CB350 Built by a teen (Weld Now, Grind Later)

[teazer]

Re: CB350 Built by a teen (a TON of parts on order!! )

FYI, 30mm VM Mic's are 30mm at teh outlet and 30mm at the venturi. Those look as if they are 30mm outlet and much smaller in the middle. Appearances could be deceptive, but it's worth measuring:
Slide Diameter
Outlet ID (bore at the flange)
Venturi ID (bore where the slide sits i.e. just before or after the slide)

That will provide some insight into what size they really are.

 

[crazypj]

Re: CB350 Built by a teen (a TON of parts on order!! )

There are two types out there being sold.
The accelerator pump ones look like genuine Mikuni, seller may think they are too wide to fit on CB350?
The others, although they are marketed as Mikuni's they really look like Kei-Hin copies with Mikuni 'badge'
They look like they have oval bore (taller than they are wide)
Very very easy to tune.
Even if the actual size is closer to 26mm it will flow enough for a 100mph plus CB350 (downhill with a following hurricane )
As I've posted several times previously, I've run CB360 with 391cc motor at 120mph on VM28's, smaller motor will be fine, particularly at lower speeds

 

[Rocan]

Re: CB350 Built by a teen (a TON of parts on order!! )

There are two types out there being sold.
The accelerator pump ones look like genuine Mikuni, seller may think they are too wide to fit on CB350?
The others, although they are marketed as Mikuni's they really look like Kei-Hin copies with Mikuni 'badge'
They look like they have oval bore (taller than they are wide)
Very very easy to tune.
Even if the actual size is closer to 26mm it will flow enough for a 100mph plus CB350 (downhill with a following hurricane )
As I've posted several times previously, I've run CB360 with 391cc motor at 120mph on VM28's, smaller motor will be fine, particularly at lower speeds

so the smaller carbs are better because they are easier to tune?

 

[t71ford]

Re: CB350 Built by a teen (a TON of parts on order!! )

Ease of tune is always "better"
Small carbs are easier to tune, simply because the engine is consistently receiving a better atomized fuel mix. If you have too large a carb installed on the bike, air velocity through the carb is slowed. Since atomization of fuel is a directly related to air velocity (not enough air to cary the fuel), a more liquid fuel mix is delivered into the combustion chamber which does not burn as well. Bigger than stock carbs just usually have this problem until at the upper end of the RPM range. Which is not to say that smaller is always better, since a carb can be too small, and restrict intake mixture as well.
In the case of the oval slide carbs, they are easier to tune due to the shape. The air volume under this style slide is less, allowing the slide to raise with less vacuum (weaker engine suction pulse). The rectangular shape minimizes the vacuum loss caused by raising the slide, and the consequent loss of fuel draw from the float bowl. This allows for improved responsiveness at lower RPMS, as the carb can still mix fuel with less air volume than a round slide carb. It also minimizes fuel delivery lag. This shape was a precursor to the flat slide style carb.

 

[Swagger]

Re: CB350 Built by a teen (a TON of parts on order!! )

I believe we're talking about the same carbs I posted today in the lounge. Having seen a set first hand, they are quite well made and nicely cast etc. They do neck down just slightly at the slide, but it's ~28mm, not much really and for smaller bikes, the added velocity at the business side of the slide will only help the above mentioned atomization.

As stated in my other post, a customer's xs400 was totally transformed by a set of these and a pair of uni-filters. Getting them tuned was cake.

 

[JRK5892]

Re: CB350 Built by a teen (a TON of parts on order!! )

well i got a set of VM30's for my TX in the mail this week, i have not been able to tune the bastard with the other carbs no mater what i did! so we will see how this goes with the new carbs!

 

[VonYinzer]

Re: CB350 Built by a teen (a TON of parts on order!! )

I can tell ya that the ones I picked up are very high quality. There actually stock carbs for older 125 - 250 Honda singles. They are odd carbs. If I remember the measurements, they are 38.61mm at the intake, 24mm at the slide, and 29.9mm at the flange.

http://cgi.ebay.com/ebaymotors/30MM-MIKUNI-CARBURETOR-CRF-XR-100-200-250-CARB-ATV-CA09-/400149058286?pt=Motorcycles_Parts_Accessories&hash=item5d2abe12ee

 

[Rocan]

Re: CB350 Built by a teen (a TON of parts on order!! )

ok guys, chill out with the thread jack


K1 cam pictures anyone? also got my forks finished and did some mock up... mmm, shes gonna look perty! i was hoping to use the k1 head since mine has a stripped spark plug hole... one of the cylinders was SERIOUSLY oxidized, and more or less unusable (id always have low compression on that cylinder). pics show everything... i ended up just pulling the valves and other parts off of it, which are nice to have when i end up screwing one or two up . The destroyed head is going into my room on a shelf labelled "offerings to the gods of speed", since burt munro was an absolute genious in doing that.
Pics below... LOTS of pics below... no real organization.

