Building a 350/500GP Bike

Mr. Bill "Big" Johnson has finally bugged me enough and I'm building my own bike. I have my provisional novice ticket, just finished my first race at Beaverun on Bill's bike, and I plan to race this bike (350/500GP) at VIR in March 2010 to get my license. I'll update my progress and probably be asking a lot of advice and looking for parts. I'm local in Maryland.

1. I'm pretty sure it's a 1974 CL350.
   
2. I have 35mm forks from a CB350F. I'm looking for good triple trees. Any suggestions/offers?
   
3. I have a good condition 2LS front drum from a T500 (Titan Cobra?). I found a few hairlines that need attention. I am looking for someone to weld the T500 drum - Any help?
   
4. I'm rebuilding the carbs now (115 main and #38 slow jet). I can't get the two smallest jets out of either carb. Any suggestions? Anyone selling a pair?
   
5. New lightweight sprockets on the way from Sprocket Specialists (17/33) to go with a new D.I.D. 520 chain.
   
6. New Woodcraft split clip-ons and 1/4-turn throttle ordered.
   
7. I'm hoping to run a PVL so I don't have to bother with points and battery. Any PVLs for sale?

 

I'll call these the "Before" pics:

 

christian. first, its a t500 suzuki titan. are you sure they are cracks and not casting marks? some times they look very similar. the t500 cracks in about the same spots. take a photo and post it. some people here will say to weld it regardless. but

dont force anything on the carbs. you can bring them back to bill, or me and we'll take care of it or show you exactly what you need to know. your primary jet is a 68, not 38. you probably have a 105 secondary. bump them both up one size to start. by the way. i assembled the one carb brand new from scratch. youre old original one is sitting here with acorns and mud still jammed in it. do a compression test on that motor. pat close attention the left side. it had a ton of debris in the intakes. and i blew air in the plug hole and a ton of crap came out the intake. so i know the primary jet will come out. and i pulled the other carb apart. so, i know they come apart. so i think you may be talking about something else on the carb. bring them to summit if you want and i can pull them down to bodies for you.

buff at todd henning racing has pvl's. drop him a note. but for your first season, run the points and a battery. keep it simple at first. you can use the clamps you have with the 350, or i have a set of 81 750ss clamps.

join the caferacer.net forums. more cb350 guys over there than you can shake a stick at.

 

Welcome busa: here's a great discussion on triple clamps:
http://forums.13x.com/showthread.php?t=226406
I like Greg's idea [SL350 triples]
Also, your bike will probably not pull 17/33 gearing which is reccommended for V1 bikes at the longest tracks....

 

Welcome to the CL350 club.

You will have a lot of fun on your bike.

I suggest you get a 15 and 16 front sprocket as 17/33 will be to tall!. The V1 guys can run that but GP350/500 doesn't have the power or top end.

Good luck

Keith

 

Welcome Busa, you will have fun!....sounds like you already have a good start.

Joe is right on your T500, post a pic.....I have a pic of a cracked one, if I can find it. I can also describe a quick inspection to clarify if needed, but.......IF its NOT cracked, dont weld it....alot are cracked tho....if it IS cracked, there are a couple approaches depending how bad its cracked.

I'd also take his advice on the carbs, sounds like he has you covered.

We differ slightly on the ignition. I think the PVL is simplier. If you have the smack, I would go PVL (or similar) and be done, over.....I hate frikkin points, battery, old coils, but they do work....I didnt know what a pain they were until I got a PVL.

On tree's/front end.....the thread THC linked is good. Late SL's are 35mm??....I need to look into that, have a couple.....I like KenE's bore the trees.....for the record, first couple years was BONE Stock CB350 33mm front end for me....I now run CB550, or CB750, depends on which bike.

On gearing, the consensus is generally correct, with a couple anamolies. With a stock motor, I ran 34, with a 16 or 17. You may pull a 17/33, but you are gonna have to be fast and keep it wound up....like Walker:up:

Good luck

 

Here is the T500 front drum with the hairline cracks I found.

If the cost isn't too prohibitive I'd just as soon get it welded for piece of mind now that it is off the bike with no rubber.

 

Yes, thats the typical spot.

Are all the gussetts cracked, or just that 1? ...Also look near the "button" (casting gate) at the end of the gusset....I wouldnt weld anything that is NOT cracked, the heat matters.

I recently fixed one that looked similar. Took a dremel and opened up the crack slightly (edge off), and tried to keep the heat input low, espicially close to the root or big flat face/base.

