Hotrods Dyno numbers

[petejw]

Hey BDF,
Im running the DJ set up in my bike (81 sports) with uni filter pods
and velocity stacks.
u said u were running 132 main jet,
are u running a stock air box or pods,
Im currentlty running a 130 mains and im lean and the
138s are to rich.

[Dan Hodges]

Sniffing Gas

That actually makes some sense, since the higher the octane the less energetic the gas is. Unless the engine is engineered for it, your not going to be able to take advantage of it. I find that as I move up the octane scale that gas mileage goes down.

Pretty much unless you have computer controlled ignition timing and a knock sensor you can't take advantage of fuel that the timing wasn't designed for. With the knock sensor the computer can always keep the max advance that doesn't ping at all times, thereby getting the maximum performance out of the fuel your running.

It's not the octane numbers of the spook gas that does it, it's the oxygenation of the gas and the U4.2 only has a motor octane number of 92 and was designed for motors with compression ratios between 9 to 1 and 10 to 1.

VP makes several blends of gas with C-44 being their mack daddy for ultra high compression motors and it also just happens to be the most expensive @ $50.00 per gallon.

Generally speaking, the higher the octane number the slower the gas will burn and so using too much octane for a given combination is a loser horsepower wise but all gas with the same octane numbers are not necessarily the same.

VP Hydro Carbons has a very good web site that has lots of information about their various blends of gas and their intended usage.

Static compression ratios also mean very little because the intake valve closing event will alter the pumping compression and pumping compressiuon is really the most important of the two. The pumping compression of two motors with the same static compression can vary greatly depending on the intake valve closing event, i.e. a more radical intake cam duration wise will make less pressure than the same configeration with a smaller cam.

To rule out as many varibles as possible I used BP for all my test with their mid grade blend giving me my biggest numbers but to be honest I didn't do a gas flog of all the various brands of gas and so I can't say that BP is the best but I did do a test between BP mid grade and their premimum and the difference between the two was miniscule however bike dynos do not measure the brake fuel specific numbers and without that it's difficult to say which blend made the most power from a given amount of gas but then again I could care less what the fuel mileage is, I just want more power.

Gas is more misunderstood than the invasion of Iraq or Obama's bank bail out.........well maybe not now that I think about it.

[Big Daddy Funk]

Good to have a baseline

I would figure as much. I figure that if I do anything other than try to keep this beast in good stock condition that I will take it down and get it dyno'ed before anything to it. That will give me a baseline for any changes that I made as I go.

I agree absolutely Cy. That way you know what effects any changes you make have on your motor. I got surprised a few times. Even doing a tuning dyno run can have a big effect on a stock motor.
Rick

[Big Daddy Funk]

DJ Mains

Hey BDF,
Im running the DJ set up in my bike (81 sports) with uni filter pods
and velocity stacks.
u said u were running 132 main jet,
are u running a stock air box or pods,
Im currentlty running a 130 mains and im lean and the
138s are to rich.

There are a lot of variables but on my bike with the mods I listed, I found that the best pulls in streetable form were with air pods and 132DJ mains.
You can order different jet sizes right from Dyno Jet.

[red bandit]

Big Daddy Funk and Dan, what oil and clutch combination are you guys using. Did you creat clutch slipping problems with the increase in power?

[Big Daddy Funk]

Clutch Slip

Big Daddy Funk and Dan, what oil and clutch combination are you guys using. Did you creat clutch slipping problems with the increase in power?

I do believe we both ran into clutch slip. The good news is the replacement clutch's and HD spring set are available (mine are from MikesXS) and work great. I also did the clutch mod of adding an extra steel plate.
I use factory Yamalube for no other reason than I've had no issues with it. It would be good to hear from Dan on this subject.
Rick

[81xsproject]

Yamalube = Honda's oil (whatever it's called) = Valvoline 4-stroke oil (way cheaper)

[Big Daddy Funk]

Valvoline it is.

Yamalube = Honda's oil (whatever it's called) = Valvoline 4-stroke oil (way cheaper)

Good to know. The Yamalube is expensive. I wouldn't have risked the abuse of directly asking an oil question. Thx Rick

[petejw]

Thanx for the BDF, I ended up putting the
stock air jets back in and that made a big difference, from 3000 onwards,
I picked up some bigger jets and am going to play with those,
as the dj is set up for bikes from the states, ive got a bit more fiddling to do.
Any chance did you take any pics of the porting to the head?

[Dan Hodges]

I do believe we both ran into clutch slip. The good news is the replacement clutch's and HD spring set are available (mine are from MikesXS) and work great. I also did the clutch mod of adding an extra steel plate.
I use factory Yamalube for no other reason than I've had no issues with it. It would be good to hear from Dan on this subject.
Rick

I blew through my clutch which had about 15,000 miles on it on my first dyno pull.

I pulled the clutch and checked the friction plates and steels and they were within speck and so I assumed the friction plates gave it up because they had been submerged in oil for 15 years.

I replaced the disk and plates with new Yamaha OEM stock ones along with a set of stiffer springs made by EBC. I also purchased a new set of stock springs from Yamaha and a set made by Vesrah and checked all of them on a spring tension checker and the ones by EBC was the stiffest and the ones I used.

Once the new clutch was installed, I went back on the dyno and had no further clutch problems.

I use Yamalube in all my Yamaha's but similiar quality oils are available however you don't want to use synthetic oil with the stock Yamaha cork lined friction disk.

