High Speed Engine Building

ttmaniac · Full Member Joined: Dec 22, 2006 Posts: 468

Seeing as how I always went for street performance (off idle acceleration), I've been wanting to do something a bit different, mainly, high speed performance, for this next build.

I don't have much experience in this area, but basically I want a bike that will hit 150 mph or better (give or take 10 mph) in the top end of it's range. Something just starting to hit the powerband doing 75mph (in high gear) is what I'm shooting for.

Plans so far include:

680 or 750 big bore kit
Increased compression
ikuni 36mm flatslide carburetion
axi X pipes (tt style pipe) with no baffles
Possibly conversion to magneto driven electrical system
Webcamshaft 87 (?) cam grind
High lift valve springs
520 chain and sprockets (reduced unsprung weight)

I'm kind of clueless as to what to do with the porting and with the gearing. I know guys like XSJohn have consistently worked to optimize gearing on the freeway in order to be in the power range for 65mph cruising speeds, so I hope I can get some advice there.

I have a long time tuner and bike mechanic also giving me some advice but I want to pick up as many ideas as I can possibly get before I blow money in the wrong places.

Like I said, I always built for low down power and torque for off the line performance, but this time I want to do something more radical. I'm not building a daily driver here, so fire away. Maybe I have it all backwards, but regardless, I would love to hear from some speedfreaks.:)

Thanks for all advice, tips, tricks, etc in advance.

gordo · Posted: October 25, 2009, 5:13 pm Post subject: Re: High Speed Engine Building

TT, these engine's are not really one's for prolonged high revolution's. For what your looking for, your going to need to build the crankshaft up, because of the 'floating' crank pin's. The journal's that hold the connecting rod's in place are press fit. I've read about guy's rephaseing the engine, then having the crank welded up & balanced. But then you've got roller bearing's on the rod's, so, you can get allot more power, but the price can be staggering. And forget about longevity, it just won't take it. Yes, allot of these were flat tracker's, but there only running for 15-20 minute's at a time, & not at 9000 rpm.

uwould · New Member Joined: Oct 04, 2008 Posts: 8

How about you add an overdrive transmission?, shift thru the bikes 5 gears -then you start shifting the overdrive trans?

650skull · Support Staff Joined: Jul 19, 2007 Posts: 1186

You would need to rephase, with a welded crank and a set of racing primaries to get that sort of top speed and mikes 5th gear, I think this set up is coupled to a 17/36 gearing .Here is a link to Ivan Hoey's bike that has an 840 rephased with a set of racing primaries that he got made. I was talking to Ivan about his racing primaries and he said that mikes big bore kit seems to be quite strong for this sort of set up

www.xs650.org.au/idle_talk.htm
Scroll down to near the bottom of the page

some more reading
www.xs650.org.au/The%20Pits.htm

Ivan races against some ex Wane Gardener and Graeme Crosby 4 cylinder 1000cc bikes and came 3rd in the NSW Forgotten Era Unlimited , that was in 2006

May be able to get some ideas from here, (though they don't want to give to much away as this is to be a competitive racing bike).
www.xs650.org.au/Club%20Racer.htm

dwyatt · Last edited by dwyatt on October 29, 2009, 12:53 am; edited 2 times in total

650performance.com for factory spec head porting is the only way to go.

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

"XS650performance.com" I didn't find this site? I may have and not realised it was the one you are refering to do you have a link for it?

Srinath · Posted: October 26, 2009, 12:03 pm Post subject: Re: High Speed Engine Building

I dunno about high speed or low speed per se ... but a 4 stroke performance is all in the head. The pistons and re phase and what ever yes its all going to add somewhere, but you'd get better mph for every dollar you put in the head than you will else where.

You probably can get it bored but make sure your pistons are the same weight as stock, you can get it to work fine wihtout a re phase - maybe. But make sure you stay in the 8-9 range for compression.

red line is almost entirely controlled by valves. Larger wil lfill the chamber better, 3 angle will seal and cool better, lighter valves and stiffer springs will rev to a higher rpm and taller gearing will cover the speed you want with the extra power.

However rememeber that an SV650 barely manages 130-5 in the real world, and a 1000 would pretty much make 145-150 (I have run mine into the 130's and it seems stable as a freight train and not even like its breathing hard) you may be asking for a bit too much from a 70's 2 valve over weight, air cooled 650.
Cool.
Srinath.

yamaman · Posted: October 26, 2009, 12:38 pm Post subject: Re: High Speed Engine Building

Going to Bonneville tt?

www.motorcycle.com/new...88752.html

650skull · Support Staff Joined: Jul 19, 2007 Posts: 1186

Yes you need the head to breath properly but without a rephrase the engine wont rev freely enough to reach the speeds required. In fact rephrasing needs to have a limiter on it to stop it from reving out

yamaman · Posted: October 26, 2009, 2:07 pm Post subject: Re: High Speed Engine Building

TT, just roughly, if you want to do 150.......Mikes 5th gear & 18/30 sprockets, you'd be looking at around 8200 RPM........Not too much engine work & a fair bit of streamlining should get you there!

xsjohn · Posted: October 26, 2009, 2:22 pm Post subject: Re: High Speed Engine Building

Why not just go for the sound barrier...... Laughing

jayel · Posted: October 26, 2009, 2:31 pm Post subject: Re: High Speed Engine Building

ttmaniac wrote:

basically I want a bike that will hit 150 mph or better (give or take 10 mph)

a really tall building and streamlining Laughing

ttmaniac · Full Member Joined: Dec 22, 2006 Posts: 468

Quote::

But make sure you stay in the 8-9 range for compression.

Why are you so worried about compression. What do you have against 10:1 or slightly more? I have a decompressor from an older machine for ease of kicking purposes.

Quote::

TT, just roughly, if you want to do 150.......Mikes 5th gear & 18/30 sprockets, you'd be looking at around 8200 RPM........Not too much engine work & a fair bit of streamlining should get you there!

Now you are talking my language.

I'd like to pull the crank apart and install rods and bearings. Same goes for the transmission. About 15,000 well worn miles on that bottom end right now.

I was gonna sell all my XS stuff but no one had any money and so I kept getting lowballed.

Plus, I'm sick of seeing lame bikes all over. Doesn't anyone outside of xs650 builders ever do anything cool? I never hear any good tone these days, always the same crap running by the house. Besides, I've got more faith in these motors than 99% of the junk being produced today.

So I figure since the bike is together right now, I'll just do the streamlining bit first so I can mount all the tabs and get proper clearance when I re-assemble.

Quote::

Going to Bonneville tt?

I just want to give some crotch rocket thugs a run for their money once in a while.

yamaman · Posted: October 26, 2009, 4:30 pm Post subject: Re: High Speed Engine Building

Cool, can't wait for a ride! Wink

lol
aybe the Dellorto's might be the go over VM 36's........
Yeah, go the hi-comp, just have to find good fuel to burn in it...methanol would be the go, keep it running cool.

Dunno about this keeping the pistons the same weight as the 650 versions theory.......Seems to me that mine runs smoother with the 750 pistons & their extra weight. Maybe that corrects some inbalance, don't know. Just is smoother for sure.

Re-phasing is for pussies Laughing

.........Can't change the motors ability to rev or make hp, only make life more comfortable!

Using the online dyno www.rpmoutlet.com/dyno.htm, your going to want to go on a massive diet, the bike as well...........
550lb + 70 rwhp = 11.6 second 1/4 mile @ 118mph

I would guess that with that combo + good fairings, 150mph would be achievable!

But you know there's only one real way to find out! Mr. Green

royfisk · Posted: October 26, 2009, 4:30 pm Post subject: Re: High Speed Engine Building

