Author Topic: My turbo bike build (finally) (Read 9451 times)

JLeather · « **on:** January 22, 2010, 04:15:32 PM »

CycleOne manufacturing CB750 frame. 250-tire and a jackshaft.

The rest of the pics is the engine I am gonna put together for it. I'm an engine guy at heart, and this is the one I've been gathering parts for years. CycleX forged rods, backcut trans, new bearings and primary chains, etc. Topping it all off is a very ported head from MRieck on the SOHC board:

Here's the truly "fun" part:

Custom JE low-compression forged 836 pistons, copper headgasket, APE tool-steel wrist pins. But why low compression pistons? This is why:

ATP turbo kit. That's an old picture. The turbo's been rebuilt, I've got a better set of exhaust piping that's stainless, and it's ready to rock and roll (well, almost).

Ok, so anyone who knows me knows this project has started and stopped 20 times. I had a frame being built for it, til the a$$hole took $3k off me and left me with nothing. I had another frame, that ended up being tweaked and un-usable. I had the engine coming together once, but my MTC turbo pistons were no good from 30 years of abuse (hence the new custom slugs). So that's the long/short of it. This time, damnit, it's happening.

The world is not all roses, however. This frame doesn't fit the turbo kit. The single downtube has to go back to a double-downtube setup like a stock CB750 frame to clear the piping. The backbone is gonna become a straight one at the same time, and it's getting an HD neck cause it already has an HD rear. Sorry Red, I gotta cut up your frame

That's it for now. Progress when I get to it. Game on.

squirley · « **Reply #1 on:** January 22, 2010, 10:03:20 PM »

That's a nice looking hardtain frame...!

Lets see some pics of the rebuilt turbo...please!?!

lordmember1969 · « **Reply #2 on:** January 23, 2010, 04:29:47 AM »

Yes!!! More!! Please

754 · « **Reply #3 on:** January 23, 2010, 09:36:05 AM »

Hey what happened to the Amen frame? Thought you were using that?
I am picking one up today..

andy750 · « **Reply #4 on:** January 23, 2010, 09:50:21 AM »

Sign me up this should be good!

good luck!
Andy

sinister902 · « **Reply #5 on:** January 23, 2010, 10:28:16 AM »

I'll def. be keeping an eye on this......

JLeather · « **Reply #6 on:** January 23, 2010, 05:02:39 PM »

754 - the red amen frame that I stretched way forward ended up being too tweaked in the rear section from a previous wreck. I'm gonna make a frame jig sometime and straighten it up, but for now it's off the table. I've still got the gray Amen rigid that'd make a real nice bobber, but then this frame fell into my lap so I'm doin' a wide-tire build just this once.

I'll get some more good pics up tomorrow. I'm still waiting on material to make the rear axle and the new motor-mount bolts from so I can start cutting into the frame. I get to use my new lathe

Flying J · « **Reply #7 on:** January 23, 2010, 05:30:30 PM »

that frame is cool. Is it built for a 750 or is it a harley frame that your going to put mounts on?

Simpson · « **Reply #8 on:** January 24, 2010, 09:29:05 AM »

This will be good. Breaking out the popcorn.

JLeather · « **Reply #9 on:** January 24, 2010, 06:25:58 PM »

ffj, it's a frame for a 750 SOHC. The motor-mounts and jackshaft are aligned for a 750 already. I wouldn't have to do anything to it except that the turbo piping hits the downtube and I can't figure out a clean tank setup for the curved backbone.

junkyardjon · « **Reply #10 on:** January 24, 2010, 06:35:42 PM »

can i have nacho's instead of popcorn?

you know i'll be watching and expecting to see it done in june LOL

BLUE71TURBO · « **Reply #11 on:** January 27, 2010, 12:55:39 AM »

I'm definitly gonna be watching YOU my turbo brother !!

The_Crippler · « **Reply #12 on:** January 29, 2010, 09:49:59 AM »

Quote from: junkyardjon on January 24, 2010, 06:35:42 PM

can i have nacho's instead of popcorn?

you know i'll be watching and expecting to see it done in june LOL

Mmmmm...Nachos....

Great. Now I'm hungry and jealous.

JLeather · « **Reply #13 on:** February 07, 2010, 05:50:08 PM »

Ok, finally got a little bit done. I had a few setbacks along the way, but since I got snowed in this weekend (30") I finally got time to work on it again. The frame takes a 3/4 axle, not a 1" like I thought. So I had the wrong bearings in the wheel, and the wrong axle material. Got new bearings, made a new squish tube from some 1" .095 wall stainless, and reassembled the wheel. Made spacers, made a 3/4" axle from 1045 with 5/8" threads on the end (thanks Blackjack for answering my Q's). Got my new tires in, mounted on the wheels. And finally made a good mockup of the frame. Sets dead-nuts level at 5.5" and with the Sporty frontend it's gonna be 45* of rake. Cut the Honda neck off the frame and getting ready to notch the backbone and tack on the new neck. That's tomorrow's job. Once that's done I can cut out the single downtube and put the turbo pipes on the motor and get read to bend new dual downtubes. The motor mounts in the pic are temporary. I've got 1.125" tubing in for the new downtubes and 1/4" cold-roll plate for the correct motor mounts later. Honestly, I wish the bike had a little bit more rake, but I guess 45* is enough. I don't really want to cut the backbone out of that frame because then I've got a lot of things to get straight again without a jig. Here's the mockup as it stands now, the frontend is just sitting there not welded yet:

Frontend is a '90 sportster. Stock 19" sporty wheel. Rear is a 250x18" 60 spoke. No idea what to do about the tank yet. I had a line on a set of stretched fatbobs that I was gonna narrow, but it's been 30 days and they ain't showed up yet so I may make other plans. Gotta be deep tunnel and fairly long. Anyway, maybe I'll even have a second update tomorrow

bgfootball67 · « **Reply #14 on:** February 07, 2010, 06:30:36 PM »

Love the set up, how was cycleone to deal with? Can we get some pics of the jack shaft set up?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #15 on:** February 07, 2010, 07:28:21 PM »

Turbo or no turbo, I like the direction you're taking. Just glad you're going with a 250 rear. You can still see the engine from behind sticking out beyond the rubber!

JLeather · « **Reply #16 on:** February 08, 2010, 05:13:35 AM »

Hopefully by the end of today I'll have the backbone notched, the neck tacked in place, and the turbo piping mocked up for downtubes. I'll get some good pics of the jackshaft setup while I'm out there. I've talked to someone else who has the same cyclone jackshaft and he gave me some pointers to make it work a bit better. He spaced his up and back to get more chain on the front part because it wore out too fast when it was shorter. He also put a spring-loaded tensioner on the front because the front chain is hard to adjust. I don't know if it'll look right with spacers, so I may cut the jackshaft off and weld a taller mount for it. We'll see. Maybe I can figure out a cool looking spacer, or a sheet-metal cover so you can't see under the jackshaft.

I didn't buy this frame directly from CycleOne, but I've dealt with Red and Kate before and they've always been great. If I had ordered the frame myself I could have gotten it with a sporty neck and the dual downtubes I needed. This frame was done by them years ago. It shows up on their website 4th up from the bottom on the Honda frames page. It's been through a couple different owners, none of whom apparently did a thing with it. Caught it on eBay this winter and it only went for $530 so it came home to me (since that's like less than 1/3 the price to have it made by CycleOne new). For that price I'll modify it to suit me. Well, off to the snowy garage

And there's 5+ more inches coming to my area Tuesday.

jwl41085 · « **Reply #17 on:** February 10, 2010, 04:23:40 PM »

Quote from: JLeather on February 08, 2010, 05:13:35 AM

Well, off to the snowy garage And there's 5+ more inches coming to my area Tuesday.

the almost 6 foot drifts here are really good for insulation around the garage.. you pile it up around your garage and make an igloo

Soos · « **Reply #18 on:** February 10, 2010, 07:12:33 PM »

NICE....

