trenchtractor

Hi... my name is Brad. I am a motorcycle nutcase, general mechanical fiddler and ideas man.

I'd built up some nice custom cal style VW's... manx... baja... typeIII.

Then I discovered bikes... worked my way up through 250 4T, 250 2T, 600 I4, 600 singles, 2T motorcrossers, a couple of motards, the 1200cc XB12 Buell and big FZ1N (x2)...

I prefer to build something no one else has got but sadly, my 'spare no expense' build method of the past has been stomped on by the wife, 2 kids and mortgage, but that's ok, cos I have a plan.

I once owned a 2000 model TTR600 Yamaha thumper... it was a kickarse bike and I want another. This is great because the bikes are super cheap and totally indestructible. But what to do with it?? I was thinking a low budget, long duration, gradual build, consisting of the usual moderate increase to CC, head work, carbs, etc... but how is that different to anyone else?? And what do I do without a bike between now and then??

How about a turbo?? So I start trolling the interweb to glean what I can about turbo charging a 600cc single cylinder... I am surprised to find there has been very little REAL information around. This is good news, it means they aren't common, which means I'll have something totally different. But it also means I am on my own.

I am now in search of anyone else that has successfully done anything with a turbo single, specifically to discuss problems/issues/consideration from a practical perspective.

Here is some information about the TTR600 that might be of interest...

1. 595cc single cylinder, 4v head
2. Air/oil cooled
3. Compression ratio is 8.5:1
4. Remote oil tank (something like 2.5l)
5. external braided oil lines
6. 155kg dry weight in standard trim

Here is the 2004 model brochure Yamaha Trail PDF

The stock TTR600 can be found in the brochure at page 3, the specifications can be found at page 5.

I think the low standard compression, remote oil tank and general indestructible design would lend itself to turbo charging quite well. My cousins busted **** old '86 XT600 (which shares the same motor) had the same compression as the 2000 TTR600 I bought new... so they last nicely.

Here are my major concerns...

1. Single cylinder = long duration between pulses, which might equal power delivery problems, and may make correct turbo selection even more critical than with a multi-cylinder engine.
2. Limited space... I want an absolute minimalist approach to aesthetics... if it's not performing a critical function, it doesn't get fitted to the bike. Intercooler takes up room. I intend to fit an oil cooler as a minimum, so I'm already looking at taking up more room than stock. Unless I can find a TINY intercooler to fit between the turbo and the carbs...
3. Added weight... as with the space issue... the brief with this project is to keep the weight to absolute minimum. I've even taken to practicing making carbon composite parts so I can reduce weight as much as possible. I even intend replacing some steel brackets with custom carbon fab'd parts (it's actually quite easy).
4. The TTR600 uses a 'one and a half' carburetor system... that is, one full carburetor and one 'almost' carb... you can tune when the second one comes in and thus create more torque, or higher speed operation, each with a sacrifice to the other... I imagine going to dual carbs, properly set for concurrent operation... but then I have to build a plenum chamber... of course, the other option is dual, staged turbos...
5. TTR600 is kick start only... no battery... stator ignition... bike has to be rotating at almost 600rpm before spark is generated. But no battery = less weight = GOOD. However this might not boad so well if I have to fit a high pressure fuel pump that doesn't run until the bike is started... I am tossing around the idea of a manual fuel start primer pump... you know, pump twice prior to starting. I can convert the TTR to electric leg (using XT600 parts), but want to avoid that if possible.

Of course there is quite a bit of information around the place directed at multi-cylinder car applications, and even some multi-cylinder bike applications...

There are a LOT of TTR600 supermoto's on the interweb, but none quite as good as this one...



This image shows the air box and bodywork removed...



So my plan is to have no side covers, no air box... a custom tail plastic... silencer run on the centerline, under the seat as high as possible... I figure the turbo would sit where the air box used to be. You can see the stock headers run right by the air box. Air intake would be through a pod pointed at the left (clutch) side of the bike.

I imagine reasonably low boost without intercooler or water injection... the ignition advance curve is quite tame... compression really low.

