Cam upgrade??

denverscoot50 · Post by **denverscoot50** » Wed Apr 14, 2010 2:25 am

Hi guys - I have a 125 Buddy - O.K. - So I installed a 161 NYC cylinder kit and 150 NYC head - here is my prob - once I put the new larger head on it lost some power and got louder. I changed the main jet from 92 to 95 (I live at 5200 feet - Denver) and changed my Dr Pully sliders to 13 from 11 and it did very little. This scooter is a bit of a learner's project for me.
Could you guys suggest a next move - is it a larger cam? I also have a Prima pipe, Dr Pully Variator, belt, upgraded clutch springs and contra. It was running faster with the 125 head on it. So I am a little lost - thank you to anyone who has time to figure this one out : )

ScooterTrash · Post by **ScooterTrash** » Wed Apr 14, 2010 3:54 am

I would recommend taking it in and having it tuned. You are doing it all wrong. My guess is that the proper jetting is in the 100+ range.

No offense but you are a prime example of why I don't advocate DIY for performance. You can't just bolt things on and change the jet.

The reason it lost power is because you have the same amount of fuel coming in with twice the air. Also you may have had some installation issue's. Is everything torqued properly?

The install isn't the difficult part so I'll give you the benefit of the doubt and say you installed everything properly. Tuning is a bitch even for qualified people like me. It took me a couple weeks to dial mine in just from the cylinder kit.

Once again, no offense. The truth is harsh but it could save you a burned up piston. Please have it tuned before riding any more. Without even looking I can tell you that it's running lean.

If you decide to try it yourself, start with a 110 jet and see how it runs

denverscoot50 · Post by **denverscoot50** » Wed Apr 14, 2010 4:42 am

Hey - no I had a shop install the head. I actually installed the cylinder it ran great and yes I used a torque wrench. I do realize what you are saying and I don’t take any offence. This scoot is kind of a way for me to learn about engines – and yes I really do feel like I am over my head at this point. I guess what I am trying to do is get some opinions about what to do and progress from there. Just let me ask you – I put a 100 jet in and it ran even boggier than the 95 and you say to use a 110. Once again I repeat I will not be offended and I will take to my shop too at this point I just want a reliable scoot. Thanx….

Kaos · Post by **Kaos** » Wed Apr 14, 2010 5:14 am

I'll second some of Scootertrash's comments. It sounds like its not tuned right. There's more to tuning than just jets.

You should notice a BIG difference from stock to a 161 and head if tuned right. Unfortunately tuning is one of the hardest parts of moding, and the one thats least likely to provide a tutorial for

I spent over a month dialing in my head install, and I know what I'm doing. I've got 1000's of hours in tuning time on my bike all told.

Your best bet is ask you mechanic if you can watch while he tunes it. Then you get to learn what he did, AND its in tune

denverscoot50 · Post by **denverscoot50** » Wed Apr 14, 2010 5:26 am

Kaos wrote:I'll second some of Scootertrash's comments. It sounds like its not tuned right. There's more to tuning than just jets.

You should notice a BIG difference from stock to a 161 and head if tuned right. Unfortunately tuning is one of the hardest parts of moding, and the one thats least likely to provide a tutorial for I spent over a month dialing in my head install, and I know what I'm doing. I've got 1000's of hours in tuning time on my bike all told.

Your best bet is ask you mechanic if you can watch while he tunes it. Then you get to learn what he did, AND its in tune

Cool - I'm going there in the morning - the more I think about the more scared I am getting

I need to take a class on the basics and I had a feeling these were the answers I was going to get - thank you gentlemen

ScooterTrash · Post by **ScooterTrash** » Wed Apr 14, 2010 6:09 am

denverscoot50 wrote:Hey - no I had a shop install the head. I actually installed the cylinder it ran great and yes I used a torque wrench. I do realize what you are saying and I don’t take any offence. This scoot is kind of a way for me to learn about engines – and yes I really do feel like I am over my head at this point. I guess what I am trying to do is get some opinions about what to do and progress from there. Just let me ask you – I put a 100 jet in and it ran even boggier than the 95 and you say to use a 110. Once again I repeat I will not be offended and I will take to my shop too at this point I just want a reliable scoot. Thanx….