I fixed another earlier, where I removed those gussetts entirely from the bearing housing to that button, made new gussetts (thicker), and welded them in....but I dont think I'd do that again, too much heat I think...its holding up fine, but I'm learning.

If I had to do another, and all gussetts were cracked pretty bad, I would make new gussetts...but NOT remove the old ones....just tack the new ones next to (resting against) the old ones, good tacks, almost stitch welds.....and I'd do it with a axle running thru the bearings.

Has anyone mentioned Smokin158 Eric at sundial? I'd be interested in his approach, or vintage brake.

Long-winded, sorry.

Also....Hey Bowie, Duck150....post a pic of that one you have that failed....I learned alot from that one....IMO, there was "too much" welding done, I think the heat changed some things.

 

man that gas tank of yours sure gets around!

christian.....going to summit?

tex

 

I am really sure the CB350F had 33mm forks, same as the CB350K. If you have 35mm forks, they are from something else. I have the adjustable reamer that I used to open up the triples. If you want to borrow it You can use it for the cost of shipping. That offer goes for anybody that wants to give it a try.

Ken

 

Thanks for the advice - just ordered a 16t front sprocket. Money running out - I'll work on the 31t and 35t rears over winter.

I'm hoping I can meet up with J. Clancey this weekend to look at my front drum and the carbs. I'll post what we find.

 

Right now I'm planning to go to Summit as a spectator unless I can find a ride, but it seems like EVERYONE is already racing that weekend. I would love to get rid of this provisional before the end of this season...

See you there.

 

Welcome Aboard

Welcome to the cheapest racing fun availble on the planet.

Lots of good recommendations above.

CharlieY offered the best I can concur with for a first year racer. STOCK!

In your first year YOU will be experiencing the most improvement, not your bike. And, stock is cheap, readily available, and easy to bring spares.

The list I would recommend updating to stay stock and keep your bike on the track (because if you don't keep your bike on the track, YOU won't get any better):

Line your tank ASAP. I am a firm believer in POR-15.

KH1200 Carb Kits for the stock carbs from my sponsor Sirius Consolidated Inc. www.siriusconinc.com SCI(many of the parts you want will be found with one stop shopping)

Do replace fork oil and seals early in the process!

Same source for NEW points, condensors, plugs, petcock gaskets, cables, steering stem roller bearing upgrade, etc...

Ferrodo brake shoes for the stock CB/CL350 will surprise you. And, will make you comfortable taking your time getting the T500 front brake system configured correctly without a rush. Available at www.vintagebrake.com

Clip-ons (tightened just enough so they stay while you're racing but slip if you dump) would be a cost effective race upgrade from the get go if acquired for less than $75.

This five year Avon tire race will be switching to Dunlop next purchase.

For the first year or two, consider staying with a positive charging system (go solid state recitfier I have em for $30 each) so you can learn racing, then learn the cost for weight saving features like a total loss ignition.

Create your own wiring harness. Solder connections everywhere. Do not trust crimp connections.

If you think your motor can go the first season with the stock cam chain tensioner, adjust it religiously and correctly. Then at the end of the season, upgrade to the Teflon tensioner AND flat edge chain.

Use the STOCK rubbers that go between the carb and stock breather/filter assembly as your velocity stacks!

1/4 turn throttle might be a good first year upgrade to consider if the budget allows.

Double or tripple rubber mount the stock tach to keep it vibration minimized. Properly isolated, the stock tach will do the trick. A new stock tach cable from SCI would be advisable.

Eliminate the linkage based shift mechanism. SCI has nicely displaced shifers for CL/SL/and CB350s.

The stock CB/CLs came with 530 chain and sprockets. Changing to 520s can wait while the budget grows.

Remove the steering lock! You wouldn't want to hear "I told you so!".

For the stocker class, leaving the kick starter on can be beneficial.

SCI also sells spark plug caps. When replacing the caps, remove 1/4" of the outside insulation ONLY! Allow the strands of the conductor to extend out. Then, run a nail inside the strands, flairing then out, leaving a place for the threaded insert in the NEW caps to screw into.

As for reinforcing the frame, unless you have a crack or the traditional frozen frame buldge at the bend(s) under the motor, run what you brung the first year. Everything about the bike is over-engineered.

Synthetic oil can get you in trouble with a slipping clutch. The bike was made before synthetics.

Steering damper: So long as you are diligent about having a decently trued wheel, properly mounted and balanced tire, and tuned spokes (all in the same octave), your steering damper needs are minimul. The majority of the super bike stock take off dampers (available on eBay for around $10 off season, will do the trick).

