Postby DewCatTea-Bob » Fri May 16, 2014 6:15 pm
[quote= NewKidOnTheBlock ...
" cutting hardened steel is no issue as I have access to a wire EDM at work which should find it no issue. "
____ Then the job could be rather fun for you, (if still a bit risky).
However with access to such a shop, you might rather be able to produce a 5.5mm shim-plate to place between the head & bearing-support/cap-cover, so as to allow the installation of the longer camshafts (so that you then wouldn't ever have-to cut-down another standard-length shaft) ! _ Or modify the bearing-support so as to be able to sink the 6202-bearing 5mm deeper into the cap.
I'd think that these solutions would be preferable to cutting-down camshafts at-least 5mm !
" A white cam is however, exactly what I was after, "
____ I think one of us is confused about something...
You had mentioned that you wanted "a slightly more aggressive cam", yet a scrambler-cam is very-MUCH MILDer than the cam.model which your engine is supposed to have.
So what is your actual goal as far as engine-performance goes,, more mid-range, more peak-power, or what ?
__ From my-own experience, I know that a milder-cam (than those two noted by Jon) would be a better match to go-along with your long-stroke motor,, so I'd agree with choosing to install a more appropriate cam.model.
__ Another concern is, the 'White' cam.model designation was unfortunately used for at-least 4 significantly different Scrambler-camshafts !
Do you know which specific one you most desire ?
" I am unsure if I want to get rid of the stock cam,
would you consider selling your white one? "
____ I have a collection of most-all Duke-camshafts, of which the one I'd trade is part of,, but it's only for-trade for any cam.model that's not yet in my collection.
I deem having Duke-camshafts as better than having cash-money, so I really don't wish to sell any (before I ever become cashless).
" I do have another unidentified cam which I would be more willing to part with which I can take some measurements from if you’re interested? "
____ Perhaps but, lets get it identified ASAP !
Can you post some pix of it (mainly showing it's cam-profiles) ?
" I have a spare 28mm amal which I was planning on using with this engine so the intake wouldn’t be any larger than that certainly, "
____ That's a pretty-reasonable goal !
Have you yet checked to see exactly how much porting-work that would require ? - (I can't hardly believe it's so much as you've indicated, and think you shouldn't have-to remove much more than just 1mm.)
" I was considering 36mm intake /33mm exhaust, however I cannot obtain a 36mm intake and wondered if 37mm is just too large. "
____ If your 69-bore 250-head is actually the same as a std.200-head, (as I think it should be),, then a 37mm intake-valve is not too large. _ But I think your 250-head OUGHT-to already have 36 & 33mm valves in the first place, (or at-least 33 & 32) !
__ Have you checked to measure the exact size of those stock valves yet ?
" The crown of the piston – I do not yet know, I have one on order from Spain but have yet to see it! "
____ Exactly what kind/type of piston did you order ?
In any case, I expect it will have a 38mm cut-out/relief valve-pocket in the crown-top.
Let us know the exact size when you get it.
" starting with a scrambler engine would perhaps have saved me much work, it was an issue of availability over here. "
____ Too-bad you're so far away, otherwise I'd swap a 250-Scr.motor for yours !
" but trans-Atlantic shipping made it unreasonable. "
____ You're certainly right about that ! ... I've had a couple boxes of bike-mags shipped over from your country, and the shipping-cost was indeed unreasonable to the point of being ridiculously atrocious !
So I ended-up letting the seller keep the other two boxes which had yet to be shipped.
" I’m never one to shy away from a challenge so, regardless of how the results compare to others I would like to make this engine the best I can "
____ That's the right attitude to have, and there's a certain reward attained by doing just the work in itself ! _ And afterwords you then finally have a very unique completed project to be proud of.
" I believe my engine is a De Luxe. "
____ According to Jon's posted data,, it's my good-opinion that that model has the PREFERABLE cam/valve-timing ! _ But still it's not what I think would work best.
Hopeful-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob