choppers_polska wrote:
Is which differences between voes and TPSmod in real?

They both do the same thing, but get around to it differently. Both are designed to arrest spark at fairly open throttle positions to reduce pinging. The TPS (Throttle position sensor) is a mechanical device that mounts to the carb and based on throttle position will arrest timing. The VOES is a vacuum switch that will do the same thing, but does it based on vacuum in the manifold.

I have heard of great successes with both. But suspect getting the VOES just right is probably a little more difficult without real good data with respect to the type of VOES to obtain and use.

Gram

choppers_polska wrote:
Is which differences between voes and TPSmod in real?

The voes is a switch (off/on) operated by vacuum, at CT (closed throttle) it acts as a short so the voltage required to go into WOT (wide open throttle) is at minimal. as throttle increases, vacuum decreases, VOES opens, 5 volts is sent to the pin of the ignition module and goes into wot. Aprox 4, 4.5v is needed for the module to go into wot timing.

The TPS is basically a potentiometer (variable resistor)the advantage to the TPS is that between the 1v it starts at aproximately till 4 volts there are addition steps that the voltage does in changing the timing, granted, we are talking in Thousandths of a second, but all these minute steps in timing change you do not get with a voes since it is on or off.

However, you do not need to run either with a 42hsr carb, timing will be a hair off on the low end since without a tps, the ignition module by default will go into WOT timing. With or without the mod, the bike will not lose performance nor loss of tq. however, if using the stock ignition module you will get the blinking code on the dash since it will not see the tps, if you go with the dyna2k without the tps, it will eliminate the alarm code blinks.

I have had my 42 set up in all 3 ways, without any mod, with VOES, and with TPS mod. My experience that it (TPS MOD) helped in low end with a smoother idle, a slight change in exhaust note at idle, and an increase of aprox 4mpg in city riding. And of course there are those that say it does nothing . any way, use what info ya can, toss the rest

OK, so I'm about 90% done bolting on my HSR42 and I had a few questions/observatons I wanted to run past the "HSR guys".

- I did the TPS mod & mount. Works good but the TPS is basically touching the front cylinder head with the carb mounted. Is this normal & do you think the possible vibrations will harm the TPS ?

- I have a stainless steel braided "stock" configured throttle cable. I've found a way to route it to near the carb but it's going to be a real pain to get it into the bracket. Any suggestions ? I'm thinking of trying to bend the end just a bit more.

- I re-used the stock choke cable but the 90 deg elbow is touching the front cylinder. It seems to me it won't be long before the plastic nut holding the choke cable in place breaks from the vibes. Sugestions ? (other than getting a mikuni choke cable ?)

Can the Carb be tilted slightly ? If I tip it toward the rear of the bike a bit it will resolve my TPS and Choke cable issues (although it will make my throttle cable issue worse) by giving a touch more clearance to the front cylinder.

Thanks !

- I did the TPS mod & mount. Works good but the TPS is basically touching the front cylinder head with the carb mounted. Is this normal & do you think the possible vibrations will harm the TPS ?

Take a sander to the corner of the tps that touches the cylinder head. it's a pretty thick cover I think i took 1/4" off the corner. just go slow.

- I have a stainless steel braided "stock" configured throttle cable. I've found a way to route it to near the carb but it's going to be a real pain to get it into the bracket. Any suggestions ? I'm thinking of trying to bend the end just a bit more.

I bought custom ones from Maxair Eng. which have a HSR on the carb end and R* on the throttle end. I tried bending mine and pretty much broke it

- I re-used the stock choke cable but the 90 deg elbow is touching the front cylinder. It seems to me it won't be long before the plastic nut holding the choke cable in place breaks from the vibes. Sugestions ? (other than getting a mikuni choke cable ?)
You need to get the mikuni cable. several guys run theirs with the stock but, in my research the stock cable does not work right and could keep the enricher open a slight bit reducing the gas milage and opening yourself to SVS. IMO it was not worth the risk.

Can the Carb be tilted slightly ? If I tip it toward the rear of the bike a bit it will resolve my TPS and Choke cable issues (although it will make my throttle cable issue worse) by giving a touch more clearance to the front cylinder.
Yes mine is tipped a little (not much) make sure you trim the nub off the stock manifold to make it match up better.


