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Post by 90GTVert on May 29, 2011 14:03:33 GMT -5
You'll probably want squish 1.5 - 2mm. Ideal is supposed to be as low as .9mm, but that's a guarantee for detonation even on premium unless the head is reworked.
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Post by drawkward on May 29, 2011 15:00:12 GMT -5
Wow, so I'm going to be running REALLY safe. Fine by me, as long as it runs decent and I don't end up with another one of these anytime soon...  
So I shot up to the hardware store across town on my father's scoot sporting a new-to-him shorty 150cc engine and picked up a M10x1.25 hardened nut. However; it's not a "half nut". Hopefully this doesn't cause a problem; I don't think it will.   We'll see... |
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Post by drawkward on May 29, 2011 15:06:31 GMT -5
Ha. Just noticed from the picture that my vari fan is broken! Swapped for a fresh one. Came off the motor I bought from Reign. Looks practically new...  |
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Post by 190mech on May 29, 2011 20:26:58 GMT -5
I never worried about a few chipped fan blades..I did notice that the inner vari pulley doesnt show a wear mark all the way to the top..Whats going on there?
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Post by drawkward on May 29, 2011 22:20:24 GMT -5
I don't worry about it too much either - but on a fresh build like this; I want everything to be just right. That pulley was on a setup that never ran correctly, and I think it was actually running with this belt. 788's are actually a bit short for a long case Mina, right? Good eyes on the markings, though!
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Post by 90GTVert on May 30, 2011 6:08:17 GMT -5
You can make a 788 cover a whole vari face with some work.
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Post by drawkward on May 30, 2011 9:04:54 GMT -5
We'll worry about that once it's smokin' and tuned ;-). Should get some decent work done. It's a beautiful day to be out working on the scoot.
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Post by drawkward on May 30, 2011 10:35:02 GMT -5
The stator I installed was the fried one from last year. Had to spend 30 minutes replacing it  2nd fire. Of course I'm not going to record the first start - because I didn't know if it would start! When it started it jumped forward, and I didn't notice how it was sitting on the stand - down she went. Couldn't help but to laugh at my self. Took it for a spin. Running riiich. I can already feel the massive torque - even severely out of tune. Boost bottle is installed, less compression in the cases, and the red contra probably help. I think the red contra and the rich running stopped me from getting more than 38.3 mph. Letting it cool down before I check the plug, change the main jet, and swap out contras. 
New Plug (#88 main jet):  
Edit (1:47PM EST):Dropped to #85 main. Power increase. Still bogs at WOT when I cover part of the air inlet on the airbox (my richness test). Going to drop it to an #82 main. Sounds crazy to me, but I guess I am using a stock pipe. Also switched out from the red "2000" TS to the blue "1000" TS. Went from 7.6 gram rollers to 8.6 gram rollers. Might even go up to 9-10 gram rollers after I drop the main down. All of this is so new to me. I mean, the rollers I'm using right now are brand new - which is crazy because I have had them for over a year. |
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Post by drawkward on May 30, 2011 13:31:20 GMT -5
I think I'm going to go back up to the #88 main.
When I left off the throttle completely from high RPM, it doesn't engine brake at first. It's hard to explain. It cruises along at the same RPM for a few seconds then starts to finally drop in RPM - or it won't and I need to blip the throttle to get the revs to drop. It reminds me of when I was getting my plug so hot last year that it was causing it to run even after I cut the ignition.
So back up to the #88.
Now I gotta get this CVT situation straightened out. I just can't get full travel on that variator. Still pushing 38 mph after switching from 8.5 to 9.5 rollers and dropping stiffness in my torque driver spring. I know the engine has the power to push it to atleast 50, as I'm almost doing wheelies from a dead stop. Torquey.
Is it the belt? I just checked and all I have are 788's. I was doing 60mph + last year. I just gotta figure out which of the CVT components that I've got here were the ones that got me to that speed. Oh well. I like tuning the CVT better than the carb anyways.
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Post by 90GTVert on May 30, 2011 13:48:29 GMT -5
Congrats on getting it running!
Any idea what your revs are? Maybe mark the vari to see where the belt will ride at the moment to see just what you're dealing with. Under 40MPH max should mean you either have a real lack of power or the CVT is way out.
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Post by drawkward on May 30, 2011 15:00:24 GMT -5
Thanks man! I was way excited. After trying main jets from 80-100, stock, blue, red, yellow torque springs, and rollers from 5 grams to 12 grams, I finally ended up switching out my torque driver. Problem solved. Just went up to the store with an #85 main, stock 7.6gram rollers, and yellow TS. 44.7 mph (gps) on slight down hill. Going to swap in heavier weights to see if I can get that high speed low rev cruise going! But first - air conditioning and cold beer. No ideas on the revs. I want to get a tach, but I want to buy a Koso like you've got. I suppose I should just suck it up and get a cheap one for now until I can afford the Koso - but I'll wait on the temp gauge, since the Koso comes with one built in.
