My Roketa Fiji 150 6,000 Mile Notes and Comments

[earlwb]

I noticed that the forward muffler strap broke again. So I redid my muffler bracket, and put it on to serve as a washer on the two muffler standoff mounts. I think the small sharp edge on the standoffs is actually causing rhe straps to break by causing a stress riser to form along that sharp edge. I'll see how it does this time. As the straps are up against the cross plate and not right up against the standoffs. I have a photo of the muffler mounting bracket further back in my running commentary. Just picture that all the muffler straps on on the outside of the cross brace now.
On the straps that broke, it is always the inside lip where it is bolted up against the standoffs.

[demon]

Earl, i dont exactly have small hands, but i had little trouble getting in there... if i really didnt feel the difference in the plug i would have told you not to worry about it...

So tell us.. can you fell the power...lol

[earlwb]

I'll let you know Monday, I haven't ridden it yet since the plug change. I only test started it to ensure it was working.

[Dennis D]

earlwb said:

Oh yeah, i am still running the OEm CVT belt and the OEM spark plug that came on the scooter from the factory.

Have you looked at your CVT belt recently. Mine was turning close to the kind of rpms yours is turning, when I replaced the belt. The OEM belt was pretty warn, and the CVT had so much rubber dust in it that it was gumming things up and not working right. I couldn't possibly get the outside part of the clutch assembly to squeeze together and move beyond a certain point, so after I removed the variator to replace the belt, I also removed the clutch, and used the air hose to blow all the dust out of it.

Now the engine runs 8600-8700 rpms at an actual 64 1/2 mph, so my clutch being stuck had me running around in a lower gear at road speeds.

[demon]

nice dennis, i cant get my rpm past 7400 @ 55mph... it gets there no problem.... if i hit a decline it will hit 60mph and hold it well..not sure what the rpm at 60 is though.. never actaully looked... but i'd be surprised if its over 8k... we'll see if the exhaust and intake filter free it up a bit

[Dennis D]

Exhaust & Intake plus going up to a 125 jet(since by most sccounts it sounds like yours has a 115 stock jst) should pick it up some. I also have that Puig windshield, and that was good for an immediate 1.5 to 2 mph when I put it on.

[twitch]

Dennis and Demon, I have a roketa tahiti with a 150cc, and around 50mph I hit 8 to 9 grand on my tach, depending on the road. Does that sound normal, or should I think about cleaning my variator out to get belt dust out of there. I only have 150 miles on my scoot, and it has a Bando belt so I hope it isnt a problem yet. So far everything runs great. The only things I have done so far are change the plug(what a difference) and tune the carb a little bit. I just find myself wanting to find that top speed, but worrying about over revving. What should my redline be? What rpm should I NEVER go past?

[Dennis D]

Hard to say... Earl's Roketa and yours sound similar so maybe Roketa gears em for 50-55mph max. I wouldn't necessarily say NEVER go past 9000rpm, but I'd make those excursions beyond 9000 very brief. 1) the 80s Honda small engines would often go 10,000 or 10,500, but there's a big difference between Honda quality and chinese QC, even if it is a Honda design, and 2)the variator pulley spinning that fast for extended periods of time could prematurely wear belts not only because of the increased RPMs but also the increased heat, which is a known problem with these variators.

Bando's a good belt, but at those RPMs, I'd probably open the CVT to check for the belt condition and excess dust every 1300-1500 km or so. IF you can rev your scoot safely on the center stand to at least 6500 or 7000 rpm(or more) without your back wheel starting to bounce or vibrate too badly, you could always watch your CVT pulleys to see if it looks like they're working smoothly and properly. If your clutch is sticking you would probably notice it that way, but if belt or clutch were slipping during normal use, there's no saying it would do that under a "no load" situation. If you do that, have someone hold the front of the scoot down and in place to help keep it from bouncing, or starting to "walk" across the pavement or concrete on the centerstand(which it will start to do otherwise). And if it shakes or vibrates bad, back right off right away. I'd test like that only briefly, but bring the speed up smoothly and gradually while watching it.... not real fast.

[earlwb]

Interesting. I haven't checked the belt for about 1700 miles. I checked it at around 1,000 -1,200 miles and it looked OK. There was some rubber dust, but not a lot of rubber dust. It was easy to blow out at the time. I'll have to pull the CVT cover off and check it out again.

