RGV Challenge

mj43 · Post by **mj43** » Tue Aug 04, 2009 8:48 pm

No problem - I will post the specs for the engine on Krazy-Katts dyno web page http://www.krazy-katt.com/16may09/EvoKR1S.JPG the 08 Race Bike.

They work well with stock ignition and Lomas pipes.

This is the same engine, albeit a very tired one, that Dan used to take 0.5 of a second off the F250 lap record at Cadwell

mj43 · Post by **mj43** » Tue Aug 04, 2009 8:52 pm

spannerman wrote:obviously you must be fairly confident and may i say slightly amused at certain claims that may be made from certain marque supporters. kick ass mark
on a similar note is there any gain to be had from staggered port timing as in A G Bells book on two stroke tuning on a kr1s or is the crankcase pressure too high, have you explored this avenue my bike is standard porting apart from matched bottom etc. will understand if u would not like to say.
dont want to set the world on fire but just looking for a little more zip
ade.

I tried staggered porting can't say it made any difference - i.e. didn't see any gains.
Good gains from flowing the crankcases that was the difference between the Bonny bike and the stock machine

SHimmer45 · Post by **SHimmer45** » Tue Aug 04, 2009 11:54 pm

mj43 wrote:
This is the same engine, albeit a very tired one, that Dan used to take 0.5 of a second off the F250 lap record at Cadwell

that is a HUGE amount to take out of a lap record at somewhere like cadwell i guess.
one of the tracks where grunt is key i imagine.

has prompted a good response, interesting about the idea of opening this up to other stroker forums.

the-elf · Post by **the-elf** » Thu Aug 06, 2009 2:48 pm

I'll get mine down to James' dyno next month providing she survives the shake down at Cadwell on the 17th (SATT two stroke day). Will get some proper setting up on the ignition curve and powervalves then I'll post the power curve up here so Mark can put me to shame.

The old engine made about 60BHP at James and the Bob Farham one 59 (on a different dyno and with standard pipes) which I guess is more like 53BHP.

A quick question Mark, What exhaust and powervalve port heights did you finish up with giving the best power with the Lomas pipes?

the-elf · Post by **the-elf** » Thu Aug 06, 2009 2:53 pm

mj43 wrote:
spannerman wrote: on a similar note is there any gain to be had from staggered port timing as in A G Bells book on two stroke tuning on a kr1s .
I tried staggered porting can't say it made any difference - i.e. didn't see any gains.

I've staggered the powervalve port height on my latest barrels, with the outer ports being about 0.3mm higher. The seat of the arse dyno reports an improvement over my old barrels, but well see when I get her to Krazy Kat's next month.

Bertie_Mollie · Post by **Bertie_Mollie** » Thu Aug 06, 2009 8:28 pm

mj43 wrote:
Bertie_Mollie wrote: MJ - I think some guys on the RD forum may be interested in following this as they know you. Do you mind if I put up a link on there?
Nope the more the merrier

Dun

http://www.yamaha-rd.com/forum/topic-61297.html

kwackman12 · Post by **kwackman12** » Thu Aug 06, 2009 9:37 pm

Dont know if this helps in anyway but here's the dyno printout from my 300cc Stan Stevens conversion

JanBros · Post by **JanBros** » Fri Aug 07, 2009 12:39 am

the-elf wrote:I've staggered the powervalve port height

what is this "staggering ports" ???

the-elf · Post by **the-elf** » Fri Aug 07, 2009 8:07 am

JanBros wrote:
the-elf wrote:I've staggered the powervalve port height
what is this "staggering ports" ???

You have two powervalve ports but you make them a slightly different height which changes the overall port shape etc. This takes into consideration alot of other things like the resonate chamber on the outside of the barrels etc.

Come to think about it, Is it the inner one's which are 0.3mm higher on my barrels

and not the other way round? Bloody old age

the-elf · Post by **the-elf** » Fri Aug 07, 2009 8:46 am

Looks like there's some falling out and bickering already over in RGV land

. I wonder if anyone will stop argueing long enough to actually build an engine

TwoStroke Institute · Post by **TwoStroke Institute** » Fri Aug 07, 2009 9:12 am

It's the quiet one's you have to be careful of

mgtkr1 · Post by **mgtkr1** » Fri Aug 07, 2009 3:08 pm

funny old lot in rgv land!! plenty of big ideas and no doubt, little by way of action. geoff will have a serious go and a few that dont say a lot will likely come up with a suprising attempt. elegy is one who i know can build a fast bike although he say's little on the forum. like you said, their the ones to watch!! this is a brilliant idea of marks though and makes for exciting reading. i hope the thread on both sites continues and we are kept up to date of who's making progress and what has been done to acheive it at the end. elf, have you been on a dyno with staggered port barrels?

garye345 · Post by **garye345** » Fri Aug 07, 2009 4:15 pm

Niceone

That Jeff seams like the only serious taker to me

I will stand £20 of the money Mark,should you lose,and you know i ain,t into parting with £20's-unless it's over the bar.

TwoStroke Institute · Post by **TwoStroke Institute** » Sun Aug 09, 2009 8:35 am

Here you go Sheik some pipe developement for you

Sheik Yerbouti · Post by **Sheik Yerbouti** » Mon Aug 10, 2009 8:44 am

Here you go Sheik some pipe developement for you

Hope they're coming out under the seat

going to share the dimensions?