CB350 racing advise needed

13834 Views 47 Replies 16 Participants Last post by XB33BSA, Jun 22, 2017

tbh37620

Discussion Starter · Mar 20, 2017

Hello, I recently picked up a 1972 CB350 to prepare for racing in both the WERA and AHRMA races near me throughout the year. I have read some build threads on here and also on other sites to see what common modifications are. However, I am wanting to check with the experienced folks here who race these bikes and find out what modifications are real priorities. The bike is 100% stock and has 1,100 miles on it. I am wanting to have it ready in 2 months and I am not wanting to spend tons of money doing a top notch rebuild. Basically wanting to upgrade what is necessary to have a safe reliable bike to race. I wont be fast so no need to have a championship level bike.

Any suggestions on engine parts and mods to make sure it will last the racing season and hold up to race use?
Suspension or brake suggestions?
I am also curious about any common modifications that are not legal or will not allow the bike to race in BOTH series.
Anything most people overlook when building one that is important to have?

Thanks for any help guys.

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Norton 357

· #2 · Mar 20, 2017

2

You need to look at the rule books for both orgs. WERA has a GP 350 class that is popular because you run a stock engine and it allows things like frame bracing and rearset footpegs, add in some good shocks, tires and fork springs and you can go racing. You won't be at the front but you can still have fun.

I raced an SL 350 with a CB 350 engine and it was competitive but it took a lot of work and it would have had to race in Sportsman 350 with AHMRA, where it would not have been competitive.

AHRMA has a production class that is good for beginner racers but doesn't allow moving footpegs so check the rules before you start moving things around. You will be severly limited by the stock pegs

You should attend a race or two and talk to some of the guys who are already racing these bikes, they usually have some good advice and parts for sale, just bring beer and you can get help.

There are some simple and basic things that you will have to do to get on the track but you can find all that out by reading the rulebook. Also, check out the 13x forums on the WERA site. There is a vintage section there and a lot of those guys have CB 350s.

Here are a couple of pics of the bike I built a couple of years ago for WERA GP 350

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Good Luck.

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tbh37620

Discussion Starter · #3 · Mar 21, 2017

Norton 357 said:
You need to look at the rule books for both orgs. WERA has a GP 350 class that is popular because you run a stock engine and it allows things like frame bracing and rearset footpegs, add in some good shocks, tires and fork springs and you can go racing. You won't be at the front but you can still have fun.

I raced an SL 350 with a CB 350 engine and it was competitive but it took a lot of work and it would have had to race in Sportsman 350 with AHMRA, where it would not have been competitive.

AHRMA has a production class that is good for beginner racers but doesn't allow moving footpegs so check the rules before you start moving things around. You will be severly limited by the stock pegs

You should attend a race or two and talk to some of the guys who are already racing these bikes, they usually have some good advice and parts for sale, just bring beer and you can get help.

There are some simple and basic things that you will have to do to get on the track but you can find all that out by reading the rulebook. Also, check out the 13x forums on the WERA site. There is a vintage section there and a lot of those guys have CB 350s.

Here are a couple of pics of the bike I built a couple of years ago for WERA GP 350

View attachment 56585 View attachment 56593

Good Luck.

Thanks for the reply Norton. I have been reading the rule books and trying to wrap my head around it. I planned on racing in Sportsman 350 for AHRMA and V1 and also V2 hopefully in WERA to maximize track time. I am not looking to run in any "production" classes. Im trying to find out if you can run in multiple classes in AHRMA on one bike. Just dont want to show up and one little mishap or misinterpretation keep me from racing when I will be driving 3-6hrs to race.

Found a good page however on upgrades. Welcome to the Vintage-Roadrace List Honda CB350 Road Racer FAQ Also reading peoples build threads and trying to notice what they run.

If anyone else has info on how to set this bike up to allow running in the most possible classes with both organizations please let me know.

