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The short answer is NO. The only thing to avoid is do not have the front end of the internal stinger at the mid point of the convergent cone.  Forward of mid point or rearward all good. Angle will make little difference to exhaust flow or pressure wave action.

Sounds like air being drawn through the reeds.

Pull them off and see if it goes away.

You are spot on Chuck.  We could see from the Air:Fuel ratio that it was rich all the way on the main jet and the fuel curve was fairly flat. It got marginally richer as revs rose ( on full throttle) so I'm happy that you told me to cut down the spray bar, or else it would have gone from rich to super rich.

I decided to leave it rich to be safe.  The owner already texted this morning to say that on the street it is scary fast.  Way more than he was expecting.

How long before he calls back looking for more....   As they say, too much is never enough.

As long as the drag motor makes more power I'll be happy. We're starting out with a more or less stock 750 top end but I need to build the 400 with wild porting as soon as I design some bigger reed houses to take some large 6 petal reeds from something a bit bigger.   

So I put it together with ported cylinders, milled cylnders, YZ85 reed cages and reeds, 400n head gaskets, Lomas pipes and it runs extremely well. Jetting was as advised by Chuck Q and to my surprise it fires up first kick and has a flat linear powerband. 

Peaked at 52hp at 9,000 and 30 ft pounds to torque at 8600.  Air to fuel is slightly lean off idle suggesting it needs 2.0 slides and top end is slightly rich with 220 jets.

Could not believe how cleanly it picks up throttle and how flat the power curve is from 6 to 9.  Nice curve, not steps. No power below 5000 maybe 5500 but it runs cleanly down there - just no one at home.

Very happy the way it turned out.  There's more in there I'm sure but happy owner.  Happy dyno guy, so I'm OK with that.  Next i need to try our tame drag bike and see what it makes.

 

I just did two like that.  Your cush rubbers are completely shot and need to be replaced.

Remove the rivets and clean up the mess inside.

You can tap the basket 6mm x 1mm and use countersunk screws and loctite them in place.  Banshee rubbers are available on the web for around $20-$25 and fit.  They are the same as RD rubbers.

That was a good looking bike - and a really early one with bolt on inlet manifolds.

Are you thinking mild restomod or something outrageous for the one you have left?

Barrels and cranks are TZ750 with Blaster Reed cages.  The pipes arrived as a set of cones that I had to weld and then cut at angles to re-weld to get the curves.  Right side cover is an R5 modified to take a TZ waterpump. Other than that it's more or less stock RD.

That 500 is lust worthy.. It's a really nice job you are doing.

And you are correct that I was having some issues with the GT that I had zero time to address.  And over the winter I had an RD350 to strip and rebuild and port and so on and a GT750 barrels to port and head to machine for a guy in Colorado, so not a lot of time for my bikes.

I also started to refresh the Dunstall.  There were a number of details that I wasn't wild about, so I ordered a small pile of shiny stainless hardware from the UK, got some fresh powder coat on some other parts, and I am about to send off the chrome parts for some extra bling. And to add to the confusion, Dave Derrick finished the changes to the GT750 "Altered" and I need to clear the decks before that arrives and then I'll have more work that I know what to do with. I have to build a motor as well as fabricating the bodywork and wiring it for data logger etc.  Was planning on using the Ignitech TCIP4 V88 on that but may upgrade to the multichannel CDI which as similar functionality but more power to the plugs.

And in an idle moment I stuck another GT750 on the frame jig and started removing OEM frame tubes which will be replaced with Chome moly in a slightly different pattern.

I did the same thing on the RD350 drag bike and of course it took way longer than I budgeted for, as did the one piece carbon fiber tank and side covers.

Looks great with those Dymags.  Not yellow so it's slower than ours....

Don't piss off our dyno guy.  I have a pair of RD's to take there soon as well as the Phat Trakka (again).

Thanks for all that really useful input.  I have some chrome moly - not sure if any of it is a suitable diameter, but if not, hardware store 3/4" tube will probably be OK.  Back to teh drawing board to see what I can adapt from those suggestions.

I have an RD350 in front of me fitted with a beautiful set of Jim Lomas pipes and of course the side stand bangs into them and hangs lower than I would like.

The first thing I did was to remove teh spring end piece and weld it back on so it didn't hit the pipes.  That helped a little.  Then I heated the stand and bent it so that it more or less follows the pipes and when retracted is much closer to the lower frame rail.

It looked good and fitted well and all was good with the world until I rotated it down to lean the bike on the stand and of course it's now too far "out" and the bike leans way to much.  So the stock stand doesn't work with JL pipes and a modified stand doesn't work well as a stand.

Before I cut the last 4 inches or so off and weld in an insert, what am I missing?  Who has fitted JL pipes and what did you do to get the side stand to work?

Can an Accent system for a GT750 be made to fit?  Simple and reliable. 

If not try an Ignitech TCIP4 system with single pulser (pickup) and 3+1 lobe reluctor.  Fully programmable including 2 step, 2d or 3d timing curve, quick shift kill with variable timing and tacho and shift light output.

That's all true.  I didn't phrase that prior response very well.  I was trying to say that there are a few places around if you look.  In my experience, it's not so much where to send them as WHO to send them to.  Some shops are much better than others.

I had a set of GT750 barrels bored and honed by Redline in Kenosha, WI.  Good work.  A set of RD350 bored and honed in Palatine IL recently along with a set of GT750 barrels for a different project. 

If I were on the East Coast I'd go to Chuck but since I'm in the Midwest, I'd consider Bill Bune in MN as well.  For plated barrels it would be Millennium in WI.

They were and when they need to be re-plated, send them to Millennium and have them strip off hard chrome and re-plate with Nickle silicon carbide.  I have ebven done taht to a brand new (NOW) TZ250A cylinder.