I can't tell you exactly what jet to run but in the world of tuning, Better to be rich than lean. Running a bit rich will at most foul a plug. Running lean can burn up the motor (the motor runs hotter when lean)

I'm honestly surprised a shop would install these parts without tuning. If you were to burn it up it could be there responsibility. In all honesty, it is. I don't even throw on a pipe without checking a customers scooter's tune.

If you want you can post a pic of the end of your spark plug (spark side) and I can tell you if it's lean or rich (if in excess). Too lean will be ghost white, too rich will be wet and black

babblefish · Post by **babblefish** » Wed Apr 14, 2010 10:15 am

He didn't say whether or not he's still using the stock exhaust system and stock air cleaner assy - if so, these could cause restrictions for the upgraded cylinder and head. And...what size is the stock 125cc carburator compared a 150cc carb? Just a thought.

denverscoot50 · Post by **denverscoot50** » Wed Apr 14, 2010 12:55 pm

It has its stock air/ carb (new 95 main jet) and has a Prima pipe… What happened was that I was installing the head and got frustrated so instead of putting it all back together I put it in the back of my pick up and drove it to the shop. They never test ran it because I said that I would but it back together to save some money- he did say to be careful and bring it by when I had a chance. So I brought it by a couple of days later and was accosted by the owner saying that I shouldn’t play with my scoot and that we live at 5200 feet and you have to be high altitude mech to know what you are talking about - also the mech who worked on it was not there at the time – so I left frustrated. Anyway I am going to go by there today and I hope the mech who worked on it will there so we can progress. If it wasn’t for cost I would have had them do everything – but man it get pricy fast….

ScooterTrash · Post by **ScooterTrash** » Wed Apr 14, 2010 1:20 pm

babblefish wrote:He didn't say whether or not he's still using the stock exhaust system and stock air cleaner assy - if so, these could cause restrictions for the upgraded cylinder and head. And...what size is the stock 125cc carburator compared a 150cc carb? Just a thought.

Says on his first post that he has a prima, scooterworks generally recommends putting in the 95 jet for just the pipe.

I'm not sure what the stock jetting on the 150 is but the main difference in tuning is going to come from the big valve head

Kaos · Post by **Kaos** » Wed Apr 14, 2010 1:21 pm

babblefish wrote:He didn't say whether or not he's still using the stock exhaust system and stock air cleaner assy - if so, these could cause restrictions for the upgraded cylinder and head. And...what size is the stock 125cc carburator compared a 150cc carb? Just a thought.

The 125 and 150 use the same carb, though the 150 comes stock with a slightly larger jet than the 125.

Lostmycage · Post by **Lostmycage** » Wed Apr 14, 2010 1:37 pm

Actually, the Blur 150 comes with a larger jet stock (102). The 150 and the 125 use the same carb and jetting (same restrictive intake and exhaust). That is, unless they changed the 150 carbs in the last 2 years.

Denverscoot, I'm at a loss here... Did they test run it or not?

What is the current state of the scoot? Is it complete?

If it is, check that the valves are set at .08mm clearance. If the valves aren't set right, it's not going to run worth a crap. At your elevation, you'll need slightly smaller jets that a lot of folks on here (who are at or near sea level). The 95 sounds like it'd be too lean though. I'd start around 110.

Make sure the bike is otherwise in good condition: clean air filter, good spark plug, good rollers and belt.

When the 161 kit was breaking in, did you use synthetic or dino oil? Synthetic is not recommended for break-in... it's too slick to cause the rings to seat well and if those don't start off right, it'll never be right.

Just a few ideas.

Something doesn't sound right with the shop... They're being screwy or there's part of the story missing. What's going on there?

Kaos · Post by **Kaos** » Wed Apr 14, 2010 1:43 pm

Lostmycage wrote: Something doesn't sound right with the shop... They're being screwy or there's part of the story missing. What's going on there?

Yeah, the whole 'high altitude mechanic" comment smells funny. So they're saying that their mechanic doesn't know what he's doing?

And the only real difference for high altitude is the jetting anyway...

Lostmycage · Post by **Lostmycage** » Wed Apr 14, 2010 1:46 pm

Kaos wrote: Yeah, the whole 'high altitude mechanic" comment smells funny. So they're saying that their mechanic doesn't know what he's doing?

