won't rev

RatBlaster

RatBlaster

Member
Jul 19, 2011
30
11
50
to start with this isn't my first build I have done several blasters they all run great. I have recently done a total rebuild on my brothers due to a gear blowing through the case. I have installed a new bottom end along with the top. The issue is it will idle but as soon as i hit the gas you can hear the rpm remains the same but it sucks louder through the intake. i have new reeds and have cleaned the carb good and did a complete rebuild. It has great compression and passed the leak down test before it was started. it cranks on the first kit but only idles. also did the block off kit and removed tors. running a 290 jet with air screw at 1.5 turns. it's set up identical completely to my other blaster which runs great. im thinking either i have developed a leak on the crank seal or the carb float isn't allowing enough gas into the bowl. any ideas
 
yeah I would start with the floats. or maybe an obstruction in the carb somewhere. it happens even after a good cleaning sometimes
 
If it has passed the leak down test then a leaking seal should not be the problem, unless it has fallen out.

If you crack open the drain screw at the bottom of the float bowl a constant stream of gas should flow.

If the flow is intermittant you could have a blockage in or above the needle and seat.

Or the gas tank is empty, it has happened.:D:D:D
 
One other thing came to mind, piston in backwards?

If not, Swap your carb on, see if it does the same thing.
 
i have fuel flow like i said it will idle and I also have clear lines so I can see it. I may throw my carb on it just to see if it's a carb problem. I know the the piston is in the right way so I will conduct these few test thanks
 
slickerthanyou said:
One other thing came to mind, piston in backwards?

If not, Swap your carb on, see if it does the same thing.
Click to expand...

Beat me to it Slick. I vote for piston backwards too.

Hey guys, you know the difference between a leak test and a leak down test?
A leak test you pressurize the crankcase to look for case leaks.
A leak down test is a timed test of the piston ring seal. Piston on TDC and high pressure in plug hole.

Usually you use high pressure on a leakdown test, like 100psi into the sparkplug hole and then count down how long it takes to drop to a second lower value after you shut the blocking valve.
A very valuable diagnostic tool on 4 strokes, done with the piston at the top (crank blocked!) and bottom (cannot do with 2 stroke) and listening for leaks into the water jacket (headgasket) or past the intake or exhaust valves. Even better than a compression test, it tells what parts are worn and where the compression is leaking and how much.


Steve
 
Last edited:
There is not an ebrake on the bike plus if there was it would not affect the rev in neutral it would bog it down while trying to go. also the piston is in correctly the ports in the skirt of the piston are on the intake side of the engine. I am banking on an issue with fuel delivery i'm thinking the float needs adjustment. so I will not know until the weekend when I get back out to work on it. Thanks for all the input guys it's greatly appreciated I love this forum.
 
I have attached a pic of the engine without the jug with the piston installed
 

Attachments

  • BLASTER ENGINE.jpg
    BLASTER ENGINE.jpg
    33.1 KB · Views: 166
ok guys still a no go. I checked my seals again and I checked the carb. I took the carb off my running blaster and put it on this one still same results. I also took a spray bottle and sprayed fuel trough the carb it didn't increase rpm. it seems the engine has the will to go. It seems like the engine isn't firing at the right time. it has a ricks adjustable stator could this possibly be the problem or could I have a faulty coil. all the electronics are brand new it's not the cdi because I put three different ones I had on it to end with the same result. I'm thinking either stator or coil maybe the issue what do you all think.
 
RatBlaster said:
ok guys still a no go. I checked my seals again and I checked the carb. I took the carb off my running blaster and put it on this one still same results. I also took a spray bottle and sprayed fuel trough the carb it didn't increase rpm. it seems the engine has the will to go. It seems like the engine isn't firing at the right time. it has a ricks adjustable stator could this possibly be the problem or could I have a faulty coil. all the electronics are brand new it's not the cdi because I put three different ones I had on it to end with the same result. I'm thinking either stator or coil maybe the issue what do you all think.
Click to expand...

My suggestion is start at stock timing if you haven't already, yes the stator could be bad, you can do the source coil/pick up coil checks or swap a known good one in there. I have had the coil ohm good but be bad, only way I found that was swapping a know good stator in. It sound like maybe the pick-up coil could be bad-

I have stickies in the engine section for how to check all those-
 
reeds are brand new boysen dual stage in stock cage. everything for the motor is new i'm thinking it's either the stator or the coil so what i will do is take the stocker off my running blaster and try it on this one. I will post the results after I try it. Thanks again guys eventually we will get this thing going
 
You must log in or register to reply here.

Similar threads

Carter Prater
Compression
Replies
0
Views
96
Engine
Carter Prater
Carter Prater
Nathon
2005 blaster boggs and smokes
Replies
0
Views
105
Engine
Nathon
Nathon
Mts8888
New here. 2004 blaster has been sitting
Replies
1
Views
64
Engine
RIDE-RED350r
RIDE-RED350r
Bighoss860
Won’t idle
Replies
9
Views
214
Carburetor
RIDE-RED350r
RIDE-RED350r
T
Piston Skirt Explosion
Replies
1
Views
302
Engine
RIDE-RED350r
RIDE-RED350r
Top Bottom
Back