Two Stroke Motocross Forum > Non-Moto
My 380 road racer project
2T Institute:
--- Quote from: TMKIWI on June 27, 2013, 04:11:26 PM ---School me on the isoelastic engine mounts.?
And you should be wearing gloves when tig welding.
--- End quote ---
Opps, forgot I wasnt on my PC, this is JERAM
--- Quote from: Jeram on June 27, 2013, 04:11:26 PM ---
big bore 2Ts like to vibrate alot... and when in a stiff aluminium frame things can become diabolical easily.
Vibrations are the main cause of these projects to fail (either through frames and componants breaking or the rider not enjoying the bike)
We came up with the idea a few years back to isolastically mount the motor on urethane bushes.
The idea of rubber mounting a motor isnt a totally new concept however, you just need to look at a banshee or a BSA for instance to see rubberised mouting system.
However this system has much more dampening. 4 dampening bushes at the front and 2 in the head stay.
We HOPE that by combining this with tungsten inserts in the clip ons, rubber mounted rear sets and a foam seat that this will make the motor feel silky smooth. Failing that we will also have the crank rebalanced as required.
--- End quote ---
citabjockey:
I saw this cool project on another site (KTMtalk?) some time back, was wondering about its current state. Cool to see it so close to alpha test.
What performance do you expect to get out of the 380 versus a twin cylinder mill (RZ/Apillia)? I would think the 380 is significantly lighter but if you breathed hard on both the smaller jugs would be better at sheer horsepower for a road racer?
How do you isolate the engine vibrations from the pipe? Flex header or flex mounts?
Coop:
Excellent.
Jeram:
--- Quote from: citabjockey on June 27, 2013, 10:02:12 PM ---I saw this cool project on another site (KTMtalk?) some time back, was wondering about its current state. Cool to see it so close to alpha test.
What performance do you expect to get out of the 380 versus a twin cylinder mill (RZ/Apillia)? I would think the 380 is significantly lighter but if you breathed hard on both the smaller jugs would be better at sheer horsepower for a road racer?
How do you isolate the engine vibrations from the pipe? Flex header or flex mounts?
--- End quote ---
At the momment we are aiming for 65 horsies at the rear wheel with silly amounts of torque at all RPMs. We were aiming for even more with a one-off racing cylinder prototype but I think 65hp and 70 nm and 105kg is enough for now
It wont quiet have as much top end as my 85hp 421 banshee/rz motor but it will be quicker around a track due to its usability and lack of weight.
Jeram:
Here we go guys, an update from the weekend...
As expected, we got painfully close to firing up the bike for the first time.
We were just short of a few engine mount bushes and perhaps a roller starter.
What we did achieve though was some bloody good progress over a solid 3 1/2 days in she workshop. The bulk of the time was spent finishing off this absolute beauty of an expansion chamber which took the two of us a solid few days to complete.
The rest of the time was spent doing the other odds and sods required to complete the bike including coolant/plumbing, installing and wiring up the ignition, fuel delivery/overflow/vents, carb jetting and generally checking over the entire bike to find any outstanding issues.
All in all we ended up with a 99% complete bike that just requires a head stay and PV system prior to being brought back to Melbourne where I will finish off the little details myself (paint, dyno tuning, CNC rear caliper bracket) over a few solid weekends.
Mocking up the last few pipe sections, which we definitely the most difficult as the had to fit between the swingarm, rearsets, rear tire and come out under the bike at the correct angle for aesthetics.
The new headstay and frame mounted bracket,
The finished pipe
We've also organised for an A-grade rider to help us set up the bike and race it in a couple championship races to see what the bikes full potential is. I'll be riding it also in between.
Hopefully I'll have the bike freighted back to me in a few months where I can finish off the final details before entering in a few events.
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