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 The very latest and no technical two stroke tuning topic !

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bettsd



Number of posts: 854
Age: 50
Localisation: worcestershire
Registration date: 2007-06-14

PostSubject: The very latest and no technical two stroke tuning topic !    Thu Feb 24, 2011 10:17 pm

just spotted johns post

i agree with john I just can not keep pace with all this extra tech stuff on here latley ? but would help if a little bit more background was forth comming. - Just two comments on this, it must be me, but I seem to be doing a lot of a)assuming -b) guessing, on what people are saying
just joking john - hope ur well, did the earth movement for u or your bike, hope ur ok down there from what I here , a seriouse peek. ?

Mike come on !! bhp and FTLBS ? I like ur style, I do this in a meeting it usually opens peoples eye's or ears!.

I thought Robbies's bike looked quite quick. !

regards Derek
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mjpowell



Number of posts: 797
Localisation: Lincoln England
Registration date: 2006-12-08

PostSubject: Re: The very latest and no technical two stroke tuning topic !    Fri Feb 25, 2011 2:04 pm

More assuming and guessing for you!? This is the right side crankcase of my new 'Evo' engine, study it carefully and you should have a few questions to ask? (I copied Evo from Harley not the Ducati 848Evo, Ian/Tom refer to his new motors as 'ironclads' think it coz they weigh the same as an 'anicent portculis') Wink





Last edited by mjpowell on Sat Feb 26, 2011 12:42 pm; edited 10 times in total
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bettsd



Number of posts: 854
Age: 50
Localisation: worcestershire
Registration date: 2007-06-14

PostSubject: Re: The very latest and no technical two stroke tuning topic !    Fri Feb 25, 2011 4:10 pm

WoW pictures paint a thousand ?--- Great Picture like to see the other side too !

- have a number of questions, but first, I'm actually looking forwards to the season start. More importantly has anyone had regs yet>? was wondering when we would get them.?

Alan could you please post on here or mail me about the bellmounth work you spoke about, I now you have some really interesting comments to make on this, hope you well and the recovery it still on course, not heared from you in a while.

Planning to dyno my bike again first thing sunday morning, so hopfull will have some technical stuff to post about. On the dyno you asked about, we have same set up as last time, all bar- some smaller jets- a new belmounth to try, a mock diff pipe-bogged made from two, once I get a good design, I will re-make properly, enjoy doing this myself, will show results, also due to overheating, we have reduced the comp ratio again. somthing wrong here ? ?.

out of interest you 125 riders what head volume are all you running, Im on 15cc volume, is this big now, I had assumed avgas could afford a lower volume, as we bought the jetting down the temp went through the roof, its air cooled so don't want to distroy the thing, lifted the head looked ok initially, under closer inspection, slight det on front side piston exhaust edge. we are assuming its either breathing well or has a hot air leek, as when cold its fine. losing 2 psi in hrs.

Mike on your photo. mine engine been in the frame a few months, ? your leaving it a bit late ?.
1)On that very interesting shot of the transfers "two, as you previously said, i see no screws below barrel, are these D7 cases?.
2) interesting full size? / larger diameter flywheels ?.
3) no packing rings ? no screws, "why" I understand this is not needed on a reed valve. ? your PISTON PORTED please elaborate.
4) Bearing diameter those are not large bearings ? what size, shaft size looks large but not the o/d - 22/47 ? I assume it leaves the cases with a thicker material round the bearings after boring, please elaborate your theory?.
6) welded in? gearbox plate lower needle or ball bearing . our is screwed in. ?
7) The rear selector plate looks thick, sorry made of a thicker material is it or what D10/14 std ?
Cool !!!!!!!
I'm clearly missing a few points, anybody spot anything else. ????????.

I'm even more confused, and in pain, so please relieve my pain/assumptions.!


regards Derek

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mjpowell



Number of posts: 797
Localisation: Lincoln England
Registration date: 2006-12-08

PostSubject: Re: The very latest and no technical two stroke tuning topic !    Fri Feb 25, 2011 10:09 pm

Hi Derek ref your post-
Forgot to take a picture of the other side when it was apart on Monday... when its apart next?
Leaving it late - No.... I've smashed a hole in the cases before in practice,replaced gears,filled hole with plastic padding and gone out and won races 2 and 3! So its never too late...

Regs not out yet. Will ask at committee on Wednesday.

I'm interested in anything on bellmouths? and inlet tract lenghts Alan if you have something pls tell.

