GS500 Restrictors.

tango_kid · Two Stroke Sniffer Joined: 03 May 2011 Karma :

Hey all,
some of you may remember that after passing my mod two i went out, bought a gpz305 and was happy as larry. Unfortunatly that never got on to the road, electrical issues and my lack of time in which to fix them has led to to buy a much newer, GS500. However, as i am still under my restricted liscense and it isn't restricted i was wondering if anybody knew of anywhere i could grab some restrictor washers cheap?? This is very important as i have very very little money (i have had to sell things to get the new bike and i havent a clue how im going to afford insurance). So if anybody has any old home made ones that they no longer need or knows of anywhere i could get some for a couple of fivers type thing, that'd b great, cheers
Mike

P. · Red Rocket Joined: 14 Feb 2008 Karma :

The GS develops between 40 and fuck all HP.. you wont get tugged on it...its top speed is about 10mph different restricted. Honestly, no difference Laughing

Would save the money.

tango_kid · Two Stroke Sniffer Joined: 03 May 2011 Karma :

So its worth getting it dyno'd before I ride it :L

Cheers, but as unlikely as it is me getting pulled for it, i dont want to be on the wrong side of the law. I can't afford to be, insurance is already a killer!!

Cheers,
TK

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

The GS500 claims 47hp - it'd have to lose quite a lot to get down to the ~36bhp estimated at the crank that would make you safe from prosecution.

Intartubes says...

https://i53.tinypic.com/9lcpdk.jpg
https://i53.tinypic.com/10xzora.jpg
https://i53.tinypic.com/6rn19w.jpg

You may need to re-jet, you may not.

By the way, you could probably part out the GPz305 - the camshaft alone should be worth a fair bit if it's in good condition.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Shouldn't need to rejet for restriction...

It already mixes the fuel and air... just stops it all going in to the actual engine..

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

I agree that you shouldn't need to, but some kits do rejet, e.g. the FI and Honda kits for the CB500 upjet it. I think it's worth keeping an eye on the plug colour just in case.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

tango_kid · Two Stroke Sniffer Joined: 03 May 2011 Karma :

right, cheers for all the info guys. I shall talk to my dad and see what he says concerning drilling new washers to fit. If he doesn't think it is a goer, does anybody know of anywhere which sells them (home made if thats....that) cheeap??
Cheers,
TK

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Just remember there are 2 types of engine, the 54hp and the 47hp.

Im sure there are 2 different washers for each.

tango_kid · Two Stroke Sniffer Joined: 03 May 2011 Karma :

its a 1998 bike...? Guys? Razz

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

38mm repair washers, B&Q or intartubes. A decent step drill bit will increase the holes to 20mm in short order.

https://toolspot-static.co.uk/i/521t.jpg

Honestly, with a GS500 I'd just go with 20mm holes and assume that it's close enough. Dyno it if you like, you may find that you can actually drill them a bit bigger.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

tango_kid · Two Stroke Sniffer Joined: 03 May 2011 Karma :

Seems to be silver (going off crappy ebay pictures, as i don't have the bike at home yet.)

Also, would the hole displacment from the centre of the washer be an issue when using a step drill (the restrictors i've seen don't look to be centred)

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

They're supposed to be offset (towards the bottom) as shown above, but I can't see that it'll make an enormous amount of difference. I'd actually expect the FI ones to be offset to make them look as though they're something more than penny washers as much as for any particular flow reasons.

You could drill a new pilot hole at the centre point of the offset location, then incorporate most of the original hole in the 20mm hole. If it creates a slightly oversize snowman shape, eh, what matters is the dyno reading.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike