Billet cylinder head

Not a bolt on part.

Taffy,

Stuff it! Stop being such an arrogant prick... If you're so sure that yours is the "only way" to do it, then why don't you build your own billet cylinder head!
Well? We're all waiting...
Mats, YOU are amazing. (Sorry to interrupt your work.)

sean999r said:

DR C when will you next me be machining CNC Billet heads

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I have nothing scheduled. Why, are you interested?

blumpkin said:

Mats, YOU are amazing. (Sorry to interrupt your work.)

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Thank you very much!

Today I assembled the bike and put it on the scale with myself in full gearing in the seat. In ready-to race condition I have 48% on the front wheel. I believe 50-52% on the front wheel is what is considered good for a racing bike. I was planning to move the engine further back and use the swing arm pivot shaft as rear engine mount, but with this weight distribution I will have to make a longer swing arm instead.


Then I stripped the chassis from "everything" and started taking measures. Some more things to check, then it's CAD-time!

Hello Mats

Suggest the longest Swing-arm you can go with. this will cause less squat/anti-squat.

http://www.tonyfoale.com/
he used to do a free calculator so you could work out the weight distribution. have a look around.

I'm always explaining on UHE Mats how if people want to turn their 550 into a 650 (or 450 into a 550) they have to have a spacer, a liner, a crank and a rod that allows 6 extra links etc. maybe that is the misunderstanding.

have a look at those speedway rods before you go any further.

I went and got my old Ducati heads back from this fella named Reg Randall in Norfolk a Month ago. he's had the heads since 1993 to put new exhaust seats in and he still hadn't! anyway, he started showing me speedway rods.

the business is called "Van Nys" I think. he has retired now.

would you believe he is married to Ove Funden's sister! just to keep it Swedish.............. anyway, you can get this info anywhere but he used to do Muller's engines from Germany so he is/was the best and has all the con rods. piston weight is the critical thing. 90mm versus 100mm.....

just a thought

Taffy

Dr-C
Yes I would be interested

Is that a Honda GP 250 chassis ? I going build a 4130 cr/mly steel chassis similar layout to a GP250 but perimeter trellis design, I've fabricated many replica 70's era frames, but my next would be for a Husaberg supermono.

Here is a Kawasaki KR750 I did around 10 years ago

Taffy said:

1. Suggest the longest Swing-arm you can go with. this will cause less squat/anti-squat.

2. have a look at those speedway rods before you go any further.

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1. I agree and understand.
2. How can I "have a look"? Is there a site, shop or pictures somewhere? If I order custom made conrods from Carillio, Falicon, Arrows, they will do the maths and I will sleep better.

sean999r said:

Dr-C
Yes I would be interested

Is that a Honda GP 250 chassis ? I going build a 4130 cr/mly steel chassis similar layout to a GP250 but perimeter trellis design, I've fabricated many replica 70's era frames, but my next would be for a Husaberg supermono.

Here is a Kawasaki KR750 I did around 10 years ago

Click to expand...

Nice work, Sean999r! Yes, I took a Honda RS250R from 1999, removed the engine and made brackets and a cush drive for a Husaberg engine. There are some pics of this in my gallery here at UHE. I'm going for something in this direction: https://www.facebook.com/photo.php?fbid ... =1&theater
I will make the "brackets" for the swingarm pivot shaft out of alu and bolt the steel tube fram to it.

I've just had a word with him Mats

044 1603 872177 Reg Randall. He doesn't expect to sell you anything and will have a word with you.

you won't know what a Norfolk accent is till you hear his! his sister married Oly Nygren (my mistake!)

His rods are by Arrow in the UK
He has rods of anywhere between 160-164.5mm C to C in 0.5mm increments.
he likes Arrow for their depth of hardness.
they can also make them in Titanium.
all Jawa, GM and Weslake engines are near enough the same.
they rev them to 14,000rpm when leaving the line so 9-10,000 isn't a problem.
speedway bikes suffer from wheelspin which means that the rods etc have to be good way past the red line.
20mm little end, 20mm wide.
42mm big end eye, 3.5mm rollers, for a 35mm big end pin.
they do various big end pin sizes to help the pressing process: 35.01, 25.02, 35.03 and 35.04mm
the rods are the modern i section.

I asked about the piston weight at 320 grammes and it is about the same as a 90mm speedway piston.
he also agreed with me that whatever the weight, to rev to 14,000rpm and not break means that it'll be good for whatever you do.

regards

Taffy

few words that may help :wink:

speedway bike have nothing to do with road racing bike , absolutely nothing :roll:

it's not just a matter of rev's , wheelspin mean an engine who doesnt give any good torque , speedway bike have no top speed , those engine never stay at full torque at high speed , not many much at low speed , etcc... its just an other world :roll:

road racing engine need choices that came from road racing experience and it's way far from just a matter of rod lenght or piston weight , all the data are connected together , so , you change one and the all thing go wrong

and as far as i understud the Dr-C bike is only for road racing :wink:

Cheerio lads!
My primary goal with a taller conrod is to reduce the piston-to-wall pressure and reduce the accelerations at TDC/BDC. With a 135mm rod, the liner looked nice up to appr. 70-75 RWHP. But with current power, the liner looks really used already after 3-4 hours and oil magnet looks like a hedgehog. Reduced accelerations will ease life for the piston, piston rings, rod, crank and mains.