Head volume mines 10cc and 11cc... I think your ignition is too advanced or your exhaust bleed pipe is of to small a diameter.
Ref head volume/compression ratio/squish band:-
Fixed timing say 18/20degrees needs low C/R 11:1
Retard ignitions needs C/R 13:1

Is your exhaust bleed pipe smaller than 19/20mm? Its just that a low comp motor should not be detonaming...

Pressure test? mine go from 10 to 0 psi in about 3minutes...

Ref my pic... don't want to comment just yet want to see other peoples assumptions first? Then I'll tell ya...
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johnSbantam



Number of posts: 184
Localisation: New Zealand
Registration date: 2006-12-01

PostSubject: Tuning and other things   Sat Feb 26, 2011 1:32 am

Derek, thanks for your concern; I was at work in Palmerston North oblivious to the earthquake down south in Christchurch. Yes, it is very serious, my daughters home is a mess inside and unrepairable, but they are all safe.
High tech manufacturing things are what we have actually done. Still puzzling about set ups though. My short stroke wc bike goes well what ever I do to it. CR 15:1, Avgas, 17 degrees advanced on old Motoplat (Rex Caunt stator coil gone). But my 175, big flywheels, CR12.3:1, 19 degrees and shortened Betts "Sprint" pipe is more difficult to get going well. Nothing below 6K, hard to get on pipe, then goes like a raped ape as the EGT shoots up to 1400-1600 F. 108 needle jet in Amal MK1.5, plug and piston look good ?

Mike, sorry your Evo has dissappeared ?
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bettsd



Number of posts: 854
Age: 50
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PostSubject: Re: The very latest and no technical two stroke tuning topic !    Sat Feb 26, 2011 2:33 am

john where are you measuring EGT, sounds very hot, im only measuring under plug temp ,

"if"- u can measure EGT accuratly, its a better method, than what i am doing.

derek
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mjpowell



Number of posts: 797
Localisation: Lincoln England
Registration date: 2006-12-08

PostSubject: Re: The very latest and no technical two stroke tuning topic !    Sat Feb 26, 2011 4:15 am

Picture back online wish i knew how to operate computers aswell as bantams...
Glad you are all ok in the turmoil down there.

Technical tell us about your 4speed c/r boxes - not that our rules allow it!
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mjpowell



Number of posts: 797
Localisation: Lincoln England
Registration date: 2006-12-08

PostSubject: Answes to assumptions....   Sun Feb 27, 2011 11:28 am

Derek hope your rolling road session went well today. Looks like your questions are the only ones... there have been a fair number of views though.. so hopefully people are getting some ideas etc..
Answers:-

1. Yes D7 sandcast
2. Well spotted fullsize crank chamber on this case
3. No packing ring - but Primary comp is average 1.3/1.4:1
4. Bearing is large just look smallish in full size case
5. its a 6205 52mm o/d 25mm i/d
6. Screwed in bearing retainer plate running a 6001 bearing on the layshaft
and a HK1212 needle roller on the other end
7. Gear selector plate/parts must be late D7/3sp D10 they are beefier!
Auto jumbles the best place to find these..
4spD10/D14/D175 are compleately different...

Hope this makes everything clearer?????


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ROBBIE



Number of posts: 261
Localisation: Swanscombe Kent UK
Registration date: 2006-12-24

PostSubject: Re: The very latest and no technical two stroke tuning topic !    Sun Feb 27, 2011 3:22 pm

Hi Mike
hope that gearbox mod that tom done for you works as he has done mine yesterday
could not find anything wrong with gearbox Shocked
but wen I was at brands could not get into 2nd gear from 3rd

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bettsd



Number of posts: 854
Age: 50
Localisation: worcestershire
Registration date: 2007-06-14

PostSubject: Re: The very latest and no technical two stroke tuning topic !    Sun Feb 27, 2011 4:15 pm

hi rob think i have an idea what this could be - !

wait for it - Try pressing the gear peddle in the opposite direction. LOL bounce


Mike - u sure this is a A D7 it looks home made to me can see the hammer marks or has it been modified - distance holes changed.

you really running large diameter flywheels ?

