Topic: Can I ask a CB450 question here?

[maduncle]

If not delete me!

But you all race so much I figure someone here might be into both CB450's and SOHC/4's.

I have a CB450 Hansen replica race bike almost finished. Running 74mm pistons, Megacycle mild grind cams, ported and polished head, race oil pump with external lines to the cams, and a set of CR33 roundslides.

Now the fuel over here can be methanol for period racing, and I need to work out the jet sizes for the carbies - where do I start?

I have been Googling but to no avail - so I figured the brains trust here might point me in the right direction.

Or otherwise tell me to sod off.

Cheers,

Cliff

[bwaller]

That sounds like a fun project. No bright ideas from me but I wonder about if you posted the question on a race association forum somewhere there where guys have experience with methanol. On the other hand as you know there are plenty of guys on here that are full of surprises with their knowledge. If they don't know you'll get pushed in the right direction.

Just wanted to ask you to keep us updated, it's a race forum and yours is a 70's motorcycle, perfect fit to me.

Good luck

[Sam Green Racing]

As a starter it's thought to go twice the size of your gas jet.
Unlike gas/petrol running rich, it don't cause power to fall off but if it is to rich but you get the chance of blow past the rings and contaminating the oil.
Don't forget, all the openings in the carb have to be able to cope with the increased flow of fuel that is required also.
Also check all the seals in the tank and carb and make sure they can be used with methanol, also don't splash it on your paint work.
This info is from the late 60s early 70s when I ran my little Honda twin on it, I can't see the rules changing much though but feel free to get a second opinion. This info is for the use in any four stroke regardless of make, number of cylinders or where the cam is or how many.

Sam.

[Old Scrambler]

Sam.............is that a Benly next to a Bently?  A very handsome photo

[Sam Green Racing]

It is a Benly Dennis. 1965 C95 motor, not quite the same as your CA95, but the untrained eye would struggle to tell them apart.
The car is a Ex police 3.8 Jaguar. Bike fitted in the trunk OK with the forks hanging out. hahaha

Sam.

[turboguzzi]

lovely photo sam, post in the "inspiration" thread, i bet youll get a lot of followers

[SOHC4 Cafe Racer Fan]

As a starter it's thought to go twice the size of your gas jet.
Unlike gas/petrol running rich, it don't cause power to fall off but if it is to rich but you get the chance of blow past the rings and contaminating the oil.
Don't forget, all the openings in the carb have to be able to cope with the increased flow of fuel that is required also.
Also check all the seals in the tank and carb and make sure they can be used with methanol, also don't splash it on your paint work.
This info is from the late 60s early 70s when I ran my little Honda twin on it, I can't see the rules changing much though but feel free to get a second opinion. This info is for the use in any four stroke regardless of make, number of cylinders or where the cam is or how many.

Sam.

Fantastic photo, Sam.

[Sam Green Racing]

lovely photo sam, post in the "inspiration" thread, i bet youll get a lot of followers

Early 1971 Yossef. 25 years old, black hair and beard. hahaha

Sam.

[Sam Green Racing]

Cliff, it might be an idea to ask Brian with the sidecar, I think he runs methanol.

Sam.

[Retro Rocket]

Cliff, what compression ratio are you running, methanol needs higher compression to run well, adding methanol to a relatively normal compression ratio engine doesn't really do much for added power at all ?  Methanol has a lot of inherent problems and its usually a good idea to get the bike set up well on normal fuel first. You'll consume twice as much fuel running methanol than fuel, Methanol absorbs moisture so the fuel system needs to be completely drained and flushed after every meeting, also you only buy as much fuel as you need at any given time, it doesn't store well, Methanol is also highly corrosive and eats gaskets and seals, another reason fuel systems must be flushed after every racing day is over and the engine is then run on petrol to flush it all out, a lot of people run additives to help  too. If you already knew this then ignore my post, if you didn't, consult someone who runs methanol on a regular basis and take their advice. 

[bear]

Cliff, it might be an idea to ask Brian with the sidecar, I think he runs methanol.

Sam.

G'day Cliff, how have things been going?

Haven't caught up with you since Talbert.
I appreciated the visit.

It sounds like we might see you around the place on race days shortly.

I can't give you much info off the top of my head but I'm happy to make a couple of calls and get back to you.

I suggest you give Mick DeWith a call and book some dyno time when the bikes ready.
He has a wealth of experience setting up bikes running A.
And he's not to far from you from memory.

I will PM his number.

Give me a yell if I can help with anything else.

Cheers,
 Brian

[maduncle]

Cliff, it might be an idea to ask Brian with the sidecar, I think he runs methanol.

Sam.

G'day Cliff, how have things been going?

Haven't caught up with you since Talbert.
I appreciated the visit.

It sounds like we might see you around the place on race days shortly.

I can't give you much info off the top of my head but I'm happy to make a couple of calls and get back to you.

I suggest you give Mick DeWith a call and book some dyno time when the bikes ready.
He has a wealth of experience setting up bikes running A.
And he's not to far from you from memory.

I will PM his number.

Give me a yell if I can help with anything else.

Cheers,
 Brian

Hey Brian - good to hear from you!

Got both your messages, thanks. I will give Mick a call next week.

Cheers,