Author Topic: CB350K Race Engine Build Video (Read 3257 times)

StanLipert · « **on:** October 02, 2019, 07:51:42 PM »

Sharing my latest CB350 race engine build:
Yes, not a four, but many of the same build techniques:

Piston measurement
Cutting valve seats and flashlight inspection
Valve spring measurements and installation by spring pressure
Setting degree wheel
Cam timing/ slotting cam sprockets/cam timing diagrams
Clay squish measurements
Solder piston/valve/squish measurements
Dynojet 250i testing- 48HP

Building race winning vintage Honda's since the 80's.

RAFster122s · « **Reply #1 on:** October 02, 2019, 10:08:48 PM »

Wow! A two hour YouTube video...a lot of stuff in that video from your list. Serious screen time commitment to watch it all.
Thank you for sharing your techniques and methods, very useful info!

StanLipert · « **Reply #2 on:** October 03, 2019, 06:27:06 AM »

"Wow! A two hour YouTube video...a lot of stuff in that video from your list. Serious screen time commitment to watch it all."

YouTube has a playback speed in "settings", to shorten the viewing time. I felt that this would allow the viewer to have control over the viewing time, plus show actual real time assembly at normal playback speed for those who want to know the time of the operations.

Another tip is to use the space bar on your computer for quick pause/play functions, without a mouse.

Stan

bwaller · « **Reply #3 on:** October 05, 2019, 03:12:41 PM »

Pretty cool Stan. Sorry man I wasn't patient enough to watch the whole deal, but breezed through.

What I appreciate but what is boring and never shown is the parts cleaning aspect. I also clean all parts as they come apart so that when the building begins, it all happens quicker with cleaner hands! I expect you do all the measuring/adjusting/machining before building as well, but you include this interesting bit to show how it's done. Well done.

napoleonb · « **Reply #4 on:** October 08, 2019, 01:00:21 PM »

Nice video!

turboguzzi · « **Reply #5 on:** October 10, 2019, 02:16:49 AM »

Im mostly envious of your Serdi Micro tool! Would be nice to have one at home but last time i looked into it, cost was several thousands! I could buy a super cool lathe AND a nice milling machine for that kind of money...

Now i see that you do motors for a living. Not that easy to get the return on investment on kit like that

StanLipert · « **Reply #6 on:** October 13, 2019, 09:34:07 AM »

turboguzzi,
Yes, I was lucky to buy the Serdi Micro 20 years ago for $1000.
If I were to re-tool from scratch, I might consider the ball-socket tooling to use in my Bridgeport mill from Goodson:
https://goodson.com/

Prior, I was getting poor results from my Neway set with flexing pilots and the cutter following non-concentric seats.

Regardless of what one uses, stones, radius cutters or Neway, as long as the seats are excellent, they can be radiused into the port and chamber. It is unfortunate that there are methods for checking seats being perpetuated today that just don't work, such as filling the ports with a liquid and seeing if any comes out....

turboguzzi · « **Reply #7 on:** October 14, 2019, 02:23:48 AM »

yep, indeed, have a similar to neway kit, help to lubricate it so it doesnt "grab", but gives very iffy results.... made worse by the even thinner/flexier stems in a 500/4 compared to a 350

maxheadflow · « **Reply #8 on:** October 14, 2019, 06:58:38 AM »

Quote from: StanLipert on October 13, 2019, 09:34:07 AM

turboguzzi,
Yes, I was lucky to buy the Serdi Micro 20 years ago for $1000.
If I were to re-tool from scratch, I might consider the ball-socket tooling to use in my Bridgeport mill from Goodson:
https://goodson.com/

Prior, I was getting poor results from my Neway set with flexing pilots and the cutter following non-concentric seats.

Regardless of what one uses, stones, radius cutters or Neway, as long as the seats are excellent, they can be radiused into the port and chamber. It is unfortunate that there are methods for checking seats being perpetuated today that just don't work, such as filling the ports with a liquid and seeing if any comes out....

I've had issues getting a good seat cut by hand with the Neway cutters. I found the best way to get good seats was to drive the cutter with a slow moving variable speed drill like a milwaukee LI cordless set on slow speed. When turning by hand, the pressure on of the cutter on the seat is hard to control. Neway make a machine for this but the drill works just fine.

MRieck · « **Reply #9 on:** October 14, 2019, 06:03:26 PM »

Quote from: StanLipert on October 13, 2019, 09:34:07 AM

turboguzzi,
Yes, I was lucky to buy the Serdi Micro 20 years ago for $1000.
If I were to re-tool from scratch, I might consider the ball-socket tooling to use in my Bridgeport mill from Goodson:
https://goodson.com/

Prior, I was getting poor results from my Neway set with flexing pilots and the cutter following non-concentric seats.

