installation tips on putting 18" GSXR wheels on a '78 GS1000

[Diamondj]

Sprocket Specialists should be able to hook you up. I had to machine the sprocket carrier face on mine down by about 1.5 mm and use a spacer behind the engine sprocket to get everything to line up when converting it to a 530 chain. The 630 countershaft sprocket is superwide on the GS1000 as it's got that rubber damper in it. I used CBR600F2 wheels on mine with a Metmachex swingarm for a GS1000 as I was going for a Marchesini 5 spoke look without spending $2000.... The rear rim on mine is 17 x 4.5"



Jim

[Steveb64]

18" wheels

Can't help you with the spacer problems - BUT I have been running 18" wheels on my old GSX for years (even before it got stored) - though mine were spoked rims (Akront and Borrani), laced up to early GS(2v)750 spoked hubs, with 2.5" front rim width, and 3.5" rear. Bolted straight in, and turned the old girl into a turning demon! Could get up the inside of (early) GSXR's on tight twisty corners!:-D The main thing I HAD to do, was get the front suspension stretched out as much as possible, as having the rear raised with 18", and the front lowered with 18" - it got kinda twitchy. Ended up with the forks on max preload, oil height raised by 2-3cm (can't remember exactly) AND 10psi of air!

One thing I was wondering about - why use cross-ply tyres? I started off running Pirelli sportscomp Phantoms (the original cross-ply ones) which worked well enough, but the bike would still get the 'weaves' if I hit a sudden dip/bump in mid corner. Then the first radials came out - and a mate who was racing at the time did a big rave about them - so next tyre change (after two sets of the Pirellis) was to Michelin A/M59X's (with tubes in, due to spokes). MAN what a difference. It was still a little twitchy in a straight line - but pitch it into a corner, and it was like it was on rails! NO wobbles, weaves, headshakes, ANYTHING! One example I remember well (for some reason), I was blasting downhill at 180k into a FAST LH sweeper, and hit a patch of loose gravel mid corner. Back stepped out. :shock: Well out. Then it hit the tar again, kicked straight and just continued on as if nothing had ever happened! NO twitch or wobble!

Errrm - one odd thing I remember now - the countersteering went kind of weird. I'd give a shove on the bars to get the bike tipping in and control the first part of the lean - but the more lean - the less countersteer - until I was actively turning IN to the corners when really peeled over! Never worked out exactly why, just rode around it...
Mind you - this was also the bike I learned to rear wheel steer with too - just start feeding the power on as you apex - but use some proper slide carbs - NOT CV's, as they don't really give a quick enough response when you need it...

[irwnn]

... why use cross-ply tyres? ...

... comes down to availability of race compound rubber in a size and style allowed by the rules.

p

[Steveb64]

... comes down to availability of race compound rubber in a size and style allowed by the rules.

p

Thought that might be the case. ...just been looking at what IS available in 18" sizes - bugger all these days! Though Michelin do a Pilot Road that's a 160 - but that's going to be a tight fit, as I had to squash the rear caliper stay arm to fit the old 150/? x18 M59x that's on it at the moment.

Damn. ...(I'm planning on taking mine out in the pre '82 post-classic class here in NZ)... At least our class here doesn't have too many rules regarding tyres... :-D