Thanks again

Reactions: 1

Teazer

· #4 · Mar 21, 2017

tbh37620 said:
Thanks for the reply Norton. I have been reading the rule books and trying to wrap my head around it. I planned on racing in Sportsman 350 for AHRMA and V1 and also V2 hopefully in WERA to maximize track time. I am not looking to run in any "production" classes. Im trying to find out if you can run in multiple classes in AHRMA on one bike. Just dont want to show up and one little mishap or misinterpretation keep me from racing when I will be driving 3-6hrs to race.

Found a good page however on upgrades. Welcome to the Vintage-Roadrace List Honda CB350 Road Racer FAQ Also reading peoples build threads and trying to notice what they run.

If anyone else has info on how to set this bike up to allow running in the most possible classes with both organizations please let me know.

Thanks again

They used to say that the easiest way to eat and elephant is to cut it into pieces. You might want to try the same approach.

Safety rules: What needs to be safety wire locked in each organization? What other safety rules do they have eg dead man's lanyard switch or kill switch etc.

Reliability and personal safety: Fit good tires and cables and chain and flush forks and service the engine etc Rubber mount the battery ( a good one). Replace points, plugs etc.

Eligibility: are mufflers required, can footpegs be moved are stock carbs required etc

Performance: upgrade shocks, brakes, forks etc to get around corners faster. Reduce weight. And last of all look at high compression big bore pistons and cams and other exotica.

Good luck and have fun.

Reactions: 1

kenessex

· #5 · Mar 21, 2017

Have you ever raced?
The bike will not be a limiting factor on your lap times when you are first starting out. So, first off make sure your engine is in good shape, especially take a look at the cam chain tensioner rollers. Replace with a slipper type tensioner. As long as you have the top end off, replace the rings and lap the valves. Leave the rest of the engine stock. Leave the electric starter in place, but check the sprag clutch behind the alternator rotor and make sure the screws are tight and the rollers and caps and springs are in good shape. You will want the starter more than you will want to get rid of the weight, at this point.
Starting at the front, replace the front brake shoes with some EBC. Replace the front tire with the race compound tire of your choice don't forget a new rim strip and tube . Check the front wheel bearings and replace as needed or just replace because they are cheap. Rebuild your front forks including new oil, seals and fork springs, I like Progressive Suspension. Replace your steering head bearings, the stock loose balls work ok, but I like tapered rollers. Put on some superbike bars and new cables and grips. You will probably want to move your footpegs up and back to suit your needs. Check your swingarm bushings and replace them with bronze bushings as needed. Replace your rear shocks. Replace your rear tire with the racing tire of your choice. check your rear brake shoes and replace as needed. Replace your chain and sprockets. Replace the mufflers with some that will give more ground clearance. You can replace your airfilters with foam Uni filters if you use the stock velocity stack type rubber connectors from the OEM air filters. You will need to rejet your carbs accordingly to match the airfilters and mufflers.
Now you can race prep. Remove you headlight lens, but keep the bucket. Remove the side stand and center stand and turn signals, mirrors and tail light assembly. Safety wire you axles, fork drains, brake stay bolts, oil drain, oil filler, axles and axle clamp nuts and for AHRMA, the throttle cable. Install your belly pan, catch can and number plates.

All of the stuff I have listed will run about $1300 - 1500 in parts prices alone provided you do all of the labor. You may want to look into finding a racebike that somebody else has already gotten track ready; unless you just want to spend the money and do the work. Note that I haven't figured in any engine work other than the tensioner rings and gaskets. You start looking at headwork, cam, pistons and rebore and you are looking at even more money. Upgrade to a 35mm fork and even more money, emulators = more money. Jemco exhaust =more money, 30mm Mikuni carbs =$, Tannermatic tank and seat =$, Braced frame and swingarm = $ how about wider alloy rims on a bigger brake with heavy gauge stainless spokes.

Remember, at this point the slowest part on the bike is you. There are some really fast guys out there on basically stock bikes. So get out there and have fun. When you get the bike and have specific questions, there are plenty of us on here that have raced or still do race CB350's and if you have lots of money to spend. we can help.

Where do you live and which tracks do you plan on racing?

