Just wondering if the stock cooling on a m7 can provide enough cooling for mods. I have an 06 m7 with slp twins and rkt cut head and I am getting a bad bog after about the 3rd run at pounding a hill. At first i thought it was my clutching but now am leaning towards the cooling system. If I stop and pop the hood for 5min. things work just like they did for the first pass. Anybody else running twins have this problem and how did you solve it? I'm thinking about either getting a mesh hood or adding a bigger cooler. I don't want to get rid of the twins because I like em when they work but I would like to not have to stop and let things cool after a couple pulls. Thanks for any suggestions.
Does a M7 have enough cooling??
- Thread starter bigjb
- Start date
cooling
I have an M7 with Cutler 1000 top end and twins.No cooling issue.Mayby you need to add/subtract fuel?belt?It also could be a weak primary?Clutching can be a mystery.Still trying to sort out eveything on mine!
I have an M7 with Cutler 1000 top end and twins.No cooling issue.Mayby you need to add/subtract fuel?belt?It also could be a weak primary?Clutching can be a mystery.Still trying to sort out eveything on mine!
I would say it is your clutching which can cause a engine to bog. do you have vented side panels if not that is where i would start.
Yes side pannels are vented and vent in the shock tower in front of the clutch plus the rkt hood lift (lets alot of heat out). I changed my clutching to a 36 and black orange team (almost same as m8 orange) in the secondary and am running a slp black/pink with 66 dakota performance weights. The set up change helped from the previous set up, at least I don't smell belt anymore pulling a hill. It could still be clutching but this is a fairly proven system for many people. The last few rides have been real warm (50-60) with deep wet snow and has been hard to tell cuz everything gets hot. Colder temps its not as noticable. The clutches do get plenty hot, moreso in the primary, secondary is not so bad.
What's your temp light saying? flashing or steady during time of bog, where's your bog?, in the bottom, mid (around the time the p.v's should open), top?. I know what you'r saying I like em when you can tune 'em, been plenty of discusion on here 'bout the M-7 bog and fuel controllers??. Wish I had the answer 
.
.Never seen the temp light, but thats not to say it hasn't flashed at me and I didn't see it. The bog is only on the top end, starts at 7900 or so and pulls down hard to about 76-7400 at wot. I have not had a bog or hesitation anywhere in the power band, only the top end pulling down after repeated runs.
i would guess its the clutches getting to hot. all three m7s in our group seem to do the same thing especially now its warmed up outside. run fine for a few pulls but if we keep pounding on them they start to lose some rpms, let them cool for a bit and fine for a while again. we figure its heat soaked clutches making the belt stickier and pullin rpms down. we usually only make a few pulls and take a break anyhow to not run the risk of blowing belts. its not as bad when its cold outside and the snow is softer.
Talking with a buddy last night about some of the times it boged hard on me was when sidehilling on the clutch side and the vents would get covered and then instant bog so I think I know where my problem lies and now just need to figure out how to solve it.
Another Cutler 1000 owner chiming in
I run in the deep heavy stuff in WA and I don't think the cooling system cuts it. Just boondocking around in the flats and small hills and the water temps comes up in the 160-170, which sounds fine, but Cutler wants them sub 150, which can't be done if you want to ride for longer than 10 minutes in a row. Long pulls (like 60 sec) do this as well. Underhood temps are blazing and I am vented everywhere. Its either a u-coolers or mesh hood I think for me. I think the mesh would be the way to go as its kind of one or the other for me given that the prices are similar. I know the clutches get hot and mine definately doesn't hold the RPMs when clutches are warmer, which is all the time. I don't mind stopping to take a break with the hill climbing but the boondocking heat build up bothers me. Maybe I am being too demanding to want to wail on it in the meadows and small hills for 20-30 min. straight.
I run in the deep heavy stuff in WA and I don't think the cooling system cuts it. Just boondocking around in the flats and small hills and the water temps comes up in the 160-170, which sounds fine, but Cutler wants them sub 150, which can't be done if you want to ride for longer than 10 minutes in a row. Long pulls (like 60 sec) do this as well. Underhood temps are blazing and I am vented everywhere. Its either a u-coolers or mesh hood I think for me. I think the mesh would be the way to go as its kind of one or the other for me given that the prices are similar. I know the clutches get hot and mine definately doesn't hold the RPMs when clutches are warmer, which is all the time. I don't mind stopping to take a break with the hill climbing but the boondocking heat build up bothers me. Maybe I am being too demanding to want to wail on it in the meadows and small hills for 20-30 min. straight.
