Engine builder needed

[drtracr]

I need someone that can build, modify a 175 engine. Also need some expansion chambers. I am buying a 200 and will put 175 stuff on it. Need someone good to build the motor, I will do the rest.

Thanks,
Jimmy

[ztnoo]

Are you talking about someone who can merely assemble a motor or someone known for tuning race winning bikes?
I would assume you are looking for someone with porting and transfer modifying skills, matching cylinders to cases, modification of heads and squish band, and someone who can build and tunes chambers for your displacement and specific power requirements........maybe someone like Scott Clough or Ed Erlenbach in CA.
These guys are primarily Yamaha specialists, but might be convinced to work on something of a unique nature like you are doing.
Are these the types of specialists you are seeking out?
http://home.earthlink.net/~scloughn/index.html
http://erlenbachracing.net/

[drtracr]

Yes that is what I am lookng for. Thanks,
JM

[ztnoo]

I should ad this guy to the mix too: http://www.rb-designs.com/

And you might want to read this:
Machine shops-to trust or not to trust?!
http://www.2strokeworld.com/forum/index.php?topic=9173.msg69854#msg69854

Again, I'll say it, these guys are all Yam gurus.....but the important thing to note is that the KNOW racing and hopped up 2-strokes inside out.
That's what you want.
You want machinists and tuners show KNOW 2-strokes.
The novelty of your project might really get their blood flowing, so to speak.

[1966BS175]

Jimmy

Good advice.  I do not want to start a fight. But i feel I have to  say.

Yamaha guys?  Most modern Yamaha builders  while they are experts at piston port Yamaha's  are NOT Bridgestone experts. I bet they will say that too.

The 175 is very different than, say a Yamaha RD350.  The BS is a twin rotary valve, built as a hand made old school engine, not a mass produced engine.
The Yamaha is a piston port engine, way different in design.

There are many people on this site, who know how to build a Bridgestone,  no reason to send a friend to a outside Yamaha shop.

Bridgestone even published a book"Tuning up for Competition"  Its even posted
on this site.  See http://bridgestonemotorcycleparts.com/index.php?action=downloads;cat=4

This is a Bridgestone site, much great information and knowledge here.  I bet you can get help if you ask.

Contact    bsracer  and OldSwartout  on this site, I bet they can help.  I think both of them actually race 175's today.  There is your "go fast" answers.

Just my opinion. DG

[Mike Anderson]

Great response:
I was just getting ready to post a reply. These bikes are not at all like a Yamaha. The hop up manual gives you a very good step by step process to build a good running Bridgestone. We built many of them back in the day just using the manual and a little common sense. You might even consider talking to Steve Reed about doing the job but he may be too busy right now. I have been at his shop and can tell you he is very qualified. Not to mention the fact that he has been a motorcycle wrench for over 30 years racing and otherwise. I think you will enjoy just possibly trying to do it yourself with the manual. It will give you great satisfaction when finished, and then if you have any questions during the process you can certainly get some advice from this site. Just my two cents worth.
Thanks Mike

[reed]

You will be surprised how many members on this site can build a race wining BRIDGESTONE
Thanks.
Steve.

[bsracer]

Hey Jimmy,

just wondering what it is exactly you're shoot'n for? Everyone out there has there own ideas of what will work. I've been racing this sr175 since 2003 and it still seems like a mild street bike. Mine is pretty much based on a stock sr175 with some modifications. If you go with a competent 2 stroke guy that knows anything they should be able to set you up with a pretty quick little bike. Feel free to give me a call if you have any questions. Scott Clough built a 200 motor for Craig Hirko (sp?) recently. There are lots of stuff that interchange between the 200 and 175, however the cylinders are one thing that don't without major modifications.

paul 

619-675-4060

[drtracr]

Thanks guys, I am wanting to pay someone to do the engine build. I am not an engine guy. I can do the chassis and the rest. I would prefer to be a B/stone guy if someone wants to do it. I figure I need around 400hp or 40hp, one of the two.
Just want to have fun and make B/stone guys proud.

[ztnoo]

Jimmy,
That's what I figured and why I assumed you were asking for advice on engine builders. The hop up specs will work well I'm sure, and can probably be done by a competent machinist with engine modification experience, but this is 40-45 year information. A lot has been learned about 2-stroke performance since that material was written. If you look at the graph chart on HP after the suggested mods, it says to expect a little over 27 HP @ approximately 10,300 rpm. I'm not sure that's the knife that will cut the cake you want to eat. That's a long way from the 40 hp you maybe are hoping for. IMO you need a two stroke motor guy who has full machining capabilities and skills, who understands port maps and port timing, has experience with newer metal treatment processes which decrease heat and increase HP, and has real world knowledge about what will work and what won't work. You need someone who can squeeze as much reliable top end power out of a 175 as possible. A guy who rebuilds Kohler lawn mower motors isn't likely to fit the bill.