Derek

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mjpowell



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Localisation: Lincoln England
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PostSubject: Re: The very latest and no technical two stroke tuning topic !    Sun Feb 27, 2011 8:06 pm

Derek definately std unmodified selector parts no brazing or welding or hammering! I think that ragged edge you can see on the notch and flag plate was done by BSA in manufacture. Has the Tom mod of a 7mm pin and tensioned bantam clutch spring. My pin was to slack in the holes (in the fixed and moving plates) so now has a 7.15mm pin - works on the bench..
Rob - Have you got a bespoke pin in your box now too??

This is the other crankcase half from the outside(motor built).... I think it gets more interesting?

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ROBBIE



Number of posts: 261
Localisation: Swanscombe Kent UK
Registration date: 2006-12-24

PostSubject: Re: The very latest and no technical two stroke tuning topic !    Sun Feb 27, 2011 10:03 pm

Yes mike tom has made me a new pin too lets hope that fixes it Laughing
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bettsd



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PostSubject: Re: The very latest and no technical two stroke tuning topic !    Sun Feb 27, 2011 10:21 pm

Hi Mike -
Its been a long day we just finished.

mike have to take my hat off to you, had me going there,!! actually believed you!!, full size flywheels, ? tut.

Can not believe others are not commenting on this, we had a good day extracted some additional information, should be more for us to use come season start, hoping this will be enough for me to hang on to those just in front, who were pulling away from me at cadwell and Pembrey.

Mike on the photo's - I can see two feeds for water so your not running full size crank wheels ? tut- as you first agreed you were ??!! tut tut,

Anyway with my assumptions, dad said he like's the way you have seperated the flow between tansfers starting in the crankcase mouth.

I' on the other hand' really can not see how this would make a difference, what is the theory behind this, and does it make a difference.

I would like to see the other side of the timming side in last photo, anyway well-done to you for getting this on, looks like my assumption was wrong.

Anyone spoke to Alan recently, not heared from him in a while, hope he's ok, sent him mails off line hotmail - with no answer.

anyone else got interesting photo's we could look at.

regards

Derek.



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mjpowell



Number of posts: 797
Localisation: Lincoln England
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PostSubject: Re: The very latest and no technical two stroke tuning topic !    Mon Feb 28, 2011 10:23 am

Hi Derek glad you had a productive day and gleened some info..

My new motor is basically Tom's creation but with input from his many contacts and a couple of requests from me.
As you know Ian Scutt rode the first test and development motor (in my 003 chasis) in 09 and last season Ian's motor was housed in his own 008 and my new Evo motor in 003. Unfortunately it only did 180miles - so still early days. Thx to test riders Michael Brown and Andy Checkley.

Transfer ports - I've no idea why they are split in the cases, i'll ask Tom?

Cases - rightcase no packing ring. leftcase a water cooled packing ring ???

I think your still guessing ??? lol
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bettsd



Number of posts: 854
Age: 50
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PostSubject: Re: The very latest and no technical two stroke tuning topic !    Mon Feb 28, 2011 5:33 pm

Hi Mike

Yes thank you - had some interesting results -indifferent from the last run, but all the same we seem to be making progress, identifying the issue stopping progress, one such issue found by chance, "tail pipe - causing over heating - gone and able to reduce exhaust /plug temp drasticall. Allowed us to come down to sensible size main jet - the power gone back up, planning head comp ratio increase, ran ot of time,

on the other issues I will decide when a get some quiet time what to do.

"now" on your own evo-evo-evo 008 and / new or was it old evo 003 in the 007 frame or was it 002 frame in 2007, all this OO is very confusing, I think a trip down the pub is in order this evening, it sounds to me like a story of a guy who was moderating your speed down a back straight in order to hide your true top speed surprised him on the last lap !!

On the Guessing "NO" Mike i'n not guessiing anymore, why don't you be brave and do the full monty. !!!

besides we and all can not see but only measure what a tru difference is, when we hide things we hide the design, but its all been done before.

I feel its open and good for the forum, makes it interesting for others looking to see what your doing from time to time, if its the same old thing week after week then it not so interesting, its the same in retail the guy next door to a show room, changes his window every week - just so people will look in to see what the diffference is, the theory is when they have the time or it comes to a point they are in the market they will choose him first to shop/try, its the same theory here, "so try telling me and others all we need to know so we can beat you" !. LOL

Now this new guy from Australia sounds interesting, 20 years racing and tuning bantams, dad had some guy send him photo's some time back of a 175 watercooled bantam with a rotay vale in the drive side and ingnition on the same side, no seal on inlet side just a plate, ? not a typical Bantam racer.

i will ask if he still has the shots.

kind regards

Derek





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