Regardless of what one uses, stones, radius cutters or Neway, as long as the seats are excellent, they can be radiused into the port and chamber. It is unfortunate that there are methods for checking seats being perpetuated today that just don't work, such as filling the ports with a liquid and seeing if any comes out....

Agreed

seanbarney41 · « **Reply #10 on:** October 14, 2019, 07:31:34 PM »

Quote from: MRieck on October 14, 2019, 06:03:26 PM

Quote from: StanLipert on October 13, 2019, 09:34:07 AM
turboguzzi,
Yes, I was lucky to buy the Serdi Micro 20 years ago for $1000.
If I were to re-tool from scratch, I might consider the ball-socket tooling to use in my Bridgeport mill from Goodson:
https://goodson.com/

Prior, I was getting poor results from my Neway set with flexing pilots and the cutter following non-concentric seats.

Regardless of what one uses, stones, radius cutters or Neway, as long as the seats are excellent, they can be radiused into the port and chamber. It is unfortunate that there are methods for checking seats being perpetuated today that just don't work, such as filling the ports with a liquid and seeing if any comes out....
Agreed

ok guys, what is a good way of checking seats?

turboguzzi · « **Reply #11 on:** October 15, 2019, 02:46:39 AM »

so you didnt watch the video! caught red handed

seanbarney41 · « **Reply #12 on:** October 15, 2019, 02:56:49 AM »

Lol, hey man, that is lonnng.

cb550fcafe · « **Reply #13 on:** October 15, 2019, 03:36:58 AM »

I spy a nice windage tray.

StanLipert · « **Reply #14 on:** October 15, 2019, 05:30:59 AM »

"ok guys, what is a good way of checking seats? "
I prefer to use a flashlight. I can seen exactly the size and shape of a gap. Spin the valve as it sits on the seat, and see if it is bent or has a gap.

Kevin KDI- Yes, good windage tray!

Stan

MRieck · « **Reply #15 on:** October 15, 2019, 05:35:02 PM »

Quote from: StanLipert on October 15, 2019, 05:30:59 AM

"ok guys, what is a good way of checking seats? "
I prefer to use a flashlight. I can seen exactly the size and shape of a gap. Spin the valve as it sits on the seat, and see if it is bent or has a gap.

Kevin KDI- Yes, good windage tray!

Stan

That is a good start. Vacuum testing is the best IMO.

scottly · « **Reply #16 on:** October 21, 2019, 08:08:55 PM »

Hey Stan, please post a chart of the 48HP dyno run.

StanLipert · « **Reply #17 on:** October 22, 2019, 10:20:35 AM »

Scotty,
The run and graph are in the video.

scottly · « **Reply #18 on:** October 22, 2019, 10:12:49 PM »

Thanks Stan. Where is the torque curve??

StanLipert · « **Reply #19 on:** October 23, 2019, 04:26:09 PM »

Dyno graph

turboguzzi · « **Reply #20 on:** October 24, 2019, 02:02:48 AM »

Scottly, not really recommended for street use, just in case you were contemplating using similar cam timing...

Stan, as im coming from the 500/550 , it's pretty impressive how you get that 2 valve design breath so well at 10K+. Maybe it's the higher included valve angle of the 350 that gives room for very large inlets % wise. Most dynos ive seen for mid size sohc you can see torque falling off more after the peak torque rpm point of 9500 or so.

Ricky_Racer · « **Reply #21 on:** October 24, 2019, 05:52:19 AM »

Stan, this was an excellent tutorial. Thanks. I've been sitting on a basketcase '71 CB/CL350 and trying to decide what to do with it. I'm inspired! This looks this would a fun project after I finish a bigger one. Thanks again!

RR

scottly · « **Reply #22 on:** October 24, 2019, 08:01:30 PM »

TG, I'm also impressed with the output from the twin compared to our fours!
Stan, there is almost a 2 HP difference in run 8 between the two charts you posted, which I think is due to the 3 vs 4 smoothing? The PDF version was very hard to read; next time, place both HP and torque on the same graph, and the same scale, with the A/F below.

turboguzzi · « **Reply #23 on:** October 25, 2019, 07:19:53 AM »

Scottly, your graph is a perfect, strong, enjoyable street engine with torque varying only 20% from 4.5K to redline.
Comparing it to any race tune motor is really apples and oranges. My race Gpz750/810, about same size as yours makes 90 rwhp, and yet, I wouldnt want that motor in a street bike for everyday use.
My Gpz810 motor is not even heavily tuned, maybe stage 1 porting, good compression/squish and inlet cam, not surpised to see a 96 hp "700" is possible with proper dev work.

Stan's motor is a racer making an unstable 18 ft/lb at 4.5K, goes up a bit, then dips to 18 again @6500, then shoots to 25 @9500, that's a 40% difference in torque between low-mid and high range. perfect for the track, a bit less for the ordinary road.

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Author Topic: CB350K Race Engine Build Video (Read 3257 times)