly try use the crankcase bolts to pull it that last bit closed, but the crank seemed to just get tighter when trying to turn it. In a hope that it would eventually seat properly I kept tightening the bolts in a pattern with a torque wrench. This is when disaster struck, even though one of the bolts were not to the correct torque yet (not even tight yet) it snapped. Even worse it snapped flush at the bottom of one well of one of the bolts holes that had a location spacer. The bolt was a brand new Piaggio original bolt supplied by AJ Sutton, I do not think I will trust them again. This meant I had to order an extractor and source some new same spec bolts as I did not trust any of them.

    Another week later, I managed to get a guide machined for the extractor which could be put into the location spacer hole with the snapped bolt enabling me to drill straight down the centre of the bolt. Being a brand new bolt and knowing it had not even tightened it would come out easily and so it did, just screwed in the extractor by hand and it started to come out. I did try get the bolt out without the extractor but it would not budge.

    So realising I needed a different approach to getting the case together I decided to go back to my mate with the press and get him to weld up a tool that I could use to pull the crank into the crankcase bearing. There is a commercial tool but you can make one very easily with a piece of pipe, threaded studding and some nuts (a couple that fit your crank, and a couple that fit the stud thread).

    Now that all is back to where it was two weeks previously, and armed with my new tool I went in for another attempted. Reapplied sealant. Same idea as the second bearing, I planned to use the hot and cold technique in combination with my new tool. Once the bearing race was hot with the heatgun, the got the small case with crank out the freezer, put them together as far as they would go, then used my new tool to pull the crank through the bearing race into place. It worked perfectly, pulled the crank in sweet and was turning perfectly after a few taps on it.

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    Last edited: Apr 29, 2016
  5. scubabiker

    scubabiker NITROJUNKIE

    Messages:
    7,321
    nice build thread. a quick note to anyone else following about the crank, use some grease on the bearings/crank, it makes it much easier, not sure if you did, but guess you did. nice work with the dremel you look like a pro almost!
    (i polish the combsution chamber, piston top and exhaust port!)
     
  6. TeeZer

    TeeZer Member

    Messages:
    124
    Rides:
    R1, DNA 50
    Gearbox

    Upon inspection of the bearing which came already installed in the new crankcase we realised that the bearing was faulty. It would spin for ages and then jam solid. This was discovered before we even started cylinder matching, so it was not a result of that. Believe it or not, pressing the bearing out was not the hard part, trying to remove circlip was. My friend with the workshop and the press fortunately has a decent automotive service shop next door which had a large pair of SnapOn pliers which did the job. The problem is that the clip is large, thick and only goes 2/3 around, making it an extremely hard to remove and fit without some very wide pliers that did not have too much angle on the location pins when opened. Once removed we simply pressed out the old damaged bearing and in the new using suitable sized sockets.

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    Now for the gears. I purchased a Malossi Gearup kit which required pressing the original primary gear off the transmission shaft, and pressing on the new Malossi straight cut gear. This was done easily without and problems with some care making sure it goes in straight, but does require a press. There was no options on gear ratio as there is only one kit available for the DNA.

    Malossi Gearup.JPG Malossi-Gearup-diagram.jpg

    After all this was done, I was off home to assemble my gearbox. I replaced the bearing in the gearbox cover (reversed cover, on the outside for the DNA), this just slipped in by hand along with the all the required new seals. Assembly was easy as all goes in one way. If you doing it, DO NOT FORGET YOUR SHIM WASHERS. Next, I put some sealant on, put the overflow pipe in and simply bolted it together with new bolts.


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    After my experience with the inferior quality original bolts, I meticulously sourced new bolts with the same specification.
     
    Leeder likes this.
  7. TeeZer

    TeeZer Member

    Messages:
    124
    Rides:
    R1, DNA 50
    Stage 6 Water Pump

    Fitting of the water pump itself was really simple, just make sure that you do not press it in too deep. The difficulty came trying to align the pulley on the crank shaft with the water pump (orange anodised alloy) pulley. The misalignment was extremely obvious when I turned the crankshaft using the flywheel and watched the water pump belt slowly shift off the pulleys. I had purchased some stage 6 spacer shims for variator adjustment which worked perfectly to space the crankshaft pulley out from the crankcase. This process took some time with multiple attempts/reassemblies/turns to get perfect.

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    Cylinder & Piston

    The only difficult here was trying to get the gudgeon pin clips in, they are seriously tight. I followed this handy vid taught my some technique.



    I purchased some metal base gasket spacers for the cylinder. First we assembled the cylinder and head with standard gaskets, torqued it up to the correct setting and checked the squish. It turned out to be perfect.

    Tips:
    1. Try not scratch the piston whilst fitting the clips
    2. Make sure the piston is the correct way around (arrow to exhaust port)
    3. Be gentle fitting the ring
    4. Do not drop the second clip into the crankcase. To be safe shove a clean cloth into the hole before starting.
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    Variator

    The Malossi variator instructions were not that clear. We basically assembled it using common sense and the spacers available that seemed to fit. There was this weird plastic spacer in the kit which threw us off a bit, but we leaving it out. We also found that the thick spacer spaced the variator out too far. We solved this by purchasing a Trend BW24 15mm Bore Bushing Washer 30mm Diameter offering the perfect spacing and would also double as a guide to keep the belt in place. Yes, the spacer is from a router! On top of that we also used a few more of the Stage 6 shim washers.

    The key is to get the variator spaced out from the water pump crankshaft pulley perfectly so that the the kickstart plate is clamped sufficiently by the variator nut, not too much and not too little.

    20150808_180304 (Small).jpg $_35.JPG

    General Engine Assembly

    Everything else basically bolted straight on so not much to write about.

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  8. Jamos

    Jamos New Member

    Messages:
    2
    Awesome looking project bud
    Just bought my own dna project
    Good luck with the build
    Jamos
     
  9. TeeZer

    TeeZer Member

    Messages:
    124
    Rides:
    R1, DNA 50
    Thanks Jamos, almost complete now. Just got to iron out some carb probs, just waiting for a spare sunny day. Let me know if you have any questions and good luck on your project, finding info on the DNA is a little difficult at times.
     
  10. Jamos

    Jamos New Member

    Messages:
    2
    Yeah tell me about it bud
    Then again they stopped making them 10 years ago now so no surprise really.
    I'm looking forward to pulling mine apart its been previously "tuned" by its last couple of owners so lots of work to do ha ha
    Thanks for the offer I may well take you up on that
     
  11. scootzmadness

    scootzmadness Left the forum.

    Messages:
    4,235
    Rides:
    None.
    Not seen this until now. Some nice work there :cool:
     

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