Ivan's Jet Kit installed on my 750!

[Tokalosh]

I'm a very happy man, so is my KAT.

I was running with a K&N filter and a Carbon Can Co slip on, until I order a jet kit from Ivan, as apposed to the Dynojet kit and K&N jet kit. After doing a lot of reading and asking a lot of questions I decided to take it to the Pros to install, so off to HM Racing I went.

http://www.hmracing.co.uk/Default.asp?strTemplate=temPW3_001.asp&intPage=413&strLang=en&intLang=2&intLevel=3&intLevel2ID=387&intLevel3ID=&intLevel4ID=&intLevel5ID=&intLevel6ID=&intLevel7ID=&intLevel8ID=&intLevel9ID=&intLevel10ID=

When the above setup was dyno'd I was getting 84.0bhp Max power at 11500rpm, and the fuel mixture was very, very rich.

They then installed Ivan's jet kit to his specifications, so now it was set up with the stock filter and the needles where set on position #4.
This set up was still not correct as the fuel mixture was still very rich. They then decided to change the Pilot jet's to 107 as apposed to using 110.
They also changed the needle clip position to #3 then again to #2.

The new set up was much better with the fuel mixture almost perfect and #2 clip position on the needle, with the stock air filter.

When this was dyno’d I was getting 86.0bhp Max power at 11500rpm. I rode the bike home and could not get over how different it feels. It is so much more responsive and oh so smoooooooooooth, when idling the bike is quite and smooth, On the twisties the power is more responsive and there when you need it. All in all I’m very happy with my bike. :mrgreen:



Tokalosh

[rockadaous]

congrats. that sounds like one mod I'd like to do

[xbubbax]

i cant wait to do a jetkit on my bike

[trinc]

thats amazing - lowering the pilot & the needle. most bikes are tuned lean for emissions from the factory. your the first person thats posted lowering even farther the idle circuit.

tim

[Tokalosh]

Lucky for us in the UK, we are not tested for emissions on bikes.

I would post some pictures up but the site tells me I've reached my 2MB limit, cant work it out as I've deleted most of my pictures, some help would be great.

Tokalosh

[The CyberPoet]

Lucky for us in the UK, we are not tested for emissions on bikes.

I would post some pictures up but the site tells me I've reached my 2MB limit, cant work it out as I've deleted most of my pictures, some help would be great.

Tokalosh

(A) I can host pics for you. Email them to me.

(B) When I installed Ivan's 750 kit in Malloc's, we ran into the same "too rich" issue and simply turning back the pilot set-screw a half turn pretty much cured it. Ditto on my 600 (again turning them back to 3-1/2 turns out instead of 4 seemingly took care of it).
I suspect that a lot of that has to do with the time of year Ivan designed the kits -- the fuel in the northeast USA was winter fuel at the time, which has MTBE (oxygenators) in it for pollution control and a higher-than-average amount of aeromatics (because they won't evaporate as readily in the winter)... But I'd have to slap both bikes on a proper exhaust analyzer to really know for sure if I tuned them perfectly, or left them running a bit rich (but they haven't fouled any plugs in 3-4k miles).

Cheers
=-= The CyberPoet

[trinc]

i'd like to see the dyno sheet ( sniffer readings )

tim

[Tokalosh]

This post has now been updated please see above.

Tokalosh

[The CyberPoet]

Might as well post mine as well...
Results were: carb settings good, could use a 1/2 shim on each needle. Ivan also suggested cutting down the stock springs 1/3rd of the way, but I couldn't bring myself to do so...
This run is bike hot (205 degree oil temp), really hot garage (97 degrees, ramping up to 104 at times), high humidity day, chain slack as hell (intentionally for other reasons).



Note this does not display torque; this print out displays HP and Air-Fuel ratios, which is what I wanted (to see if it's going lean/rich/etc).

Cheers
=-= The CyberPoet

[ThAzKat]

where is the pre98 750 kit?

[The CyberPoet]

Update: I just got off the phone with Ivan, and he sez...
"that big dip [in the fuel-air ratio around the halfway mark] is a combination of a bad resonance in the exhaust and the fact that some DynoJet's Dyno's [including this model] use a load control that is artificially high". He asked if I could get it run again with the load-control off (since the drum weight alone is 800lbs), in which case he would expect the major dip half way through the RPM range to become a very small downward dimple instead.

He also again re-emphasized the idea of using a weaker spring or cutting the stock springs down -- said it would reduce that off-idle initial drop depth and increase the speed of the rebound upward as the engine starts to compensate for the throttle coming wide-open. I'm going to talk to the dyno guy later this week and see if I can get him to run it again with the load-control turned off to see what happens.

Cheers
=-= The CyberPoet

[The CyberPoet]

where is the pre98 750 kit?

Is there one? Did you bring him a pre-98 750?
Go the easy route: swap to the post-98 carbs :P


=-= The CyberPoet

[trinc]

Update: I just got off the phone with Ivan, and he sez...
"that big dip [in the fuel-air ratio around the halfway mark] is a combination of a bad resonance in the exhaust and the fact that some DynoJet's Dyno's [including this model] use a load control that is artificially high". He asked if I could get it run again with the load-control off (since the drum weight alone is 800lbs), in which case he would expect the major dip half way through the RPM range to become a very small downward dimple instead.

He also again re-emphasized the idea of using a weaker spring or cutting the stock springs down -- said it would reduce that off-idle initial drop depth and increase the speed of the rebound upward as the engine starts to compensate for the throttle coming wide-open. I'm going to talk to the dyno guy later this week and see if I can get him to run it again with the load-control turned off to see what happens.

Cheers
=-= The CyberPoet

thanks for posting that CP - interesting results & shows why fine tuning is important.

i will only add that with the dynokit i used (k$n label ) it came with new springs that i thought were a bit stiffer. the instructions stated you could use them or not ( i did ). i've never been able to 'tune' out the off idle problem - it would be interesting to see a new run with a cut spring.

tim

here's my first run w/ sniffer

[The CyberPoet]

here's my first run w/ sniffer

Note that the dyno operator (someone I trust quite well -- a mechanical engineers by degree, and former investment analyst turned MMI mechanic) said that although 14.7 was theoretical perfect burn, DynoJet's tuning (both in their jetkits and fine-tuning on the dyno) always targets an idealized 13:1 air-fuel ratio as being optimal for power performance... I was rather amazed at that statement, thinking they would target a 13.8 to 14.2 range... but in retrospect, shooting for 13 should keep it from going too lean (i.e. - above 14.7) even in the worst scenario (high-rpm, shut-throttle decelleration) to keep the engine cooler and more ready to respond to fresh throttle inputs.

Cheers
=-= The CyberPoet

[ThAzKat]

14.7 is neer sea level and anywhere else will be higher. Thus the reason my bike runs richer now than it did in Arizona. Arizona is at sea level in Phoenix or damn close and at 14.7 a pre 98 750 or mine ran 97 hp.