YammaGamma RG250/RZ350 Hybrid

[Diablo007]

After 4 years I've finally had the frame repaired  and have started the YammaGamma build.  A previous owner had cut one of the engine mounting tabs off the rear, supposedly to fit an early TZ motor after the stock motor seized in a race.  Found someone who came highly recommended and had the mount rebuilt.

Does anyone have a copy/scan of the December 1987 Performance Bikes?  I have build descriptions found on the interwebs, but I cannot find the December 1987 Performance Bike article which was apparently written by Stan Stephens, who probably built the first one.  I'd like to compare the original walkthrough with the write-ups that I've found.  In particular the modifications to the side covers.

If anyone reading this has the magazine/article I'd really appreciate a scan.

Thanks in advance

[Diablo007]

More pics

[Diablo007]

Engine mocked up

[2 Stroke Jamoke]

Just finished my yammagamma,  it's a serious little ripper , heres a pic

[Diablo007]

Current question is regarding the side covers.  The info I have states the left side cover needs to be trimmed and filed, and that the right side needs to be filed to clear the lower frame rail.  my current mounts have the right side sitting on the frame rail, the left side is clear but the cover needs to be cut to fit at the rear towards the swingarm.  Did you end up cutting and filing?  If so how much?  If not, how did you accomplish that?

Still would like a copy of the article to add to my notes though, if anyone has one.  We went through all the old magazines in the shop but were unable to find that issue (dang Nargles...)

[2 Stroke Jamoke]

I had to file the ypvs cover just a little to get a 1/8 air gap right there. The clutch side engine was sitting on the frame just a touch, I filed the frame some and the engine some right there. The stator cover is plastic and you will need to trim it but it's easy stuff! Good luck!

[Diablo007]

Thanks, I'm looking at doing the same thing.  Just wanted confirmation.  Your bike looks a lot better (well, more stock) than mine will.  I'm missing some bodywork (side panels and tail), and possibly some nuts and bolts.  Thinking about running a vintage fairing that's hanging in the shop on it.  Once I have a rolling chassis I'll start mocking it up.

[motodreams]

Fairings should be easy to find on Yahoo Japan.  Few bucks to get them over here but likely worth it.

[2smokeRonin]

Is this the article you were looking for?

I remember cutting a bit of the sproket cover, but I don't think i did much on the clutch side.

[teazer]

I also have a copy of that scanned if you are missing pages.

[Diablo007]

2smokeRonin,

Thanks so much for the scan!  For some reason I thought there'd be more to the article, but it will make a nice addition to my notes.  For once I'm going to try to keep notes of the build so I can keep track of what I've done and what still needs to be done.

teaser,

If you have any additional information that would also be appreciated, thanks!

[Diablo007]

If anyone following this thread is interested, I have information found before posting the request for the PB article.  The file sizes are too large to post, if I can get them small enough I'll post them.  You can also PM me if you'd like.  One article is from a website that appears to no longer be there, 'Cult of Elsie'.  It appears that all of the important information was taken from the PB article.  There is a miscalculation in one of the write-ups, the length of the adapter plate was listed as approximately 35mm and not 55mm.  (10+5+27+5+10=57 : edge thickness + 1/2 hole diameter + distance between centers + 1/2 hole diameter + edge thickness)  This is what prompted my search for more information.  Though none of the articles actually says '27mm center to center', and only one gives the thickness of the plate, 9mm.  So the actual dimensions (if MY calculations are correct) are 57mm X 30mm X 9mm, with 10mm holes drilled 27mm apart center to center, 10mm from the edges of the plate.

Hope this helps anyone thinking about creating their own.

As a side note for any offended purists, the main reason for the conversion is that we had 2 RZ350 motors salvaged from motorcycles that were left outside so long the frames were rusted out beyond saving.  This and the fact that parts were missing from the RG (cylinders, heads, bodywork, etc) after years of being left partially dismantled and moving to new owners.

[pdxjim]

As a side note for any offended purists, the main reason for the conversion is that we had 2 RZ350 motors salvaged from motorcycles that were left outside so long the frames were rusted out beyond saving.  This and the fact that parts were missing from the RG (cylinders, heads, bodywork, etc) after years of being left partially dismantled and moving to new owners.

Seems obvious to me.  RG motors were crap but the aluminum frames were light and strong.  RZ motors were and still offer almost unlimited tuning potential.  Seems a no brainer to me. 

[2 Stroke Jamoke]

I loved my rg engine but it was definitely a tiddler compared to the meaty rz power. My yammagamma feels like a gp bike,  no real change on weight but almost twice the power, win win! At next years 2 stroke meet I'll let any of you blue smoke breathers give it a ride, I guarantee you will have an ear to ear grin under you helmet 

[Czakky]

I'm going to have my schedule clear for this.