[Big Daddy Funk]

Thanx for the BDF, I ended up putting the
stock air jets back in and that made a big difference, from 3000 onwards,
I picked up some bigger jets and am going to play with those,
as the dj is set up for bikes from the states, ive got a bit more fiddling to do.
Any chance did you take any pics of the porting to the head?

No pics but I guess I should have cautioned everyone that porting a head is not for everyone. The stock head flows really well and porting will hurt rather than help unless you are doing a full performance build.
The best way to do it is get a professional to do it and just pay the money.
If you are undaunted, the next best thing to do is find someone with a flowbench that is willing to let you play with it. (that's what I did)
You will need a scrap head to practice on. Removing a small amount of metal from the wrong area can make major differences to flow and velocity. You really want to have it right when you start the head you are going to use.
I'm glad I did my own for the experience but I doubt I would do it again.
There are shops out there that will get it right the first time as long as you give them all your engine info. Thx Rick

[red bandit]

Hey Dan, do you remember the differences betweeen the three springs in lbs. or whatever you used? Was there much diff. or just a little? Thanks.

[Dan Hodges]

Hey Dan, do you remember the differences betweeen the three springs in lbs. or whatever you used? Was there much diff. or just a little? Thanks.

The new Yamaha springs and the Vesrah springs were the same in terms of tension, number of coils, OD, heighth and wire diameter.

The EBC springs used the same size wire diameter, the same free standing heighth and spring OD but had fewer coils and had 15% (4-5 lbs.) more pressure at installed heighth and almost twice as much fully compresed.

You can determine the pressure of a spring by measureing the wire diameter, spring OD, number of coils and the free standing heighth of the spring.

A spring will loose pressure from repeated compression and it's exposure to heat and the only sure method of knowing for sure what the pressure of a spring is, is to test it with a spring pressure checker.

[Dan Hodges]

My Elusive Dream

A pleasure as always, Dan. I am still waiting anxiously to hear your report on the 1311

The (new) block has been bored/machined and fitted with the new sleeves and they have been honed to accept my new 78 mm bore Ross pistons.

The upper crankcase has to be relieved and cleaned up to accomodate the larger OD of the sleeves and the combustion chambers in the head have to be opened up to match the larger bore which means this isn't a bolt on deal and I will have to use my present head which I had planed to do anyway because I don't want to spend another $1,000 to have another one ported and it would probably cost more than that now.

I bought a complete motor for this deal however the transmission needs major work and so my only realistic option is to use my existing motor and head which is itself a pretty trick piece and so I'm going to wait a bit before I field strip it again because I only have 4,000 miles on it since I field stripped it the last time.

The block, sleeves and pistons for this deal were a no brainer but having to machine the crankcase to accomodate the larger sleeves makes it a chore because the motor has to come completely apart and the cases split.

If I had gone with a 77 mm bore using my new sleeves which are 3.232 OD I could have used a step on the bottom portion of the sleeves (that which goes into the case) and maintained a .060 sleeve thickness in that portion of the sleeve with a 3.15 OD and I would not have had to machine the upper crankcase and could have used a stock base gasket as the stock sleeves are 3.09 OD. The portion of the sleeve that sticks out of the block that fits into the case doesn't need to have the same wall thickness as the top half of the sleeve does.

Of course I already have the 78 mm Ross pistons and the block work finished and so I'll have to tear it apart and clean up the case but if I had it to do over I would go with the 77 mm bore which would still fetch 1278 cc's and a bunch more compression than my present 1179.

Another thing that I wish had done when I had the thing apart last time was to have the counter weights on the crank shortened and tear drooped which cuts down on parasitic drag at high rpm and will fetch an additional 3-5 hp in a Susuki and a motor is a motor. The crank in an XS is a heavy mother and the counter weights are like brick bats however this mod requires the use of heavy metal (Mallory) installed in the counter weights to balance it which isn't cheap and is the reason I didn't do it the first time but will the next.

I also have a new FJR-1300 that I've been tweaking and I haven't messed with the XS since the early part of summer when I put a new intake cam in it in search of my elusive 100 hp from my little 1179 but to make a long story short, the V-Max eatin 1311 has yet to fire.

[tinman905]

I have finished with the engine performance upgrades on the Hotrod (80 Special) The final streetable dyno numbers are 95hp and 72ftlbs of torque at the wheel. These numbers came off a new state of the art dyno, so I believe they are trustworthy. Without air filters and exhaust baffles the numbers picked up 3 more horses and a couple ftlbs of torque but you wouldn't want to ride it that way. The bikes torque curve starts sooner and climbs quicker than it did before. It pulls scary hard to the redline. I'll see if I can figure out how to post the dyno sheet.
The upgrades were: 1196 Big bore kit, Megacycle cams. Dynojet carb kit, 4into1 header, ported and flowed head, Mikes air pods and Green coils.
I learned alot about these engines through trial and error. The main thing I learned is that they love to breath, getting air in and out of these motors is critical. They are also very sensitive to A/F mixture.
I did do all the work myself but I would like to thank Dan Hodges posts for leading the way, as well as Brad Prong at Prong Built for giving me full access to his shop and dyno as well as his help.
Next up for the Hotrod is XS Chop's chain drive conversion. When completed I'll post the new dyno numbers.
Rick

Hey Big Daddy Funk did you do a dyno run without the dyno jet kit installed. It would be interesting to see the difference in the torque curve. I am just about to rebuild my carbs and would like to see if it's worth going to a Dyno Jet kit.