I also have the cutler 1000cc in my M7. I put a crossfire rear cooler on, because in certain snow conditions, my water temps were also getting into the 150's and higher (with that motor as stated, you want to be a lot cooler than that, and I've noticed a lot stronger motor if you can keep it no hotter than the 120's). After putting the bigger cooler on, I haven't had a problem ever. As far as the bog at WOT, I do get it once in awhile on long hard pulls, so it has to be clutches. I have the side vents, a mesh hood, and I even drilled some holes in the belt cover (probably didn't make much diff. but I did it anyways). I don't know how I could vent more. It doesn't happen very often, and I've just learned to deal with it. Of course, the 1000cc bogging a little and dropping even 1000 rpms is still stronger than the stock 700 motor, so I just deal with it. I don't have a flow-rite near the shock tower but have one on order. Other than that, how can you get more ventilation than that? In the spring I take the hood off and there isn't any really long hard pulls in those conditions like when there's powder, but I never have a problem, so I think it is clutches getting hot. I've seen a few put electric fans inbetween the clutches on the belly pan, but I haven't tried that.
your just trapping to much heat under the hood and the pipes are getting to hot, pipes get hot there tune length shortens, they dont perform as well at lower rpms. They will cause a lean bog, just try to get more air under the hood to cool the pipes, or find a way to keep the pipes that hot and jet it up to loose the bog.
i seriously doubt its clutching or clutch heat. I lean more towards heat soaking in the motor itself. I'd venture a guess that the billet RKT head would do better than the current stock cut version as it increases cooling flow across the head...
I only had this problem with that sled ONE time and it was on a VERY deep day and temps were HOT under the hood. with all the venting i put on there and the additional RKT hood lift, heat outside of the engine is likley not the issue, but instead heat in the motor is the issue. Try getting a temp guage on there so you can see what happening before you do anything else.
also, put a 10.4 clutch on there - it will do better.
I only had this problem with that sled ONE time and it was on a VERY deep day and temps were HOT under the hood. with all the venting i put on there and the additional RKT hood lift, heat outside of the engine is likley not the issue, but instead heat in the motor is the issue. Try getting a temp guage on there so you can see what happening before you do anything else.
also, put a 10.4 clutch on there - it will do better.
I think heat sink makes the most sense but...
I think it is heat sinking everything, motor, clutches, pipes...
No hood is not an option except in the spring and I don't think the mesh hoods or vents everywhere (like I have) create that much flow (think of a screen door in the wind), maybe enlarging the coolant system would be the trick.
Does it make sense using something like a Timbersled intake with a mesh hood so that it is constantly refreshing the air under the hood and pulling air from every non-snow covered area of the hood? I think that it would be a little warmer air at times but ensure a steady pull through the hood. Also it would ensure that the motor is at least getting air instead of the bogging that you get when you cover each stock intake 1/2 way with snow.
Also, I am running the Cutler low compression head which has a lot of coolant flow but don't think that matters as much when you are flowing hot coolant into it.
So mesh hood, u-coolers, timbersled intake and better clutching?
I think it is heat sinking everything, motor, clutches, pipes...
No hood is not an option except in the spring and I don't think the mesh hoods or vents everywhere (like I have) create that much flow (think of a screen door in the wind), maybe enlarging the coolant system would be the trick.
Does it make sense using something like a Timbersled intake with a mesh hood so that it is constantly refreshing the air under the hood and pulling air from every non-snow covered area of the hood? I think that it would be a little warmer air at times but ensure a steady pull through the hood. Also it would ensure that the motor is at least getting air instead of the bogging that you get when you cover each stock intake 1/2 way with snow.
Also, I am running the Cutler low compression head which has a lot of coolant flow but don't think that matters as much when you are flowing hot coolant into it.
So mesh hood, u-coolers, timbersled intake and better clutching?
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One more thing to think about when it comes to venting. My brother brought this up to my attention. We all put vents in the hood and on the side panels around the clutches so that cool air can come in, but we don't provide vents (usually) for the hot air to exit. My brother and I have cut holes on the back of our side panels above the footrests to help let air exit out. I think it helps, but isn't nearly enough for how much air is coming in the front. My mesh hood I believe lets a lot more air flow in, but what we need is a better way to let air out so we have a continuous flow of air coming thru the engine compartment and out. Just something he and I have talked about but haven't come up with a real good solution just yet.
RKT has a hood riser that allows the heat to flow out towards the rider. Probably could make one the same. Saw it on here some where. The lift raises the center of the hood, read on here that lifting the hood just a little makes a big difference with under hood heat. Some questioned it but according to those who have tried this it works without causing snow ingestion. The part sets in front of the steering post. Most of the heat is trapped even with top vents. Without high air flow the heat won't evacuate from under the hood. I think the part was 20 or 30$.
