Ingram's 2005 Yamaha Zuma Build

[ingram]

Ok I got a big update! Finally got the courage to open this bike up and installed a bunch of new stuff. I officially no longer have a sport build anymore and definitely into the mid race territory. I just got it all together and still trying to get through my first tank of gas and get some tuning in but oh my this has really woken up and has much more power!

Here is what I ended up installing:

• Stage 6 Sport Pro MK2
• Malossi standard stroke crank 10mm wrist pin
• Yasuni City 16 derestricted exhaust
• MVT Digital Direct inner rotor ignition (DD19)
• Polini CP19 carburetor
• Vforce3 reeds
  
• Malossi La Furia Rossa Overrange system
• Artek K1 air filter (good airflow but still low noise)

I am currently running a 102 main jet with needle clip at the second from top position. The pilot is a little lean as I had to turn the air screw in to about a half turn out so I ordered some larger pilot jets and will keep tuning the carb.

As for CVT I started with 5.5gr rollers and white contra spring with red clutch springs in the Delta clutch. I currently have 5gr sliders and it seems ok but I think I liked the 5.5gr rollers a little better but I need to get the carb dialed in more before playing too much with the CVT. With 5gr sliders I am hitting just below 11,000rpm WOT whereas 5.5gr I was hitting around 10,700rpm. No top speed runs yet but I hit 60mph already and it definitely still had more available.

I also ordered a timing light to try and check this MVT ignition as I have seen too many people having issues with it not being setup right. Not sure I trust the standard setting the manual recommends enough to leave it alone. It definitely has a rougher idle and low end that I have not been able to correct with the carb adjustments yet so I'm also wondering if the timing of the MVT has something to do with that.

This was really fun to work on and I definitely was reluctant to crack open the cases but overall it went pretty smooth! The only issues I really had were trying to get the new crank bearings seated using the hot/cold method. I ended up using the case splitter tool as a press to seat them in all the way which you can see from my pictures below. Super glad I had both the Tusk crank puller and case splitter tools!





Variator side bearing didn't come out with the crank so I used the case splitter tool to push the bearing out.




I tried doing this using the hot/cold method but didn't have much luck getting the bearings all the way in so I used the case splitter tool like a press and pushed them in all the way.






New Malossi crank when in real easy using the crank puller tool.





Cylinder installed!




Reeds and intake on as well as the new seals.





I was real nervous about setting this MVT DD19 rotor up but used the 49cc scoot youtube video on this to get all the help I needed. Since I have a standard stroke crank I set it up to be .40mm before TDC.




I finally took the time to vent my CVT cover with 4 large holes in the front and then 2 large slots with 2 large holes in the back. I used a step drill for the holes and then a dremel to make the slots in the back by connecting holes I had drilled.

[ingram]

Here is a video of the first heat cycle after I finally got all the wiring correct and cleaned up!

[Zino]

You have the upgrade fever .
Nice pictures ingram .

Keep us posted on your results

[aeroxbud]

You have been busy. Sounds good. 👍

[Kenho21]

Nice build. I like It.

[ingram]

I put a yellow Malossi contra in and the low end bog went away. Tried some 6.1gr rollers just to see and could only get about 10,100 rpm max.

My timing light came in so I setup the printed degree wheel downloaded from this forum and noticed at idle I was around 40 degrees advanced timing so I moved the stator forward to basically line up the mark on the stator with TDC instead of .40mm BTDC which is what I originally had it set to. After that my timing at idle was right around 30 degrees advanced and the idle was much smoother.

Took it for a ride and now I have a slight low end bog again but wow the top end was a huge improvement! Still on the same 6.1gr rollers I hit 10,500 rpm and needed more road so I will be keeping the ignition set where I have it as I really like the top end pull I am getting now and believe the timing was too advanced before. Before calling it quits for the night I raised the clip on the needle which eliminated the low end bog with the new timing but I could tell it was a little too lean at part throttle as my temps were rising higher than desired when cruising and I could hear the tinning noise in the pipe so I will change the needle back and start dropping my weights instead to help with the low end.

[ingram]

Today I tried 5gr weights and still had a slight low end bog but it was better than before but the top end just felt not as powerful. Those revved out to around 11,450 rpm
I then changed the torque driver groove to the more flat slot which then everything felt much better throughout the rpm range so that was a definite help.
Lastly I put some 5.5gr weights in and I really like those the best. The pull in mid and top just feels much better with the 5.5gr weights and there is just a slight bog from a stand still now that I think I can get out by going one notch stiffer on my delta clutch red springs which would put them at the stiffest setting and give me close to an 8K launch. Currently I am at a 7K launch.

After the 5.5gr weights I decided to finally do a good top end run and hit right at 65mph at 11,000 rpm on a completely flat road with temps leveling out to around 310 degrees at WOT. That was plenty fast for me and I could easily cruise at 55-60 so I think I will leave everything the way it is on the top end and fix my stand still bog.

