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Post by whitedrifter on Oct 3, 2012 21:14:46 GMT -5
Hey guys,
I am new to this forum. this is my first post. I need some help with my cpi gtr 50. Its a 2005. I bought this recently and i found that the day after i always have such a hard time starting until about a month ago i just gave up and brought it to a "scooter mechanic" who changed some fuel tubes. added a new petcock. changed some rubbers for the air filter tubes and changed the rollers which were flat. On the way home the bike started making a grinding noise and eventually stopped. It had done this before at the mechanics he said but every time i rode it before it didnt so it must be something he did. regardless now it doesnt start. I do notice that even though the petcock is closed there is a little clear fuel filter after it and all the gas in there does disapear after a day of sitting... could this be a problem?
second question is for a 70cc kit. the bike has about 6000km on it and mechanic says i need to change the crank and bearings and upgrade to 70cc plus change the variator and clutch etc etc... what do i need? Ive tried looking at some of the sites provided in other threads but looking at these parts is just like a guy looking at ingredients to bake a cake... yeah theyre all there.. but wtf do i do with them? which do i need? is there anyone who has a specific setup they like alot?.
sorry to ask so many questions guys and i really hope someone can help me!
thanks!
-pat
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Post by rollingwrench on Oct 3, 2012 21:22:55 GMT -5
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Post by skuttadawg on Oct 4, 2012 0:15:16 GMT -5
Without seeing and hearing it can not say what it needs . Now a BBK , a tuned pipe and rejetting can do wonders . Many use 4 or 5 gram slider or roller weights . Jetting will not be the same for everyone since we are not at the same elevation or climate etc . Its a testing game and its fun to wrench . Once you get it right you will smile as you pass by those on 4T scooters and cars
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Post by james03x1 on Oct 8, 2012 5:27:35 GMT -5
It's much hard to diagnose the problem without watching it, i think you should look a mechanic in your town who must be expert.
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Post by carasdad on Oct 8, 2012 9:45:36 GMT -5
Hey guys, I am new to this forum. this is my first post. I need some help with my cpi gtr 50. Its a 2005. I bought this recently and i found that the day after i always have such a hard time starting until about a month ago i just gave up and brought it to a "scooter mechanic" who changed some fuel tubes. added a new petcock. changed some rubbers for the air filter tubes and changed the rollers which were flat. On the way home the bike started making a grinding noise and eventually stopped. It had done this before at the mechanics he said but every time i rode it before it didnt so it must be something he did. regardless now it doesnt start. I do notice that even though the petcock is closed there is a little clear fuel filter after it and all the gas in there does disapear after a day of sitting... could this be a problem? second question is for a 70cc kit. the bike has about 6000km on it and mechanic says i need to change the crank and bearings and upgrade to 70cc plus change the variator and clutch etc etc... what do i need? Ive tried looking at some of the sites provided in other threads but looking at these parts is just like a guy looking at ingredients to bake a cake... yeah theyre all there.. but wtf do i do with them? which do i need? is there anyone who has a specific setup they like alot?. sorry to ask so many questions guys and i really hope someone can help me! thanks! -pat No offense...but your mechanic does not seem too brilliant. Has he even done a compression test? Possibly the noise you heard was the engine trying to seize or soft seize. Ok it doesn't start..do you have spark? The gas 'disappearing' may merely be that the carb float needs adjustment. As far as a 70 BBK...you don't need knew bearings for one. Regarding the other parts..BBK first...then one piece at a time after that..because when people just toss in a boat load of parts all at once..they end up with problems they can't figure out. By going one piece at a time..and you end up with a problem..guess what the problem is?...Exactly! The last thing you changed  So have someone check for spark...do a compression test..then we will all be able to better help ya...  |
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Post by whitedrifter on Nov 3, 2012 21:26:55 GMT -5
Hey guys,
Ok so i am attempting to do this rebuild kit. I did find the problem. My crankshaft bearings were COMPLETELY dead. both sides. they were leaking quite badly into the CVT area and i had to do alot of scrubbing and cleaning to get things back in order. My mechanic had changed the belt and hadn't noticed this?!...STEVIE WONDER couldve noticed this!!!! I am going to replace the bearings. I do have a couple of questions however.
1. Did anyone ever take off the Flywheel/stator cover without that special pulley tool? if so how? if not where do i get one?
2. To install a 70cc do I need to change crankshaft? or in that case do i need to change carb or air intake or basically anything else at the same time?
3. I noticed there are different models of 70cc kits. 10mm and 12mm etc... if I can use stock crankshaft which kit should I be looking at? Are there any particular models you prefer on this bike?
Thanks guys! this is very much appreciated!
