Another 350gp questions

I'm thinking about building a 350 for next year. I have a couple of questions about whats allowed with the wheels.

I think I'm getting V1 and 350 confused but I keep reading about people using different wheels and hubs. For the stock class am I correct in assuming that the wheels must stay stock size but I can use the front hub/drum from a different bike? Does any one have a source for new wheel hoops and spokes.

I've also read that the SL frame is much stronger then the CB/CL frame, does any one use them on the track? Since the SL has smaller carbs would a CB engine fit in a SL frame and still be legal since it's still a honda 350 twin?

 

Hello....and welcome. I race the 350 and 500GP (Stock) classes....its alot of fun, and affordable.....more bikes are even better!

I'm going to try to answer, but I'm not the "keeper of the rules". I've abbreviatted (chopped) here, but these are from the rulebook:

Brakes: GP and V1 will employ internal expanding drum brakes front and rear regardless of original equipment.

Wheel Types: GP, V 1 will use wire spoke built-up wheels.

Wheel Sizes: GP, V 1, V 2, Formula 500 and V 3 rim diameter will be 18” or greater unless original equipment was fitted with smaller rim diameter.

Rim Width: GP, V 1 and V 2 may not exceed 2.75..... GP, V 1, V 2, Formula RD, Formula 500 and V 3 cannot use racing slicks or racing rain tires.

I ran stock wheels for awhile, then laced some alum from here: http://www.buchananspokes.com/index.html

Most run Avon's, I run 90 /90 18 front, 110 / 18 rear.....V1 bikes might go alittle bigger.

Run a stock CB / CL rear hub......you can also run a stock front with some racing shoes.....I'm working on fitting a T500 front drum....there are several options, another is the CB450 drum.....but stock will get you going, I mean stopping....aaahhh, on the track! good stuff here.....and ebay http://www.vintagebrake.com/index.html

I'm also pondering the SL.....I believe the CB motor will fit, but its tight.....I may be trying it here in a couple weeks.....anybody else here know the in-and-outs of the SL as a stocker race bike?

CB / CL are pretty straightforward, so are the rules....stock carbs, an aftermarket exhaust, and no frame bracing like you see in the V1 bikes.....some of us have re-welded the 30 yr old seams and spot welds, and welded a crack or damage.....but no bracing...just get it all working and come on out!!!

Lots of good parts sources on here....Buff, "Footwork", Todd Henning Racing on this board....and Bill Moeller at Boretech in Ohio.

Look forward to seeing you at the track.

 

beech,

welcome!

you must run 18" rims, front and rear. use any drum brake you want. you can get rims on ebay (i just sold two akronts for $130/ea), i think your gonna have troulbe ebaying new spokes and nipples, but you can call buchanan's in cali and order excell rims, tell them what brake you are running and they will sell you s.s. spokes and nipples, or just send them your brakes and they will build and true your wheels for you.

buchanan's is very good!

sl frames, yep.....people run them. i plan on running one next year myself. swingarm is longer, but you'll have to machine a different spacer for the rear brake....no biggie! the motors were all the same for CB, CL, or SL.....it bolts in! are they stronger, or lighter.....dunno! basically they are cooler looking, and i'm all about style and cool points, ask anybody!

hope this and charlie's reply helped. make sure you copy the rulebook and read the freakin' thing. your less likely to get your stones broken if you do.

see you trackside,

tex

 

Thanks for the info and links. This post is what confused me. http://forums.13x.com/showpost.php?p=1154218&postcount=2 I was reading the rules and wasn't sure if the rim width was fixed. So I am ok to run 2.5 wheels if I want to. Now I just need to find a bike in my price range with in a reasonable distance.

 

When I was having trouble with my V-1 cb350 engine, I looked at 350gp rules and came to the conclusion that my V-1 bike would be 350gp legal by changing to a stock engine and carbs: my 350gp understanding is that you cannot substitute the frame/swingarm with aftermarket or custom items but bracing is not restricted at all......

 

Hey Beech.....nobady is really looking at wheels (at least I'm not) for a couple reasons....

1. you can run any front drum brake you want.

2. These stockers are not going fast enough to need all the tire a wider than legal rim would give you!....

2.5 is legal I believe....??...

