DS 80 mod questions

[taynton]

Hi all, rather than hijacking the DS 80 build thread I thought I would post one of my own, I have an 88 DS 80 that I want to mod, firstly by adding a 24 mm flat-slide carb
Is this a good idea?
Will it be better than stock?
Is there an existing manifold that will accept the 24 mm flatslide?
If not, has anyone modified one to fit?
I dont know what the stock carb comes as so im not sure of the size difference,
I do know that carb is a racing one and has very little throttle play (0 to WOT in 1/4 turn). not really a big deal as I ride it mostly WO anyway.
I was also looking into some stiffer springs for the front forks. anyone have a source for this?
As well, a FMF pipe and a slight decking of the head to raise compression. (Anyone know what the stock compression is?) also possibly extending the rear swing arm by about 2" (what do you guys think about this?)

I know its alot of questions but help me out where u can. Thanks a bunch

 

[my67xr]

welcome to miniriders,

make sure you drop by and post in the introduce yourself thread too

the standard DS80 carby is a Mikuni VM20 (22mm) from memory
an FMF expansion chamber is available, one from a JR80 will fit.

extending the swingarm would be easy enough as it is made from steel, so do you have a Mig handy ?

compression ratio is around 7.3 to 1 standard, milling the head 1mm will take the compression over 11 to 1.

 

[my67xr]

fitting a Flatslide carby to it will make it more of a MX bike, with an on/off type throttle
you could always fit a quick throttle to your standard carby, a 1/4 or 1/8 throttle ?

what brand Flatslide would you want to fit, Mikuni,Keihin or OKO
there would be manifolds available that could adapt the carby to the engine
something like this,
you would have to measure yours to get the bolt pattern, and measure the carby for the size

 

[GooseMan]

Definetly get the fmf pipe, or a rm80 exhaust is also better then standard, I find the stock pipe restricts the airflow, my67xr above^^ has made his own header pipe for it and that seemed to help it out.

how you thinking of extending the swing arm? wouldn't want it to brake while riding is all.

As for the forks, are they not hard enough? Cause then a thicker oil would be a good place to start, that will harden it up. Harder spring will make it rebound quicker, by putting in thicker oil the rebound will be a little slower, not very noticable but you may want them if your gonna go all out on the yellow rocket
(I did a quick ebay search but couldn't find any HD springs for it)

 

[taynton]

Sweet, Thanks guys I have a MIG and a TIG at my disposal so the swing arm wont be a problem I have done extensions before. As for the forks, I will try the oil, as I need new seals anyway.

As for the carb, I have a 24 mikuni flatslide, I only will use it if it will be beneficial to the other mods that Im doing, Im ok with the on/off style as most of my two strokes are like that. 22 to 24 isnt a big jump but I have the carb already with a 1/4 turn throttle kit and my stock throttle housing is cracked so I will replace the whole deal if it will increase performance at all. My67xr, where can I find these manifolds?

 

[taynton]

as well anyone have specs or a template for some minor porting? and my76xr what should i mill off the head to run 94 octane fuel?

 

[taynton]

looking into reeds now as well.... things are adding up on this build lol

 

[my67xr]

where abouts are you from ?

you might be able to adapt one of these to suit ? -
http://www.ebay.com.au/itm/GENUINE-..._Parts_Accessories&hash=item19b349876e&_uhb=1
from memory they are closer to the Daytona type adapter, but these are around $50ea

^^ it will need the threaded holes to be drilled right through, and the outer ring might need notching for the bolts ?
i cant remember the DS80 bolt/width pattern, so that will need to be considered too.
the new flatslide carby will need to be jetted/tuned to suit as well.


i fitted some Carbon Fire reeds to my DS, as the originals looked a bit so/so, they cost about $25 inc delivery

with my forks, i pulled them down, cleaned out all the ports in the valving and reassembled them, i used 10 weight fork oil, made a big difference
you might be able to use some springs from another brand bike too.
my spare DS forks are apart, i might be able to measure the length for you at some stage.


with milling the head, i would take off .5 - .75mm

with the piston sitting down the bottom of the stroke, check how much lower than the bottom of the exhaust port the piston sits.
normally there is a couple of mm's that can be taken out the bottom edge.
or the other option is to run a thicker base gasket, fitting a 1.6 - 2 mm thick gasket will help the bikes' bottom end.

 

[my67xr]

here are some dual stage Boyesen reeds-
http://www.ebay.com.au/itm/Boyesen-..._Parts_Accessories&hash=item20dae288b3&_uhb=1

FMF expansion chambers/Mufflers -
http://www.ebay.com.au/sch/i.html?_...313.TR0.TRC0.Xfmf+jr80&_nkw=fmf+jr80&_sacat=0

 

[taynton]

Thanks for the links my67xr! I am located in kelowna BC. strange, there are two Craigs on opposite ends of the planet with the same bikes and love for minis! I have two YSR's one 50 and one 80 as well as 2 XL 80's (82 and 83) really good to meet you and ill keep you posted on my progress, I think most of the mods will have to wait for spring as I will be spending most of the winter away from my shop at the mountain however Im going to start gathering parts now. do you have a recommened source for head gaskets and fork seals?

 

[my67xr]

ok, no problems,
i have 2 cousins that live in Vancouver.

i don't have a preferred source for my parts, usually wherever is cheapest.
it could be cheaper buying your parts direct from the Suzuki dealer too?

here is a head gasket-
http://www.ebay.ca/itm/NOS-Suzuki-O...ccessories&hash=item1c340b8c2d&vxp=mtr&_uhb=1


Fork seals, from Australia too, lol -
http://www.ebay.ca/itm/Pyramid-Part...ccessories&hash=item5aee52f782&vxp=mtr&_uhb=1

i would replace the o ring's in the fork top caps too when you pull them out, they shrink and perish etc.

 

[taynton]

Thanks again! and If you ever make it up to the great white north let me know, I have some minis we can ride

 

[my67xr]

all good mate, that's what we're here for !

if you need anything else for the DS80, just ask here

cheers, craig