Tri-Z Bogging down

[Groundworx]

I have an 85 Tri-Z 250. I just bought it a week ago and have only got to ride it about and hour due to clutch problems. I got that fixed, but I am noticing that in 3rd, 4th, and 5th gears it seems to bogg down when it gets to higher RPM. It is acting like like it is starving for gas. The shop that worked on the clutch cleaned out the carb and fuel pump. The only thing we can think of is the jetting may be wrong. It has a full DG pipe. I didn't put it on so I don't know if it was re-jetted or not. Does anyone have any suggestions? Also, does anyone have any idea on the size jets that should be in it?

Thanks
Scott

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[TRI-Zbrian]

what size main jet do u have in it???

[mbg75]

is the air box and cover still on it. usually it bogs down when the cover or entire airbox is removed and not properly jetted

[TRI-Zbrian]

yes very true about the air box i had a friend that did that on his 200x and thought it would give him a huge power increase and all it did was bog out and pop untill he put the air box back on it.

[mymint87]

sounds like it needs a new top end...wouldnt mess with the jets

[Groundworx]

I don't know what jets it has in it. I bought the bike last week with the pipe on it already. I was also told that the top end was just rebuilt. And the air box is complete and on the bike.

The shop that worked on the clutch didn't say anything about the top end and he looked over the bike. I am not sure if he rode it though, but the bike runs really good everywhere else. After the shop cleaned out the fuel pump it didn't seem to do it as bad. The mechanic that worked on it just thought it might be the jetting. I really don't know much about it. I will run it by him next time I go up there. Does anyone else know anything it might be?

[nitekrawler]

Sounds like jets to me. On my carb there is a BIG bolt at bottom, if your is the same, remove it. Then you will see the jet, remove that and read us the number. Thats the main jet. How does it idle :?: If bad, then you need to look at the slow jet too. Its easy to do. My son has been doing his and his sisters 250r Atc since he was 9yrs old :shock:
PS. Shut the fuel off first :-D

[Groundworx]

Right now it doesn't idle at all. I have tried adjusting the idler screw and it doesn't change anything. I think something is missing in there. I haven't really had time to mess with it, but I know something in there is gone.

[nitekrawler]

You need to rejet, samething happen to me. The idle screw only adjust so much, your to far past the mark.
http://www.rageperformance.com/carburetorparts.asp

[TRIZREE666]

The same thing happened to my 85 Tri-z. At first i thought it was the spark plug. Put a new one in and still had that problem. So i rode it back to my house and parked for the night. A few days later I went out to start it and it wouldn't. So after a few hours of trying to start it. I took the top end off and i actually broke a ring in half and it stratched the cylinder wall pretty bad. So right now i'm rebuilding the motor. Gotta get it bored out. That's why i'm rebuilding project Z from the frame up. Good luck finding out what the problem is.

[Tri-Z Pilot]

I had similar problems with my new tri-z, is it cold in your area? If it is, it could be that the colder air on your radiators is making it run rich, maybe your thermostat has been deleted? When it gets really cold around here,(PA), my tri-z would rev out strong in first, and second, but in third when you hit the top end power, it would start to die out, and fourth it got even worse, and so on. I blocked off my one radiator with a piece of cardboard, and just gave er hell, seems fine now.