Suzuki Dragbike

[Herman T]

Would I need a thermostat for the dragbike? If so, I don't have one. I see they are available from Suzuki but I'm thinking (hoping) that I don't have to have one. I also need the gasket and see they are available also.

[water cooled]

Gary,

You dont need a thermostat. The purpose of it is to raise the engine temps relatively quickly by routing the coolant through the Bypass line instead of through the radiator. As the coolant comes up to temp, the thermostat opens to allow the coolant to flow through the radiator.

For your application, you want the motor and coolant to be as cool as possible since a hot motor will transfer heat its heat into the Air/Fuel charge being pushed through the transfers and into the combustion chamber making the air less dense. The GT was designed with comparatively close tolerances between the bore and piston so you wont be giving up a lot of efficiency by not warming up the motor in the staging lanes.

Its more important to keep the motor cool which keeps the air going through it more dense. I removed my Bypass line and thermostat.

[Herman T]

Finally moving forward after over a year of doing nothing on the bike. I've probably gotten more done in the last 3 weeks then the entire time I had the bike before. Things that should take a few minutes to get done have ended up taking a few days, such as bolting down the thermostat cover. The custom cover didn't line up with the holes in the head for one. Then the radiator hoses were leaking. Kevin (watercooled) helped me with that by sending the hoses from his bike that he doesn't use anymore. I never thought I would be impressed by radiator hoses but these hoses he sent me are really top shelf. The upper radiator hose I had already purchased from Suzuki because one didn't come with the bike so I already had that one on. Getting the head bolted down was a pain due to the custom frame with very little clearance above the head making it very difficult to get the bolts in some of the cylinder head holes. Here is what I have at this point....




I got the head bolted down and put some distilled water in the radiator and right away it started leaking really bad. That is when I discovered the leak in the lower hose. I replaced that hose along with the bypass hose and the filler neck hose (which also had a cut in the middle of the hose)

I got the bike cleaned up really good without replacing any parts.





This is what I started out with...





The problems that I am dealing with now are that the carb slides don't go down all the way. I can only get the slides down to about 1/4 throttle. I have mikuni's on the bike and may have a throttle cable that is for the original carbs. Not sure if that is the answer to that problem.




The other problem that I have now is that after replacing the hoses and filling up the radiator with distilled water, there is a drip about every 20 seconds or so. I found a leak at the cylinder head to the left of the thermostat cover when looking from the back. I think that's the area that has the bolt that needs the copper washer. I haven't addressed this issue yet. That is where I left off on Sunday when I quit working on the bike.





So, that is where I am at to date. I'm hoping to make the first attempt at starting the bike in the next couple of weeks and should be able to unless I run into some other problems or can't fix the problems that I currently have. I'm hoping to get the bike to the race at Martin in a couple of weeks but it won't be ready to race. Just hoping I have it running by then or that the experts can look it over and accomplish that. Now my van is doing it annual ritual that seems to happen every year around this time and that is broke down. I hope this doesn't stop me from making it to Martin.

[water cooled]

Gary, check the throttle cable at the junction. one of the cables is not seated all the way. It might be the cause of the carb slides getting hung up.

[Herman T]

Gary, check the throttle cable at the junction. one of the cables is not seated all the way. It might be the cause of the carb slides getting hung up.

I think I spotted that after looking at the picture. That cable is the one that goes to the oil pump. I think I fixed it but I will look again today if I get to where the bike is. My van is broke down again but I'm going to take out the H2 in a few minutes and will probably go work on the bike.

[Herman T]

I'm wondering what size battery I should get for my bike. I'm still using the electric starter. The way the bike is set up now, I couldn't use a kick starter even if I wanted to because I wouldn't be able to kick it through with the brake pedal where it is. I see that stock the buffalo comes with a 14 AH battery. Not sure about the CCA. Do I need one around 14 amp/h to handle the starter? I hooked up my H2 battery to the bike just to see if the starter worked and it did but that was without the plugs in it. When I put the plugs in, the starter barely turned over the motor but the battery might have been a little low on charge. The H2 battery is 4 AH. I only have around a 5 1/4 x 3 1/4 battery box so finding a battery may be a problem if I have to get a higher AH battery. The alternator also won't be hooked up.