I'm afraid that a very tall conrod will give a (too) large dwell, killing the inlet inertia too soon in the rpm-range. This will reduce mid-range power, but increase top-end. I need an engine which picks up already from 5-5,5k and doesn't roll off until 9k.This is not comparable to speedway or formula 1, where rod/stroke ratios preferably can be 2-2,5. I do not think a 163mm conrod will do me any good. 145mm or maybe max 154mm I hope will do the job, without the negative effects being significant.

To make the crank stronger, I have changed to the 35mm pin. So, if I need new liners anyway, the stroke is down to 80mm, and I needed a even more dished piston to lower compression ratio to 13,5:1 - Why not go to 104mm bore (steel liner), custom Mahle pistons, 145/154mm rod and a suitable head packer and sheet metal head gasket?

home spun packer and liner?

I can't say I know which length of rod you need but as you say, going up in 9.5mm increments due to the chain will get you to 145, 154, 163 or so.

sounds like you're taking positive steps toward reliability.

Taffy

i saw that crank pin on husaberg is 35 mm , any possibilities to size it up :?:

I agree, I often pull apart 35mm big ends and oil ha stained the pin in a pattern inside each (both) ends. this proves it is flexing and oil is washing in.

with the present rod you could go to 36mm pin and 3.5mm rollers Mats? Max Kingsley at alpha bearings can do the work.

regards

Taffy

I have just designed a model of the crank and mailed it to a buddy who will do some simulations with Ansys. I would like to know what is the best way of increasing the cranks' stiffness. I fear that increasing the big end dia will make the cheek too weak "outside" of the hole for the big end. There is also a limit for when the press fit for the big end will get too short for its diameter. Maybe the only thing making the 80mm stroke crank working so well, is the smaller stroke, reducing the strain! We'll see...

Anyhow, this is not a top priority problem for me. As long as normal ball bearing mains are lasting 10 hours, I will not complain. The wear on the liner has higher priority to me right now.

Mats - maybe a litle out of focus here since this is your billet cylinder head-thread but how are things going with the "how to connect the rear wheel to the front"-plan ? 8)
Restless minds need to know...

regarding your liner , is it free to move when installed or is it compressed like a standard cylinder :?: , and is the center of the cylinder is the same axis as the crank center , :?: ,

moving 1 or 2 mm the cylinder foward help a lot to reduce that wear

the tickness of the liner is also very important , in your case the liner is not pressed in the cylinder , which doesnt help :cry:

I think for the power you are producing you may have to look at a one-piece crank or even a two piece as some form of 'improvement'. had a word with Max and the idea of YOUR rod, 3.5mm rollers and a 36mm big end is not a problem. he described the work as easy and just need to find a bearing...

the pistons are over the middle of the crank. I have a piston with the middle machined out and the piston is often off centre to the right by 0.5 - 1mm.

Taffy

Jocke_D said:

Mats - maybe a litle out of focus here since this is your billet cylinder head-thread but how are things going with the "how to connect the rear wheel to the front"-plan ? 8)
Restless minds need to know...

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Cheers Jocke!
Well, I've done a fair part of measuring, located CrMo-tube suppliers, contacted an experienced "tube bender" close to home, had a discussion with my machinist regarding the alu sides, decided the frame/swing arm design "inside my head", decided to go with a 52mm taller swing arm and try to move more weight to the front.

fdracing said:

regarding your liner , is it free to move when installed or is it compressed like a standard cylinder :?: , and is the center of the cylinder is the same axis as the crank center , :?: ,

moving 1 or 2 mm the cylinder foward help a lot to reduce that wear

the tickness of the liner is also very important , in your case the liner is not pressed in the cylinder , which doesnt help :cry:

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The alu liner is not supported more than on top and bottom. I going for a steel liner (machined from a solid shaft of high tensile mtrl), which hopefully will be a lot stiffer. Doing the bore off-set will add too much rework! I'll save that one til I decide to do a whole engine..

Taffy said:

I think for the power you are producing you may have to look at a one-piece crank or even a two piece as some form of 'improvement'. had a word with Max and the idea of YOUR rod, 3.5mm rollers and a 36mm big end is not a problem. he described the work as easy and just need to find a bearing...

the pistons are over the middle of the crank. I have a piston with the middle machined out and the piston is often off centre to the right by 0.5 - 1mm.

Taffy

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We are currently running simulations in Ansys to help quantify the improvement a larger big end would bring. A two piece crank would work. I do not use the fly wheel anyhow, so I could install a second main bearing on the outside of the existing at the right hand side.

Please bare in mind this only reduce my cost for bearings! I need to strip the engine anyway after every second race weekend, so replacing mains is really not a super important issue for me! But many thanks for the interest!

you can go to double bearing on both sides if you like then! two on the left is a trick with the crank re-balanced.

Taffy

Re: Sv: Billet cylinder head



The frame fixture is in da house!

Dr C
"I'm afraid that a very tall conrod will give a (too) large dwell, killing the inlet inertia too soon in the rpm-range. "

My thought exactly, Long rods are good for under valved/small port heads allowing more time to fill the cylinder.

My conclusion regarding the crank flex is that the pin is to close to the outside of the flywheel so there is not a lot of strength in that section of the flywheel installing a bigger pin could make make this worst.
Just from my observations and gut feeling. :lol:

Have thought about shorter stroke to increase flywheel strength, with perhaps larger piston 105mm to regain capacity.

Is their an advantage with the single sided swing arm? Looks heavy to me I know is is the fashion statement on a lot of road bikes these days. :roll:

Keep up the good work Dr C

Cheers spanner