Hey....is that PM Mike Ewer or another mike from PA?

 

Charly.....I once read the bracing rule the same way as you....BUT was convinced by numerous BBS users that I was MIS-interpreting things.

There was another lengthy thread about this (anyone?).....In a nutshell....I was informed (and eventually I agreed) that this portion of the rulebook:

Honda 350cc twins with the following limitations: OEM Honda twin frame and swingarm, OEM, stock, non-modified engine parts (no material removed or added), OEM carburetors (jets may be changed). The following modifications are allowed: aftermarket cam chain and cam chain tensioners, any ignition system and coils, any internal expanding drum brakes, any diameter period forks to class maximum diameter, any period exhaust system, any period body work/fairing.

And specifically this portion of that:

The following modifications are allowed:

Supersedes the other rules.....because it was put in AFTER the other rules, as part of the CB350 index, allowing us to race.

I know, I know, I argued for the other side holmes (Bracing allowed, with stock motor)....but was convinced otherwise.

I was also convinced that if this line gets "Blurred" between GP and V1....someone will lose out.....look at 250GP....look at the RD class....

Anyhow sir....just my humble opnion....GP classes = UN-braced chassis, and stock motor.

That is my opnion because I believe that was the intent of the index for the Honda 350 into 350GP.....IMO.

 

DUBS

Buchanan's, Excell rims, S/S spokes & nipples, stock rear brake, T500 front. Avon's All good. :up: Rich

Black Sheep Racing
Honda #646 V-1

 

CharlieY: I remember the other lengthy thread on the issue, I base my belief on the added exclusive language clarifying engine modifications: "oem STOCK NO MATERIAL ADDED" etc this is not the language used when describing the "oem frame and swingarm" it does not say "unmodified oem frame and swingarm" or "oem frame and swingarm-no extra bracing allowed" I really think the intent was to exclude special one-off or aftermarket racing frames, but I am wrong alot.

 

Charly....I thought the same EXACT way.....same words....that lead me to any "Period GP" frame mods.

But once the point was made that the period GP language was original, and the 350 index wasnt.....well...AND the "Modifications Allowed" list....with the "If it doesnt say you can, you cant...." approach, I started to see more of the history to this issue.

Ya know....maybe its not out of line to request a rule clarification directly addressing the verbage....???...

Is it intended by WERA that 350GP bikes are allowed to run the same chassis mods as a V1 bike?....or keep 350GP stock chassis...??

On the chassis note, like I said in the other thread.....I dont see any problem with welding up 35 yr old seams / spot welds....its a safety issue......or fixing damage / cracks / dents.....once again, safety....

 

yep, mike ewer from pa.

texy

 

Allow me to add another perspective to reinforce CharlieY's accurate point.
In the GP350 Class where the newer CB350 was indexed into a class of bikes that otherwise had to meet these rules "Pre 1968 4 stroke twins up to 350cc"
The CB350 of 1969 to 1973 was retroactively allowed in under specific stock requirements.
V1, however, is a class of "Pre 1973 OHC up to 360cc" and therefore the CB350 was not only NOT indexed in, it was designed for the class. The general Component Specifications for vintage racing requirements were just that, GENERAL.
The Indexed CB350 in the GP350 class were specific requirements to allow an out of class bike into the class. Hence the specific statement of what is allowed and what is not allowed...
"Honda 350cc twins with the following limitations: OEM Honda twin frame and swingarm, OEM, stock, non-modified engine parts (no material removed or added), OEM carburetors (jets may be changed). The following modifications are allowed: aftermarket cam chain and cam chain tensioners, any ignition system and coils, any internal expanding drum brakes, any diameter period forks to class maximum diameter, any period exhaust system, any period body work/fairing."
Its kinda like interpreting the constitution.
As one who appreciates the ability to run a slightly more bullet proof newer bike, WITH RESTRICTIONS, in a class that would otherwise not allow entry and would probably disappear as a result, I'm grateful.
As such, I will self govern.
Adding to the discussion and having met John Early, primary identity that indexed the bike, he did say that intentions were to allow re-welding the existing frame welds for safety.
That's my 2.5 cents worth.

