Topic: Salt Racer CB 750 OZ style

[Bill/BentON Racing]

Haha,haha, went deep bat caving, found Larry a RC 836cc used kit! And well as they say.....
Mine's bigger!  We getting there! K. See maybe I want to build one! LSR one day.Don't y'all have a 836cc class
That's what these are! Oh man, K Bill

[Retro Rocket]

Haha,haha, went deep bat caving, found Larry a RC 836cc used kit! And well as they say.....
Mine's bigger!  We getting there! K. See maybe I want to build one! LSR one day.Don't y'all have a 836cc class
That's what these are! Oh man, K Bill

Geeze Bill, i like that "short stroke" rod on the right....

[valt]

Alright I gotta ask here. I am using that same manifold set as you and I cannot for the life of me get these things mounted. I dremeled out the inner rib on the stock rubbers to get them to slide onto the RC manifold. But even using all 2&3 rubbers I cannot get it on the head. This picture shows the 1&4 rubbers but I didn't have any more luck with 2&3. Any advice?

[johno]

Hi Valt, can be fun.

First ! yes as you know must use all 2 & 3 rubbers.
It is too difficult with genuine hard rubbers full stop.
If using genuine rubbers they must be fairly new and soft, if using genuine rubbers you will not have to touch the head side only dremel out the manifold side.
You will have to use a 28 to 34mm emery drum and open the end up at least a couple of mm , I left about 2mm interference from memory.
Mate do your self a favour and invest in some cheapo rubbers from Japanese ebay, they are so soft they done need machining on the end , they are 32mm diam through the whole rubber as opposed to 28 to 29mm with the stock type.
Because they are soft you will have to take the weight with a support like in this pick.   They come with new clamps as well.

And just like a good bonk you will need some KY jelly. 

[valt]

Hi Valt, can be fun.

First ! yes as you know must use all 2 & 3 rubbers.
It is too difficult with genuine hard rubbers full stop.
If using genuine rubbers they must be fairly new and soft, if using genuine rubbers you will not have to touch the head side only dremel out the manifold side.
You will have to use a 28 to 34mm emery drum and open the end up at least a couple of mm , I left about 2mm interference from memory.
Mate do your self a favour and invest in some cheapo rubbers from Japanese ebay, they are so soft they done need machining on the end , they are 32mm diam through the whole rubber as opposed to 28 to 29mm with the stock type.
Because they are soft you will have to take the weight with a support like in this pick.   They come with new clamps as well.

And just like a good bonk you will need some KY jelly. 

Well that is good news, I had spoken with Bill Benton about it. But he remembered it being a pain with new rubbers in the 70s, so perhaps its just not possible with old hard rubbers. The plan was always to support carbs in the rear as well.

One other thing can you tell me what throttle linkages you are using there? I looked around but I didn't see ones that would work. Thanks so much!

[MRieck]

You have to start with new insulators. Try getting the RS-34's on...even with new pieces!

[mick7504]

Those RS34's with new rubber added some very colourful words to my vocab. 
A 3rd armpit with another arm attached would've been handy.

[valt]

As far as Japanese ebay goes, do you have a link to what you are talking about? I'm not sure that it would save me any money having to get something shipped over seas. It looks like new rubbers go for around 80-100 dollars in the US.

[johno]

Hi Valt,
quote from another thread over halfway down the front page, some good chit chat re rubbers etc.


Re: Mikuni RS34's & CB 750
« Reply #91 on: April 21, 2014, 10:21:41 PM »
QuoteModifyRemove
Try googling " Cruizin Image "   he has a ebay store happening,
cheers johno

[johno]

I Thought I better post the valve and seat tidy up on Mikes head so he knows is hard work is not wasted. 

I wished I had taken a photo of what the exhaust and port looked like, UGLY it looked like it had been sprayed by a aluminium spray gun, the entire exhaust port was coated as was the exhaust valve,

What was intersting to me was how strong was the reversion effect at low revs, the inlet valve was sprayed from molten ally as well.
It really highlights just how powerfull reversion is, especially with tuned open exhaust.  Anyway I popped them both  in the lathe and polished the ally off with 800 grit and then refaced both vlaves just to make sure.  Both valves were spot on and need just a kiss across the stone.

This pic of the inlet shows the 60 deg backcut angle for people not sure what Mike means when he gives the good oil.

[johno]

both the seats had ally stains I couldnt buff off so I made up a 5mm + 1 thou mandril and just gave the seats a kiss by hand with the stones, two turns by Hand Mike and they are still perfect. I didnt even bother to lap them.

[johno]

I used a thin light coat of bearing blue just to highlight the seat for you Mike , its still spot on

[MRieck]

Thanks Mark......I'll sleep better now I am at my son's college graduation right now. 
  OK....home now. Exactly what I figured with the molten aluminum being slung all over the place Johno.....very, very happy you were able to clean it up without to much fuss. I have those those backcuts done on all intakes.....and there is no charge....it is just part of a correct valve job.
 Muriatic acid will pull the aluminum off of steel but I prefer what you did......good thing it only ran for a few minutes!
 And yes.....reversion is a very strong device. Most people do not understand how a 4 stroke engine works at high revs. With large cams and large ports charge is going in both directions fiercely.....even with a tuned exhaust. Folks tend to think of a static model where each stroke happens independently from the other. In truth and practice that $hit (charge) is going back and forth like crazy....a very scientific explanation. All we can do is try to get it to get the most charge going in the right direction to make big power.
 