Because the bike runs on carb's only (no FI), I'm not entirely sure how to set it up... I imagine a pressure transfer from just before the head to the fuel bowl... I've heard of this being done, but I've no practical knowledge of this method and it's efficiency.

I intend to use a small oil cooler mounted at the front, left (clutch) side, just under the corner of the tank. This will happen even if I don't turbo the bike. This will add to the oil capacity and improve cooling of the engine. I am tempted to build a larger capacity oil tank and mount it just in front of the bottom end, much like the CR&S VUN machine... moving the 2.5L of oil forward will improve weight distribution and free up room under the seat, adding to the minimalist design... also will help keep oil temps down, I imagine if the oil tank is sitting right beside the turbo it will get quite warm. The oil tank is cast alloy, so building a custom one from sheet alloy should reduce the dry weight also.

These bikes can probably be made to produce 60bhp with an increase of capacity, heads and compression... I would hope I can improve on that with a stock engine and a moderate turbo set-up. They probably make less that 40bhp standard. But they have torque curves that look like coffee tables, and my last supermoto made several liter bikes look silly in the hills.

I'd like to point out here that bikes are weight critical... less weight not only means better acceleration... but the handling can be improved quite dramatically, not just from a suspension perspective, but speed of change of direction. Yes I am going on a diet, but if I have to, so does the bike.

I'm the type of guy that would run a single silencer because it's lighter, over a dual silencer because it looks cool.

TTR600, TT600, XT600, XT500, SR500 are all extremely similar engines.

txdohczc

holy ---- dud lets get some cliff notes on this. im not going to read a book about your situation/ideas

88dx

If you want to do wheelies all day go for it, but if you want to actually enjoy a SM dont do it.

88dx

ALso ur first post is suppose to have A lot of **** in it Not a Discussion

trenchtractor

Ok, I'll try again...

Hi, I'm a noob.

I want to turbo a 600cc single. Please help me. :1

In reality, I'm only a noob around here, I have a bunch of experience. I've made most of the decisions on how to do this already... but the devil is in the details, and I have very little detailed info on turbo charging carb'd engines (I helped out my brother with his S5 RX4 project and as an electronics tech I'm good with FI). I have some concerns about turbo'ing a single cylinder engine and selecting the right turbo for this application.

I'm after constructive thoughts...

trenchtractor

Well, I've had a couple of Motards already. I'm pretty happy about taking this path so long as I do it right... or to put it another way, the 'burgs and huskies make mid 50hp's stock... you can get almost 70 out of them. People have claimed almost 70hp out of XTZ's, but they are water cooled. But they are expensive bikes, and working them is expensive... and every man and his dog has one.

Problem with working the motors is you shift the power up top, but lose some of that massive bottom end... this is what I loved about the little brothers 13Bt RX4, it had all the torque in the world, unlike the NA 13B... essentially the same motor. I could work the TTR6, but it's gonna cost and move the power up.

I guess I'm looking for a tiny turbo to spool up real quick... I mean, the air cooled single will only rev to 6krpm anyway...

But you are right, if I ballz it up the thing will have nothing off the bottom, then launch the front wheel... which is not the intention of the project. I just don't know how deliverable the power will be with a carb'd set-up... if it becomes evident I can't deliver good, strong and smooth torque with the set-up, then I'll leave it alone.

Couldn't be any worse than a CR500E, right?!?!

trenchtractor

I've no idea if this has been posted before... but I kind of like it for comapring stock turbo's against power output and family designation...

http://www.dieselevante.it/turbochargers.asp

trenchtractor

I'm finding a bit of information on XR650 turbo set-ups... no specifics. All anyone seems interested in talking about is boost pressure...

Looks like the plenum chamber needs to be quite large, like 3 liters?? Anyone got any thoughts on plenum chamber size??

yamaha6611

not sure if there is alot of bike stuff on here, but im sure i saw a guy putting a turbo kit on his a month or so back, it was a yellow bike or something .. either way that bike looks sick and dont want you to blow it up

Toysrme

1) there's no ****
2) buy a bigger ------- bike.