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Post by teddy554 on Nov 3, 2012 21:42:43 GMT -5
1. yes you can take flywheel off with out puller, but i would buy and use a puller, think it should be m-27 i use this on my cpi oliver www.partsforscooters.com/202-10-Flywheel-Puller2.if you are leaking oil, you only may need to replace crank seal only (like 10 dollars and dont need to split the case) and not the bearing replacing bearing require splitting the case and if you do that you might as while go to hpc (high primary compression)aftermarket crank which is need for certain high rpm 70cc kit. you can run the stock intake and carb with little issue but would recommend carbon or fiberglass reeds. 3.To know wiether you have the 10 or 12 mm wrist pin measure the spines on the output shaft 18mm =10mm 21mm =12mm wrist pin or measure your stock wrist pin Some links this is the forum you really want to be on for 2t build 49ccscoot.proboards.com/index.cgi and here is a link to 90GTVerts youtube channel full of how to's www.youtube.com/user/90gtvert/videos?flow=grid&view=0 |
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Post by skuttadawg on Nov 3, 2012 23:34:28 GMT -5
Our knowledge database is growing, but we know a few things. Adly's and Hammerheads are 10, so are the Italian Minarelli engines like Malaguti, Italjet, Beta, and Aprillia. The 12mm pin is found on later CDI's, chinese JOG-2T, Vento Triton. These engines are poplular in 2-stroke full size scooters and ATVs such as Malaguti, Yamati, United Motors X-Speed, Aprilla, CPI, Benelli, Vento, Eton, Adly and many more. Italian made units tend to use 10mm pins (Chinese JOG 2T clones tend to use 12mm) please measure and check before ordering. Certain brands such as CPI / United Motors / Muz older models used 10mm newer post 2004 use 12mm. All Italian made models use the 10mm such as Aprilia / Malaguti / Italjet that are Yamaha Minarelli based. Probably the most accurate, without complete disassembly, is to measure the inside diameter of your variator pulley. If it is 21mm, your wrist pin is 12mm. If it is 18mm, your wrist pin is 10mm. You can also count the number of splines on the outer variator face where it mates with the crank. The smaller 18/10mm crank has 17 splines, the larger 21/12mm crank has 15. The larger crank was originally designed for the JOG90 engine, but comes in 50cc too. Also, don't confuse your Minarelli 2stroke with the Franco Morini type two stroke found in TGB R5 Laser, Key West, 101S, the Suzuki Address, and some Italjets. These kits are also available from Scrappydogs, as they are authorized dealers for TGB products. Hope this helps. MO! Here are our Minarelli based parts link. Minarelli If your taking it apart that far down I would get a forged crank so that you can built it to be a screamer or at least have a stronger crank to have one less worry . A wimpy clutch or variator should be upgraded but CPI is a good brand and the stock parts should be ok . I would put on a fresh belt and go with slider weights . If you can afford it Dr Pulley clutch is the best and comes with many spring sets and weights in order to fine tune it and the Dr P variator is the largest diameter so more top end just measure clearances first . I bought a 70cc pipe and tried to fit it on the stock 49cc engine but it would not line up but when I put on a BBK it fit perfect so you may want to save up for a 70cc exhaust . I have a MMG that so unrestricted that I lost bottom end since it does not build up enough pressure but it can hit 11,000 rpms and it is between a weedeater and a MX motorcycle in sound and loudness . It is not suggested to go past 10,000 RPMs with a stock crank to be safe I just wanted to see what it would do and I went way past the 50 MPH mark where the 49cc would sometimes hit 50 but mostly 45 . From my research a Leo Vince HM70 would be a better pipe but around 300 . The exhaust is more important on a 2T in order to have it in tune . I had a Cr 125 and rock hit the pipe just before the expansion chamber and dayum I had a major power loss at high RPMs . Here is a great article on many 2T HP exhausts 49ccscoot.proboards.com/index.cgi?board=exhausted&action=display&thread=1391Here is a place with high end parts that may interest you if you have the budget or just want to look anyways www.spmotostore.com/category_s/176.htmStock carbs can be 14 to 19mm but the 70cc Power Kits come with a 21mm carb , a smaller one can work but it will not have as much flow needed for top end and bigger than 21mm may be overkill . A Suzuki RM 80 has a 28mm carb and will scream way more than a scooter engine . I said this to let you be able to see that a big carb may work for the RM but not a street scooter . I am a Mikuni fan , Kehin is also very good and I read many like Dellorto . After the holidays if things go right I hope to go with EFI since my Echarm has EFI and it is superior in every way over a carb . Here is a kit www.ecotrons.com/2_Stroke_Small_Engine_EFI_kit.html this one you can opt for a secondary injector if desired to really make the power band kick in . I just missed getting a CPI GTR by an hour dang it , so enjoy your blessings on owning a above average scooter It is so much fun to out run 4T 50s and even 150s while saying " its just a 50 " wink wink and give them 2T envy |
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So have someone check for spark...do a compression test..then we will all be able to better help ya... 