 

[Rocan]

Re: CB350 Built by a teen (a TON of parts on order!! )

 

[Rocan]

Re: CB350 Built by a teen (a TON of parts on order!! )

just blasted the cam box... came out mighty pretty.

dealing with major fucking shit with the parents, again. so might be on hold for some time. god i hate them... more hate for my mother though.

 

[Rocan]

Re: CB350 Built by a teen (Just blasted cam box, getting near paint time! Parts in!)

tappet covers got first polish! also blasted my caliper and rotor. started polishing the caliper, but stopped for dinner.

sister leaves for college tomorrow, so ill try and snap some final pics tomorrow morning before she goes and takes the camera with her.

 

[Rocan]

Re: CB350 Built by a teen (Just blasted cam box, getting near paint time! Parts in!)

what, no one likes my project anymore? (then again, i guess it IS dragging on a bit too long)


oh well. Bikes finished.... looks great!



kidding. i wish ;D

But i did get tappet covers polished. and caliper polished/piston installed (i accidentally ordered wrong speed bleeder xP). i just have to blast/polish the bracket and brake side of things is DONE. Also modified my buffer a bit more... pushing way faster RPM... wow, my parts are coming out better than ever before! now all i need is to upgrade to 1hp and dual 8 inch wheels...

engine should be getting sent out to be bored in next two weeks... swingarm is getting braced this wednesday (thanks AD pete!), then within the month i see the engine being assembled, wheels having tires, and most everything done/installed (including wiring) besides the tank/seat/headlight bucket (i need to make a new bucket for my huge 8incher... mmmm)

that came out wrong. but its a headlight. not something else.


No pics. sister ran off with camera... but, i have a 8 gig CF card coming in for my old school olympus c-2500l camera, which i can take DECENT shots with.. and which actually takes amazing macro shots... dont know why. only issue with the camera is autofocus sucks, but i do manual focus anyway (if only i didnt have to go through menus to fricken autofocus :)

now. somebody reply. before i ditch this project entirely and decide to study for school instead... (p.s. my new schedule alots me about 8 more hours weekly for bike work... YES!)

 

[RatBag22]

Re: CB350 Built by a teen (SO SHINY... getting near swingarm brace time!)

Noooo not school work!!! :-X

aha I kid, Sound's good mate, what bracing are you going to put on the swingarm, what clearance are you looking at?

hope you get some more shot's soon

 

[Maritime]

Re: CB350 Built by a teen (SO SHINY... getting near swingarm brace time!)

OK I will say your polished parts look great, now just waiting on the completed picture ;D

 

[Rocan]

Re: CB350 Built by a teen (SO SHINY... getting near swingarm brace time!)

OK I will say your polished parts look great, now just waiting on the completed picture ;D

haha im waiting just as patiently as you =D

all in time... in the end it will be worth it. now i just hope another 15,16,17 year old doesnt come and build a better bike then me

 

[thearcticsea]

Re: CB350 Built by a teen (SO SHINY... getting near swingarm brace time!)

Hey rocan, special request : mind hitting me with a PM with step by step instructions on polishing these things? I've started working on my 450 and believe it or not I've never polished aluminum bits. I want to do the engine coverts, triple trees, fork lowers, etc...

If it's too much trouble, no worries. You're just a pro so i figured i'd try to get some inside pro tips.

Biggest question after process is what materials do i need?

Thanks in advance if you can help me out man.

 

[KrashManhatten]

Re: CB350 Built by a teen (SO SHINY... getting near swingarm brace time!)

Where on gods green earth did you get that lumpy mattress of a cam? man that thing is going to sound like an APE in heat humping along.


good luck with the parents I know it can be a Major PITA but just live with it, and do your homework.

cp

 

[Rocan]

Re: CB350 Built by a teen (SO SHINY... getting near swingarm brace time!)

Hey rocan, special request : mind hitting me with a PM with step by step instructions on polishing these things? I've started working on my 450 and believe it or not I've never polished aluminum bits. I want to do the engine coverts, triple trees, fork lowers, etc...

If it's too much trouble, no worries. You're just a pro so i figured i'd try to get some inside pro tips.

Biggest question after process is what materials do i need?

Thanks in advance if you can help me out man.

ill PM you... i just PMed midcoast with everything i know... its about a page or two.

 

[Rocan]

Re: CB350 Built by a teen (SO SHINY... getting near swingarm brace time!)

Where on gods green earth did you get that lumpy mattress of a cam? man that thing is going to sound like an APE in heat humping along.


good luck with the parents I know it can be a Major PITA but just live with it, and do your homework.

cp

haha, thats the plan man! shouldnt be tooo lumpy, but will sound goodd... maybe ill invest in a 123-20 somewhere down the road... just cant justify 400 bucks on a cam just yet


forgot to mention in last post... i polished the exhaust valves that came with the cam... i think ill go ahead and do the valves ill actually use. its very easy... sandpaper+press drill on high speed. ;D

 

[thearcticsea]

Re: CB350 Built by a teen (SO SHINY... getting near swingarm brace time!)

I appreciate it. Thanks man