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drgonzo

· #6 · Mar 21, 2017

2017 AHRMA rules do allow rearsets in production classes.
From the AHRMA handbook:
f) CONTROLS AND FOOTRESTS:
Controls: Handlebars must bolt to the stock
locations. Clubman bars are allowed. Footrests may be trimmed down or raised for
ground clearance; rearsets may be used.
One could easily build a CB350 that is competitive in WERA 350GP and AHRMA Production Lightweight.

Reactions: 1

Norton 357

· #7 · Mar 21, 2017

Good to know that Gonzo. I have been out of racing for a few years now so I'm not up to date on rule changes.

To the OP. The AHRMA Sportsman class is pretty serious racing and you will need a pretty serious budget to keep up. Don't let the stock appearance fool you , those bikes are built from the ground up.

I know of a national champion racing a CB 350 in WERA with a stock front brake, just replace the shoes like Kenessex recommended.
Ken made a lot of other good points in regard to prepping the bike, especially the steering head bearings.

If you are new to racing you need to get a safe and reliable bike out there to get some track time before investing big money in performance mods. You may try it and decide it's not for you. Chances are if you have never raced you will love it and get hooked, but that is when you start opening up the wallet for some real performance parts.

Reactions: 2

tbh37620

Discussion Starter · #8 · Mar 21, 2017

Thanks for all the input guys I do really appreciate it.

I have raced before(not in WERA or AHRMA) but honestly I enjoy the riding and racing myself/the clock. I know I wont be fast right off the bat(or ever more than likely) because this will be my first go on a vintage bike.

The cam chain tensioner/chain seems to be the one must have on the engine I keep hearing mentioned. Beyond that I plan on upgrading the carbs and exhaust and just making sure the rest of the engine is solid and within spec for this year.

drgonzo said:
One could easily build a CB350 that is competitive in WERA 350GP and AHRMA Production Lightweight.

This is the core of my concerns, building a bike to run in both series and be able to ride in other classes as well to get 2 or even 3 races in.

This weekend I plan on sitting down and reading the rule books and making a list of what is allowed and not allowed in these series. I will post what I come up with to see if you guys that have actual experiences with these organizations can spot any errors before I start making any irreversible modifications.

drgonzo

· #9 · Mar 21, 2017

AHRMA Prody LW and WERA 350GP usually have decent size grids and with the inclusion of the rear sets in AHRMA, they are essentially the same bike.

Buckets

· #10 · Mar 21, 2017

tbh37620 said:
but honestly I enjoy the riding and racing myself/the clock. I know I wont be fast right off the bat.

I used to think this too but unless you are dead last or dead first you likely wont be racing yourself. I was in dozens of sportsman races with a stockish FCB cb350 (USCRA) that was not competetive in "bump" classes. Didnt matter cuz there were other guys my speed in the field. When you are dicing it up for 6th place with another racer you won't care that you are about to get lapped by the leader. And you will have a stupid grin on your face for the next couple hours cuz it was so damn fun.

Ultimately, follow ken's advice. Build a bike that will keep you on the track and not in the pits with a wrench in your hand. Make go fast mods along the way.

Reactions: 2

knappyfeet

· #11 · Mar 21, 2017

Norton 357 said:
I raced an SL 350 with a CB 350 engine

Are these frames similar? .............the cl, sl, cb, etc.

Norton 357

· #12 · Mar 21, 2017

The SL frame was different on the later models but the motor mounts were the same with the exception of the right front and you have to fabricate a mount for that, pretty simple though.

You can't use the electric start in the SL frame and have to block off the starter hole but that is a pretty good place for a breather anyway.

I had a CB engine and a complete SL so I made the switch because the SL motor is detuned for dual sport type riding.

I don't think the SL frame was better, some say the CB frame is much better, but it was a fun project.

drgonzo

· #13 · Mar 21, 2017

The first year SL makes a great race bike. My friend Chris Adams had one. It uses the same frame as the CB/CL except it has a steel rear inner fender that is welded in between the rear down tubes and I believe does add some rigidity to that part of the frame. If you can find one it's a great frame for classes that don't allow frame bracing. It also uses the same engine and carburetors as the CB/CL bikes.

