HVA-Factory WR300 Extra Special!

[suprize]

Just installing one of your allooominum clutch covers on the 400, so far so good. Will look into the fork mod, I need a 15% improvement over the stock wr's and that should do the trick. give me a little more control and confidence. cheers

 

[jimspac]

Andy,

Regarding the crankshaft, are you offsetting the rod pin 5mm to get the 10mm stroke or are you turning down the flywheels on a 430 crank that already has the 10mm stroke increase targeted to achieve the balance?

 

[jimspac]

OK ! And why didn't you choose a standard stroke with a bigger piston ?

The oversquare long stroke configuration yields better powerband condition than simply doing a significant oversize piston. also 70mm piston is a standard 1st over for pre 87 250 model and those pistons are still commonly available. The mid range is stronger with this kind of configuration and is well suited for off-road as opposed to motocross

 

[Michel Dufayard]

I'm back!

Thanks for all the interest in coming to the UK! I have accepted an offer, so, sorry to the others!

Anyway, here is a pic of the Alloy liners for the 300's...
AndyView attachment 24750

" 10 mm more stroke than the 250 Michel and a 70mm bore. The key is the correct crank mass and balance and a compression change though....

Oh yes a new carb. and a change of jetting too.

Andy."

Ok you get 10 mm stroke more !
Do you put a 5 mm spacer under the cylinder to have the same position at TDC ?
Have the new 300 aluminium liner you made , a different diagram to compensate for the 10 mm stroke added ?
Thanks for the answers.
Michel

 

[Michel Dufayard]

The oversquare long stroke configuration yields better powerband condition than simply doing a significant oversize piston. also 70mm piston is a standard 1st over for pre 87 250 model and those pistons are still commonly available. The mid range is stronger with this kind of configuration and is well suited for off-road as opposed to motocross

As in the same way HVA built the 500 motor with 10 mm stroke more than the 430, keeping the same bore piston.

 

[MOTORHEAD]

The Cylinder:

There are 3 variants of the aircooled 250 primary kick cylinder. Most are missing 2 x extra induction ports at the gasket face on the inlet side and 2 x extra exhaust sub ports. You can add both of these with some careful machining work if you like. The 300 Liner is also 5mm taller. This is for the extra stroke.

Andy Elliott.

So I'm assuming that you'll have 5mm of liner sticking out the top of the cylinder and you'll cut the head with a 5mm recessed combustion chamber? Must be a lot of meat in the heads.

 

[troy deck]

Man, what a cool trip that would be. Would love to do that but can't swing it.

Kelly don't you know i can't never got anything done

 

[hva-factory]

If you look carefully at the alloy liners, you will notice I have added 5mm to the top of the sleeve. Don't try raising the cylinder - it will not run well - I have tried this!

You can use a spacer to achieve this, but watch the ring does not leave the top of the sleeve!

Hope to have the nikasil'd cylinders back this week.

Andy.

 

[Michel Dufayard]

So you haven't changed the height of inlet and exhaust port !?
But the diagrams have changed due to the stroke change ( +10mm).

Sorry but I try to understand how it works !

 

[hva-factory]

No, I have left the ports stock for now - as this seems fine. I have been using this configuration for two years now...
Andy.

 

[husqyman]

If you look carefully at the alloy liners, you will notice I have added 5mm to the top of the sleeve. Don't try raising the cylinder - it will not run well - I have tried this!

You can use a spacer to achieve this, but watch the ring does not leave the top of the sleeve!

Hope to have the nikasil'd cylinders back this week.

Andy.

Who did you use to nikasil them Andy?
I had very good results and service from Langcourt down Bath way

 

[hva-factory]

Yes, the cylinders are at Langcourt. Can't wait to try one!

Andy.

 

[hva-factory]

They are back! Fitted one to a 300 last night, so will give it a test later. The liner was full of sand from I guess part of the processing, so needs a good washing out - something to watch for!

 

[husqyman]

They are back! Fitted one to a 300 last night, so will give it a test later. The liner was full of sand from I guess part of the processing, so needs a good washing outView attachment 25089 - something to watch for!

No matter how good the platers and borers are they always leave you to clean the barrel (I think the residue is dust/grit from the honing process) Langcourt were reccomended to me by Stan Stephens and TAG Racing of Ashord in Kent they said that they have recovered some hideous damage to RGV250 barrels when they raced them (pieces of needle roller imbedded etc)

 

[yzrider]

Did you ever try a lectron carb on these machines? Im finishing up a restoration on a Rickman zundaap and really can't wait to ride it. Is swapping the habdlebars to a set of aluminum tall bars a good addition im new to vintage bikes (is that an oxymoron?) and the"accepted" mods

I would love to enter some vintage races with it. From all the reviews ive read the Rickman's were pretty decent bikes. The short wheelbase and explosive power band sounds like some back wheel shenanigans are coming soon. Im going to be taking go pro videos. Look for them this summer, im out with a broken ankle until july-ish.
Are certain tires better or worse for these sizes? My go to tire on the modern bikes are the 403/404 Bridgestones. If they size them for the smaller Rickman wheels should I go with them or is there a stronger brand for the smaller wheels and vintage handling characteristics?

 

[Kartwheel68]

I use Langcourt here in the states for my plating, top notch work.

yzrider, the Bridgestone is a fine front tire, but for a small displacement vintage bike (I'm assuming its a 125) the modern rear tires are WAAAAAY too big. Those small vintage 125s need to be able to spin the rear tire, and the modern 100/100s are designed for 40hp 250Fs. To get a rear tire small enough (width) for a vintage 125 you have to go to something like a Cheng Shin or Kenda or Duro brand in a 4.10. Those tires, while they label them as 4.10, they are really closer to 3.50 which is perfect for a vintage 125.

I used to use the Cheng Shin C755 in 4.10-18 on my Penton 100, but they discontinued them so now I use the Duro HF 335, its kind of a copy of a Metzler and works great.

 

[yzrider]

thanks alot! Thats exactly what I was looking for as far as feedback!

 

[hva-factory]

Oh yes! The 300 does go better. Need to give it a bit more breaking in, and then it is a full strip down and check-up prior to riding the French modern 3 day event called the 'Trefle Lozerien' at the end of May. I hope I am up to it!

Three of us are riding Twinshock Huskies in this Televised event. Just for a bit of fun you understand - we wont be looking to beat riders on modern bikes....But it would be nice if we did! If anyone in the region wants to come and help with re-fuelling etc. Let me know.

Andy Elliott.

 

[Kartwheel68]

Unless you are a young elite level racer, chances are you can go just as fast on a well prepped twin shock Husky as you can on a modern bike. The brakes are really the only place you give up a lot. I regularly race vintage bikes in modern hare scrambles and enduros in the 40/45+ age class and if I ride well, I do well, the bikes are up to the task for sure.

 

[Michel Dufayard]

Oh yes! The 300 does go better. Need to give it a bit more breaking in, and then it is a full strip down and check-up prior to riding the French modern 3 day event called the 'Trefle Lozerien' at the end of May. I hope I am up to it!

Three of us are riding Twinshock Huskies in this Televised event. Just for a bit of fun you understand - we wont be looking to beat riders on modern bikes....But it would be nice if we did! If anyone in the region wants to come and help with re-fuelling etc. Let me know.

Andy Elliott.

You have a place in "Trèfle lozérien" ?
You are lucky !