Best 2 stroke drag engine builder

[JR]

Hi Everybody! I'm looking for some forum opinions on who might be the best 2 stroke engine builder for a dirt drag build that I want to do. Thanks, JR

[teazer]

What motor?

Banshee or something more interesting and how much power are you looking for.

[JR]

Well, I want to use a RD400 bottom and either a RD250 top end or re-sleeve a RD400 top down to about a 250. The track that I want to run allows 2 strokes to be 310cc for their 250 class. Since the RD400 has a longer stroke than the RD350, I should be able to get to 300cc's.

[teazer]

Interesting idea.  The 62mm stroke plus 115mm long rod put ports in a different place than a stock 250 top end.  A sleeved down 400 might work and has the advantage of the thicker walls which could improve transfer flow potentially.

A big bore 250 with 54mm crank might be an easier package to develop assuming that suitable pistons are available.

[JR]

Hey Teazer, I would like to pursue the re-sleeve option, if it's possible, because Ed Erlenbach had worked with Wossner to develop a racing piston for his 250 land speed project. I just need to find someone who does re-sleeving?

[SoCal250]

You're on the other coast, but I would check with LA Sleeve https://www.lasleeve.com/

Custom Sleeves: https://www.lasleeve.com/tech/custom-sleeves
Street Catalog: https://www.lasleeve.com/downloads/2013-Catalog-Streetbike-Section.pdf

[JR]

Thanks for the info SoCal 250! I checked out the custom sleeves and they offer an aluminum sleeve that then would need plated after installation. I wonder if a plated cylinder would perform better?

[teazer]

I love the idea of plated aluminum sleeves but the cost of sleeve plus CNC porting and plating takes it out of my budget range.

If you sleeve a set of 400 barrels, you have the right porting to start from, but with shorter 250 barrels or 350 barrels, you will need to adjust for different crank throw plus rod difference plus/minus barrel height difference. Sleeves in a 400 block sound like a fun project. You will also need to allow for any difference in piston heights from pin to crown and skirt length.

I wonder how a 56 bore*62mm stroke (305cc) long rod motor would compare to a short or long rod say 60 bore*54 stroke (305cc) assuming that a suitable piston could be found.

[sav0r]

It's probably not worth it. We had our GT750 cylinders plated and it was a major pain in the ass. We want the cylinders to last because they are fairly well worked out, but it was costly. For a drag bike, where run times are miniscule, I don't see any benefit in getting the cylinders plated if they aren't already. We of course did all our porting by hand, then sent the cylinders to get plated. It took 6 months to get them done. We run the engine around 2 hours per weekend, this being on road courses in a race car. A lot more wear and tear than a drag engine. Thus far, we probably have a good 30 hours on the engine at race pace, wear looks great, but again a drag application is never going to see that type of engine time. Seating rings is also harder with plated cylinders, not a great feature for drag engines.

[ElFuegoBlanco]

How far are you from mount pleasant? Eric Thomas (the Kaw Shop) bored my cylinders and did some other work for me. He drag races an H1. He may not be able to do the work you're looking to have done, but I bet he knows who in PA could.

[pdxjim]

Kevin Herr at Herr Jugs Racing.

He's in San Diego, but is very well regarded in the drag Banshee world.

http://www.herrjugsracing.com/porting.html

[JR]

Mount Pleasant is about an hour away from me. I will check him out. I did talk to John Ritter about the project, and he said he would be happy to do it starting in October. He has some good ideas about how to accomplish what I am trying to do. While he is on vacation this summer, I will concentrate on designing the frame and the rest of the chassis. I am in the manufacturing business, and have flat lasers, tube lasers,
both Mig and Tig welding as well as robotic welding, CNC tube bending etc.

[ElFuegoBlanco]

Let me know if you need Eric's number. I'm sure I have it on a receipt.

[Liability]

Another option for cylinders is Advance Sleeve. They can make a sleeve for anything you want. I just talked to them today, very responsive.

[racerclam]

Advance sleeve I also recommend , I had a porting job and reed conversion for a Bultaco flat tracker , the built a  aluminum sleeve for it then I did the porting then had it nicasil plated then dressed up the ports after . Advance does a good sleeve job

Rich