Yamaha Genuine Racing Cam

[charge]

Joel, if I have a company trip to Bangalore, I'll definitely pay you a visit to look at your engine modding skills *cheers*

Inspire, mine can't even start to pull at 120kph on 4th gear (m'sia meter). But right now, first to third gear acceleration is freaking great.

1st : 55kph (prev. 40kph)
2nd: 85kph (prev. 70kph)
3rd: 120kph (prev. 110kph)
4th: 135kph (prev. 150kph+)

4th gear somehow missed the powerband when I upshift from 3rd gear. I am using sprocket 15-42, which suppose to have more accel and lower top speed, but the first 3 gears are pulling a lot further now.

Our stock carb takes in too much air and not enough fuel. I've tried to polish the intake port of the carb slightly, but problem still exist. Lifted the jet needle up by 1 'tick' still does not solved my problem.

Right now, my Mikuni 28mm is using #230 mainjet. It gives me freaking good power, but the mid range pull is still a bit sluggish. low end is good if I am using idle jets, anything after 80kph on 4th gear starts to get sluggish..

inspire, where do you get this lo-cam? How is the lobe separation angle and duration compared to stock cam?

 

[lc-motospeed]

our bike's fourth gear has always been liddet... loss f power when shifting from 3rd to 4th gear... solution, change whole gearing or juz change the 4th gear to 21 turns... reason for the loss of power on 4th is the factory made the gear ration for fuel saving reasons, not power =)

 

[charge]

Yea, the gearing is pretty sux to match racing camshaft. Stock camshaft is still a good match. I think 1st and 2nd gear still good, 3rd and 4th can make them closer a bit.

I've just finished a 1 hour hill run. Damn, discovered something funny.

At about 3000rpm, I can't suddenly throttle up to 1/4, else the engine feels like choking.

At about 4000rpm, I can go up to 1/4 throttle, but a sudden 1/2 throttle makes the engine feels like choking.

At about 5000rpm, I can go up to 1/2 throttle ady, but a sudden 3/4 throttle again... makes the engine choking.

Damn, it is a very tough ride on long uphill and drag. I can only slowly open the throttle passed through 5000rpm. Can't use the full potential all time. What should we do to fix this problem?

 

[AZ135]

You need to read your spark plug, sounds like you are running too lean.

 

[charge]

You need to read your spark plug, sounds like you are running too lean.

Thanks for your advice
The plug color is nice.


I have a question here. In SOHC system,
retard timing = shifting powerband to upper RPM?
advance timing = shifting powerband to lower RPM?

If the cam timing is retarded, do we need to advance the ignition timing?

 

[inspire]

Joel, if I have a company trip to Bangalore, I'll definitely pay you a visit to look at your engine modding skills *cheers*

Inspire, mine can't even start to pull at 120kph on 4th gear (m'sia meter). But right now, first to third gear acceleration is freaking great.

1st : 55kph (prev. 40kph)
2nd: 85kph (prev. 70kph)
3rd: 120kph (prev. 110kph)
4th: 135kph (prev. 150kph+)

4th gear somehow missed the powerband when I upshift from 3rd gear. I am using sprocket 15-42, which suppose to have more accel and lower top speed, but the first 3 gears are pulling a lot further now.

Our stock carb takes in too much air and not enough fuel. I've tried to polish the intake port of the carb slightly, but problem still exist. Lifted the jet needle up by 1 'tick' still does not solved my problem.

Right now, my Mikuni 28mm is using #230 mainjet. It gives me freaking good power, but the mid range pull is still a bit sluggish. low end is good if I am using idle jets, anything after 80kph on 4th gear starts to get sluggish..

inspire, where do you get this lo-cam? How is the lobe separation angle and duration compared to stock cam?

charge>
This lo-cam is popular, brand is Ride It. I'd need a cam degreeing chart to get the angle & duration (which I don't). However, the apex of the cam is 1mm higher than stock cam.

I've done what Haen suggest, i.e 0.2 in, 0.15 out. Whoa, what a rickety sound it made. BUT, juz a little change made a whole lot of improvement.

150kmh (m'sian meter) is point of change to 4th gear, & still kicking all the way to out of meter- with the kangaroo pipe lah.
I usually can't run till CDI cut-off for the first 2 gears, but it did. (1st model cut-off 8k rpm)

& mind you, this is still with stock but polished carbs & jetting.

 

[traxxas-modifier]

does anyone here know the exact count of the cam wheel? I've not counted but only measured the retard and advance on an angle finder.

are u looking for the number of teeth?

 

[traxxas-modifier]

Joel, if I have a company trip to Bangalore, I'll definitely pay you a visit to look at your engine modding skills *cheers*

Inspire, mine can't even start to pull at 120kph on 4th gear (m'sia meter). But right now, first to third gear acceleration is freaking great.

1st : 55kph (prev. 40kph)
2nd: 85kph (prev. 70kph)
3rd: 120kph (prev. 110kph)
4th: 135kph (prev. 150kph+)

4th gear somehow missed the powerband when I upshift from 3rd gear. I am using sprocket 15-42, which suppose to have more accel and lower top speed, but the first 3 gears are pulling a lot further now.

Our stock carb takes in too much air and not enough fuel. I've tried to polish the intake port of the carb slightly, but problem still exist. Lifted the jet needle up by 1 'tick' still does not solved my problem.

Right now, my Mikuni 28mm is using #230 mainjet. It gives me freaking good power, but the mid range pull is still a bit sluggish. low end is good if I am using idle jets, anything after 80kph on 4th gear starts to get sluggish..

inspire, where do you get this lo-cam? How is the lobe separation angle and duration compared to stock cam?

charge>
This lo-cam is popular, brand is Ride It. I'd need a cam degreeing chart to get the angle & duration (which I don't). However, the apex of the cam is 1mm higher than stock cam.

