The International CBX Owners Association

I could see beneath the surface of being put away for a long time, she was special...7000 miles, no mods, all original but the tires and the DynoJet kit I put in it...runs like we all hope they will...undecided future, I have a very nice '80 I got in 1995 with 33 miles on it...may have to keep both, crazy huh?

Great-looking bike and a great find! Just curious, why did you see the need to install a Dyno-jet kit? Please tell me you kept the stock carb components.

Dave

Very nice. She appears to be in fantastic shape!

Crazy to have two? Nope!
When the cop asks if you know how fast you were going tell him your speedo is temporarily out of order. haha.
Welcome to the site.

CRAZY??!!! Keep 'em both!

steve murdoch icoa #5322 wrote: ↑

Sat May 30, 2020 9:34 am

Crazy to have two? Nope!
When the cop asks if you know how fast you were going tell him your speedo is temporarily out of order. haha.
Welcome to the site.

good eye...the speedo was noisy so I pulled the cable till I resolve it...

Given the few clues I've been able to glean, it would appear your on the north side of Indy?

Fabulous bike. Keep them both.

Rick Pope wrote: ↑

Sat May 30, 2020 3:47 pm

Given the few clues I've been able to glean, it would appear your on the north side of Indy?

Fabulous bike. Keep them both.

West side, and you're in my favorite place to drive a sprint car...

daves79x wrote: ↑

Sat May 30, 2020 7:28 am

Great-looking bike and a great find! Just curious, why did you see the need to install a Dyno-jet kit? Please tell me you kept the stock carb components.

Dave

Yes, I always keep the stock stuff...I've been using DynoJet on all the DOHC Honda's I've worked with since the first time I used one. I've found the CBX if stock responds very well to the jet sizes and especially the stepped needles in the kits...I put them in as a matter of course, they've awakened every CBX I've used them on...especially the bone-stock one's...

Give a holler next time you visit. I live about 6 miles from the track, just off Rt. 1. I can hear them on Saturday nights from the back porch.

I'm glad you're happy with the way your bike runs - many are not with Dyno-jet kits and I've removed a bunch of them and went back to stock. If you jet for any kind of decent mileage, the bike suffers from lean issues somewhere in the powerband, and if you jet that out, your gas mileage is terrible. The reason I asked is that those of us that have been rebuilding these carbs specifically for years feel the same way about it. If the carbs are right in stock form, they will perform on a stock bike best, for performance and mileage. I understand that you'll disagree and again, glad you're happy with the way it performs.

Dave

So, why does the plate have a 5-14 sticker if the bike was out of commission for 18 years?

EMS wrote: ↑

Sun May 31, 2020 8:57 am

So, why does the plate have a 5-14 sticker if the bike was out of commission for 18 years?

my plate from another donor...this one has not yet been registered by me...the inspection sticker on the fork leg says 1995, I left it alone...

daves79x wrote: ↑

Sun May 31, 2020 7:23 am

I'm glad you're happy with the way your bike runs - many are not with Dyno-jet kits and I've removed a bunch of them and went back to stock. If you jet for any kind of decent mileage, the bike suffers from lean issues somewhere in the powerband, and if you jet that out, your gas mileage is terrible. The reason I asked is that those of us that have been rebuilding these carbs specifically for years feel the same way about it. If the carbs are right in stock form, they will perform on a stock bike best, for performance and mileage. I understand that you'll disagree and again, glad you're happy with the way it performs.

Dave

I'll take this debate...I rode my '80 from 33 miles to about 5500 miles before i changed anything. I took the carbs apart when i got it in 1994 as it had been sitting for more than 10 years inside and covered, but no fuel in it...the carbs leaked chronically so I got gaskets and cleaned/adjusted floats and accelerator pump linkage. It was really good for another 2000 miles, no problems but never as crisp and seamless as I wanted it to be. I had a long-time Honda tech tell me some CBX's were good and some not as good from the factory. He put it down to headwork details and valve adjustments causing lean conditions...he recommended the DynoJet kit to help with the responsiveness. I took his advice and installed a Stage 1 kit (needles 92 mains, opening the slide balance holes slightly, slide return springs) and the change was cathartic. It ran better in every way, I never did check for mileage but noticed no big difference at the International CBX rally in Norcross, GA that year. We did a 475-mile day to Deal's Gap and back, I noticed no mileage drop although I did not actually measure it...I've done several of these on stock CBX's and one on a modified CBX (yuck, pods and 6-1) using a Stage 3 kit, they've all been great results.

For this bike, the PO tried to do the carbs and got very nervous with the process, I took the reigns and chose the DynoJet Stage 1 kit since I was going through the carbs anyway...I did put NOS floats and valves in it as well. My theory is that the stepped needles and smaller mains fit the profile of the CBX air pumping character given the tune of the stock cams and valve sizes/compression ratio...full disclosure, I've had some experience tuning two-strokes and four strokes of many configs for 50 years, the CBX changes work for me, it's just my opinion, I could be wrong...I'd encourage anyone to ride a similarly modded stock early CBX for themselves and gain an opinion first hand...but I appreciate your perspective of course...stock is almost always better...I argue this same point from your side with any SOHC CB750 build, I've done LOTS of those over time, stock jetting on a stock bike all day...

When I acquired my Prolink it had a Stage 1 Dynojet kit installed with the carbs restored (at not inconsiderable expense) by Old School and it was smooth and ran well on the road but had a slight pause if the throttle was cracked open hard, I put this down to the vacuum delay. I took no notice of fuel consumption.

In some ways I wish I had left it alone. When RPE ported the motor for historic racing and ground the base of the cams off it gave me an extra 30 hp but was unreliable. With a more conservatively ported head and CR carbs we have slightly less power but if I was starting again I would adopt an entirely different approach to tuning.

I'm aware that the slight pause in the operation of CV carbs can be tuned out. My NC30 racer has CV's and no pause and there are well known mods to achieve this. I just wonder if anybody has experimented with the CBX CV's to improve throttle response? I hasten to add that I'm not talking about normal road riding but for racing where the throttle is generally either closed or wide open and the transition between the 2.