rough engine 1/4 throttle

[billglass]

I have a extremely rough engine at about a 1/4 throttle. Is that normal for a blaster. It doesn't smooth out until mid throttle.. Just wondering? I tried checking close to make sure my carbs are both closing at same time. a did adjust a tiny bit.. Is that the only thing to check for that.. Thanks

 

[Mike W]

What are your mods?

 

[motoman3000]

Jets ? Air/ fuel screws jiggy ?

 

[billglass]

Mods are taper bored 38 by group k, r&d arrestors, ADA head 185 compression, dual cooling, rrp pipe. Lightened flywheel by group k MSD ignition enhancer, ngk coil and wires. Fuel air separator by group k. That's it for engine mods. Oh carbon fiber reeds by Jetworks that go on boyensen RAD cages. Jetting 150hsj 90lsj 11/2 turn hss and 1 lss pop off 32

 

[jetx]

How dos it run other than the rough spot? That's some pretty rich jetting for 38's but could be what the pipe needs

 

[billglass]

I had to go that rich since the taper bore, but only runs rough on low end. Once on plane, runs like a beast. That is very smooth. And it does take off from that throttle position like a beast. Maybe I'll take a video of it.

 

[Darcysine]

Mines the same as well , I've been wondering about this , engine runs rough going slow but as soon as I go past 1/4 throttle she takes off super smooth . She idles great as well

 

[billglass]

Yep, Is your dual carbs or single carb?

 

[Darcysine]

Single

 

[billglass]

hmmm, That blows my theory that something could be off between the carbs..

 

[Darcysine]

I think it is just the way she runs with the higher compression I have and exhaust , i played with my pop off and re did my whole carb .

 

[billglass]

That's what I am thinking. No sense trying to try to tune it out.. I guess it's like a old muscle car. sounds like a grumbling POS until you step on it.. LOL

 

[Darcysine]

Plugs are nice and tan too

 

[billglass]

Nice. I have to finish tuning the high speed screw.. I have that a little rich right now cause I just changed the pop-off cause it seems to be loading up. Then I'll go back to high speed tuning.

 

[tuneman]

Check your fuel vent lines and make certain of no leaks. Also, make certain the check valve is working. A leak will starve the carb at lower speeds.

 

[billglass]

I check that too..Thanks.. I am really close.

 

[Mike W]

Mine runs the same way. Right off idle it runs like $hit but idles great and is like a light switch when you nail it. I run an ADA head with 180psi and a B pipe so it's a very typical setup. I'm a riding group of one so I have nothing to compare it to so I just have to assume me that's how they run with these mods.

 

[billglass]

Nice to have confirmation on this. I am a riding group of 3. me, myself and I. What's great about that is that we all have the same days off and same interests etc..

 

[Mike W]

Nice to have confirmation on this. I am a riding group of 3. me, myself and I. What's great about that is that we all have the same days off and same interests etc..

Yea, I have every other Monday off which is about the only time I can ride. Or after work during the week so it gets very boring.

 

[billglass]

Yeah, I like riding during the week too. tues, or wednesday