I've done what Haen suggest, i.e 0.2 in, 0.15 out. Whoa, what a rickety sound it made. BUT, juz a little change made a whole lot of improvement.

150kmh (m'sian meter) is point of change to 4th gear, & still kicking all the way to out of meter- with the kangaroo pipe lah.
I usually can't run till CDI cut-off for the first 2 gears, but it did. (1st model cut-off 8k rpm)

& mind you, this is still with stock but polished carbs & jetting.

bro can you confirm the valve clearance 0.20mm in and 0.15mm out ?
isnt it the otherway?

its time for u upgrade cdi

 

[nadlina7]

that's true bro...time for upgrade cdi's...hehe

 

[charge]

charge>
This lo-cam is popular, brand is Ride It. I'd need a cam degreeing chart to get the angle & duration (which I don't). However, the apex of the cam is 1mm higher than stock cam.

I've done what Haen suggest, i.e 0.2 in, 0.15 out. Whoa, what a rickety sound it made. BUT, juz a little change made a whole lot of improvement.

150kmh (m'sian meter) is point of change to 4th gear, & still kicking all the way to out of meter- with the kangaroo pipe lah.
I usually can't run till CDI cut-off for the first 2 gears, but it did. (1st model cut-off 8k rpm)

& mind you, this is still with stock but polished carbs & jetting.

OMG, this is mind blowing!!

Where can we can Ride-It lo-cam in Malaysia? What is the price?
Wow, I'll insist the mechanic to do 0.20mm in and 0.15mm out this weekend regardless what they said, hohoho.

Hey inspire, what sprocket combo do u use?

anyway, thanks a bunch!

 

[lc-motospeed]

@charge
Ride-it cam has changed in company but still carries n produces the same cam... i can't really remember the brand but its something like CMS... its available in most modification workshops bro

 

[inspire]

traxxas>.. yep, as haen tried 20IN, 15OUT . CDI?.. that'll be my last upgrade. How much you're charging for the rextor adjustable?

charge>.. I'm using 15-36.
..and oh yes, this is still with a large GIVI box at the back & I'm 75kg's
...and charge, I've change it back to stock cams & stock mufflers as this is my daily ride. both cams and kangaroo pipe is toooo loud.

 

[charge]

Mister LC, thanks for your info

Mister inspire, I am 75kg and with a Givi Box as well, lol. I hate my current sound level too, everytime see white car oso scared is police car, hahaha. So where is your RideIt camshaft sitting now? Wanna sell 2nd hand to me?

 

[haen]

yup, i confirm that 0.20 IN and 0.15 OUT, for the malay cam and mine.. found out about that after lots of hassles, troubles and burned palm.. lol.. sad but true.. whats annoying is the need to replace the water coolant every time we want to change valve clearance setting... go.. buy Rextor Adjustable from Traxx...

 

[inspire]

um, thanks to haen for burning his palm just to get the settings correct. This'll will be a good reference when needed for racing. But not for daily use cuz the tic-tac sound will make you feel crazy. (or your wife nagging, whichever comes first)

charge>I've sold & installed it to a friend of mine who's crazy bout top-speed & he's got a red rextor installed to fully utillize till 14k rpm.
As mentioned, both of us are heading to penang under kom135lc. Hope to meet you.

 

[joel]

whats red rextor ?

 

[joel]

Joel, if I have a company trip to Bangalore, I'll definitely pay you a visit to look at your engine modding skills *cheers*

Inspire, mine can't even start to pull at 120kph on 4th gear (m'sia meter). But right now, first to third gear acceleration is freaking great.

anything after 80kph on 4th gear starts to get sluggish..

Sure man, do meet up.

The reason why u loosing on higher up acceleration is coz cams with higher duration will need really high compression. No wonder this. U need to really bump the compression to get the higher end power. Torque levels will also improve crazily.
use a high dome piston if possible. Something from TDR, 57mm.

 

[charge]

yo inspire,
do you have access to any lo-cam at your place? Mine to poslaju to me?
sure, let's meet up on 29th Nov. We can arrange the time later on, but I can go to Teluk Bahang to meet you up

haen, that piece of info is super valuable! saves me some coolant and medical fee. Thanks!

Joel, I want to increase the compression ratio too, perhaps using metal gasket. I am still using stock piston, cannot find high dome stock size piston at my place yet

 

[joel]

^ If u want to increase compression on a stock engine, just remove the cylinder base gasket and apply some threebond. U'll save 0.5mm on the overall cylinder height. U'll get a bump of 20psi nearly.

If u have already done this and still wnat to bump compression further, u can remove metal off the head or the bore and then deepen the valve pockets on the piston to prevent valve bang.
On my engine, I'm running 12.5:1 compression ratio. Stock is 10.4.

 

[traxxas-modifier]

yup, i confirm that 0.20 IN and 0.15 OUT, for the malay cam and mine.. found out about that after lots of hassles, troubles and burned palm.. lol.. sad but true.. whats annoying is the need to replace the water coolant every time we want to change valve clearance setting... go.. buy Rextor Adjustable from Traxx...

hey bro
wont this makes the engine sounds ticking noise?
ive tried mine but it makes tick tick tick noise if using
that valve clearance.
now i use the stock valve clearance and noise is removed.

also the the EX is more bigger than IN?
stock
IN 0.10
EX 0.16

while in your mods EX is bigger than IN.
IN 0.20
EX 0.15

is that fine?