RoadRace / canyon carver engine - GS1000's vs GS1100E - 70's Rickman CR chassis

[Chuck78]

The modified "GS1000 66mm stroker crank" (modified 1100E crank with machining to swap primary gear and besring positions + MTC straight cut gear, w/later i.e. stronger GS1100G rods) is looking to be a done deal. Wiseco K1085's will yield 1105cc and a slight bit more compression ratio with this setup.
I'll need to send the 1000 transmission to APE or similar to have it back cut. And of course H.D. clutch backing plate upgrade and welded rivets.

What all is involved in the H.D. clutch basket backing plate upgrade? Just swapping in a straight cut gear and a different backing plate? Then weld together with existing factory rivets that were ground off? Or do the plates come with new rivets or weld-in fasteners? New clutch hub springs included? Or is this something to buy seperately?

 

[Nessism]

The clutch backplate upgrade is simple in comparison to most other things you are doing. I think Rustybronco (Dale) has some photos in his Skunk rebuild thread.

Question: what is your intention for this engine/bike? Are you going to be racing it at the track on a regular basis and spinning the crap out of it? Reason for asking is that you are going down this very expensive road that is completely unnecessary for a normal road going bike.

 

[Chuck78]

Question: what is your intention for this engine/bike? Are you going to be racing it at the track on a regular basis and spinning the crap out of it? Reason for asking is that you are going down this very expensive road that is completely unnecessary for a normal road going bike.

My intention is to build a bulletproof bottom end capable of handling racing abuse (WERA & maybe AHRMA road racing, possibly ECTA top speed racing, and street riding excursions into the hills and mountains on occasion) and capable of handling whatever top end work I may upgrade to in the future. Initially, it's looking like the 66mm stroke crank (on its way) & 1085 pistons, with my 1100G D-port head or possibly a 79 1000 head. Either route will be sending the head to Rapid Ray for porting work to improve low lift flow in particular. Yoshimura isle of man spec race cams. Yoshimura Series 1 exhaust. CR31 or possibly VM33 smoothbores.

In all reality, my Formula 500 GS425-489cc project will see the majority of the track time, as it is more forgiving and less of a heartache if I crash it. Rickman parts are much more difficult to come by than GS400/425/450 parts...
The Rickman I am building up to WERA spec but I don't see it getting as much racing use for the above reasons. If I do end up getting very immersed into vintage heavyweight racing, I may transfer the engine into a Harris or other (XR69 replica) frame.
I realize this is a pricey route to go, but with the bottom end, I wanted to build it the absolute strongest within reason in anticipation of any future upgrades and of course to handle any abuse dished out...

I do a lot of riding in the hills and mountains of the Appalachian region, more sane than on the track, but still get healthy doses of throttle twisting regularly on any bike I ride.

the back cut trans gear dogs I was on the fence about, but I don't really want to have to tear down the lower end again any time soon. I keep hearing that 2nd and 3rd gears on most bikes are the most critical ones in need of back cutting for racing power loads, but am unsure if I should go for just that or do an up-down back cut on all 5 sets.

if it makes it live substantially longer, then it is worth it. After all, 1 of the 2 prospective engines I'm looking to pick up is a GS1000 with a bad trans, jumps out of gear...

 

[bobgroger]

My intention is to build a bulletproof bottom end capable of handling racing abuse (WERA & maybe AHRMA road racing, possibly ECTA top speed racing, and street riding excursions into the hills and mountains on occasion) and capable of handling whatever top end work I may upgrade to in the future. Initially, it's looking like the 66mm stroke crank (on its way) & 1085 pistons, with my 1100G D-port head or possibly a 79 1000 head. Either route will be sending the head to Rapid Ray for porting work to improve low lift flow in particular. Yoshimura isle of man spec race cams. Yoshimura Series 1 exhaust. CR31 or possibly VM33 smoothbores.