The hood lift works well, alot of heat come out of there. Thanks for all the replys I think I will be using a billet head next year and I do have a 10.4 to put on just haven't done it yet. If I can find a good deal on a mesh hood I will do that too. Thanks again.
M7 cooling
I had a problem with both my 05 M7 and 06 CF (early build) overheating. The solution was to put the larger rear cooler from the later build Crossfires on both sleds. No problems since I put them on. Check with Troy at RV Sports in Thief River Falls, he may be able to find something at Cat salvage. If you have to buy a new one they are not very expensive. The only other parts you will need are 2 hose clamps (they are a wierd size so order them from Cat), and rivets for the hose guard.
I had a problem with both my 05 M7 and 06 CF (early build) overheating. The solution was to put the larger rear cooler from the later build Crossfires on both sleds. No problems since I put them on. Check with Troy at RV Sports in Thief River Falls, he may be able to find something at Cat salvage. If you have to buy a new one they are not very expensive. The only other parts you will need are 2 hose clamps (they are a wierd size so order them from Cat), and rivets for the hose guard.
lots of hot air ?
If your air intake system is stock, you are going to be sucking underhood air into your engine and when you get twins hot with no pipe insulation on them you can easily be sucking 400+ degree air under there...........don't think the cat efi system has that wide a range of compensation in the M7 brain.
Suzuki redid the M8 in motor cooling system because even a big heat exchanger can't over come poor coolant circulation in the engine.( one of the biggest limiting factors on a lot of the BIG BORE WOOP AZZ) after market engine projects over the years. Yes you can make hp which = heat, but how do you get rid of it.
1.....REcheck threads on plugging the m series hot air sucking hole, will help all year around.
2. yes I think my 700's worked better with bigger heat exchangers, used a FABCRAFT and used a cross fire, both helped.
3. floppy tracks that don't throw snow are a problems, ONE OF THE GOOD POSITIVE side affect of the Pclaw is it hucks snow at your heat exchanger, the worst I've seen is the A20....... super wimpy in stock configuration for hucking snow on the heat exchanger.
4. long snow flaps are good, short or no snow flaps are problematic for cooling.
5. some lessons I learned fooling with triples, hard to ditch weight off triples because of the three big pipes, you have to basiclly ditch the hood because when you get 3 big pipes glowing hot you can't over come all the heat issue, two big glowing pipes is bad, 1 fat hot pipe you migh be able to deal with. Not lost on the factories that fought the same problems and ditched triples.
Read up on how engineers get rid of heat in super high performance engines and look at the evolution of the laydown M engine.........faster water circulation / thinner water jackets. Check you equipment.
If your air intake system is stock, you are going to be sucking underhood air into your engine and when you get twins hot with no pipe insulation on them you can easily be sucking 400+ degree air under there...........don't think the cat efi system has that wide a range of compensation in the M7 brain.
Suzuki redid the M8 in motor cooling system because even a big heat exchanger can't over come poor coolant circulation in the engine.( one of the biggest limiting factors on a lot of the BIG BORE WOOP AZZ) after market engine projects over the years. Yes you can make hp which = heat, but how do you get rid of it.
1.....REcheck threads on plugging the m series hot air sucking hole, will help all year around.
2. yes I think my 700's worked better with bigger heat exchangers, used a FABCRAFT and used a cross fire, both helped.
3. floppy tracks that don't throw snow are a problems, ONE OF THE GOOD POSITIVE side affect of the Pclaw is it hucks snow at your heat exchanger, the worst I've seen is the A20....... super wimpy in stock configuration for hucking snow on the heat exchanger.
4. long snow flaps are good, short or no snow flaps are problematic for cooling.
5. some lessons I learned fooling with triples, hard to ditch weight off triples because of the three big pipes, you have to basiclly ditch the hood because when you get 3 big pipes glowing hot you can't over come all the heat issue, two big glowing pipes is bad, 1 fat hot pipe you migh be able to deal with. Not lost on the factories that fought the same problems and ditched triples.
Read up on how engineers get rid of heat in super high performance engines and look at the evolution of the laydown M engine.........faster water circulation / thinner water jackets. Check you equipment.
I tend to agree with you on this... However, when Mjunkie flipped his A-20 to HC position on his cutler 1000, his sled seemed to run hotter
He has since switched it back, as well as installed the crosfire heat exchanger.
I also agree that they need more flow, not just capacity.
