Blaster No power After 3 mil stroker port and polish shaved head

[Blasterboy1998]

picked up a 2000 yamaha blaster off a buddy as projects im 14 and ive built over 20 blasters from the ground up (took me 2 hours to get this thing down to the frame and engine apart) and whatever problems ive had ive fixed with no problem
im stumped on this one problem. a guy i bought a blaster from gave me a +3 stroker crank witht the base plate so i decided to use it he also gave me a cylinder ported and polished with boost ports and a shaved head (.030 over wiseco top end) anyway i built the bike and while waiting for my 40$ fmf (guy had no reserve memerial day weekend no one bid but me ) i put it together with super stock reeds (while waiting on the power reeds i ordered) and a dg pipe with a 360 main bike started up 3rd kick after a fresh build broke it in and it reved great then i went to ride it and it was hesitating woulding go fast atall put a 290 in it and was able to drive it problem is it has no powerband hit like the most of them, it cant wheelie to save its life and the top speed sucks my banshee can smoke it in 1st gear! (remember all the mods this blaster has too) and it feels like 10hp? stock is 13 did a compression test with my crappy gauge and the needle was screwed up but it read 90 psi????? new piston and rings, stroker crank all new gaskets and bearings and seals) i dont get it please help me!!! right now it has a 330 in it its not smoking and it cant even get out of its own way and taking off the aurbox made no difference and changed the plug and pilot made no difference also the A/F screw made a faster idle but no power difference

 

[Blasterboy1998]

sorry it was a long post wanted you guys to know where im coming from

 

[jus_me]

Did you leak test? Have you checked the exhaust for a critter nest? 90 psi sounds quite low. Leak test and report back. How does plug look?

 

[Jeric J]

im 14 and ive built over 20 blasters from the ground up

Wow youre 14 years old and built over 20 Blasters? Thats awesome man you sound like you know what youre talking about. I'm 13 and still learning my first one LOL! Hey good luck hope you fix the problem!

 

[89blaster89]

actually stock horsepower is 17 but whatever, did you leak test the motor, I guarantee you have at least one airleak even if that's not the problem, is the tors still hooked up? is the parking break on?

 

[Larry's Shee]

Other than tests mentioned make sure carb is to spec, float level, etc.

A faulty comp gage will give misleading results. 8-|

What was the squish clearance on the shaved head? CCs ?

Did you re-torque head and cly nuts after heat cycles?

This is a fresh bore, new piston&rings? Is piston clearance correct? Rings right side up? Gapped? Piston facing correct way? Have seen more than one put in backwards.

One other possibility is that with a ported cyl + 3mil + spacerplate the exhaust "timing" may be in the "drag" only zone and the pipe won't allow it to reach high enough RPM to "get on the pipe". Only a degree wheel will confirm this.

When tuning it is best to change one thing at a time, and make small changes.

 

[Blaaster]

Firstly with your vast experience behind you I fear you are expecting way too much from a DG pipe, with the combination of port and polish and a +3 crank.

Secondly a #360 main jet is absolutely over kill for a DG, a DG should run quite happily on a #260+.

If there is a #330 in there now and not smoking I would be performing the leak test again, that is if you have ever done one.

Tweaking the air screw should not make any difference in power, the air screw is primarily for setting the idle.

Have you tried plug chopping the needle, someone may have fitted a crappy needle from a jet kit.

 

[01blastingwv]

I'd leak test first. Might want to adjust your timing too. Like dude above said 360 is a bit too much. Id throw a 300 in and plug chop (after leak down)

 

[best]

There is a whole lot wrong with this post, listen carefully to these principles:

1) "Shotgunning" a whole bunch of changes is a sure recipe for trouble.
Want to try some mods? Start with a "known good" engine and add mods one at a time.

2) Unreliable tools. A broken compression gauge tells you nothing.
If it is 90psi you have a problem that will need fixing before proceeding.
If you cannot trust the reading on the gauge, throw it away. It is completely useless.

3) Guessing at jetting cannot be done. Learn to read plugs.
The plug chop method recommended here is the simplest and most reliable,
but first get a reliable compression gauge and a leak tester, because...

4) do a leak test. 10 minutes spent leak testing save HOURS, even DAYS of mystery.

5) Shaved head. The stock chamber shape sucks. Shaving the stock head is trouble.
Get a properly rechambered head and check it for proper squish, ESPECIALLY with a stroker.

It may be another problem, but these 5 principles are sure rules to make life simpler.
Follow them and you will learn and solve problems quicker.

Steve