Yeah, I don't want to run it up around 9,000 rpm too much. I usualy don't go over 45 anyway.
I did it a couple of times to see how fast it would go, and satisfied my curiosity.

[earlwb]

I am amazed, the NGK spark plug does make a difference, as the scooter seems to pull better up the hills, and feels a little bit more powerful. Who would have figured. Interesting.
I also switched to Mobil One 15w-50 oil and the scooter seems to like that a lot too, it quieted the motor up more as well and makes it feel a little smoother when running on the roads.

[surfbum96818]

You may want to watch out after you switch to ngk plugs I did and eventually had to switch to an ngk spark plug boot because the oem boot would wiggle too much cause the scoot to "jump spark" and bog down. BUT with the ngk boot she is running like a top! FYI O'rielys auto parts carries the ngk irridium plugs fairly cheap!!!!

[earlwb]

Thanks that is nice to know, I'll keep that in mind, just in case.

[earlwb]

Well my first major failure today. At about 2896 miles, I had to stop, and get back home to get my truck, so I could cart my scooter back home.
While riding to work, i started smelling gas, and at first I thought it was from a gas station, but then I noticed the fuel gauge was getting lower and lower. Which isn't good, so I stopped to check it, and saw it was leaking fuel. I figured a fuel line was leaking.
well it wasn't the fuel line, it looks more like the fuel fitting in the carb has cracked or come loose on me. Second I noticed the carb was loose and the intake manifold has cracked or split on me too. But not so bad it was leaking yet as far as I know.
So I'll let you all know how that goes this weekend when I get into pulling some parts and checking it out more.
I suspect I need to either make a metal manifold or buy one of the racing ones. I have a spare rubber manifold, byt 2800 miles before they go bad isn't a good track record.

[schoei1]

I went through the same problem with my intake manifold after just one month after buying the scooter brand new. I immediately replaced the manifold with a MRP chrome intake manifold so I would not go through that problem again. It was almost like the fuel had burned right through the rubber manifold. Good luck this weekend.

[scooterollie]

The standard issue manifolds on many, if not all, of the Chinese scoots are of pretty low quality. Although, the one on my 250 CFMoto engine has been OK to-date (2,100 KMs). A dealer friend of mine showed me a stock manifold from a 50 CC and an after market one. The after market one was considerably heavier in weight and thicker. The original had failed, just as many others have described. You can get one here (http://www.oregonvintage.com/ScootpartsGY6.html) at Stan Jessup's website.

Interesting about the fuel inlet nipple on the carb. What brand is the carb.?

[earlwb]

Thanks,
Yeah I figured the rubber intake manifold was pretty crappy. It was interesting experiment to see how long it lasted. I should have checked it more often than I did.
The carb is a copy of a keihin CV carb, so who knows who made it.

On a more positive note, I did a Ebay search on "GY6 filter" and I was surprised to see a number of hits for air filters like my scooter uses, come up in the list.
search.ebay.com/search/search.dll?from=R40&_trksid=m37&satitle=gy6+filter&category0=
So if anyone was looking for that style of air filter, there were some for sale at the time I posted this message.

[earlwb]

I think I forgot to include my thread on the rear trunk box locking mechanism escapade.
In this case the latch mechanisn fell apart one day on me. So I had to do some improvements.
scootdawg.proboards59.com/index.cgi?action=display&board=tipsandtricks&thread=1175567472&page=1

And here is my thread on wheel bearings for the scoot as well.
scootdawg.proboards59.com/index.cgi?board=talk&action=display&thread=1182769824

I actually found out today, that there are two oil drain plugs on some GY6 engines. Back at the first message, I mention that the large chrome bolt on the left side downlow and to the right is a second oil drain plug. I learn something new everyday.

[earlwb]

I finally had the time to mess with my broke down scooter again.
I tried using the aluminum racing manifold, but it puts the carb about 1/4 to 1/5 an inch too far back, so the carb jams up against the frame motor mount. So I used another one of the rubber manifolds. I'll have to stock up on those things I guess. But I suspect I'll have to machine out a aluminum manifold out of a block of aluminum. So then I can keep the same shape and angles as the rubber manifold too.
The fuel leak turned out to be marvelously simple. The fuel line was loose, the clamp was not tight. Pretty amazing if you ask me, as it must have been a senior moment or something, because I thought for sure that the clamp was tightened up good on that tube.
But in any case it is ready to ride again.