 

OK-since you are THE guys I would be racing with in 350gp [if my V-1 bike blows up] I will respect the no bracing convention on my pure 350gp bike; how do you guys feel about losing the helmet hook/seat hinge/seat lock/centerstand/footpeg/sidestand extra brackets and tabs?

 

Hey Charly.....dont forget to incorporate those required 2 50lb lead bricks either!!

But seriously....I have removed all those things you mentioned.

This is just my take, and maybe it comes form working at an airplane factory.....I dont see anything wrong with removing "trinkets" that have nothing to do with "primary structure".

I also dont see anything wrong with "Repairing" or "Maintaining" a primary structure to restore it to its original (or close to orig) structural integrity....not doing this could cause structural failure, and that could hurt!

And THAT I guess is kind of where I see the line / intent of the rules.

I see frame bracing as an attempt, mostly by ADDING structure, to IMPROVE the capability of the structure in some way (accurate description?? agree? or Not?)......on aircraft, the structure is hardly ever improved by removing structure (not trinkets)....unless you've added structure somewhere else that negates load.....I digress, you know what I mean.....you've built what appears to be a sweet bike sir!....I can see you've gone thru this scenario...

Its my understanding that the CB350 Indexing rules were written sort of by committee....I dont know the gent jack talked to, but I have talked to others.......And....

I've heard no one say that allowing frame bracing / V1 type chassis mods was part of the intent of CB350 index into 350GP.....

I've heard nobody stepping up and saying "Yes, we meant to allow frame mods, but left it off the allowed modifications list in the index rule, sorry".

Just my thoughts sir.

 

Material added or removed...

I am in concurrence with Charlie on this one as well. I received my CB350 which already had such street trinkets removed (all but the center stand clamps which are part of my stand configuration still). It was a V1 bike that had only had Mikunis added. So, when I replaced them with Keihins, it was "back to stock".
Also, you will note that the line (no material removed or added) in the CB350 indexing follows "non-modified engine parts".
For that matter, I think it is important to point out that line is preventing the balancing and blue printing of the motor.
As for actual motors parts removed... the starter (about 10 lbs), alternator stator and rotor (close to another 10 lbs) removal is recommended. If you leave those parts in and race the motor, they will be the parts most likely to grenade you into danger.
Charlie has removed his. I will be removing mine as I rebuild it this week.
Take em off or pay the price!

And, if you haven't been racing before, I really recommend getting your feet wet at a GP350 and GP500 pace. V1 bikes are impressive at how fast they can get you into the sphincter factor. I helped Russell recover from going into the sand trap at Talladega last year. I believe it was a matter of the the highest speed portion of the track and trying to scrub it off for the switch back turns prior to the start finish line.

Come on down. We're wanting big grids in the "Old Guys on Old Bikes Club".

 

OK--we can cut lots of stuff off our "oem" frames! [ok with me]
two more questions:
Jack: how do you utilize the centerstand brackets for a race stand?
Charlie: where do you get avon 110 x 18 rear race tyres? [ I only see fronts available in the T/R catalog]

 

Center Stand

I use the center stand clamp and bolts to hold a couple pieces of angle iron in place. Then, I can use the home made welded stand that came with the bike. I am looking for a cheap stand to replace this configuration since it is a pain to operate and somewhat unreliable. I dumped the bike at Nashville in the garage when taking it off last season. In other words, I don't recommend this setup.

 

Hey guys. We are talking about racing bikes here. The difference between 350 GP and V1 is the engine and performance oriented components. There is no reason you should not make your frame as competitive as possible. If I ever decide to GP race you can bet I will brace my frame and SA. My frame will be OEM stock - sure- but it will also include measures to ensure rigidity and strength AND safety. Someone peed in your popcorn.... film at 11.

 

Like I said earlier here.....maybe we need a rule clarification.

Sounds like it will either happen here or at the track.....but appears to be inevidable, so why wait till 11?

Odviously a difference of opnion.....which just makes things interesting.

 

OK-here's one way to solve it: I will blow up my V-1 motor trying to keep up with Russell: I will then slip in my stock CB350 engine into my V-1 [braced] bike, I will then run my cheater V-1/2 bike against you 350gp guys totally dominating you [because of a couple 6" lengths of 1/2" tubing], then you can protest me and then maybe we'll get an official ruling on the issue......