[MRieck]

I modified my reply to my original post johno.

[scottly]

Folks tend to think of a static model where each stroke happens independently from the other. In truth and practice that $hit (charge) is going back and forth like crazy....a very scientific explanation. All we can do is try to get it to get the most charge going in the right direction and at the right timeto make big power.

[Tintop]

Thanks Mark......I'll sleep better now I am at my son's college graduation right now. 
  OK....home now. Exactly what I figured with the molten aluminum being slung all over the place Johno.....very, very happy you were able to clean it up without to much fuss. I have those those backcuts done on all intakes.....and there is no charge....it is just part of a correct valve job.
 Muriatic acid will pull the aluminum off of steel but I prefer what you did......good thing it only ran for a few minutes!
 And yes.....reversion is a very strong device. Most people do not understand how a 4 stroke engine works at high revs. With large cams and large ports charge is going in both directions fiercely.....even with a tuned exhaust. Folks tend to think of a static model where each stroke happens independently from the other. In truth and practice that $hit (charge) is going back and forth like crazy....a very scientific explanation. All we can do is try to get it to get the most charge going in the right direction to make big power.
 

Guess I'll find out how well those pieces coming your way help out the sidecar engine Mike.

[MRieck]

Thanks Mark......I'll sleep better now I am at my son's college graduation right now. 
  OK....home now. Exactly what I figured with the molten aluminum being slung all over the place Johno.....very, very happy you were able to clean it up without to much fuss. I have those those backcuts done on all intakes.....and there is no charge....it is just part of a correct valve job.
 Muriatic acid will pull the aluminum off of steel but I prefer what you did......good thing it only ran for a few minutes!
 And yes.....reversion is a very strong device. Most people do not understand how a 4 stroke engine works at high revs. With large cams and large ports charge is going in both directions fiercely.....even with a tuned exhaust. Folks tend to think of a static model where each stroke happens independently from the other. In truth and practice that $hit (charge) is going back and forth like crazy....a very scientific explanation. All we can do is try to get it to get the most charge going in the right direction to make big power.
 

Guess I'll find out how well those pieces coming your way help out the sidecar engine Mike.

They arrived yesterday Brian...interesting pieces. I'll try and post a pic.

[johno]

Hi Guys,
Looking for some advice !
To get my bike going I had to make up a set of rollers and they worked fine.
The only motor I could lay my hands on the day was a 240 volt so I had to use that. Now I am changing it to a 12 volt starter system so I dont need a big Gen set in the van taking up space.

Looking at Billy Bike Boy's drag bike on the bench I spotted a starter in the making, Bill said Captain drag racer was going to help him make something.  That got me thinking , do I need to lug the rollers around taking all that space on a trip or would a crank driven starter be the go ?

Whats the trend at the bike drags, with these aircraft type starters, what works , what doesnt , does the rotation on the crank dyno end unwind ? can you buy them commercially or  easy to make ?

If you have any pics or advice let me know.
cheers Johno 

[jweeks]

Gear reduction car style starters run on 24 volts. That will turn over any SOHC motor. You need something to hold on to and something to keep the starter from rotating while the bike motor laughs. Racing starters can be wound for upwards of 3 hp. Lots of Chryslers came with factory gear reduction units. Add the appropriate socket to mate with the nut on your crank and it will spin over. Stall the bike away from the starter and there will be a lost time issue. I use a dual battery cart with wheels. It's shaped like an appliance mover. Large gauge insulated wires with welding cable connectors for separating the starter from the batteries when transporting. Make sure that the plugs on the cables can be hooked up only one way....

It's the lightest way to start a race bike. No on board starter, no big or dual bike batteries, no external rollers, etc. Hope this helps.

[sohc boy]

As jweeks said johno , 1.6 hp chrysler v8 fizzed up on  24 volts ,will pretty much start anything especially with locked up ign , easier to buy starter nuts from A.P.E  ( should be hardened rattle gun socket this one isn't ,have seen em split ) think same taper as early z900? lota guys cut down Honda alternator hub , mill into nut 11/8,

[Bill/BentON Racing]

As jweeks said johno , 1.6 hp chrysler v8 fizzed up on  24 volts ,will pretty much start anything especially with locked up ign , easier to buy starter nuts from A.P.E  ( should be hardened rattle gun socket this one isn't ,have seen em split ) think same taper as early z900? lota guys cut down Honda alternator hub , mill into nut 11/8,

Yeh and the long bar goes behind cylinder to brace starter.....ask me how I learned, cranked Dave Fletcher's KZ1075 MTC bike, first thought as bike cranked and starter went flying and my arms twisting like play dough... Wow that JimF one strong f*cker to hold on to this!!  Haha, Dave showed me, he was laughing so hard might a messed up his run, can't remember if he won or not, was trying to untwist my wrists! As Jon said, the way to go, Bill

[Jerry Rxman Griffin aka MuthaF'er]

Yeah Bill, I saw that #$%* too  You are SO busted.... LMMFAO!

[Bill/BentON Racing]

Didn't happen.... No pics....I hope! 

[Sam Green Racing]

That's correct, there were no pics but the image of Billy trying to do a cartwheel while attached to a Kawasaki is burnt into my mind for ever.

Sam.

[sohc boy]

.... funny stuff