jetting

User avatar
scrubs
Site Supporter
Site Supporter
Reactions:
Posts: 240
Joined: 10 Aug 2007, 15:30
Location: Leeds
Re: jetting

Post by scrubs » 11 Apr 2008, 21:50

If you can't get hold of a stopper, it may be cheaper to buy some boysenn 633's that dont need them.

User avatar
sparky
Visitor
Visitor
Reactions:
Posts: 54
Joined: 06 Apr 2008, 19:09
Location: nuneaton
Re: jetting

Post by sparky » 11 Apr 2008, 21:53

cheers
could that have caused any of the seizure problems??
it ran fine before iv used it at least ten times for a full days greenlaning each time since i got it this is the first time its broke on me?

what about if i made a little plate that ran the length of the reeds and fitted the screws through that would that work or does it need the cage really with the reeds i have?
crm250 mk2 designed by a genius, built by craftsmen, ridden by a plonker

User avatar
knackeredMk1
Super Moderator
Super Moderator
Reactions:
Posts: 4185
Joined: 03 Nov 2006, 17:41
Bike Owned: Modified Mk1
Re: jetting

Post by knackeredMk1 » 11 Apr 2008, 21:57

After market reeds tend to make only small changes to the jetting. If making only reed changes then usually only a maximum of one size up or down is needed (But it can be as much as 3 according to the Boyesen leaflet).

Eg. Boyesen reeds tend to make the pilot jet curcuit to run lean and the main jet to be rich. So need to turn the airscrew in a little or make the pilot jet bigger and reduce the size of the main jet.

Boyesen reeds have a much reduced stop plate across the base of the reeds as do many others. I do not know of any reeds that have 'washers' at their base as this would make a variety of stresses across the plates and would increase the likelyhood of failure :? :?:

User avatar
NaBz
Site Supporter
Site Supporter
Reactions:
Posts: 226
Joined: 08 Apr 2006, 19:12
Location: at my pc
Re: jetting

Post by NaBz » 11 Apr 2008, 21:58

the boyseen reeds dont need them ??
if you aint coming off you aint riding hard enough!

User avatar
knackeredMk1
Super Moderator
Super Moderator
Reactions:
Posts: 4185
Joined: 03 Nov 2006, 17:41
Bike Owned: Modified Mk1
Re: jetting

Post by knackeredMk1 » 11 Apr 2008, 22:01

Boyesen reeds look like this -

Image

They don't need the full metal plates.

User avatar
sparky
Visitor
Visitor
Reactions:
Posts: 54
Joined: 06 Apr 2008, 19:09
Location: nuneaton
Re: jetting

Post by sparky » 11 Apr 2008, 22:04

so if i make a plate up like the one in knackered's pic and fit that across the reeds rather than the washers which are fitted now then that should be ok?
i'll take a pic tommorrow of how they are done
so whoever changed the reeds before didnt know what they were doin :evil:

@ knackered i have also fitted an fmf gold series from a cr250 i think that alone should require some changes made from what iv read about them so far
thanks

that plate on them reeds
there is nothing like that on mine just washers underneath the screwheads
crm250 mk2 designed by a genius, built by craftsmen, ridden by a plonker

User avatar
scrubs
Site Supporter
Site Supporter
Reactions:
Posts: 240
Joined: 10 Aug 2007, 15:30
Location: Leeds
Re: jetting

Post by scrubs » 11 Apr 2008, 22:07

sparky wrote:so if i make a plate up like the one in knackered's pic and fit that across the reeds rather than the washers which are fitted now then that should be ok?
It's difficult to tell, unless they were made at different tensiles and the aktivs were not designed to be stretched so far back?
If it hasent broken so far it may be OK with a metal plate, but then again, it's a gamble really, maybe phone Aktiv and ask -
see what they say.

User avatar
knackeredMk1
Super Moderator
Super Moderator
Reactions:
Posts: 4185
Joined: 03 Nov 2006, 17:41
Bike Owned: Modified Mk1
Re: jetting

Post by knackeredMk1 » 11 Apr 2008, 22:15

The washers are certainly wrong however I wouldn't guarantee that making a plate like that on the Boyesens will solve the problem. The reeds you have might need the extra suport of the original plates to stop them fatigueing (Sp?) when they are fully open.

You don't know what kind of reeds they are?

FMF pipes generally need leaner main jets (if any jetting changes), to get the most out of them but as yours is designed for a CR as opposed to a CRM then it is entirely possible jetting could go either way :?

User avatar
sparky
Visitor
Visitor
Reactions:
Posts: 54
Joined: 06 Apr 2008, 19:09
Location: nuneaton
Re: jetting

Post by sparky » 11 Apr 2008, 22:22

best to play with the jets either way then or get it on a dyno
i dont know what reeds were fitted in the first place but iv bought some aktive ones from leisure trail
do the boyessens come with the metal plates if so i may just buy some of them instead :?
crm250 mk2 designed by a genius, built by craftsmen, ridden by a plonker

User avatar
knackeredMk1
Super Moderator
Super Moderator
Reactions:
Posts: 4185
Joined: 03 Nov 2006, 17:41
Bike Owned: Modified Mk1
Re: jetting

Post by knackeredMk1 » 11 Apr 2008, 22:27

LT should be able to tell you what to do with the Activ reeds if they don't have instructions. BTW if you need the original plates I think I might still have some.

Boyesens come with the plate and instructions as to how to fit.

User avatar
sparky
Visitor
Visitor
Reactions:
Posts: 54
Joined: 06 Apr 2008, 19:09
Location: nuneaton
Re: jetting

Post by sparky » 11 Apr 2008, 22:29

there was some instructions but nothing about the plates i'll get onto lt tomorrow and see what they say if not i'll just get some boyessens and go from there
what sort of price should i expect to pay for the boyessens iv seen them on egay for around 35 plus postage is that about right?
cheers
crm250 mk2 designed by a genius, built by craftsmen, ridden by a plonker

User avatar
knackeredMk1
Super Moderator
Super Moderator
Reactions:
Posts: 4185
Joined: 03 Nov 2006, 17:41
Bike Owned: Modified Mk1
Re: jetting

Post by knackeredMk1 » 11 Apr 2008, 22:34

You can probably get them for ~£30 inc postage.

Boyesen Power Reeds CR250 1989 - http://www.racespec.co.uk/acatalog/Reeds.html

User avatar
sparky
Visitor
Visitor
Reactions:
Posts: 54
Joined: 06 Apr 2008, 19:09
Location: nuneaton
Re: jetting

Post by sparky » 11 Apr 2008, 22:37

:bow:
spot on thanks mate i'll stop with all the questions now :mrgreen:
crm250 mk2 designed by a genius, built by craftsmen, ridden by a plonker

User avatar
Jonorow
Site Supporter
Site Supporter
Reactions:
Posts: 388
Joined: 22 Dec 2005, 13:58
Location: London
Contact:
Re: jetting

Post by Jonorow » 12 Apr 2008, 19:49

if you buy reeds and they dont have any plates then the original fittings should be Refitted (back plates) if like the boyesen they require a special fitting they will always be included in the kit.
98 (94) CRM250 MK3
96 ST1100PT
99 NT650V Deauville (Gone to roads new)
http://www.rymcc.co.uk


Post Reply