I suspect there are a couple of guys here that can tell you what worked for them with their RR set-ups and may be able to ball park you some HP figures, but whether they can perform the modifications for you, only they can answer. I don't not know any of the builders I suggested personally. I have never had them do work for me. I owe them nothing. But word of mouth about who are skilled, competent, and sought after over time goes a long way. Anyone can tell you anything, its the results their work earn which pretty much says it all. Their reputations precede them, if you understand what I mean. Rotary valve engines are different than piston port engines, but not so different that what these guys know can't be applied across the board. Scott Clough has had great results with 200cc RR Yamaha twins and holds 3 AHRMA speed records at Bonneville, and Ed Erlenbach is responsible for a world record holding 164.73mph RD400. I think they can help get you where you want to go, if you can convince them to take interest in your project. They will not be cheap, but I imagine you have a much greater chance for success with them than with someone else who might be a good machinist, but understands very little about how racing 2-stoke motors work.

One of the areas the builders might able to advise you about is the carburation, based on their long term experience. I see from the manuals, the stock carbs are 17mm units. My RD 125 has bigger carbs on it. Those 17s seem tiny to me for what you want to do. My guess is they might suggest you will need more intake area to help make more HP. You likely might require carbs that are not only larger, but that are infinitely more tunable than the stock carbs......like some Mikunis for instance.  This would mean some innovative thinking about the rotary valve covers and the best means to adapt to them. Also if you are going to increase intake area (if that's the advice) then the specs of the expansion chambers in "Tuning up for Competition" would only be a starting point. I understand Clough can fabricate pipes to spec, but he doesn't list that service on his web site. Another thing to consider is that chamber fabricators usually require a "model", meaning a bike to mock fit and mount chambers to before completing fabrication.

There's a lot of things to consider, and in the end you will be the one who will have to make judgments about how far to take this and how much you might have to spend. But if you are able to do it right, your goal might be in sight.
I wish you well on your ambitious project. Keep us informed.

Regards,
Steve

P.S.  I just reviewed the SR 175 exclusive parts list and it calls for 22mm carb with 250 jet.
Also in the BS Tune Up Manual it says:
6. MODIFICATION OF ROTARY DISC VALVE COVERS
To suit the carburetor 22.24 mm bore, make and weld
the tube by cutting off the original intake tube.

[drtracr]

Steve, getting 40hp is my wish list, 30 plus is realistic. I talked to Lowell Horing at Porting By Horing. He says he can get 50 plus out of it, but I don't think it will stand that. Lowell is going out of the country for a month so have to wait if I use him, very sharp and knowedgeable.

Jimmy

[OldSwartout]

Jimmy, you should be able to go for the record you want with just SR level of power (27 HP).  Both my roadracer and Paul Piskor's are similar to SR engines, with more modern design expansion chambers.  Mine are a Harry Barlow design, not certain who did Paul's, I think it was Rob North.  My bike ran 94 MPH at Bonneville (5000 ft. elevation) on the salt, probably would run closer to 100 at sea level. Of course, it's faired, so a bare bike will be a little slower.

The BS engine will stand the high 20/low 30 HP semi-reliably, but if you try to get mid-30s or higher, you'll need pistons, transmission and crank redesign.  The stock pistons and rings failed Paul and I roadracing, but would work for a few short LSR runs. The crankshafts break somewhat frequently now, but would be good for a while for LSR, until you try to get high HP, then would need a redesign.  The transmission is strong enough, but the ratios wouldn't work for a high HP, peaky engine.  Vince Gunning in England has a close ratio design they use on 200s, but not certain if they have any extras.  If they do, it's probably $2K.  The clutch would need some beefier springs, really high HP will require additional plates I think.  Vince probably knows best of anyone what it takes to make a reliable 175, he's been building racing 200s for years. I don't know the current status of that racing, though.  Paul and I are limited to 22 mm carbs by AHRMA rules.  You can use 24's, but I think anything larger is probably counter-productive.  The design is limited on the amount of area you can get entering the crankcase without chopping away all the structure. Larger carbs would just make tuning and keeping a decent powerband more difficult. That also limits your HP potential to something in the low 30's I think.

Scott Clough is a good all-around 2-stroke guy. He currently builds Yamahas primarily, I think, but has built fast Bultacos and just about any other you can think of.  He has even done some hydroformed expansion chambers.  If you just want to go fast at Maxton, your best bet is a CT-1.  Scott could build that engine in his sleep. His CT-1 went 113 the same day my BS went 94 at Bonneville.  I'm sure he can build a BS175, but check with Vince Gunning, too, if you want to go that way.