Rearsets: the sooner the better. And, they are easy...
Using the passenger peg mounting holes, you can set up almost any foot pegs. The SV650 certain years... have shift levers that pivot about the footpeg. Thererfore, a right footpeg with a shifter pedal can be ALL THREADED directly to the flipped upright rear brake arm. Cover the all-thread with fuel line and go!

As for the passenger peg on the left, apply something that works for you and flip the SCI shifter over and go GP shift!

Either way, disconnect and remove the starter. Blanks are available from Boretech. Almost 14 lbs lighter already.

If you are going with stock foot pegs to begin with (no bad deal for learning), be sure to cut off the side stand mounting point. IT WILL CHEW UP THE TRACK AND FLIP YOU OVER HIGH SIDE!

Unless you have great 40 year old shock, and even then, replace with new. Even Redwings that I race with are better than NOS stock.

Rear fender required to keep trash/sand out of your exposed carbs.
CB360, CB400, CB450, CB500, ect... of 1974 and later have plastic inner fenders that can easily be fitted to stay, be light, and protect your KH1200 carb kits from Sirius Consolidate Inc. SCI.

SCI also carries front and rear bearings. They are inexpensive and NEW! Depending on the condition of your existing 40 year old bearings, could cut of seconds per lap.

After balancing your wheels, tape over your weight with aluminum tape. Nothing gets past it to loosen the adhesive and nothing looks better at tech time.

Drill and lockwire anything that you have any doubts about.

Without drilling, you can save parts like shifter pedal, exhaust mufflers, levers, etc...

Stainless steel Allen head screws for the motor and everywhere else for that matter. The sooner you do it, the sooner you receive the benefit over and over again.

SCI even has them for carbs!

Fuel filters are restrictive. If you lined your tank, you should skip this sentence.

With the stock petcock, which works fine for the stocker racing, you WILL want to remove the screen AND ONLY THE SCREEN! Pry it away from the ring with the tabs for placement. The rubber O-ring needs to press against this part to seal.

SCI sells the DUAL crossover quick disconnect for the under the tank crossover tube. The sooner you... the sooner you get to receive the benefits.

Gas cap latches. The "key" required gas cap latch really only needs a flat blade screw driver. I have NOS latches complete for $30 each.

When you are ready to go into your motor, SCI has .25 AND .50 over piston ring kits for less than $100 complete.

I know I have mentioned my sponsor a few time. You should also know that he opened up his sponsorship to the southeast region where he has been supporting our sport with the almost bullet proof 40 year old machines.

Have fun racing.

And, as was the motto in the day of these bikes... You meet the nicest people on a Honda.

If this was'nt TMI, send me a PM for my document "Friends and the Art of Vintage Motorcycle Restoration".

Welcome aboard vintage motorcycle club racing. Where, if you need a part or advice at the track, everybody will bend over backwards to get you to the grid. Also remember that true vintage racers are not only concentrating on the last turn of the race, but the last race of the season, the last race of the decade, and the next. Have fun racing safe to have more fun racing safe.

 

'Busa,
I have a good t500 brake freshly cleaned up, refreshed with new bearings and CDR race compound shoes. Also have a few cb450 front drums and a 305 or two. Shoot me an email or PM. Or ask Joe for my number.

 

Go with the CB77 (305 Superhawk) front drum!

I've seen the T500 cracks that CharlieY has examined with die. They are inevitable with the T500s. The CB450/CB77 (same thing) front wheels are like the rest of the Honda parts back then, bullet proof.

Vintage Brake puts it into perspective comparison with this article.

http://www.vintagebrake.com/drumspec.htm

 

The cb450/cb77 brake is great. I run one and so does most of the cb350 riders up here in the north east. The difference is the t500 is 40mm wide and the Honda is only 30mm. That gives the t5 a little more grab. There is some more info at EuroSpares on various drums and their braking abilities here: http://eurospares.com/drumbrak.htm
The t500 is a great brake, but should only be used on the lighter/smaller bikes.

 

Rosko, You bring up a very important point! No doubts there.

On the other hand, the title of this string is Building a 350/500GP Bike. If it is a Honda 350, scrubbing off speed has its costs as well. Having plenty of similar (spares) around is a good thing too.

 

no one has mentioned ole busa boy there prolly weighs about 230.

that aint lightweight in my book!!

christian, drop rosko a note!!

 

Keith, care to speak from experience?

 

I have no idea why Jack would think I have experience on this subject. I usually drag my feet through the corners to slow me down. Brakes are over rated.