And the only real difference for high altitude is the jetting anyway...

And the square shaped pistons that they use to counteract the cloud inversion intake capacitor harmonics. Those are a bitch with round pistons. Isn't that what happened to your Buddy? Got too close to the sun again, didn't ya?

denverscoot50 · Post by **denverscoot50** » Wed Apr 14, 2010 1:47 pm

Lostmycage wrote:Actually, the Blur 150 comes with a larger jet stock (102). The 150 and the 125 use the same carb and jetting (same restrictive intake and exhaust). That is, unless they changed the 150 carbs in the last 2 years.

Denverscoot, I'm at a loss here... Did they test run it or not?

What is the current state of the scoot? Is it complete?

If it is, check that the valves are set at .08mm clearance. If the valves aren't set right, it's not going to run worth a crap. At your elevation, you'll need slightly smaller jets that a lot of folks on here (who are at or near sea level). The 95 sounds like it'd be too lean though. I'd start around 110.

Make sure the bike is otherwise in good condition: clean air filter, good spark plug, good rollers and belt.

When the 161 kit was breaking in, did you use synthetic or dino oil? Synthetic is not recommended for break-in... it's too slick to cause the rings to seat well and if those don't start off right, it'll never be right.

Just a few ideas.

Something doesn't sound right with the shop... They're being screwy or there's part of the story missing. What's going on there?

Hey, well - It is complete and in real nice condition and it has a new belt and plug also I did use a blend to break in the 161 kit. My problems didn't start untill the new head. I'm going today to talk the mech who did the install and i'm hoping to get some good answers - thanx : )

This post is just me fishing for answers because you guys are great at figuring things out........

Kaos · Post by **Kaos** » Wed Apr 14, 2010 1:49 pm

Lostmycage wrote:
Kaos wrote: Yeah, the whole 'high altitude mechanic" comment smells funny. So they're saying that their mechanic doesn't know what he's doing?

And the only real difference for high altitude is the jetting anyway...
And the square shaped pistons that they use to counteract the cloud inversion intake capacitor harmonics. Those are a bitch with round pistons. Isn't that what happened to your Buddy? Got too close to the sun again, didn't ya?

I'm pretty sure that my flux capacitor failed at speed. I hit 88, the sparks started coming from the rear tire, I left a big streak of flame, but I didn't time travel. I just ended up in a corn field in northern Nebraska....

Lostmycage · Post by **Lostmycage** » Wed Apr 14, 2010 1:51 pm

It could just be that you're giving your Buddy a complex with all the new parts and the Jeep inline 6 sticker on the side. Performance anxiety or something of that like. Maybe try some flower stickers temporarily, or some of those wispy fairies and some butterflies. Maybe that's what they mean by high altitude mechanics. You've probably just got the wrong stickers on there. You need wispy floaty/flyey things on the side of it. Yeah... that's it...

Kaos wrote: I'm pretty sure that my flux capacitor failed at speed. I hit 88, the sparks started coming from the rear tire, I left a big streak of flame, but I didn't time travel. I just ended up in a corn field in northern Nebraska....

Yeah, if that had happened to me, I would have ended up in a different field of gold...

denverscoot50 · Post by **denverscoot50** » Wed Apr 14, 2010 2:09 pm

rajron · Post by **rajron** » Wed Apr 14, 2010 3:45 pm

Tuning is different at altitude – air is thinner, power is down, motor runs richer the higher you go. In my case, at 5,100 feet, with a stock motor, I was advised not to change the main jet when I added a Prima pipe – when the motor was modified a lot of the advice from sea level tuners did not apply directly for my applications.

ScooterTrash · Post by **ScooterTrash** » Thu Apr 15, 2010 12:00 am

rajron wrote:Tuning is different at altitude – air is thinner, power is down, motor runs richer the higher you go. In my case, at 5,100 feet, with a stock motor, I was advised not to change the main jet when I added a Prima pipe – when the motor was modified a lot of the advice from sea level tuners did not apply directly for my applications.

Well I'm at 4500 feet so I know about "high altitude tuning" which is the same process as any other elevation