Hope that helps

Steven

Thanks for the feedback Steven. I'll try sanding the TPS a bit just to get some clearance. Too bad I didn't ask before I got it all bolted on or I could have x-rayed that too ! I bought a tubing bender tonight to try and tweak the throttle and choke cable bends a touch. If I break them then I'll be forced to spring for new cables I guess.

I'll let you know how it goes.

I also meant to mention a little tip of my own. I modified the way I joined the TPS to the throttle linkage shaft on the HSR. Instead of removing the shaft, cutting a slot and setting in the shim stock I used 1/16" x 3/4" dowel pins. I drilled two holes, epoxied the pins in the holes, and then ground them to fit the slot in the TPS. It works great and I didn't have to take anything off the carb to do it. I'll post the pics when I get a chance.

Right now I just want to get the carb set up and get the pingel mounted to the tank so I can fire it up ! We're having a bit of a warm spell and I'd love to get 'er out on the road for a short blast to see the difference. I'm going to wait to put the 31T sprocket on until I have the carb dialed, just so I can feel the difference each mod makes.

Sooooooo exciting !

Rup

Well, it's on and running. Haven't taken it for a ride yet but it starts and idles so thats a good sign. Thanks to everyone for all the great info re: doing this mod. I wanted to share some of the things I learned along the way for future HSR mod-ers :

- When you make your TPS bracket, follow the instructions to the letter. I tapped the mount holes for the TPS before I set the resistance (oops) and I wound up having to re-do the mount holes in a different spot. Now the TPS is a bit cock-eyed on the bracket, although you can't really tell with the tank on.

- I was able to use my stock-style throttle cable with a bit of tweaking. I had to cut and drill the cable mount on the HSR as well as bend the bracket downward to get clearance between the throttle cable and the part of the frame that hangs down between the cylinders. I also had too much slack in the cable even with the adjuster all the way out. I wound up moving the throttle end of the cable to the other hole in the grip, where the return cable used to go. I had to slot the plastic between the two holes for the cable, but it worked out well.

- I did have to grind the corner of the TPS sensor to clear the front cylinder, but it seems ok. I re-used the stock (anti-tamper) style screws but I think I will swap them out for allen head style so I can fit a wrench in there in case I want to tweak the TPS while it's mounted. I found that it changed a bit once it was mounted and the bike was started up.

- As I mentioned above, I used 1/16" od dowel pins to run the TPS instead of shim stock. It made installation easier and I like the idea of the pins being sunk into the shaft 1/4" or so. It did mean that I had to be precise when I ground the ends flat though, as I didn't want any "slop" in the TPS response. There are actually two different steps in the slot inside the TPS. 0.045" and then down to 0.034". I ground my pins to length and then ground the corresponding steps into them for a good fit. I also found an o-ring that fit into the gap between the TPS bracket and the carb to keep dirt out of there.

- If you get the Pingel fuel valve it comes with a package of gasket goop that would be excellent for sealing your manifold to the heads. They give you WAY too much so you should still have enough left over for your fuel valve install too.

- I used the old idle adjuster mount for my choke. I had to bend the choke cable elbow slightly to clear the front cylinder, and I used the steel nut on the carb as it seems sturdier. I wound up cutting about 1/8" off the steel elbow with a pipe cutter and re-using the pce I cut off as a spacer on the choke knob shaft. This ensures the choke is fully off but avoids it pushing the elbow out of the rubber seal.

- I re-used the stock clamp on the carb boot to mount the HSR, but I used a bit of lube under the clamp to ensure it didn't bind up when I torqued it down (HSR outlet is slightly smaller OD). I also took the spacer off the clamp screw.

- Threadlock, threadlock, threadlock on everything - nuff said !

This was a fun install to do for sure. I encourage anyone who is on-the-fence to go ahead and do it. There is so much info and expertise at your disposal on this site that you really can't go wrong ! I hope my input comes in handy for other planning on this mod.

Pictures coming soon !!

TPS Ground to clear cylinder.

Choke knob mounted on old idle adjuster bracket.

It Fits ! Thats a Speedstar "Competition" Filter and billet backplate on it.

This is my new screensaver pic !