Edit (7:33PM EST):In my excitement, I forgot to retorque head nuts after the first couple starts. Was wondering why it was getting so damn under that shroud... Will post pics of the leakage and I might even just take the head gasket and base gasket out to see what kind of squish I get. All of this after the dishes and laundry...  |
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Post by drawkward on May 31, 2011 14:26:27 GMT -5
Got it cleaned up. Didn't snag any photo's of the leak. Nothing exciting. Decided to keep the head gasket for now - didn't feel like waiting for the rtv to dry. Running even better now. Still rich with the 85. Mission case is leaking oil. Need to reseal it soon before it causes an accident or locks up.
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Post by drawkward on Jun 9, 2011 5:58:54 GMT -5
Been riding around for the last week. CVT still needs something. Can't seem to get the belt up to the edge of either the vari or the rear pulley? Maxing at 45 mph, over revving to get there. Heavier weights, lighter contra, different belt, washers... But other than that the engine pulls pretty strong for having everything stock. Got a pipe in the works, and plan on using a 26 mm OKO carb I got a few months ago for next to nothing on ebay. Just need a suitable intake manifold (don't like the ones that go to the side, and all of the rear facing ones seems so over priced? Wish I could just fab a cheap one up... Maybe I can?) Need jets as well. Searching for OKO jets doesn't get me very far... Pictures of the carb - there are a lot, and some are out of focus. The type of intake I want.Anyone ever get a decent solution for big carbs on stock intakes? |
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Post by 90GTVert on Jun 9, 2011 7:21:15 GMT -5
I don't think there is a good solution for a 26mm carb with a stock intake. 22mm is about the easy limit. I don't think I'd wanna go boring it out for fear it would get too thin. You could probably build a relatively simple rear facing intake since you have a welder. Get some steel plate and use your stock intake or a reed gasket as a template to cut it out. Then you'd just need a section of steel tubing with a bend that will work for you. Ideally you want something just over 1" ID for your 26mm carb, so maybe 1.125" if you can find something. You can find some pretty small stuff in the exhaust section of auto parts stores sometimes. Look in junk piles or hardware stores or anywhere for something cheap that you can chop up if necessary. Once you find something, test fit, tack weld, test again. If it's gonna work, finish the weld and make sure it's leak free. Use a rubber adapter and clamps to attach the carb. Could be a bit of radiator hose or something like that. It's doable if you are willing to put the time into it.
Where the CVT is concerned, I know you said somewhere that you've never seen a need for aftermarket varis... but I think you will. I find that the 90s like to "overpower" the stocker. Even on Project 90 it seems like for the best top speeds I have to run weights so heavy that it kills a lot of acceleration so I can keep the revs within the proper range to get more MPH at times. They get to a point that you either have to mod the heck out of them to get them to allow them to close tighter as well as elongate the tracks by cutting out part of the outside wall of the vari (be careful there, I ruined the last one I did by taking it too far, little at a time). Even with the mods, they still don't do what the performance stuff does. Look at project 90's thread and check out the difference with the Hoca variator vs stock.
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Post by drawkward on Jun 9, 2011 10:47:19 GMT -5
Thanks for the tip on the intake. I was thinking it might be easy enough - I just suck at welding. I guess it should be easier than doing the exhaust and I managed that to an extent.
I just don't understand why, even with really heavy weights, I can't get the Variator to push the belt high enough? I just had a thought after looking at belts for sale online. One add claimed their belt was wider, allowing for higher belt travel on the pulleys. Maybe ALL of my belts are worn down enough to where they are not wide enough to get full travel - I have one that's almost down to 14mm! Another problem is not riding low enough on the Variator at idle - which would only get worse with a wider belt...
Plan of action in regards to the CVT:
1. Add "restrictor" washer(s) in between vari drive boss and fixed half to allow belt to travel all the way down at idle on the Vari and to outside edge of the rear pulley.
2. Use my widest belt / buy new belt to allow the belt to ride as high as possible at full speed. I remember switching from the 14mm wide belt (was about 16mm at that time) to a brand new 18mm belt, and it was a drastic change, even with only a 2mm difference. Was similar to what I imagine a gear swap would be like... Maybe that's why I can't the get the speeds out of the same CVT components that I had used with a 70cc power plant.
I believe you that the 90cc engine, even stock, is too much for the CVT - but shouldn't it at least perform at the same level as the weaker 70cc engine?
Sorry about rambling. I actually figure a lot of stuff out while I type these responses. It forces me to go through every detail, which helps me catch the little things I missed.
Must have missed the Hoca Variator bit. I think I'm going to get the power upgrades finished before I move on to aftermarket CVT components.
tl;dr: Might try the DIY intake. As for the 45mph max - I'm thinking: worn belts (width), and need to add washers to vari drive boss.
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