Main jet is a 102 and even though the temps leveled out at 310, when I came to a stop immediately after the long run the temps jumped to 355 degrees real quick at idle so I don't think I want try any lower main. Before the 102 I tried a 104 but it was definitely sputtering and my max rpms were down about 500 rpm compared to the 102.

[Zino]

Temps went up at idle you may be a tad lean on your needle or idle.
A small adjustment on the needle may clean up that low end bog or transition from idle to needle to main jet .
Does the idle hang?

You also my just have to juice it a few times as you come off a high speed run to bring the temps down .
These high rpms 2 strokes soft seize at part throttle coming off a hard run often enough .

65mph is flying .
You will probably pick up a couple mph aafter she fully breaks in .

[ingram]

The idle was trying to hang just a little I noticed so I might try raising the needle a notch and see what happens. Will also double check my air mixture setting again which is currently at 2 turns out and see if I need to turn it in some more. Just driving around the neighborhood it didn't seem to be an issue and it was only when I went full WOT for a long run that the temps jumped like that after coming to a stop.

[ingram]

Messed with the needle today and moving the clip one notch down definitely helped the idle hang and temps but it was more sluggish to get into the powerband transition. I then decided to try the 12/22 needle I had thrown into one of my Treats orders in the past and at the same clip position it was better all around. No more sluggishness on part throttle and the idle hang was gone and temps were better. I don't really notice a low end bog either anymore. Stock needle on the Polini CP carbs is 14/22 so the 12/22 has a narrower taper going to the end.

It started raining so I stopped but there is a very specific point at part throttle where it sounds just a touch lean but right before and right after sound just right so I think I will just turn the airscrew in another half turn to try and clean that up. Crazy how doing this enough does give the experience to determine the noises as when I started all this there is no way I would have determined anything based on the noise. Also having the temp gauge is key to validating everything.

[ingram]

Maybe I’m too paranoid but is this low throttle popping noise normal or OK? It happens around 3000 rpm and I’m not used to hearing that before all the upgrades but it has been doing it from the beginning of this build. The only thing that seems to make it go away is retarding the timing even more but then it feels more sluggish than I would like. I’m just concerned it is detonation or something because the mvt does advance the timing quite a bit at low throttle. I am already retarded more than the recommended setting from the manual.

[captincvmn]

I think it sounds normal.

[ingram]

Ok I think I found my issue that has been bugging me since all my upgrades... Could never get the mid range tuned how I liked and kept experiencing unusual noises at certain RPMs that just didn't seem right to me. Long story short my squish is real low at just under .4mm! 

I was in the middle of switching back to stock ignition as I wanted to make sure the MVT wasn't the culprit of all this and noticed what looks like a leak from the head gasket. I then took all the shrouds off and noticed the base gasket, which had been Honda bonded, was pushed out some from when it was originally installed.

I then decided to check my squish as I had never done that before and figured I was good based on what I had seen others use for the base gasket which was the thick paper gasket that came with the kit. Well that ended up showing right at under .4mm and seems I need to be in the .7-.9mm range so most likely my compression is too high. I still have all the metal base gaskets that came with the kit and have a Malossi BBK gasket set laying around that I will take the Oring and paper gasket from to combine with the stage 6 metal ones to get my squish up.


FIRST INSTALLED


CURRENTLY (Notice the base gasket is pushed out and signs of oil at the head gasket area)

[pewpew]

Jul 12, 2021 12:34:06 GMT -5 ingram said:

Ok I think I found my issue that has been bugging me since all my upgrades... Could never get the mid range tuned how I liked and kept experiencing unusual noises at certain RPMs that just didn't seem right to me. Long story short my squish is real low at just under .4mm! 

I was in the middle of switching back to stock ignition as I wanted to make sure the MVT wasn't the culprit of all this and noticed what looks like a leak from the head gasket. I then took all the shrouds off and noticed the base gasket, which had been Honda bonded, was pushed out some from when it was originally installed.

I then decided to check my squish as I had never done that before and figured I was good based on what I had seen others use for the base gasket which was the thick paper gasket that came with the kit. Well that ended up showing right at under .4mm and seems I need to be in the .7-.9mm range so most likely my compression is too high. I still have all the metal base gaskets that came with the kit and have a Malossi BBK gasket set laying around that I will take the Oring and paper gasket from to combine with the stage 6 metal ones to get my squish up.


FIRST INSTALLED


CURRENTLY (Notice the base gasket is pushed out and signs of oil at the head gasket area)

The very low squish probably changed the timing, when you fix it you should try it again at 0,35mm btdc

[Zino]

That is tight squish .
.7-.9 is a better target .

It will still be way snappy with an extra base gasket.