My
" NAUTO " (new auto)
88 Auto engine in an 07 WR250 frame,
Custom pipe, inlet manifold & frame mods, ported for better torque & starting, suspension set up for my weight & (lack of) ability.
Had a few head aches & learning curves but it's getting better every time I ride it, I also have an 85 Husky CR500 6speed motor with a Magura hydraulic clutch that fits straight in the frame to make it a little more versatile.
So I've been asked for a few more details about what mods where needed so here goes,
Engine- Swingarm pivot hole bored from 14mm to 17mm to fit the 07 swingarm bolt (not as easy as you'd think as the outer flanges bore out ok but the centre case locator is as hard as they come).
- OR390 kickstart to get the clearance from the footpeg & frame, I originally planned on using the 88 model kicker but you need to be 7 foot tall & it still didnt clear the foot peg.
- Cylinder ported for more torque & easier starting (great mod even if only for the starting as there is no push starting)
Frame- Cut in front of the foot pegs & lengthened 60mm which also allowed for the cut above the exhaust port clearance to be raised higher for the different height of the exhaust ports (I used a professional race car frame builder to weld the crome moly).
- Solid frame engine mounts to reduce the vibration & chance of bolts coming loose(sill not sure if this was a good idea as it makes removing the engine more difficult).
- A portion of the frame on the left swing arm pivot was cut away & strengened to allow kick start clearance.
- A hole was cut into the under side of the top frame rail directly above the spark plug to allowm me to use a ignition timing tool while still in the frame.
- I am also considering making a head to frame mount to try & reduce the vibration even more.
Swingarm- The inside edge of the bearing pivot needed 7mm to be removed to accomodate the 88 engine but I only took it from 1 side so I could get the sprockets to line up which also means the the engine is slightly offset.
- I also had to use an older style chain guide to get clearance for the 54t rear sprocket.
Other mods & sods- Radiators needed to be spaced 10mm out from the frame because of the frame exhaust port being raised.
-Custom made carb to cylinder inlet manifold.
-Custom made to 430 specs exhaust utilising the WR250 expansion chamber & muffler to keep the stock looking appearance.
-Custom made 54t rear sprocket by Chain gang.
All in all the building & riding has been a lot of fun to do especially as the fridge was close by, I am hoping to get some video on here soon.
Cheers
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