In all reality, my Formula 500 GS425-489cc project will see the majority of the track time, as it is more forgiving and less of a heartache if I crash it. Rickman parts are much more difficult to come by than GS400/425/450 parts...
The Rickman I am building up to WERA spec but I don't see it getting as much racing use for the above reasons. If I do end up getting very immersed into vintage heavyweight racing, I may transfer the engine into a Harris or other (XR69 replica) frame.
I realize this is a pricey route to go, but with the bottom end, I wanted to build it the absolute strongest within reason in anticipation of any future upgrades and of course to handle any abuse dished out...

I do a lot of riding in the hills and mountains of the Appalachian region, more sane than on the track, but still get healthy doses of throttle twisting regularly on any bike I ride.

the back cut trans gear dogs I was on the fence about, but I don't really want to have to tear down the lower end again any time soon. I keep hearing that 2nd and 3rd gears on most bikes are the most critical ones in need of back cutting for racing power loads, but am unsure if I should go for just that or do an up-down back cut on all 5 sets.

if it makes it live substantially longer, then it is worth it. After all, 1 of the 2 prospective engines I'm looking to pick up is a GS1000 with a bad trans, jumps out of gear...

Might be totally different with a Zook, but my KZ would pop out of first. It was drag raced a lot though.

 

[GregT]

Might be totally different with a Zook, but my KZ would pop out of first. It was drag raced a lot though.

Haven't had a problem with the roadrace GS1000. Didn't have to backcut anything as we started with a couple of good gearboxes.
The 1100 box is supposed to be identical but made to closer tolerances.

The GS1000 jumping out of gear is probably a bent selector fork - and possibly the selector fork shaft is bent too. Once it's got that history, yes, have a look at that gear pair and possibly recut the dogs.

I've recently gone through two Hayabusa boxes used for roadrace sidecar racing...Started at one end and cut my way across, LOL. Bent selector forks and rails in both. New forks and solid rails went in. $$$

 

[Chuck78]

Okay....well here is what I've got now!

$30 '82 GS1100G engine to donate the 1100G cylinders and D-port head
$150 78 GS1000 engine with 79 GS1000 head, bad 2nd gear and one other with dogs hammered pretty bad - all gears back cut. WELDED CRANK!!! (Had no idea!!), stock clutch basket.
$$$$ 66mm welded stroker crank from NickP w/straight cut primary gear
$375 (+ 4 racks of bs/bst carbs trade) almost new Keihin CR31 smooth bores
$200 Yoshimura Isle of Man .365" lift cams
$birthday Yoshimura GS1000 Series-1 4-into-1 exhaust
$30 ebay transmission
APE back cut job on transmission????

All I'm needing now is to call up Rapid Ray & talk about D-port head vs the 79 GS1000 small port head, & have him do some porting for me.
Then Wiseco 1085cc pistons & bore (maybe see about JE Pistons? None in their catalog so custom order)
Full gasket and seal set
Carb boots and filters
New H.D. DID Cam chain
H.D. clutch backing plate upgrade and gear to match the stroker crank


If I would have gotten the $150 engine sooner and had it torn down to find a welded crank, I probably would have just done the budget route with the standard welded crank, 1085 wiseco, & D-port head with a Serdi valve job.

With this 66mm stroker crank and MTC straight cut gear, I feel the need to definitely send Ray the head to work his magic on it.

I plan to do most of the racing on the Formula 500 prepped 489cc GS425, as it will be a better bike for an amateur racer to learn on, & less lost if/when I crash it vs a Rickman... racing the Rickman will be more of a for fun venture and less competitive, as I don't want to crash it up, but since the Rickman is the ultimate in twin shock 70's racing chassis, I also wanted to build up an ultimate engine to power it...
If I really get addicted to racing on the 1105cc Rickman GS1000, I may have to race prep a GS1000 frame and swap the engine into it, or else get a Harris XR69 replica frame or Magnum/F1 frame to road race on. Something more easily replaceable than a Rickman.


Thanks for the advice and support GSR Members... much appreciated.