TT;
I hear your quest, But realistically a xs can be built to hit those speeds as mentioned above. theres a lot of good things said above and some bs. I personally would port my heads following jacks threads and pointers, which I am not going to get into because its all here already. I would use a cam designed to build power in the upper rpm range. I would use 1.5 inch exhaust head pipes with a low restricted muffler such as super trapps. This being very important because you plan to run this thing in the upper rpm range and open exhaust will surly burn up valves in a hurry flowing the kind of flows you want to flow. Mikes od gear and above mentioned gear ratio's should get you there, along with your favorite 36mm vm carburators. As for the crank, I would just do as you planned and have the pins welded. But let me warn you up front and straight forward A good modern sportbike is still going to beat you up. Yes you have the top end , But there going to get you right out of the hole and be at 150 while your still pulling through the gears. You will always be trying to play catch up. I gave this a lot of thought myself and bought a fzr 600 for the suspension to do just what your wanting to do. After thinking about it more and more realization came through like a guiding light and I bought another fzr 600 to go fast on. As for whomever said that a 1000 would barely make 145-150 hasnt riden one. todays 600's will do that. 1000's and 1300's have ignition rev limiters to shut them down at 175 mph to meet dot regulations. I beleive that 98 was the last year to be without the shutdown feature. My brothers 98 1100 gsxr will do well over 180. But the features of the 4 cylinder is the horsepower, where as the xs is more on tork. todays 600's are pushing dam near or better then 140 horsepower. Hell my old 91 fzr has 96 horsepower. To make a xs run with one of these would brake the bank and be a granade. NO PUND TENDED HERE.

yamaman · Posted: October 26, 2009, 4:37 pm Post subject: Re: High Speed Engine Building

Go for broke I say & take on Bonneville!

ttmaniac · Full Member Joined: Dec 22, 2006 Posts: 468

Quote::

Maybe the Dellorto's might be the go over VM 36's........

I don't know how much my purposes would require a pumper carb. The dellorto's are nice, but damn pricey and I already have flatslides, which, in my opinion, are a definite improvement over roundslides.

Quote::

Using the online dyno www.rpmoutlet.com/dyno.htm, your going to want to go on a massive diet, the bike as well...........
550lb + 70 rwhp = 11.6 second 1/4 mile @ 118mph

I've cut pretty much everything unneeded off the frame already. No starter, small battery, etc. Never mind all the fenders, turn signals, fugly seats, and other associated stock junk. I'm guessing I'm under five hundred pretty easily. You should've seen the junk pile.

Right now I'm wondering if the Banshee magneto conversion is worth wasting my time. Weight savings? Trying to lighten up what's hanging on the end of the crankshaft.

jayel · Posted: October 26, 2009, 6:03 pm Post subject: Re: High Speed Engine Building

ttmaniac wrote:

I'm guessing I'm under five hundred pretty easily. You should've seen the junk pile.

stock weight is 467lb./ 212kg

xsjohn · Posted: October 26, 2009, 6:34 pm Post subject: Re: High Speed Engine Building

Less the flywheel weight.........the rattier it will run........ xsjohn

ttmaniac · Full Member Joined: Dec 22, 2006 Posts: 468

Quote::

stock weight is 467lb./ 212kg

ine was a special.

I'm guessing around 425-450 lbs now. Light bike.

y problem is I weigh 200lbs.

I'll let XSJohn make the bonneville run...lol

jayel · Posted: October 26, 2009, 6:42 pm Post subject: Re: High Speed Engine Building

give him a chance to wear his speedo thong and lay out like Bert Munro Shocked

yamaman · Posted: October 26, 2009, 8:06 pm Post subject: Re: High Speed Engine Building

Weight wont make a difference in top speed, just how long it takes to get there! Aerodynamics is where top speed lies!

From 50ccs.blogspot.com/200...cords.html
the unlimited 50cc motorcycle record. That would be 133mph, set in 2007 by the Buddfab Streamliner, breaking a record (121.7 mph) set in 1956 by an NSU team with a supercharged, two-stroke 50cc Wankel that produced 13HP running on fuel.

jayel · Posted: October 26, 2009, 8:19 pm Post subject: Re: High Speed Engine Building

Kriedler 138mph Aug 3rd & 4th, 1981 www.kreidler.nl/forum/...record.php

nudude53 · Posted: October 26, 2009, 10:43 pm Post subject: Re: High Speed Engine Building

Why go through all the time, trouble and money to waste a perfectly good XS engine. A rephased motor will set you back at least $3500 before you even put a decent set of carbs on it, let alone the magneto system and exhaust your talking about. Save the engine for another project, save the time and trouble it will take to build it, and just spring for one of these. It will get the job done.

And, oh yea, they're on sale right now!

cgi.ebay.com/ebaymotor...rtsQ5fGear

What Happened to 650rider.com?

Yamaha xs650