[water cooled]

Gary,

Im not sure if anyone will give you the answer youre looking for. Its not as though the electric start will draw the same amount of current on a well-maintained stock bike vs a race motor.

For your race bike, you will only need enough current to start the bike a couple times before you go to the start line.

An AGM seems to hold up well offering a much flatter curve as the battery discharges. The efficiency of an AGM as it discharges is also better that lead-acid. There are other batteries more compact and lighter such as Li-Po but I would start with AGM for now.

The basic idea on sizing is this: A 14 Ah battery can support a 14 amp draw for 60 minutes. But it can also support much higher amp draw for a shorter period. Example, a battery will also have a CCA figure which is more specific to starting a motor. A 12V 5 amp AGM battery will have a CCW value around 70 or 75 amps for short bursts like when you start the motor.

If your motor starts right away, you draw current for 3 seconds. If it takes repeated tries and doesnt start, you will run the battery down.

In your particular case, since you have the Alternator still installed on the RH crank, I would wire it up like stock to recharge a small AGM. The other option would be to remove the Alternator (Stator and Rotor) and run a brand new 5 Ah battery. I would also look into getting a decent charger that will let you charge AGM batteries at a 2 amp rate.

[tz375]

Duid you manage to find a set of low tops and did that fix the carb problem or did you have to have the cables modified?

[Herman T]

Haven't done either yet. I do have a set of low tops. I'm thinking if I put the low tops on, the slide won't go high enough. Probably the best thing to do would be modify the cable like Dave mentioned on the S/E forum. I do plan on trying the low top on one of the carbs to see if it works. I can at least use the low tops for the initial start so the slide will be low enough. It was also suggested to me to that I could disconnect the cable at the throttle when I start the bike which should lower the slide to an acceptable level for that initial start.

[tz375]

Gary. You are correct that long slides with high tops are different than low tops and shorter slides. Longer slides are designed to not open fully - a cheap speed/power limit device for some markets. Long slides like yours are 53mm tall. Short slides to go with low tops are either 41 or 46mm tall. I have seen both slide heights.

Pull one of your carb tops off and raise the slide until it completely clears the bore, then measure/mark the bit sticking sticking out the top of the carb and cut that much off and clean the cut up with a smooth file.

Just as a point of reference, mine are 41.1mm tall and my carbs are low tops.

[Herman T]

Thanks Richard, Very much appreciated. I still haven't gotten the slides taken care of but I did start the bike by disconnecting the cable at the slides and then adjusting the carbs so they all opened at the same time and then I raised the slides a little more to give me more idle. I started the bike today for the first time since I have had it and that has been over 2 years. Sounds great!! No throttle to rev up the motor but I am still very pleased. Good luck to you and Hatchet at the Super Eliminator race this weekend!!

http://www.youtube.com/watch?v=xI1nvuoelFA" onclick="window.open(this.href);return false;

[tz375]

Congratulations. That looks and sounds great now.

[Herman T]

Where is the water drain on these bikes? Kevin says that I can't have anti freeze in the motor due to track regulations so I would like to get the water out before winter. I found it in the shop manual online but I can't tell which bolt the diagram is referring to. Could I just remove the lower part of the bottom hose and get enough of the water out?

[tz375]

Good point. I drained mine and replaced it with water for racing and now I need to empty that out so it doesn't freeze over the winter.

The drain is the large bolt facing down on the front of the motor, below the even larger plug.

[Herman T]

Thanks Richard, That helps a lot. I know which bolt you are mentioning. I hope I can get to it though without having to remove the exhaust.