Good to hear you are making headway with the turbo!

l8r

JLeather · « **Reply #19 on:** February 10, 2010, 07:39:47 PM »

Yeah, that 5" they were calling for a couple days ago became 20"-30" with 40mph winds

Haven't made it back out yet, but maybe tomorrow I'll shovel out my garage door again.

MRieck · « **Reply #20 on:** February 12, 2010, 02:05:45 PM »

That should be a very interesting ride John. It's long so you don't have to worry about wheelies so much when it really starts building boost. Plenty of rear tire to hook up too. Nice.

JLeather · « **Reply #21 on:** February 14, 2010, 01:15:50 PM »

Got back out to the shop yesterday. TurboGrimace came over for a little help/motivation and I made headway and hit a couple more snags. First thing I did was notch the backbone for the new neck at the correct angle (right around 45*). Here's a shot of the notch. This was done by hand with an angle grinder and a sharpie. Worked out pretty well actually.

Proceeded to measure and set the frontend as straight as possible and put 3 tacks to hold the neck in place (no making fun of my welds, they're just temporary).

Popped the frontend off and hacked the downtube out of the way. Here's the exhaust manifold I have to work around.

It was going quite well at this point. We checked the neck with a plumb-bob and it was dead on straight. I'll put a bar in it before final welding in case we gotta tweak it a hair. I got 2 pieces of 1.125" .120 wall DOM for the new downtubes. We decided to give sand a shot to see if the HF bender could do a better job that way. I also had to grind one of the dies to fit the 1 1/8" tubing. First tube actually worked out pretty well. Not professional bends, but usable.

Decided to go with a wishbone style pair of downtubes. When I went to bend the second one, however, this is what I got

Yep, split that sucker right in half at under 45*. Proceeded to break the tubing 2 more times and gave up. As easily as it broke that one, I don't trust the bends in the first one. Dunno if it's a material thing or just too much stress from the crappy bender, but I'm gonna have to get better tubes bent professionally for this to feel confident about it. With my tubing in pieces we went ahead and mocked up the planned downtube on one side to see how it'll look. Here's the idea:

Try to imagine a mirror tube on the other side. I think it'll end up pretty nice. Calling a couple fab places this week to see if they'll do the bending. That's all for now.

JLeather · « **Reply #22 on:** February 14, 2010, 01:32:12 PM »

Mike, I'll be taking it pretty easy on the motor for a while til I figure out what the limits of the chassis (and myself) are. Definitely plenty of traction on the rear though

If not, I'll find a nice 8"-10" slick and really see what she'll do. It's not my usual style of bike, but I like how it's coming together. Try hard not to make it to "trendy". The good thing is since big tires are already on their way out, and 250 isn't considered big anymore, parts aren't hard to come by.

Soon as I get the topend machining finished at APE I'll be doing the motor part of the thread. Can't wait.

fastbroshi · « **Reply #23 on:** February 14, 2010, 04:33:34 PM »

Jeesh I wonder if the metal was contaminated they made the tubes with? Good job so far, you've got a lot done so far.

JLeather · « **Reply #24 on:** March 21, 2010, 06:48:32 PM »

Update, Update, Update!!!

Finally got back on track with this sucker. Took the frame to a local dude who builds race-care chassis. He also happened to have a bike jig. He bent and welded in the new front section. Here are some mockup shots of the bike as she sits now:

The tank is temporarily a mustang tank split down the middle to sit lower on the backbone. I wish it was longer, but I haven't found just the right tank yet. Anyway, atleast now I can get back to the brakes and the tank/fender combo. Hopefully the updates will come quicker now that I've got the frame back.

News:

Author Topic: My turbo bike build (finally) (Read 9451 times)