Topic: 1975 Supersport, performance cafe

[Doctor_D]

The biggest issue with the CR carbs is the cutaway on the slides. They are meant for good control in the 2/3 to full throttle range, where the street carbs are meant for good control in the 1/8 to 7/8 throttle range. Typically, the street carbs do nothing between 3/4 and full throttle: the CR carbs do nothing between 1/8 and 1/2 throttle, making them dodgy on the street. The poor-man's CR used to be the street Keihins with the slides cut up to 3.0 or 3.5, like the real CR.  

I'm aware.  It took ordering a few different slide cutaways to get them running acceptably on a T120.  They did have a mild off-idle stumble throughout (0-1/8 throttle), but above that we had them sorted. If I recall correctly, we used a 2.0 slide.  This required using a y1 needle set one or two grooves above the middle groove to lean out the 1/8-1/4 mixture that was made richer by the 2.0 cutaway.

It'll throw off the budget, but its not too late for me to go with TM28's or 28FCR's.  I have little experience with the latter and none with the former, which also adds a bit of anxiety.  Anyone care to share their experience?

[MRieck]

 I have a set of 32 TMR's but have not used them. I have run CR31's and 29's on my 915cc engine with excellent results throughout the rev range. I did change needles but had no problems with the supplied cutaways

[Doctor_D]

I have a set of 32 TMR's put have not used them. I have run CR31's and 29's on my 915cc engine with excellent results throughout the rev range. I did change needles but had no problems with the supplied cutaways

CR29's it is.

Mike, you have a pm.

[Doctor_D]

Had a few minutes tonight to pull down the motor.

I was forced to drill out a couple of those lousy phillips head screws, and the head and base gaskets were cooked on solid... Oh and the studs took double nutting AND an impact wrench to extract, but other than that it was a piece of cake.





Lots of cleaning, blasting to do, but the internals look to be in reasonably good condition.

Now if Mike will get me an address, I'll get some bits in a box, call the big brown truck and move this project one step further along.

[bikeme2001]

nice project

[Doctor_D]

Parts are off in many directions.  Mike has the head, CycleX has the transmission, etc.

Have a feeling it'll be a little loud, but I got one of Simon's CR replica exhausts.  Came in today.  I'll mock it up on another CB, for brackets, etc, and get it off to Performance Coatings for the ceramic thermal barrier coating.

Was a bit worried when the FedEx gal came to the door:


But, they looked fine after removal from the box:

[wannabridin]

whoa!!!!  SO pretty!!!  excuse my ignorance, but which exhaust is this exactly?  do you mind my asking how much?  thank you!

[Doctor_D]

whoa!!!!  SO pretty!!!  excuse my ignorance, but which exhaust is this exactly?  do you mind my asking how much?  thank you!

Simon, aka Lord Moon Pie, made a few of these.  They're replicas of the factory racing exhaust. Price?  About $1400USD with shipping to the states.

At this rate, its going to be hard to keep to my $15k budget.

[HondaMan]

WOW! They look just like the old Yosh pipes! They came in both reverse-cone and full-flare versions, with the reverse-cone style used when some back pressure was needed for tighter courses.

I gotta talk to that guy...I didn't know he made these! Very cool.

[MRieck]

Parts are off in many directions.  Mike has the head, CycleX has the transmission, etc.

Have a feeling it'll be a little loud, but I got one of Simon's CR replica exhausts.  Came in today.  I'll mock it up on another CB, for brackets, etc, and get it off to Performance Coatings for the ceramic thermal barrier coating.

Was a bit worried when the FedEx gal came to the door:


But, they looked fine after removal from the box:

Very nice...

[traveler]

Very nice build to date...and welcome to the forum!

I can't see why you shouldn't be able to stay within budget....your PM to Mike....was that for head work??  If you let him do your head and pick the right cam you will go WAY past 70rwhp.

~Joe

[Doctor_D]

Very nice build to date...and welcome to the forum!

I can't see why you shouldn't be able to stay within budget....your PM to Mike....was that for head work??  If you let him do your head and pick the right cam you will go WAY past 70rwhp.

~Joe

Thanks for the welcome.

The budget is going to be tight, but you're correct - I should make it.

Yes, the head went to Mike for the stage 3 treatment with the Kibblewhite 5mm valve stem kit. And yes, he thinks we'll be closer to 80hp.  Can't wait.

[bucky katt]

http://www.motorcyclehidlights.com/honda-cb750-hid-lights-c-97_680

Here is a set for the CB 750

thanks for that link! after the present parts/money crisis is over, that will likely be my next purchase

[andy750]

Sign me up for this - looks like a great build! A stage 3 from Mike will really get you up there! Looking forward to seeing how this turns out!

good luck
Andy

[Doctor_D]

Long overdue for an update.

Many parts are still scattered about the country and many more still have to be ordered.

Mike Reick has the head (done, but I owe him a few bucks yet).  Ported, 5mm Kibblewhite kit, etc. Can't wait to see it.

APE has the crank for lightening and polishing.  It should be done in another 3 weeks or so.

CycleX was supposed to call me a few weeks ago about having my gears backcut, but I haven't heard a word.  Little worried about that outfit. Not very proactive about customer communications.

