Snowmobile Fanatics banner

1 - 11 of 11 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
Well i have an old sled and i'm turbo charging it.I have the turbo installed but the tilliston can't pump gas when it's under boost.I think a regular carb will work but i'm not sure if it will.Any help would be great
 

·
Registered
Joined
·
948 Posts
Welcome aboard Harley Turbo! What kind of sled? I have two old Skidoos that had Tillotson carbs. We switched one of them to a mikuni for ease of jetting. Still fighting with it though. The Tillotson had the fuel pump built in and no adjustable jets so it made it hard to set up. I suspect that the Tillotson fuel pump may not have enough flow to feed the intake with a turbo. If you go to mikuni you can add a hi-flow fuel pump and that might make a difference.

My biggest problem now with that old 340 is it generates so much heat I think is vapour locking and is extremely hard to start when it gets that hot. Also wants to die unless you keep it wide open. Not the best option for a beginner. LOL

-------------------------------------------

Lest we forget...... 09/11/01

Edited by - bman on October 17 2001 6:28:56 PM
 

·
Registered
Joined
·
7 Posts
Discussion Starter #3
Thanks bman as the name indicates i have a 73 Harley Davidson I had to put on a yamaha 440 cuz the original engine was already gone and some crappy 440 was on it and it blew.I just need more power and thought why not a turbo.It's boosting 5 psi so far and will probably go up when the thing runs right.
 

·
Registered
Joined
·
948 Posts
Very interesting. Where did you get the turbo and how much did it cost? Just curious.

-------------------------------------------

Lest we forget...... 09/11/01
 

·
Registered
Joined
·
7 Posts
Discussion Starter #5
I got it from a four cylinder turbo car and it seems to do the job well.What size carb did you use and the jetting?That is the only way i can go the tillotson needs the back and forth movement to make it run right.With the boost it just makes a one way movement so the bike carb it the way to go.The turbo was 50 bucks i got two for that price and i used them both to get one good one.I have poics of it on the hybridz site(i have a turbo 76 280z) I'll post the address http://www.hybridz.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=16&t=000248 check it out and let me know what you think
 

·
Registered
Joined
·
948 Posts
Got a free Mikuni 44mm roundslide from a friend. I seriously have no clue what the jets are in it at this point. We made so many changes last year trying to get it to run consistently. Like I said, work in progress. I do like the toggle choke though.


I suspect I'm under jetted for that size of carb on the little 340. anyone else have any ideas on that? Look at the begging of the thread for more symptoms.

-------------------------------------------

Lest we forget...... 09/11/01
 

·
Registered
Joined
·
7 Posts
Discussion Starter #7
Did it fit right on or did you have to make an adapter?What size bike would that normally come off of?I think i can use the tilloston carb maybe i'll find out soon.I'm going to try putting a fuel pump on it.If it doesn't work i'm not out anything i still need a fuel pump.
 

·
Registered
Joined
·
948 Posts
Sorry Harley, can't help you. It was just a two stroke carb that was sitting at a buddy's place. He didn't know where it came from.

Not sure if putting an inline fuel pump will help you too much. The tillotson carb does have a fuel pump/metering system on the very bottom of it. Have you opened it up to check on the diaphram? Perhaps it just needs a rebuild kit? I think the inline would just pump as far as that then have no where to go.

-------------------------------------------

Lest we forget...... 09/11/01
 

·
Registered
Joined
·
7 Posts
Discussion Starter #9
Well i rebuilt the carb last year the whole thing and i have the tillotson carb on my racing go kart 5hp briggs and i have a fuel pump on that and it works.I think both pumps are working though.I'll figure it out one way or another.Did you have to make a bracket to make your carb fit or was it a direct bolt on?I do apprecieate the help so far it's putting me in the right direction.
 

·
Registered
Joined
·
948 Posts
Oops, forgot that part. The aluminum mounting flange had to be drilled out to allow the mounting posts to fit and I ordered an aftermarket carb intake boot. I also had 'issues' with the throttle cable travel so I replaced the cable. It wasn't getting full throw on the bigger Mikuni.

-------------------------------------------

Lest we forget...... 09/11/01
 

·
Registered
Joined
·
589 Posts
Don't know if this will help or not. I have installed dial-a-jets in my 650. I am not familar with the tilson or the turbo, but there is a kit for dial-a-jet that will allow you to inject additional fuel using the vaccum of the engine as it pulls fuel through the carb. The stand alone dial-a-jet pulls fuel from the float bowl, but the kit allows you to have it pull from another source. They claim that you can pull alcohol in to help cool the big engines, or additional fuel not found in the float bowls. Mabye this will help.
 
1 - 11 of 11 Posts
Top