Yamaha Blaster Hard to Kick?

[teamcrackitrace]

Hey all-
I am having a problem with my 04 Blaster. It has a fresh top end (running on the stock cylinder with a wiseco piston) but for some reason it is hard to start. When its warm, it only takes a couple kicks to start it. However, when it is cold, it takes between 10-20 kicks with feathering the throttle before she fires up. I have no idea what it could be. Could it be that it doesn['t have high enough compression? I thought most two strokes don't run unless they have over 100 psi compression. It runs beautiful once it starts, but for some reason it takes forever to kick it over. This happened both before and after I blew up the original vito's 240 on her. Any help is appreciated!

 

[super noober]

Hey all-
I am having a problem with my 04 Blaster. It has a fresh top end (running on the stock cylinder with a wiseco piston) but for some reason it is hard to start. When its warm, it only takes a couple kicks to start it. However, when it is cold, it takes between 10-20 kicks with feathering the throttle before she fires up. I have no idea what it could be. Could it be that it doesn['t have high enough compression? I thought most two strokes don't run unless they have over 100 psi compression. It runs beautiful once it starts, but for some reason it takes forever to kick it over. This happened both before and after I blew up the original vito's 240 on her. Any help is appreciated!

sounds like low compression to me

 

[sicivicdude]

Run a compression test and report back the results.

Remember kick with the throttle wide open until the needle stops moving. Repeat at least three times to get an accurate number.

 

[teamcrackitrace]

Alright. I will try that the next opportunity I get. It just doesn't seem like it should have such low compression since its a fresh rebuild. I just don't get it

 

[sicivicdude]

You say it has a wiseco piston on the stock bore, was this measured properly and determined to be a good, usable stock bore?

If the hole is .006" larger than the piston, it's going to be making a lot of noise, have low compression, and risk a broken piston.

 

[teamcrackitrace]

It has a wiseco piston on the stock bore. I don't think the bore was measured to be a good usable stock bore. We honed the cylinder to clean it up and get good crosshatching and then put it in using the stock ring and piston sizes.

 

[blasterdemon7]

I would check for a clogged choke cercuit. Will it idle just after you start it cold?

 

[teamcrackitrace]

What is a choke circuit? It will idle with the choke out after i start it cold, if the choke pops in at all it will die though. Sometimes you have to feather the throttle to keep it going.

 

[sicivicdude]

You should only have to have the choke knob out about 1 minute, until the engine warms up. If you need it out longer, the carburetor is probably clogged up.

You need some good non-foaming carburetor cleaner. Disassemble the carburetor and clean it thoroughly.

 

[teamcrackitrace]

Thats about how long it takes for it to warm up and then you can put the choke in. Plus the carb was all gone through when I did the fresh top end. The carb on it now is the stock 28mm with the TORS up top

 

[Larry's Shee]

If it's cold where you are I would leave choke out until it doesn't need it. Plus with a forged piston you have to let them warm up real good before you start hammering on it or you risk cold seizing it. I would completly dissasemble carb and clean it paying attention to choke circut which involves the tube in bowl and passage to choke knob and into throat.

 

[Larry's Shee]

Stock is only 26mm

 

[brandoz28]

What was the cause of death on the previous cylinder?? Has it passed a leak test after you reassembled it? Were there any gaps in the reeds?

 

[teamcrackitrace]

I forgot stock is 26mm... I have another pcw 30mm carb from factory 7 though. The cause of death on the previous cylinder was the intake boot. Somebody had filed down the tab on the intake boot so that the vforce3 reeds would mount flush. Of course as im sure you guys know, this will cause an intake leak which will lean it out and blow it up. Plus the reed petals were chewed up. So i put the stock cylinder on it (which had been cleaned in phosphoric acid) honed it and put the stock cylinder back on, as i didnt realize i could afford to rebuild the vito's.

 

[teamcrackitrace]

The reed petals are brand new from VForce, and I have never leakdown tested it. You can just squirt them with ether when they are running and see if the rpms jump?

 

[slickerthanyou]

The reed petals are brand new from VForce, and I have never leakdown tested it. You can just squirt them with ether when they are running and see if the rpms jump?

You can, but that isn't going to do any good if your crank seals are leaking!

If you didn't measure the cylinder and just assumed, it may just be too much clearance, a compression test will help to diagnose this!

There really is no substitution for doing a proper air leak test!

 

[teamcrackitrace]

And im going to guess there is a sticky somewhere about doing a proper leakdown test... Off to search

 

[slickerthanyou]

 

[dbowhntr]

Good strong spark?

 

[boomadge]

To help rule out some things,when you go to start it when its cold,pull the plug,put a couple ounces of gas directly into the sparkplug hole,put the sparkplug back in,pull the choke and kick it over. If it starts up withen a first few kicks this tells you its either low on compression or pilot circuit needs cleaning or float height is incorrect.