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box in the frame on cb350

2500 Views 16 Replies 6 Participants Last post by  Eric750
i havent seen any rules on this. but may have missed it.
is ok to box in the frame on the top of back bone or the spine?
any and all help is needed and thanks...

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sure. for my frame. just tig welded all the seams. braced with tubing from the center down tube to the two outer downtubes and braced between the two rear shock mounts with a tube and lost the rear loop ot the frame. others have boxed in the center down tube. have fun get creative. have been told that once you start bracing... you just move the weak points to somewhere else. i reckon bracing is a good thing

weld it up! brace it up!

eric are you new to the uscra, wera, ahrma?

are you building a cb350 stocker or modified?

tex "really needs to know" mawby
weld it up! brace it up!
eric are you new to the uscra, wera, ahrma?
are you building a cb350 stocker or modified?
Must..... not.... make.... comments.... ARRGGGHHH!


I will.

before you go too far be sure you check the rules with which ever organization you plan to race with. There is a view that you can do what you want with a stock cb350 frame. There is another view that stock means stock. No modifications. So, have you decided if you plan to race in USCRA's Formula CB350 class or do you have another organization in mind?
I race my CB350 in Lightweight supervintage and boxed mine in pretty well. Another important part is to weld up the spot welded seams.
im having my frame tig welded and my welder told me he could make the seams on the spine totally smmoth. like one piece. since were talking about all this. think its cool to have that seam dissapear and have the weld fill that gap?? i dont know crap about metal. just wood. so an hnest answer would be nice.

thats the way to go. i just had the seams tig welded. did not go too fancy. probably could have boxed shit in ... but .

next time i prep another frame i will have some fun.

flogging the proverbial dead horse......

da cb350 stocker rules as listed by the uscra:

Stock Engines with 5% overbore limit. No internal modifications.
External gearing changes, sprockets and counter-sprockets, are permitted
Drum brakes required. May use aftermarket brake shoe linings, including but not limited to appropriate racing compounds are permitted.
Stock Carburetors are required and shall not be overbored, Air boxes may be removed or modified, aftermarket air filters are permitted.
Exhaust system may be changed. Aftermarket exhaust systems and silencers are permitted.
Cam chain tensioners may be updated.
Electronic ignitions are allowed.
Clip-ons, aftermarket handlebars such as clubman, straight bars or dragbars are permitted.
All street equipment such as turn indicators, headlight, taillight, side-stand and kick stand shall be removed.
Stock frames and swingarms only. Aftermarket steering head bearings and swing-arm bushings are permitted.
35mm maximum fork tube diameter
The motorcycle shall otherwise be 'stock'. Any modifications not specifically listed above shall not be permitted.

here be the wera cb350 stocker into 350GP rules:

350 GP
Pre 1970 2 stroke twins up to 250cc.
Pre 1968 4 stroke single and twins up to 350cc.
Pre 1979 factory road racers up to 125cc.
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, fairings are legal for 2006 season.

da cb350 stocker for ahrma rules be:

Novice Historic Production is open to production street machines built up to December 31, 1972, and like design. Machines must use the standard production OEM frame, swingarm, forks and handlebar mounts. Engines must be original OEM bore and stroke regardless of displacement (plus allowable overbore, as described in rule 9.7). Classes are Lightweight (four-strokes up to 500cc, 250cc two-strokes and certain 350cc two-strokes) and Heavyweight (four-strokes up to 750cc and 350-500cc two-strokes).

so my question is, if you crack your frame, can you weld it? or do you have to take all the stuff off it and replace it with a new, oem, stock frame?

this is beginning to get re-god-damn-diculous!

tex "just race the fucker" mawby
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if you crack your frame you have to go to japan and get honda to build you a brand new cb frame.


tubefeeding assitant extraoridaire
if you crack your frame you have to go to japan and get honda to build you a brand new cb frame.
Dude, you can only use them straight from Japan. So you've got to get a NOS one straight from the source in Jay-pan. Thems the rules, bitch!

tubefeeding assitant extraoridaire
Ug dude... sorry... Hope all is well.
been looking at wera but i really dont know i need to find
out about mid america track.

if your running wera, don't worry about it. tech doesn't enforce "rules" they just look for safety issues on your bike. i think the whole gusseting, welding frame thing is a non-issue anyway (that is i'm all for it). if i can speak for the majority of wera cb350 riders (stocker or modified) and i think i can to a point, i'd say do it and don't look back. i know i'd never protest a win based on the guy in front of me having the backbone welded if mine wasn't. mainly cause if that was the difference in him beating me, i should hang up this roadracing thing and play chess.


p.s.- hopefully we'll meet at summit or nelson ledges this year.
i aggree with tex.

thanks guys. we mite run in to each other sometime. i dont know
where sumit or nelson are. could you guys tell me.

thaks eric
summits in wva near charles town. just outside of harpers ferry.

and nelson ledges is in ohio, near warren.

eric, where are you?

tex "philly, pa" mawby
tex i live in des moines,iowa cold and alot of salt sand and snow.
so i cant ride all year but i try at least one ride a month.

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