Gotta get some cash to Mark McGrew for the CR type rearset mounts, his camchain tensioner and a few other bits.

I do quite a bit of polishing myself, but Art Brass in Seattle has a lot of the aluminum pieces - and will get the frame as soon as we've got all the gussets added and unnecessary brackets removed.  Waiting on them to get my hubs back so I can get them off to Buchanan's.

A lot of little stuff is done, like the calipers and triple trees.


Engine cases have been painted, cylinders have been bored and honed for the Wiseco 836cc kit.

One of the more fun projects is blueprinting connecting rods.  It's just labor, so I'm not sure why more people don't do it.

I weighed and balanced all of the big ends, then the balanced the whole rods to within 0.5g of each other.


Then they get polished.


They'll get stronger 1978 F series rod bolts and they've already been cryo treated and magnafluxed - and should be fine in a 90 hp motor.

So much left to do, but I can't move on much until mid-month through May due to parts being spread around the country.  Should have a good update in a few weeks.

[Doctor_D]

The fabulous Mike Rieck got my head done, and it's back in my grubby hands.  All I can say is, "wow."

Also received my 125-65 cam and hard-welded rockers.



Stage 4 port, Kibblewhite 5mm valvestem conversion, ti retainers... the works.

Intake ports:


Exhaust ports:


Chambers:


It's as nice looking a port job as I've ever seen - and I've seen quite a few.  Too bad it's going to be a month or more before we turn her over.

The frame is coming along.  Got all the brackets and useless swarf off it and blasted it with 60 grit garnet.




Frame's ready for some gusseting and rearset brackets, then it's off to be plated, sprayed or powdercoated (all depends on the state of the budget at the time).

Crank and transmission are due back any time now.  Wheels should be back from Buchanan's by the end of May, then the fun starts.

[sangyo soichiro]

APE has the crank for lightening and polishing.  It should be done in another 3 weeks or so.

I sent them mine on March 8th.  I'm still waiting on it.  7 weeks and counting.  They called me on 3/23 and told me they had my crank.  I'm hoping I'll get it soon, because that's the thing that's holding me up.  So I would expect to get mine, and then about a month later you should get yours (because I sent them mine about a month before you did).    

We must be catching the spring rush or something....   



That Mrieck head looks damn nice!

[sangyo soichiro]

I have a set of 32 TMR's put have not used them. I have run CR31's and 29's on my 915cc engine with excellent results throughout the rev range. I did change needles but had no problems with the supplied cutaways

CR29's it is.

Mike, you have a pm.

So did you get the CR29's?  I got them myself, about 2 weeks ago. 

[Doctor_D]

I paid for my CR29's a few months ago and was told they'd be in in mid-April.  Not really in a rush, as there's no motor to put them on - but I wouldn't mind knowing where they are.

As for the crank, APE told me they try to run a bunch at once and that mine got to them just in time to be part of the current batch.  With any luck we get ours around the same time.

[sangyo soichiro]

As for the crank, APE told me they try to run a bunch at once and that mine got to them just in time to be part of the current batch.  With any luck we get ours around the same time.

That would be greaT!  I have to admit, 7 weeks is longer than I had expected.  I couldn't help wondering if it got lost on the mail or something.

I don't mean to stress you about about the CR carbs, but I heard they are kind of hard to come by lately.  I got the last 29s that Dynoman had.  And Cycle X says we can't get them anywhere. If you got yours from Mike R., then you have nothing to worry about.  But if you got yours from somewhere else, you might make a phone call and tell them you heard about the supplies drying up, and ask them about it.

[moham]

wow, doctor.

you aren't playing, are you?

great stuff so far. look forward to seeing it all go back together.

[Doctor_D]

I don't mean to stress you about about the CR carbs, but I heard they are kind of hard to come by lately.  I got the last 29s that Dynoman had.  And Cycle X says we can't get them anywhere. If you got yours from Mike R., then you have nothing to worry about.  But if you got yours from somewhere else, you might make a phone call and tell them you heard about the supplies drying up, and ask them about it.

So you're the guy who beat me to the Dynoman CR's.

Not stressed at this point, but Sudco's now saying late May, a change from their earlier estimate of late April.

[Doctor_D]

wow, doctor.

you aren't playing, are you?

great stuff so far. look forward to seeing it all go back together.

Thanks for the compliment.  Trying my best, but I've got a ways to go before I know how it will turn out. Right now I'm just trying to keep the budget under control - though that's looking less likely every day.

[MRieck]

wow, doctor.

you aren't playing, are you?

great stuff so far. look forward to seeing it all go back together.

Thanks for the compliment.  Trying my best, but I've got a ways to go before I know how it will turn out. Right now I'm just trying to keep the budget under control - though that's looking less likely every day.

 You know what they say about a budget David......it's a good starting place. Glad everything arrived safe and sound. Your engine should be killer.

[Doctor_D]

Mike:

It's beautiful work.  Well worth the money.  Thank you.

All:

So, what are the odds that the Sudco CR29's will come with fairly accurate jetting? What's the setup for stateside users running 10.5:1 comp and a moderately aggressive street cam on high-test fuel? I'm asking because every other carb I've ever gotten from them was way off and took quite a bit of playing to get right.