Thinking about racing vintage...eventually

Hello friends,

I love vintage bikes! I love racing! Though, I've only started racing last weekend. I am currently using an SV650 as my medium. I am interested in the V5, V6HW, and V7HW/MW classes as those are the bikes I relate to the most (being 24 y/o). I already have '83 GPZ1100 (DFI) from my dad and a '93 CBR900RR from my stepdad. I collect bikes from my family. I think it would be really cool to own a an early 90's, Scott Russell era, ZX-7, which I believe would be good for V6HW. My dad and I Kawasaki fans. I also would love to own a 916 style Ducati at some point. I just can't get over the single sided swingarm, dry clutch, and V-twin; just love it.

Now, I don't know when/if I would get the ZX-7 or Ducati. They're just ideas for now. I do have the GPZ already and want to make changes anyway for road use. It's pretty much all stock at the moment, runs decently. I was thinking about how to get appropriate 17" wheels on it first. The front is an 18" and rear is a kinda narrow 17". For the front end I was thinking looking at swapping the front end with a zrx. The offset is the same, so it should work perfectly. The back end is going be a little more difficult. A swingarm swap is in order, but I need to do more research. Whatever I do, the suspension geometry is going change. Is there any guidance people have for modernizing the suspension on these older bikes? For the fuel injection system, my friend wants to try out using the Megasquirt system. For bodywork, the bike is fully faired, but should I just run a belly pan and a front number plate cause there's not bodywork being made for it?

Would this all be legal for V5. I read the rules and believe it should be but want to double check. What other advice would you guys have?

Thanks,
Will

 

try ahrma for vintage

 

V5 is PRE 1983.

 

Fuel injection like megasquirt is probably not allowed in V5. Read the general stuff at end of vintage rules.

V7 is PRE 1996. Some of your stuff goes there. Read carefully as some carry forward of nearly identical years is allowed.

 

The V5 class specifically calls out the GPZ 1100, and the component specification section doesn't say anything about fuel injection, just the operating principal must be in use before the cutoff date.

Thanks,
Will

 

Can’t remember any fuel injectors on bikes before 1988… Duck 851 is all I can remember…

 

Oh the GPZ came with FI from the factory, but I'd like to remove the oem ECU and replace with something that is a little easier to work with.

 

I had a friend with one of those GPZs built up for drag racing. Stock FI had been yanked and replaced with a rack of Mikuni flatslides. Felt like they used a school bus leaf spring for the throttle return spring on them. IIRC the FI setup is controlled by a separate box from the ignition, so it was a very easy 'delete', just unplug things, and yank the FI box. The ignition didn't care and continued to do it's thing without it.

 

Just keep racing your SV...and then build the CBR900 that you already have into a V7HW bike.

You don't want to get bogged down biting off more than you can chew as far as projects.

Regards,
Chad

 

what are you finding difficult to work with on them? You can bump/adjust the fuel pressure, bore the throttle bodies, and put some modern multi hole tip injectors in the rack & never have to get gas on your hands vs messing with jets. You can even replace the stock denso pump with a walbro unit drama free. All stock stuff.
Sid Pogue is a good resource.
Nigel Patrick was a savant on the GPz head. He is a wealth of info on which cams & timing for the desired power levels.
While every other clown was installing carbs on the FI'd gpz, to go slower, he was making north of 140hp for the mild amount of work done before he sprayed some giggle gas thru the stock fuel injection.
For an 80s bike the tech was pretty damned good.

 

1980 Kawasaki KZ1000G-1 Classic. And I think the Munch Mammut before that. 1985 BMW K model. 1982 CX500 Turbo.

 

My plan is to continue racing the SV indefinitely. The CBR is in really nice shape, so I'm not sure I want to race it. I understand what you mean by having too many projects pile up. That's kinda where I'm at right now with my vintage trail bike. This is more of a project I want to start planning and start working on next year. I would like to make some changes to the GPZ to benefit its handling on the road anyway.

I haven't really tried to work with the current FI system. You make a lot of good points and something I should look into. I've just heard that most people remove the system and replace with carbs. Could you pm me the contact info for Sid and Nigel?

My friend just wants to try out the megasquirt system as a fun project, not because of any significant performance gain. We're both engineers so we have a decent understanding of how control systems work.

Thanks,
Will

 

Sids company #
(405) 677-9397

Nigels company
https://www.patrickracingbillet.com/contact-us.html

 

William, I was surprised to see the 1981 onward GPZ 1100 had factory fuel injection so as you say switching it out should not be a problem. As long as the 1983 is not a serious advancement over the 1982 you should be ok in V5 but I would get WERA to ok it before I started the build.

Notice that V6HW is mostly PRE 1992. This obviously limits the bikes newness.

 

I think starting out in vintage on the GPZ would be a mistake. There are too many changes that would need to be made to wheels, brakes, suspension, etc. that it would be a never ending projet at the track that would take time away from learning how to go fast on your SV. I do encourage you to go vintage racing, but suggest you just pick up an already set up vintage bike and go from there. Get a nicely set up CBR600F3 and enjoy time riding not wrenching at the track.

 

I totally agree - unless you just absolutely HAVE to know what the GPZ or some other vintage bike is like on the track, most newbie racers are better off just racing something you won't need to wrench on at the track and is already a known decent track bike. Keep racing your SV but go ahead and tinker on the GPZ and 900RR as streetbikes for a while, until they're reliable and set up to work ok on a track (maybe take them to a track day or 2 to figure that out without the stress of a race weekend?), then bring them along with the SV to a race weekend here and there.

 

I'm kinda in the same boat as you. I have a Ducati 748/853 I'm rebuilding on the side currently. I just started racing my R3 and would like to bring the Ducati out eventually as well. It should be "done" this fall so I may have it out next summer after some testing.

 

This is exactly what I'm thinking. I want continue racing the SV as my "competitive"/"skill-develping" bike. But, I ride the GPZ on the street a bunch and have been dissatisfied with some of the componentry, namely the brakes, rear shock, and lack of tire options. Now, some things could be fixed somewhat easily, but if I want to make additional changes - 17" wheels, I would be wasting money by making these "easier changes." I am just thinking that, by making the bike better on the street, I could try racing it, eventually (like maybe 2023 or 2024 VMD).

I don't think I would want to get a F3 because I see vintage racing as racing motorcycles I find to be interesting and special. The F3 is just not a bike that interests me as much, but I could be proven wrong.

I was thinking of the 748 for some V7MW and a way to try out a Ducati, but without it costing as much as some of the other models.

 

The beauty of that bike, as a street beater, is the unlimited amount of options you have when it comes to production components like forks, controls, brakes, wheels, shock, swing arm, etc. The biggest advantages is their light weight & low cost. For example... an early 80s 18" complete rear wheel weighs about ~64lbs in a 3.5" width. You can find complete kawi, yamaha or suzuki rear ends from early to mid 2000s 1k models with 6" wide rim(complete wheel, swingarm, linkage, axle , & brake) that weigh less. The stock rear shock of that vintage is pure junk plus an anchor. Most of the modern stock shocks with attached reservoir would need additional consideration for clearance... but most any remote reservoir shock would work.

Last year I started on an 85 GPz Turbo as a resto mod project. I ended up using a 46mm ZRX front end because a friend makes billet triples for them. The way the dash & warning lights are set the bling will mostly be concealed. As a complete assembly, the zrx was ~15lbs lighter than stock but it also lets me run 6 pot tokicos & 310mm discs vs 280 single pot.