The 200 cylinders are similar to the 175's but have larger transfers, hence, more casting stock to work with.  However, you'd have to have them sleeved if you start with them.  I think you can get all the transfer area  you need starting with 175 cylinders (remember those 24 mm carbs will be a limitation). You will need SR bore cylinders, not stock DT175 cylinders, to keep the size legal unless they allow an overbore at Maxton.  Paul and I run stock DT bore size as AHRMA allows an overbore beyond class displacement limits.

[bsracer]

I haven't even tried these yet. These are for a motor that should be close to 30hp using 22mm Mikuni carbs. With this setup I would be able to experiment with other carb sizes. Jos Schurgers Bridgestone was a 125 with 40hp using 28mm Mikuni carbs but I think only really retainted the engine cases. Everything was reworked.

paul

[ztnoo]

Jimmy,
Very interesting site. Lots of info and great pics. Very professional presentation.
Lowell Horning. Porting by Horning. http://www.2-stroke-porting.com/Home.html
It would appear he does primarily watercraft motor work.
His skill is very evident in the photos.
When you talked with him, did he mention any experience with air cooled, motorcycle based motors?
That is not evidenced at his site
The reason I ask is because there are differences in reliability between air cooled and water cooled motors.

He's probably accustomed to squeezing max HP out of water cooled mills. I'm not so sure the same standards can be applied to air cooled engines.
It appears he deals with primarily late model motors, with up-to-date manufacturing technology. He's found he's niche, it would appear.
The question I would ask is: does the skill and experience he has gained fit into what you want to do?

The scourge of air cooled 2-stroke motors in the 60's and the early to mid 70's was excessive heat, especially in highly modified motors with wild port timing specs.
If you didn't have the air/fuel mixture set right on the money and observed by constant plug chop readings, you always risked seizure, which was a result of too much heat.
The phrase, "have a quick hand" related to being able to disengage the clutch ASAP if you sensed seizure.
If a rider didn't have a good sense of this impending disaster, he risked unanticipated massive road rash, inadvertent meetings with Armco barriers, and potential demise. Often being quick wasn't quite good enough.
The transition from air cooled TD and TR Yamahas to water cooled TZ models allowed engine temperatures to be moderated and controlled efficiently and lead immediately to significantly lower numbers of seizures.
Horsepower didn't significantly increase, but liquid cooling allowed more consistent high power for the duration of an event. It was almost like a night and day difference.
Unlike road racers however, which often ran in 25-40 minute races where excessive heat could be a problem with air cooled motors, all you are going to require is a decent warm up and then runs of less than one minute where escalating temperatures shouldn't be a problem. Maybe a bit more can be risked considering the workload and the time frame (relatively short) the motor will be asked to perform.

The engine you will be modifying is an old era air cooled motor. I suspect Karl is pretty much right about the maximum power that might be wrung out. I think something in the mid 30s (maybe) in terms of HP would be about the end of the line when modified by an experienced 2-stroke builder with the right carburation and expansion chambers. To get this kind of power everything will have to be right and the motor will be peaky like nothing you have probably ever ridden.

As to Vince Gunning, anyone here......Karl, Steve Reed, Baron K, bsracer, anyone.......have any info about how Jimmy could contact him?
I did find he posts at the Classic Racing Motorcycle Club (CRMC) forum and his user name is vince gunning (vinny g). I was unable to access other info because I haven't registered there.
http://www.k21.co.uk/smf/index.php

Jimmy, you might also want to review this thread:  175 Bridgestone Race Bike   http://bridgestonemotorcycleparts.com/index.php?topic=1150.0

[OldSwartout]

Try Vince at vincegunning (at) hotmail (dot)com.  That's the last e-mail address I had for him.  If it doesn't work, contact Brian McDonough at  brian (at) bikeaddict (dot) freeserve (dot) co (dot) uk.  Brian raced a Bridgestone that Vince built.

[drtracr]

I did ask Lowell about a Bridgestone and he knows a lot of them. I will talk to anyone and go anywhere to make this work. I am 100% dedicated to it.

Jimmy

[drtracr]

I want to thank everyone that has added input. Karl, Steve, all of you. When I get this all done and make my attempt it will be because you guys helped. Maybe we could have a Bridgestone ride in.
Jimmy

[drtracr]

Karl, I found Vince Gunning with that address, he answered and we are talking about some gears and what else he may have.
Thanks,
Jimmy

[OldSwartout]

Maybe we could have a Bridgestone ride in.
Jimmy

Did you go to the Vintage Fest at Barber those years that the Bridgestone Rally was there ('06-'08)?

It just occurred to me, you should contact Cory Moore in Birmingham.  He has a collection of some of the nicest restored Bridgestones in existence, including the most over-restored GTR. He may have items you need for your project and he's just a few miles down the road.  His e-mail is cbmoore (at) wwisp (dot) com

[drtracr]

karl, thanks a ton, you are a blessing