[68grandprix]

My friend and I would like to build a Cl175-based motorcycle streamliner to run at Bonneville. There's an open record in the 175 class. We're shooting for about 130-40mph(possible?).
What are some good ways to get high rpm power out of one of these? I was thinking stock bore with high-dome pistons (doesn't JB make some of these, in a stock bore?), porting (probably not too hard when all you need is high rpm power), bigger carbs (suggestions?), and a cam if anybody makes one.
The chassis will be basically a very low dragbike type, with stock wheels with alloy rims, and the tank under the seat. Any other suggestions? Thanks, Jimmy

 

[texmawby]

in my opinion, definately a "dustbin" type fairing if you want to achieve those speeds, but i'd like to hear what everone else has to say. i think it sounds like a great project and very cool goal. wish i was in iowa and part of the effort. good luck!

tex

 

[FR]

Sounds very cool, I'd love to go after a record. I know JB's the man on engine tech info. I don't recall much talk about cams, but WebCam will make custom cams to your specifications...

FR

 

[68grandprix]

My plan is to make a full streamlined fairing, shaped somewhat like a cigar. I'm going to use cardboard bucks and aluminum sheeting(fine mesh) for the mold and then fiberglass mat.
I was planning on laying the steering neck way down to rake out the stock forks and get the bike as low as possible. I'm just not sure if the stock forks would be acceptable (strength-wise). I know the suspension wouldn't work very well, and the steering would be very slow, but I don't think it would need much suspension, and slow steering is a plus for a lsr.
There is a record for 175cc partial streamlined (which I assume is like a dustbin) and it was set with an rs 175 at 133mph. There is a minimum speed for open records, but I'm not sure what it is in this case.
From what I've read about streamlined bikes, I'm hoping 30-40HP will get the bike to around 130mph. I'm also hoping that much power is possible with a cl175 motor when I don't have to worry about low-end or part-throttle. Heck, if the thing did over 100mph with my 210lbs on it I'd be happy. I've had it going 70mph stock, so I'm guessing that's possible with a real swoopy fairing. Jimmy

 

[68grandprix]

I checked some old posts and JB said something about a megacycle cam for the 175 that sucked because it had too high of a powerband for track use. He also said he had one he would like to get rid of. Maybe that would work?
Anyone know of a good motorcycle streamliner site? The only ones I seem to find are about all-out efforts with two engines positioned behind a sit-down driver, nothing like what I'm planning (basically a lay-down head forward dragbike design). I need to know if I need the outrigger wheels to pop up or if they can just stick out, and how I start the streamliner(push vehicle or just some friends?). Jimmy

 

[texmawby]

i'd be very surprised to see those kinds of hp numbers (30-40). waiting to hear what the fellahs that roadrace 160/175 cb's currently get out of their machine on a dyno in roadrace trim.

with the dustbin type i think you'll need friends to start and launch the machine. i think you'll also need someone there to catch you too at the end of your run.

tex

 

[68grandprix]

Yeah I looked at an old post and saw JB said he had something like 23HP at the wheel. So 40 might be stretching it but 30 at the crank sounds achievable, since I won't have class limitations and I'm just going for all-out high rpm power.
With a dustbin I think I'd be in a partial streamlined class, because a dustbin doesn't fully enclose the motorcycle, right? I'm talking about a Burt Munro type streamliner (that's the only one of the type I'm thinking of that I've seen). Jimmy

 

[jbranson]

I checked into that very subject recently (Meaning Bonneville)...saw the 175cc class record was around 130-136mph....something like that. I'm at about 25 rear wheel hp at 209cc. Not sure of the rule specifics...if 175cc class means NO MORE than 175cc.

When I looked at the numbers it seemed possible to me. In road race trim with a full fairing, level road, no headwind I think I could get 100+ out of my bike in road race trim.

Fully streamlined, fully tuned for max hp at max rpm (no worries about midrange etc), skinny tires, etc etc....I think I could get 130mph out of my engine as it sits now (209cc). It would be a challenge at 175cc....but I think close enough of a possibility that it would be a lot of fun to try.

I'd be happy to offer any technical assistance I can. A couple of months ago I even mentioned to the wife how much fun it would be to try for a land speed record with a 175...just too far away for us.

As a base line...my bike routinely hits 88-90mph on the straight at NHIS...with no fairing, 200+ lb rider and road race gearing. It will pull around 95+ mph on faster tracks.

I think you'd be looking at around $6-8,000 for a serious effort though.
JohnnyB

 

[imslow]

read the article in the latest issue of Cycle world in relation to the best shape for a streamliner. Fish.

 

[68grandprix]

What do you think the biggest expense would be? I know tires are a lot. I'm a certified welder and a bodyman/painter so the frame fab and bodywork is free (except for materials). I was thinking about a grand in the bike(I've only got $100 in it now with two spare engines), but like I said, this is mostly for fun, but I'd still like to go as fast as possible. By the was, the 250 class msl record is 189mph.
I'll have to send in my $60 for the BNI membership to get next year's rulebook before I can really start making plans. Most of the streamlined motorcycle rules on the scta-bni site sound like they only apply to a sit-in msl. Any ideas anyone has are appreciated. Thanks, Jimmy.