[Greg]

can you just hack saw and half an inch off the aluminum manifold to shortin it up ??

[earlwb]

I had thought about that myself, but the rubber adapter for the carb sits in a grooved section on the manifold. So I would need to rig up a jig and use a lathe to machine in a new farther back groove, and then cut off the end. It looks like one could do this and move the carb back about 3/8's to 1/2 and inch. But I need to study it to ensure there is enough aluminum there to do it as it is getting down further on the curve on the manifold. The problem is it may be easier to just machine a better manifold myself. So I am thinking about it some more.

[scootermass]

One word....WOW! I have read some detailed reviews in my day, but yours is the very best I have ever come across! I'm learning a lot of different things about engines just from your posts. Really...Outstanding work.

I bought a Kymco People S200 because I "don't" know how to work on engines with the exception of replacing engine/gear oil, spark plugs, air/fuel filters, lightbulbs etc. I must admit that the Kymco is truly a fine scooter company. I have a tad over 1,000 miles on her & she has been a thing of beauty.

I know I could have saved money with a Chinese scooter & I wish I had the talent to do what so many of you do! I really enjoy reading what you guys/girls do to your scooters!

Thanks again for such a wonderful review!

Good Work!

Alex

[earlwb]

Thank you very much, I appreciate it.
That is a good choice on the Kymco. You did great.

[scootermikie]

earlwb said:

I am amazed, the NGK spark plug does make a difference, as the scooter seems to pull better up the hills, and feels a little bit more powerful. Who would have figured. Interesting.
I also switched to Mobil One 15w-50 oil and the scooter seems to like that a lot too, it quieted the motor up more as well and makes it feel a little smoother when running on the roads.

Hi Earl, I just wanted to mention a neat flexible 5/8" spark plug wrench that I used on my GY6 motor. You still have to use a regular socket (and your fingers) to remove the plug after it's been loosened with the wrench. Just opposite when installing the spark plug. Google "adjustable 5/8" spark wrench" and you should find this one.

[img src="[/img]img.photobucket.com/albums/0903/pianoman5355317/MikiesGuns1919.jpg"]

[MLN]

[scootermikie]

mln said:

How'd you get my pic to come up when I couldn't? Anyhow, thanks for posting it.

[MLN]

Your link was all messed up. You didn't put the picture link between the "[IMG*]It should have been here[/IMG*]" code. You had it after it. It was a hyperlink instead. There was something else wrong too. You removed it so I can't tell you what that was.

I had to add the * after the IMG so you could see it. That isn't there normally.

[earlwb]

Interesting tool. I think i spied one of those at our local Harbor Freight Store, I'll have to check it out more closely when I go there again.
I used a shorty 3/8" socket ratchet wrench, a sparkplug socket with a short extension. That worked out well too. You use your fingers to get it started and then snap on the wrench and snug it down.
Thanks

[earlwb]

If anyone has a purient interest in it. I ran some exhaust pipe temperature measurements on my scooter.
About one to one and a half inches from the header I measured 757 degrees F. About 1 inch in front of the flange to the muffler I measured 562 degrees F. Then at the middle of the muffler itself I measured 279 degrees F. These measurements were taken after running at 8000 rpm for about 5 minutes down the road. I had to do it several times as you have to be pretty quick, as the exhaust pipe starts to cool off fast when you stop.
Needless to say I did this a number of times. the nieghbors probably thought i was crazy or something.

[barretdm]

Yesterday, I stopped at a light with no problems, when to accelerate and my Roketa Fiji (with 1500 miles on it) felt like it had roughly half its power. I can only go 40mph now when before I could go 55mph.

I was told it was my belt. What do you think? I've changed my oil regularly and replaced the fuel filter to no avail.

Do you know what belt I should get and what spark plug I can get and where I can get them?

Thank you.

[earlwb]

Go to www.oregonvintage.com and order a 835-20-30 kevlar belt.
Also you can order either a NGK Irridium CR7HIX or a NGK C7HSA and C7HNS plugs.
Some people sell the NGK C7HSA-1 irridium plug too.

I'd have to say that one should check the valve adjustments on the intake and exhaust valves. As if they close up the gap, weird things happen like what you mentioned.