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1969 SL350 KO.

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knappyfeet

· #14 · Mar 21, 2017 (Edited)

drgonzo said:
The first year SL makes a great race bike. My friend Chris Adams had one. It uses the same frame as the CB/CL except it has a steel rear inner fender that is welded in between the rear down tubes and I believe does add some rigidity to that part of the frame. If you can find one it's a great frame for classes that don't allow frame bracing. It also uses the same engine and carburetors as the CB/CL bikes.
View attachment 56633 1969 SL350 KO.

Perfect....thank you

Norton 357 said:
The SL frame was different on the later models but the motor mounts were the same with the exception of the right front and you have to fabricate a mount for that, pretty simple though.

You can't use the electric start in the SL frame and have to block off the starter hole but that is a pretty good place for a breather anyway.

I had a CB engine and a complete SL so I made the switch because the SL motor is detuned for dual sport type riding.

I don't think the SL frame was better, some say the CB frame is much better, but it was a fun project.

Great info.

SLs around here go for cheaper than the CBs.....usually. Honestly some people think they selling gold or J-Lo's pussy for what they are asking for CBs. Plus most of the CB350s are too nice to alter severly.

Sent from my SM-T900 using Tapatalk

Reactions: 1

tbh37620

Discussion Starter · #15 · Mar 22, 2017

Buckets said:
I used to think this too but unless you are dead last or dead first you likely wont be racing yourself. I was in dozens of sportsman races with a stockish FCB cb350 (USCRA) that was not competetive in "bump" classes. Didnt matter cuz there were other guys my speed in the field. When you are dicing it up for 6th place with another racer you won't care that you are about to get lapped by the leader. And you will have a stupid grin on your face for the next couple hours cuz it was so damn fun.

Ultimately, follow ken's advice. Build a bike that will keep you on the track and not in the pits with a wrench in your hand. Make go fast mods along the way.

I have taken note of everything Ken told me and will do all of it. And to address his earlier question about what tracks, Mid Ohio, Gingerman and Grattan. Plus probably Putnam for track days.

I do like racing other people, I guess I meant that my motivator is usually just riding better and improving myself/time. If someone is riding like an idiot to take back a place on me and I cant easily put a gap on them I just usually give it to them. I have already been run off track, crashed into and too many close calls trying to deal with those people. Not worth it too me. I guess thats what I meant.

Going to start working on the bike this weekend and start a build thread on here so more experienced people can hopefully give input on the project.

kenessex

· #16 · Mar 22, 2017

You should note that with WERA vintage generally runs on Saturday and the more modern classes on Sunday. A CB350 is legal to run in E Superbike and Clubman on Sunday. It could do well in both of those classes, depending on the size of the field, but not as well as a Ninja 300 or R3. A cb350 is pretty fun at Grattan and Mid-Ohio. I have never raced at Gingerman.

tbh37620

Discussion Starter · #17 · Mar 22, 2017

kenessex said:
You should note that with WERA vintage generally runs on Saturday and the more modern classes on Sunday. A CB350 is legal to run in E Superbike and Clubman on Sunday. It could do well in both of those classes, depending on the size of the field, but not as well as a Ninja 300 or R3. A cb350 is pretty fun at Grattan and Mid-Ohio. I have never raced at Gingerman.

Wow, I really appreciate that info! I noticed only a few WERA races listed "V" vintage races so knowing that it can run in normal modern classes is great and would open up several more opportunities to get out on the track.

TrialsRider

· #18 · Mar 22, 2017

and get passed a whole bunch

tbh37620

Discussion Starter · #19 · Mar 23, 2017

3

TrialsRider said:
and get passed a whole bunch

So are you saying that since I might get easily passed by faster bikes I shouldnt bother riding in the class to get extra track time out of my weekend?

Here are a few pictures. Gotta dig the ape hangers haha

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hillsy

· #20 · Mar 23, 2017

You should keep the apes

Or modify them Japan Auto Race style....

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