 

[jbranson]

Biggest expense would probably be for bodywork, wheels and engine. For a serious effort you are looking at a couple of thousand in engine work.
Remember you need both lots of hp and lots of rpm. Highly ported head by a professional with suitable valve train work would be about $1000. If the cc limit is really 175 then you maybe use OEM pistons..although the lack of high compression will be a problem. Basically you'll want to be able to spin this thing to the moon....12,000-13,000 rpm. You'll want a PVL ignition, 26mm carbs, I'd go with a cam similar to what I use now...or better yet have a good cam grinder work you up something that makes good high rpm power but isn't too abusive to the valve train at high rpm. (medium lift, large overlap, gentle ramps if possible?). Exhaust would be fairly short and fat.
Wheels would probably be 18" WM1...alloy, with small disk if allowed...not sure about tire availability...but 130mph is not hugely fast so super exotic tires probably wouldn't be necessary.

Streamlining would be the huge factor...and an engine that can wind up the kind of rpm you need and not come apart....meaning valve train work...stiff springs, light valves (Ti would be great), bronze guides, maybe run no seals to reduce friction. Unlike a RR engine you'd need an engine that could run at redline for minutes at a time. Full streamliner body would probably be an absolute necessity...but that will put you in a particular class. I can't imagine any 175 Honda in any form being able to top 110mph without a streamliner body.

If there was a 175 speed record effort local to me I'd be in on it like white on rice. I think it would be a freakin blast to do.
JohnnyB

 

[n/a]

Watch "The Worlds Fastest Indian" about Burt Monro at Bonneville.

The fish design is what Evil is talking about.

Champ

 

[jbranson]

Excellent movie for anyone wanting to do a land speed record....and just plain excellent movie any way you look at it.
JohnnyB

 

[68grandprix]

Thanks for all the input. I'm assuming for now 175 means 175cc with maybe a few extra ccs to allow for a rebuild-type overbore. For the engine some things I had planned on (besides some you listed) were a good cam chain and some pistons like what you use (JB) except in a near stock bore size. I know I'll need as much compression as possible. I remember when I lived in Utah how much the altitude cut my '68 Prix's power, even after rejetting. Do you think stress-relieved, polished stock rods would handle 13,000rpm? I could also lighten the rockers and machine the nuts to half thickness.
For the fairing shape, I made a rough sketch a few days ago. It does resemble the Burt Munro special, just without a tail. I don't think my target speed requires that for stability. I checked out the 175 class records and there are NONE for fully streamlined bikes. Only partial streamlined. That's another reason I want to run in that class. I'm not sure if my engine designation would be vintage gas, or modified gas. Either way it wouldn't matter. If I wanted to I could run alcohol and go for modified fuel. Jimmy

 

[krapfever]

From what I've read about running at Bonneville, displacement rules are stiff, so yeah, 175 may well be your limit.

I also gather that you build your motor with surviving the return pass in mind.

I have dreams of building an honest-to-god belly tanker with a blown Hyundai in it and running at Boneville just to piss off all the hot rod purists.

Honda go sideways!

 

[UngaWunga]

RS 175? No such bike, unless they made their own cylinder for a RS 125...

Not to piss in your cherrios, but I think you'll have a hard time beating a two stroke if they both have the same displacement limits. I'm not saying that it wouldn't be fun to try, but you have the altitude, the poor traction from the salt, and a 40 year old engine design working against you.

Get a Yamaha DT175 engine (single cylinder 2stroke), or a yamaha 175 streetbike from the late 60s.

Actually, you'd be better off with a 200cc modern 2stroke engine.
KTM 200EXC or something.

 

[cafeteria_racer]

Your outrigger wheels do need to pop up. You also need a pusher vehicle, not just some friends runnin behind you. I'm pretty sure the displacement rules allow for a few cc's of tolerance, but if you do set the record your bike goes into inspection and they check all the specs. Don't forget about the elevation change too. Even with the right jets and proper tuning, your going to lose 10mph to what your used to around sea level. Go for it!

 

[jbranson]

That have various classes for four strokes, two strokes, vintage etc. The rule book will have all that crap. Land Speed records probably have ten times as many classes as any other type of racing.
JohnnyB


PS. But...as the present record shows...the record for 175cc is something like 136mph....and I think you could get a vintage Honda 175 twin very very close to that in the right body work. So either people aren't trying with two strokes...or they just don't offer much of an advantage in top speed.


Edited by - jbranson on Dec 26 2006 12:03:47 AM

 

[aaron]

Do it guy... I want to do it on a pushrod 250.

Aaron

 

[jaguar]

http://www.airtech-streamlining.com/vintage/vmv175.htm

cool bodywork for the racer. the arent that much money either...
i wanta go to the next ECTA-LSR race in the spring. think its the first week in aprill. on there website the record in 125 is like 60something mph.....my CB125 will do that! im in!


There is the right way, the wrong way and the british way to do anything!